Image acquisition and Evaluation

Question 1

If 32 mAs and 50-speed screens were used to produce a particular radiographic density, what new mAs value would be required to produce the same density if the screen speed were changed to 400?

Answer 1

4 mAs

EXPLANATION: With all other factors remaining the same, as intensifying-screen speed increases, radiographic density increases. Radiographic density is directly proportional to intensifying-screen speed; that is, if screen speed doubles, density doubles. The formula to determine how milliampere-seconds should be corrected with screen-speed changes is

CF1/CF2=mAs1/mAs2

Question 2

Which of the following causes pitting, or many small surface melts, of the anode’s focal track?

Answer 2

Repeated, frequent overloading

EXPLANATION: As the filament ages, vaporized tungsten (from the filament) may be deposited on the port window and act as an additional filter. Tungsten may also vaporize as a result of anode abuse. Exposures in excess of safe values deliver sufficient heat to cause surface melts, or pits, on the focal track. This results in roughening of the anode surface and decreased tube output. Delivery of a large amount of heat to a cold anode can cause cracking if the anode does not have sufficient time to disperse the heat. Loss of anode rotation would cause one large melt on the focal track because the electrons would bombard only one small area. If the anode is not heard to be rotating, the radiographer should not make an exposure. (Selman, 9th ed., pp. 137–138)

Question 3

The voltage ripple associated with a three-phase, 12-pulse rectified generator is about

Answer 3

3%.

EXPLANATION: Voltage ripple refers to the percentage drop from maximum voltage each pulse of current experiences. In single-phase rectified equipment, the entire pulse (half-cycle) is used; therefore, there is first an increase to the maximum (peak) voltage value and then a decrease to zero potential (90° past peak potential). The entire waveform is used; if 100 kV were selected, the actual average kilovoltage output would be approximately 70. Three-phase rectification produces almost constant potential, with just small ripples (drops) in maximum potential between pulses. Approximately a 13% voltage ripple (drop from maximum value) characterizes the operation of three-phase, six-pulse generators. Three-phase, 12-pulse generators have about a 3.5% voltage ripple. (Bushong, 10th ed., p. 242)

Question 4

A radiographer who discloses confidential patient information to unauthorized individuals can be found guilty of

Answer 4

invasion of privacy.

EXPLANATION: A radiographer who discloses confidential information to unauthorized individuals may be found guilty of invasion of privacy. If the disclosure is in some way detrimental or otherwise harmful to the patient, the radiographer may also be accused of defamation. Spoken defamation is slander; written defamation is libel. (Adler and Carlton, 4th ed., pp. 374–375)

Question 5

To demonstrate the entire circumference of the radial head, the required exposure(s) must include

epicondyles perpendicular to the IP

hand pronated

hand supinated as much as possible

Answer 5

1 only

EXPLANATION: Although routine elbow projections may be essentially negative, conditions may exist (such as an elevated fat pad) that seem to indicate the presence of a small fracture of the radial head. To demonstrate the entire circumference of the radial head, four exposures are made with the elbow flexed 90 degrees and with the humeral epicondyles superimposed and perpendicular to the IP—one with the hand supinated as much as possible, one with the hand lateral, one with the hand pronated, and one with the hand in internal rotation, thumb down. Each maneuver changes the position of the radial head, and a different surface is presented for inspection. (Frank, Long, and Smith, 11th ed., vol. 1, pp. 152–153)

Question 6

Referring to Figure 2–38, which of the following positions requires that baseline IOML be parallel to the IR?

Answer 6

SMV

EXPLANATION: The SMV (Schüller method) projection of the skull requires that the patient’s neck be extended, placing the vertex adjacent to the IR holder/upright Bucky so that the IOML is parallel with the IR. This projection is useful for demonstrating the ethmoidal and sphenoidal sinuses, pars petrosae, mandible, and foramina ovale and spinosum. The lateral projection of the skull requires that the patient be in the prone oblique position with the MSP parallel to the IR and the interpupillary line perpendicular to the IR. This position also requires that the IOML (line 3) be parallel to the long axis of the IR. The AP and PA axial projections of the skull require the OML or IOML to be perpendicular to the IR. (Bontrager and Lampignano, 6th ed., p. 389)

Question 7

Use your mouse to drag the following bony structures into order (A–D) from lateral to medial.

B. Capitate

C. Hamate

D. Trapezium

A. Trapezoid

Answer 7

EXPLANATION: (A) Trapezium
(B) Trapezoid
(C) Capitate
(D) Hamate
The wrist is composed of eight carpal bones arranged in two rows (proximal and distal). The proximal row consists of, from lateral to medial, the scaphoid, the lunate/semilunar, the triangular/triquetrum, and the pisiform. The distal row, from lateral to medial, consists of the trapezium/greater multiangular, the trapezoid/lesser multiangular, the capitate/os magnum (the largest carpal), and the hamate/unciform (which has a hooklike process, the hamulus). The joints of the wrist include the articulations between the carpals (intercarpal joints), which provide a gliding motion, and the radiocarpal joint (between the distal radius and scaphoid), which provides flexion and extension, abduction and adduction. (Bontrager and Lampignano, 6th ed., p. 132)

Question 8

A 5-in. object to be radiographed at a 44-in. SID lies 6 in. from the IR. What will be the image width?

Answer 8

5.7 in.

EXPLANATION: Magnification is part of every radiographic image. Anatomic parts within the body are at various distances from the IR and, therefore, have various degrees of magnification. The formula used to determine the amount of image magnification is

Question 9

Graves disease is associated with

Answer 9

thyroid overactivity

EXPLANATION: Graves disease is the most frequently occurring form of hyperthyroidism. Graves disease is an autoimmune disorder whose symptoms include enlargement of the thyroid gland and exophthalmos (protrusion of the eyes resulting from fluid buildup behind them). Hypothyroidism can result in cretinism in the child and myxedema in the adult. Adrenal overactivity produces Cushing syndrome; underactivity causes Addison disease. (Tortora and Derrickson, 11th ed., p. 659)

Question 10

Glossitis refers to inflammation of the

Answer 10

tongue

EXPLANATION: Inflammation of the tongue is called glossitis. Inflamed salivary glands are usually referred to with reference to the affected gland, as in parotitis (inflammation of the parotid gland). Inflammation of the epiglottis is termed epiglottitis.

Question 11

Symptoms of inadequate oxygen supply include

dyspnea.

cyanosis.

retraction of intercostal spaces.

Answer 11

1, 2, and 3

EXPLANATION: Oxygen is taken into the body and supplied to the blood to be delivered to all body tissues. Any tissue(s) lacking in or devoid of an adequate blood supply can suffer permanent damage or die. Oxygen may be required in cases of severe anemia, pneumonia, pulmonary edema, and shock. Symptoms of inadequate oxygen supply include dyspnea, cyanosis, diaphoresis, retraction of intercostal spaces, dilated nostrils, and distension of the veins of the neck. The patient who experiences any of these symptoms will be very anxious and must not be left unattended. The radiographer must call for help, assist the patient to a sitting or semi-Fowler position (the recumbent position makes breathing more difficult), and have oxygen and emergency drugs available. (Taber, 20th ed., p. 653)

Question 12

Which cholangiographic procedure uses an indwelling drainage tube for contrast medium administration?

Answer 12

T-tube cholangiography

EXPLANATION: Contrast media may be administered in a variety of manners in cholangiography, including (1) an endoscope with a cannula placed in the hepatopancreatic ampulla (of Vater) for an ERCP, (2) a needle or small catheter placed directly in the common bile duct for an operative cholangiogram, (3) a very fine needle through the patient’s side and into the liver for a percutaneous transhepatic cholangiogram, and (4) via an indwelling T-tube for a postoperative or T-tube cholangiogram. (Frank, Long, and Smith, 11th ed., vol. 2, pp. 111–116)

Question 13

Which of the following is (are) located on the distal aspect of the humerus?

1. Capitulum
2. Intertubercular groove
3. Coronoid fossa

Answer 13

1 and 3 only

EXPLANATION: The distal humerus articulates with the radius and ulna to form the elbow joint. The lateral aspect of the distal humerus presents a raised, smooth, rounded surface, the capitulum, that articulates with the superior surface of the radial head. The trochlea is on the medial aspect of the distal humerus and articulates with the semilunar notch of the ulna. Just proximal to the capitulum and the trochlea are the lateral and medial epicondyles; the medial is more prominent and palpable. The coronoid fossa is found on the anterior distal humerus and functions to accommodate the coronoid process with the elbow in flexion. The intertubercular (bicipital) groove is located on the proximal humerus. (Saia, p 89)

Question 14

A minor reaction to the IV administration of a contrast agent can include

a few hives

nausea

a flushed face

Answer 14

1, 2, and 3

EXPLANATION: Adverse reactions to the intravascular administration of iodinated contrast medium are not uncommon, but although the risk of a life-threatening reaction is relatively rare, the radiographer must be alert to recognize and deal effectively with a serious reaction should it occur. Flushed appearance and nausea, occasionally vomiting, and a few hives characterize a minor reaction. Early symptoms of a possible anaphylactic reaction include constriction of the throat, possibly owing to laryngeal edema, dysphagia (difficulty in swallowing), and itching of the palms and soles. The radiographer must maintain the patient’s airway, summon the radiologist, and call a “code.” (Ehrlich et al., 6th ed., p. 234)

Question 15

A vasomotor effect experienced after injection of a contrast agent is characterized by all of the following symptoms except

Answer 15

hypotension.

EXPLANATION: Reactions to contrast agents are named and categorized according to the body system(s) affected, the nature of the reaction (i.e., allergic vs. nonallergic), and its severity (i.e., mild, moderate, or severe). These reactions are categorized as vasomotor (a nonallergic reaction), anaphylactic (allergic reaction), vasovagal (life-threatening), and acute renal failure (renal shutdown). Vasomotor effects are principally emotional and anxiety-based. They are characterized by anxiety, syncope, nausea, lightheadedness, and sometimes a few hives. The patient usually just requires reassurance and not medical attention. An anaphylactic reaction is a true allergic reaction to e.g. iodinated media and can lead to a life-threatening situation. Immediate medical attention is required. Symptoms of anaphylactic reaction include laryngo/bronchospasm, hypotension, moderate to severe urticaria, angioedema, and tachycardia. A vasovagal reaction is life-threatening and requires a declared emergency (“code”). Symptoms of a vasovagal reaction include bradycardia, hypotension, and no detectable pulse. The fourth type of reaction, acute renal failure, may not manifest for up to 48 hours following injection of the contrast agent. Patients should notify their physician if they experience any changes in their urinary habits or any other atypical symptoms. Treatment would include hydration, dispensation of a diuretic (e.g., Lasix), and possibly even renal dialysis. (Bontrager and Lampignano, 6th ed., p. 558)

Question 16

In which section of the automatic processor seen in the figure below are the unexposed silver halide crystals removed from the emulsion?

1 developer
2 fixer
3 washer
4 dryer

Answer 16

Section 2

EXPLANATION: As the exposed film enters the processor from the feed tray, it first enters the developer section (1), where exposed silver bromide crystals are reduced to black metallic silver. The film then enters the fixer (2), where the unexposed silver grains are removed from the film by the clearing agent. The film then enters the wash section (3), where chemicals are removed from the film to preserve the image. From the wash, the film enters the dryer section (4). (Selman, 9th ed., p 194)

Question 17

Decreasing field size from 14 x 17 into 8 x 10 inches will

Answer 17

decrease radiographic density and decrease the amount of scattered radiation generated within the part.

EXPLANATION: Limiting the size of the radiographic field serves to limit the amount of scattered radiation produced within the anatomic part. As the amount of scattered radiation generated within the part decreases, so does the resultant density within the radiographic image. Hence, beam restriction is a very effective means of reducing the quantity of non-information-carrying scattered radiation (fog) produced, resulting in a shorter scale of contrast with fewer radiographic densities. (Shephard, p 203)

Question 18

The four major arteries supplying the brain include the

brachiocephalic artery

common carotid arteries

vertebral arteries

Answer 18

2 and 3 only

EXPLANATION: Major branches of the common carotid arteries (internal carotids) function to supply the anterior brain, whereas the posterior brain is supplied by the vertebral arteries (branches of the subclavian artery). The brachiocephalic (innominate) artery is unpaired and is one of the three branches of the aortic arch, from which the right common carotid artery is derived. The left common carotid artery comes directly off the aortic arch. (Tortora and Derrickson, 11th ed., pp. 761–762)

Question 19

Which of the following conditions require(s) a decrease in technical factors?

Emphysema

Osteomalacia

Atelectasis

Answer 19

1 and 2 only

EXPLANATION: Subcutaneous emphysema is a pathologic distension of tissues with air; pulmonary emphysema is a chronic disease characterized by overdistension of the alveoli with air. Osteomalacia is a softening of bone so that it becomes flexible, brittle, and deformed. All three of these conditions involve a decrease in tissue density and, therefore, require a decrease in exposure factors. Atelectasis is a collapsed or airless lung; it requires an increase in exposure factors. (Carlton and Adler, 4th ed., p. 248)

Question 20

A flat and upright abdomen is requested on an acutely ill patient, to demonstrate the presence of air-fluid levels. Because of the patient’s condition, the x-ray table can be tilted upright only 70° (rather than the desired 90°). How should the central ray be directed?

Answer 20

Parallel to the floor

EXPLANATION: Whenever a part is being radiographed for demonstration of air-fluid levels, the central ray must be directed parallel to the floor. In this example, the patient was unable to tolerate the 90° tilt of the x-ray table. If the radiographer were to compensate for this by directing the central ray perpendicular to the IR (angling 20° caudad), it is very possible that any air-fluid level would be blurred and indistinct, and would go unrecognized. Remember that air or fluid always levels out parallel to the floor. Thus, if the air-fluid level needs to be demonstrated, the central ray must also be parallel to the floor. (Ballinger & Frank, vol 2, p 376)

Question 21

A radiograph made with a parallel grid demonstrates decreased density on its lateral edges. This is most likely due to

Answer 21

decreased SID

EXPLANATION: The lead strips in a parallel grid are parallel to one another and, therefore, are not parallel to the x-ray beam. The more divergent the x-ray beam, the more likely there is to be cutoff/decreased density at the lateral edges of the radiograph. This problem becomes more pronounced at short SIDs. If there were a centering or tube angle problem, there would be more likely to be a noticeable density loss on one side or the other. (Carlton and Adler, 4th ed., p. 260)

Question 22

Which of the following pathologic conditions would require a decrease in exposure factors?

A. Congestive heart failure
B. Pneumonia
C. Emphysema
D. Pleural effusion

Answer 22

Emphysema

EXPLANATION: Emphysema is abnormal distension of the pulmonary alveoli (or tissue spaces) with air. The presence of abnormal amounts of air makes a decrease from normal exposure factors necessary to avoid excessive density. Congestive heart failure, pneumonia, and pleural effusion all involve abnormal amounts of fluid in the chest and, therefore, would require an increase in exposure factors. (Carlton and Adler, 4th ed., p. 251)

Question 23

What percentage of x-ray attenuation does a 0.5-mm lead-equivalent apron at 75 kVp provide?

Answer 23

88%

EXPLANATION: Lead aprons are worn by occupationally exposed individuals during fluoroscopic and mobile x-ray procedures. Lead aprons are available with various lead equivalents; 0.5- and 1.0-mm lead are the most common. The 1.0-mm lead-equivalent apron will provide close to 100% protection at most kilovoltage levels, but it is used rarely because it weighs anywhere from 12 to 24 lb. A 0.25-mm lead-equivalent apron will attenuate about 97% of a 50-kVp x-ray beam, 66% of a 75-kVp beam, and 51% of a 100-kVp beam. A 0.5-mm lead-equivalent apron will attenuate about 99.9% of a 50-kVp beam, 88% of a 75-kVp beam, and 75% of a 100-kVp beam. (Bushong, 8th ed., p. 597)

Question 24

The use of which of the following is (are) essential in magnification radiography?
High-ratio grid
Fractional focal spot
Direct exposure technique

Answer 24

2 only

EXPLANATION: Magnification radiography is used to enlarge details to a more perceptible degree. Hairline fractures and minute blood vessels are candidates for magnification radiography. The problem of magnification unsharpness is overcome by using a fractional focal spot; larger focal-spot sizes will produce excessive blurring unsharpness. Grids are usually unnecessary in magnification radiography because of the air-gap effect produced by the OID. Direct-exposure technique probably would not be used because of the excessive exposure required. (Selman, 9th ed., pp. 226–228)

Question 25

Conditions in which there is a lack of normal bone calcification include

rickets.
osteomalacia.
osteoarthritis.

Answer 25

1 and 2 only

EXPLANATION: Rickets and osteomalacia are disorders in which there is softening of bone. Rickets results from a deficiency of vitamin D and usually is found affecting the growing bones of young children. The body’s weight on the soft bones of the legs results in bowed and misshapen legs. Osteomalacia is an adult condition in which new bone fails to calcify. It is a painful condition and can result in easily fractured bones, especially in the lower extremities. Osteoarthritis is seen often in the elderly and is characterized by degeneration of articular cartilage in adjacent bones. The resulting rubbing of bone against bone results in pain and deterioration. (Tortora and Derrickson, 11th ed., p. 190)

Question 26

If the exposure rate to an individual standing 4.0 m from a source of radiation is 10 mR/h, what will be the dose received after 20 minutes at a distance of 6 m from the source?

Answer 26

1.48 mR

EXPLANATION: The relationship between x-ray intensity and distance from the source is expressed in the inverse-square law of radiation. The formula is

i1/i2=D2sq/D2sq

10/x=36/16, 36x=160, x=4.44

EXPLANATION: Thus, x = 4.44 mR in 60 minutes and, therefore, 1.48 mR in 20 minutes. Distance has a profound effect on dose received and, therefore, is one of the cardinal rules of radiation protection. As distance from the source increases, dose received decreases. (Bushong, 8th ed., pp. 68–70)

Question 27

Which of the following is an acceptable approximate entrance skin exposure (ESE) for a PA chest radiograph?

Answer 27

20 mR

EXPLANATION: If it is desired to determine entrance skin exposure (ESE), a small ionization chamber (pocket dosimeter) can be placed on the skin, and the approximate ESE can be read immediately. These devices are readily imaged, however, and are awkward to position. For these reasons, thermoluminescent dosimeters (TLDs) or optically stimulated luminescence (OSL) dosimeters are more easily used; they are precise and will not interfere with the radiographic image. The acceptable ESE for a PA chest is approximately 20 mR (12–26 mR is the acceptable range). An image taken with an ESE of 6 mR would be underexposed and require repeating. Similarly, ESEs of 38 mR and 0.6 R (600 mR) would lead to overexposed images that would need to be repeated. (Bushong, 8th ed., p. 586)

Question 28

Reducing the number of repeat images is an important way to decrease patient exposure and can be accomplished by

1. good patient communication.
2. accurate positioning skills.
3. using AEC.

Answer 28

1, 2, and 3

EXPLANATION: The best way to ensure patient cooperation is through effective communication. A patient who understands what the examination entails, who knows what to expect, and what will be expected of him or her is better able to cooperate with the radiographer. This patient is more likely to be able to maintain the required position and suspend their respiration when required—thereby avoiding a repeated image. Radiographers who use their knowledge along with patience and critical thinking skills are more apt to obtain good images the first time around, thus avoiding repeat examinations. The use of AEC also helps avoid repeat radiographs; AEC will adjust the exposure—compensating for position, habitus, or pathology, and reducing the likelihood of repeat radiographs. (Dowd & Tilson, p 243)

Question 29

Decreasing field size from 14 x 17 in. to 8 x 10 in., with no other changes, will

Answer 29

decrease radiographic density and decrease the amount of scattered radiation generated within the part

EXPLANATION: Limiting the size of the radiographic field (irradiated area) serves to limit the amount of scattered radiation produced within the anatomic part. As the amount of scattered radiation produced decreases, so does the resultant density within the radiographic image. Therefore, as field size decreases, scattered radiation production decreases, and overall density decreases. Limiting the size of the radiographic field is a very effective means of reducing the quantity of non–information-carrying scattered radiation (fog) produced, resulting in a shorter scale of contrast with fewer radiographic densities. Limiting the size of the radiographic field is also the most effective means of patient radiation protection. (Shephard, p. 203)

Question 30

A small container holding several doses of medication is termed

Answer 30

a vial.

EXPLANATION: Injectable medications are available in two different kinds of containers. An ampule is a small container that usually holds a single dose of medication. A vial is a somewhat larger container that holds a number of doses of medication. The term bolus is used to describe an amount of fluid to be injected. A carafe is a narrow-mouthed container; it is not likely to be used for medical purposes. (Adler and Carlton, 4th ed., p. 309)

Question 31

What should you do if you discover while taking patient history that the patient scheduled for an intravenous urogram (IVU) takes metformin hydrochloride daily?

1. Proceed with the examination if kidney function is normal.
2. Instruct the patient to withhold the metformin for 48 hours after the examination.
3. Reschedule the examination until the patient has been off metformin for 48 hours.

Answer 31

1 and 3 only

EXPLANATION: Glucophage (metformin hydrochloride) is used as an adjunct to appropriate diet to lower blood glucose level in patients who have type 2 diabetes and whose hyperglycemia is not being managed satisfactorily with diet alone. Patients on metformin may have intravascular iodinated contrast studies if their renal function is within normal limits. Since the iodinated media, together with metformin, could induce renal failure or acute acidosis, the American College of Radiology currently recommends that patients on metformin have it withheld 48 hours after the exam. (Bontrager and Lampignano, 7th ed., p. 539)

Question 32

What is the approximate ESE for the average AP lumbar spine radiograph?

Answer 32

350 mrad

EXPLANATION: Patients occasionally will question the radiographer regarding the amount of radiation they are receiving during their examination. Most of these patients are merely curious because they have heard a recent news report about x-rays or have perhaps studied about x-rays in school recently. It is a good idea for radiographers to have some knowledge of average exposure doses for patients who desire this information. The curious patient also can be referred to the medical physicist for more detailed information. The average AP cervical spine radiograph delivers about 80 mrad (0.080 rad). The average AP supine lumbar spine radiograph delivers an ESE of about 350 mrad (0.35 rad). The average AP supine abdomen radiograph delivers about 300 mrad. (Dowd and Tilson, 2nd ed., p. 247)

Question 33

In amorphous selenium flat-panel detectors, the term amorphous refers to a

Answer 33

crystalline material lacking typical crystalline structure.

EXPLANATION: Flat-panel detectors used in DR are often made of an amorphous selenium (a-Se)–coated thin-film transistor (TFT) array. They function to convert the x-ray energy (emerging from the radiographed part) into an electrical signal. The TFT capacitors send the electrical signal to the analog-to-digital converter (ADC) to be changed to a digital signal. Amorphous selenium refers to a crystalline material (selenium) that lacks its crystalline structure. Amorphous selenium or silicon is used to produce the direct-conversion flat-panel detectors used in DR. (Bushong, 8th ed., p. 404)

Question 34

An x-ray exposure of a particular part is made and restricted to a 14 x 17 in. field size. The same exposure is repeated, but the x-ray beam is restricted to a 4 x 4 in. field. Compared with the first image, the second image will demonstrate

Answer 34

less density
more contrast

EXPLANATION: Less scattered radiation is generated within a part as the kilovoltage is decreased, as the size of the field is decreased, and as the thickness and density of tissue decrease. As the quantity of scattered radiation decreases from any of these sources, the less is the total density of the resulting image. (Carlton and Adler, 4th ed., p. 256)

Question 35

Using an AEC system, how will the mAs be adjusted as the film–screen speed combination is decreased?

Answer 35

The mAs remains unchanged as film–screen speed decreases.

EXPLANATION: As the speed of the film–screen system decreases, an increase in milliampere-seconds usually is required to maintain radiographic density. However, when an AEC (phototimer or ionization chamber) is used, the system is programmed for the use of a particular film–screen speed. If a slower speed screen cassette/IR is placed in the Bucky tray, the AEC has no way of recognizing it as different and will result in the exposure required for the system for which it is programmed. For example, if the system were programmed for a 400-speed film–screen combination, and if a 200-speed screen cassette/IR were placed in the Bucky tray, the AEC would produce an exposure appropriate for the 400 speed system, and the resulting image would have half the required radiographic density. (Shephard, p. 291)

Question 36

The innominate bone is located in the

Answer 36

pelvis

EXPLANATION: The pelvic girdle consists of two innominate (hip, or coxal) bones, one on each side of the sacrum. Each innominate bone consists of three fused bones—the ilium, ischium, and pubis. Parts of these three bones contribute to formation of the acetabulum—the socket articulation for the femoral head. The ilia are the large, superior bones whose medial auricular surface forms the sacroiliac joints bilaterally. The broad, flat portion of each ilium is the ala, or wing; the upper part of the ala forms a ridge of bone called the iliac crest, which terminates in anterior and posterior iliac spines. (Bontrager and Lampignano, 6th ed., p 263)

Question 37

Characteristics of a patient with pulmonary emphysema include

Answer 37

shoulder girdle elevation & increased AP diameter of the
chest

EXPLANATION: Emphysema is a chronic obstructive pulmonary disease (COPD) characterized by pathologic distension of the pulmonary alveoli with (destructive) changes in their walls, resulting in a loss of elasticity. Emphysema is seen occasionally following asthma or tuberculosis, but it is caused most frequently by cigarette smoking. Because the emphysematous patient’s greatest difficulty is exhalation, it becomes a conscious, forced effort. Breathing is shallow and rapid. Forced and ineffective breathing results in expansion of the AP diameter of the chest and elevated shoulder girdle in established emphysema. Hyperventilation results from too frequent deep breaths in the anxious or tense individual. This results in a feeling of dizziness and tingling of the extremities. (Tortora and Derrickson, 11th ed., p. 887)

Question 38

The x-ray tube used in CT must be capable of

Answer 38

high-speed rotation,
short pulsed exposures,
withstanding millions of heat units.

EXPLANATION: A CT imaging system has three component parts—a gantry, a computer, and an operating console. The gantry component includes an x-ray tube, a detector array, a high-voltage generator, a collimator assembly, and a patient couch with its motorized mechanism. Although the CT x-ray tube is similar to direct-projection x-ray tubes, it has several special requirements. The CT x-ray tube must have a very high short-exposure rating and must be capable of tolerating several million heat units while still having a small focal spot for optimal resolution. To help tolerate the very high production of heat units, the anode must be capable of high-speed rotation. The x-ray tube produces a pulsed x-ray beam (1–5 ms) using up to about 1,000 mA. (Bushong, 8th ed., pp. 429–430; Bontrager and Lampignano, 6th ed., p. 731)

Question 39

Patients’ rights include which of the following?

1. The right to refuse treatment
2. The right to confidentiality
3. The right to possess his or her radiographs

Answer 39

1 and 2 only

EXPLANATION: The American Hospital Association identifies 12 important areas in its “Patients’ Bill of Rights.” These include the right to refuse treatment (to the extent allowed by law), the right to confidentiality of records and communication, and the right to continuing care. Other patient rights identified are the right to informed consent, privacy, respectful care, access to records, refuse to participate in research projects, and an explanation of the hospital bill. (Torres et al, p 12)

Question 40

A radiographer who tells the patient that he or she will have to repeat this uncomfortable examination if the patient does not try harder to cooperate can be accused of

Answer 40

assault.

EXPLANATION: Assault is the threat of touching or laying hands on someone. If a patient feels threatened by a practitioner, either because of the tone or pitch of the practitioner’s voice or because the practitioner uses words that are threatening, the practitioner can be accused of assault. A radiographer who performs the wrong examination on a patient may be charged with battery. Battery refers to the unlawful laying of hands on a patient. The radiographer also could be charged with battery if a patient were moved about roughly or touched in a manner that is inappropriate or without the patient’s consent. False imprisonment may be considered if a patient is ignored after stating that he or she no longer wishes to continue with the procedure or if restraining devices are used improperly or used without a physician’s order. The accusation of defamation can be upheld when patient confidentiality is not respected, and as a result, the patient suffers embarrassment or mockery. (Adler and Carlton, 4th ed., p. 374)

Question 41

Which of the following structures should be visualized through the foramen magnum in an AP axial projection (Towne method) of the skull for occipital bone?

Posterior clinoid processes

Dorsum sella

Posterior arch of C1

Answer 41

1 and 2 only

EXPLANATION: The AP axial projection (Towne method) of the skull requires that the CR be angled 30 degrees caudad if the OML is perpendicular to the IR (37 degrees caudad if the IOML is perpendicular to the IR). The frontal and facial bones are projected down and away from superimposition on the occipital bone. If positioning is accurate, the dorsum sella and posterior clinoid processes will be demonstrated within the foramen magnum. If the CR is angled excessively, the posterior aspect of the arch of C1 will appear in the foramen magnum. (Frank, Long, and Smith, 11th ed., vol. 2, p. 316)

Question 42

A lateral projection of the hand in extension is often recommended to evaluate

Answer 42

a foreign body,
soft tissue

EXPLANATION: The lateral hand in extension, with appropriate technique adjustment, is recommended to evaluate foreign-body location in soft tissue. A small lead marker frequently is taped to the spot thought to be the point of entry. The physician then uses this external marker and the radiograph to determine the exact foreign-body location. Extension of the hand in the presence of a fracture would cause additional and unnecessary pain and possibly additional injury. (Frank, Long, and Smith, 11th ed., vol. 1, p. 121)

Question 43

If the exposure rate to a body standing 3 feet from a radiation source is 12 mR/min, what will be the exposure rate to that body at a distance of 7 feet from the source?

Answer 43

2.2 mR/min

EXPLANATION: The relationship between x-ray intensity and distance from the source is expressed in the inverse square law of radiation. The formula is
Substituting known values,:
Note the inverse relationship between distance and dose. As distance from the source of radiation increases, dose rate decreases significantly. (Bushong, p 67)

Question 44

A cathartic is used to

Answer 44

stimulate defecation.

EXPLANATION: Cathartics stimulate defecation and are used in preparation for radiologic examinations of the large bowel. Diuretics are used to promote urine elimination in individuals whose tissues are retaining excessive fluid. Emetics induce vomiting, and antitussives are used to inhibit coughing. (Torres et al., 6th ed., p. 283)

Question 45

Which of the following is (are) demonstrated in the lateral projection of the thoracic spine?

Intervertebral spaces
Apophyseal joints
Intervertebral foramina

Answer 45

Intervertebral spaces

Intervertebral foramina

EXPLANATION: The thoracic intervertebral (disk) spaces are demonstrated in the AP and lateral projections, although they are probably best demonstrated in the lateral projection. The thoracic apophyseal joints are 70 degrees to the MSP and are demonstrated in a steep (70-degree) oblique position. The thoracic intervertebral foramina, formed by the vertebral notches of the pedicles, are 90 degrees to the MSP. They are, therefore, well demonstrated in the lateral position. (Bontrager and Lampignano, 6th ed., p. 316)

Question 46

An overall image density arising from factors other than the light or radiation used to expose the image is called

Answer 46

fog.

EXPLANATION: This is the definition of fog. Anything other than intensifying screen light or primary x-radiation is undesirable in terms of image exposure. Log-relative exposure is the amount of exposure required to produce a given density as measured on the sensitometric graph. Optical density is normal radiographic density. An artifact is anything foreign to the image; the term could include fog, but it also covers many physical interferences. (Selman, 9th ed., pp. 196–197)

Question 47

The primary function of filtration is to reduce

Answer 47

patient skin dose

EXPLANATION: It is our ethical responsibility to minimize the radiation dose to our patients. X-rays produced at the tungsten target make up a heterogeneous primary beam. There are many “soft” (low-energy) photons that, if not removed by filters, would only contribute to greater patient skin dose. They are too weak to penetrate the patient and contribute to the image-forming radiation; they penetrate a small thickness of tissue and are absorbed. (Bushong, 8th ed., p. 11)

Question 48

In the production of Bremsstrahlung radiation

Answer 48

the incident electron is deflected, with resulting energy loss

EXPLANATION: Bremsstrahlung (or Brems) radiation is one of the two kinds of x-rays produced at the tungsten target of the x-ray tube during interaction between high-speed electrons coming from the filament and the anodes’ tungsten atoms. The incident high-speed electron, passing through a tungsten atom, is attracted by the positively charged nucleus and, therefore, is deflected from its course, with a resulting loss of energy. This energy is given up in the form of an x-ray photon. (Bushong, 8th ed., pp. 151–152)

Question 49

All the following statements regarding pediatric positioning are true except

Answer 49

radiography of pediatric patients with a myelomeningocele defect should be performed in the supine position.

EXPLANATION: Radiography of pediatric patients with a myelomeningocele defect should be performed in the prone position rather than in the routine supine position. The supine position would put unnecessary pressure on the protrusion of the meninges and spinal cord. All the other statements in the question are true. The anatomic dimensions of children are different from those of adults, and this must be kept in mind when performing pediatric radiography. The liver occupies a larger area of the abdominal cavity in a child than in an adult. This causes the kidneys to be in a lower position. Generally, the kidneys will be midway between the diaphragm and the symphysis pubis. Chest radiography for the pediatric patient varies depending on the age of the child. Neonates are routinely radiographed in the supine position. Although infants also may be examined in the supine position, it is preferable to examine them by placing the infant securely in a support device to obtain a good PA erect radiograph. Exceptions to this rule are made if the infant is in respiratory distress. To avoid aggravating the respiratory distress, an erect AP radiograph usually is obtained. (Dowd and Tilson, 2nd ed., vol. 2, pp. 1004–1005, 1013)

Question 50

Correct preparation for a patient scheduled for a lower GI series is most likely to be

Answer 50

cathartics and cleansing enemas.

EXPLANATION: Diagnostic x-ray examinations that require contrast agents include upper GI series, lower GI series (BE), IVU, and the occasional GB series. Patient preparation is somewhat different for each of these examinations. An iodinated contrast agent, usually in the form of several pills, is taken by the patient the evening before a scheduled GB examination, and only water is allowed the morning of the examination. The patient scheduled for an upper GI series must receive NPO (nothing by mouth) after midnight. A lower GI series (BE) requires that the large bowel be very clean prior to the administration of barium; this requires the administration of cathartics (laxatives) and cleansing enemas.
Preparation for an IVU requires that the patient be NPO after midnight; some institutions also require that the large bowel be cleansed of gas and fecal material. Aftercare for barium examinations is very important. Patients typically are instructed to take milk of magnesia, increase their intake of fiber, drink plenty of water, and expect changes in stool color until all barium is evacuated and to call their physician if they do not have a bowel movement within 24 hours. Because water is removed from the barium sulfate suspension in the large bowel, it is essential to make patients understand the importance of these instructions to avoid barium impaction in the large bowel. The use of barium sulfate suspensions is contraindicated when ruling out visceral perforation. (Bontrager and Lampignano, 6th ed., p. 501)

Question 51

Which of the following criteria is (are) required for visualization of the greater tubercle in profile?

1. Epicondyles parallel to IR
2. Arm in external rotation
3. Humerus in AP position

Answer 51

1, 2, and 3

EXPLANATION: The greater and lesser tubercles are prominences on the proximal humerus separated by the intertubercular (bicipital) groove. The AP projection of the humerus/shoulder places the epicondyles parallel to the IR and the shoulder in external rotation, and demonstrates the greater tubercle in profile. The lateral projection of the humerus places the shoulder in extreme internal rotation with the epicondyles perpendicular to the IR and demonstrates the lesser tubercle in profile. (Ballinger & Frank, vol 1, pp 161–162)

Question 52

An esophagram would most likely be requested for patients with which of the following esophageal disorders/symptoms?

Answer 52

Varices
Achalasia

EXPLANATION: Dilated, twisted veins, or varices, of the esophagus are frequently associated with obstructive liver disease or cirrhosis of the liver. These esophageal veins enlarge and can rupture, causing serious hemorrhage. Achalasia is dilation of the esophagus as a result of the cardiac sphincter’s failure to relax and allow food to pass into the stomach. Dysphasia is a speech impairment resulting from a brain lesion; it is unrelated to the esophagus. Dysphagia refers to difficulty swallowing and is the most common esophageal complaint. Hiatal hernia is another common esophageal problem; it is characterized by protrusion of a portion of the stomach through the cardiac sphincter. It is a common condition, and many individuals with the condition are asymptomatic. Each of these conditions of the esophagus may be evaluated with an esophagogram. Positions usually include the posteroanterior, right anterior oblique, and right lateral positions. (Bontrager and Lampignano, 6th ed., pp. 463–464)

Question 53

Which of the following procedures requires that the patient be placed in the lithotomy position?

Answer 53

Hysterosalpingography

EXPLANATION: The lithotomy position is generally employed for hysterosalpingography. The lithotomy position requires that the patient lie on the back with buttocks at the edge of the table. The hips are flexed, the knees are flexed and resting on leg supports, and the feet rest in stirrups. (Adler & Carlton, p 202)

Question 54

During a grand mal seizure, the patient should be

Answer 54

protected from injury.

EXPLANATION: When a patient is experiencing a seizure, he or she should be protected from striking any hard surfaces or falling. The patient exhibits uncontrollable body movements. Any attempt to place the patient in a semierect position or to administer a sedative would prove futile. Following the seizure, it is important to place the patient on his or her side to prevent aspiration of any vomitus or oral secretions. (Adler & Carlton, p 248)

Question 55

A radiographer should recognize that gerontologic patients often have undergone physical changes that include loss of

Answer 55

muscle mass.
bone calcium.

EXPLANATION: Gerontology, or geriatrics, is the study of the elderly. Although bone demineralization and loss of muscle mass occur to a greater or lesser degree in most elderly individuals, the radiographer must not assume that all gerontologic patients are hard of hearing, clumsy, or not mentally alert. Today, many elderly people remain very active, staying mentally and physically agile well into their so-called golden years. The radiographer must keep this in mind as he or she provides age-specific care to the gerontologic patient. (Torres et al., 6th ed., p. 211)

Question 56

Tangential view of patella shows

Answer 56

Patellofemoral articulation
Tangential patella

EXPLANATION: Note the relationship between the thigh, lower leg, patella, and CR. The CR is directed parallel to the plane of the patella, thereby providing a tangential projection of the patella (i.e., patella in profile) and an unobstructed view of the patellofemoral articulation (Figure 2–42). A tunnel view is required to demonstrate the intercondyloid fossa and the articulating surfaces of the tibia and femur. (Frank, Long, and Smith, 11th ed., vol. 1, p. 325)

Question 57

Diseases that require droplet precautions include

Answer 57

rubella.
mumps.
influenza.

EXPLANATION: A private room is indicated for all patients on droplet precaution; that is, diseases transmitted via large droplets expelled from the patient while speaking, sneezing, or coughing. The pathogenic droplets can infect others when they come in contact with mouth or nasal mucosa or conjunctiva. Rubella (“German measles”), mumps, and influenza are among the diseases spread by droplet contact; a private room is required for the patient, and health care practitioners must wear a regular (string) mask to enter a droplet precautions isolation room. (Adler and Carlton, 4th ed., p. 233)

Question 58

Using the PA projection, which of the following tube angle and direction combinations is correct for an axial projection of the clavicle?

Answer 58

15 to 30 degrees caudad

EXPLANATION: When the clavicle is examined in the PA axial projection, the CR must be directed 15 to 30 degrees caudad to project most of the clavicle’s length above the ribs. The direction of the CR is reversed when examining the patient in the AP position. (Frank, Long, and Smith, 11th ed., Vol. I, p. 210)

Question 59

Inspiration and expiration projections of the chest are performed to demonstrate

Answer 59

1. partial or complete collapse of pulmonary lobe(s)
2. air in the pleural cavity
3. foreign body

EXPLANATION: The phase of respiration is exceedingly important in thoracic radiography because lung expansion and the position of the diaphragm strongly influence the appearance of the finished radiograph. Inspiration and expiration radiographs of the chest are taken to demonstrate air in the pleural cavity (pneumothorax), to demonstrate atelectasis (partial or complete collapse of one or more pulmonary lobes) or the degree of diaphragm excursion, or to detect the presence of a foreign body. The expiration image will require a somewhat greater exposure (6–8 kV more) to compensate for the diminished quantity of air in the lungs. (Frank, Long, and Smith, 11th ed., vol. 1, p. 520)

Question 60

The condition that allows blood to shunt between the right and left ventricles is called

Answer 60

ventricular septal defect.

EXPLANATION: Ventricular septal defect is a congenital heart condition characterized by a hole in the interventricular septum that allows oxygenated and unoxygenated blood to mix. Some interventricular septal defects are small and close spontaneously; others require surgery. Coarctation of the aorta is a narrowing or constriction of the aorta. Atrial septal defect is a small hole (the remnant of the fetal foramen ovale) in the interatrial septum. It usually closes spontaneously in the first months of life; if it persists or is unusually large, surgical repair is necessary. The ductus arteriosus is a short fetal blood vessel connecting the aorta and pulmonary artery that usually closes within 10 to 15 hours after birth. A patent ductus arteriosus is one that persists and requires surgical closure. (Taber, 20th ed., p. 2,323)

Question 61

Spinning top with 6 dots for a single-phase, full-wave-rectified unit with a timer and rectifiers that are known to be accurate and functioning correctly. What exposure time was used to produce this image?

Answer 61

0.05 second

EXPLANATION: When a spinning top is used to test the timer efficiency of full-wave-rectified single-phase equipment, the result is a series of dots or dashes, with each dot representing a pulse of radiation. With full-wave-rectified current and a possible 120 dots (pulses) available per second, one should visualize 12 dots at 1/10 second, 6 dots at 0.05 second, 10 dots at 1/12 second, and 3 dots at 0.025 second. Because three-phase equipment is at almost constant potential, a synchronous spinning top must be used for timer testing, and the result is a solid arc (rather than dots). The number of degrees covered by the arc is measured and equated to a particular exposure time. (Selman, 9th ed., p. 106)

Question 62

AP stress studies of the ankle may be performed

to demonstrate fractures of the distal tibia and fibula

following inversion or eversion injuries

to demonstrate a ligament tear

Answer 62

2 and 3 only

EXPLANATION: After forceful eversion or inversion injuries of the ankle, AP stress studies are valuable to confirm the presence of a ligament tear. Keeping the ankle in an AP position, the physician guides the ankle into inversion and eversion maneuvers. Characteristic changes in the relationship of the talus, tibia, and fibula will indicate ligament injury. Inversion stress demonstrates the lateral ligament, whereas eversion stress demonstrates the medial ligament. A fractured ankle would not be manipulated in this manner. (Frank, Long, and Smith, 11th ed., vol. 1, p. 293)

Question 63

With a patient in the PA position and the OML perpendicular to the table, a 15- to 20-degree caudal angulation would place the petrous ridges in the lower third of the orbit. To achieve the same result in a baby or a small child, it is necessary for the radiographer to modify the angulation to

Answer 63

10 to 15 degrees caudal

EXPLANATION: With a patient in the PA position and the OML perpendicular to the table, a 15- to 20-degree caudal angulation would place the petrous ridges in the lower third of the orbit. To achieve the same result in a baby or a small child, it is necessary for the radiographer to decrease the angulation or modify the angulation to 10 to 15 degrees caudal. The reason for this can be understood by examining the baselines for skull positioning. In the adult skull, the OML and IOML are about 7 degrees apart. In a baby or small child, the difference is larger, about 15 degrees apart. Remember that in adults, the head makes up about one-seventh the length of the body. In children, the head is about one-fourth the length of the body. These differences must be considered in radiographic examination of the skull for babies. (Frank, Long, and Smith, 11th ed., vol. 3, p. 193)

Question 64

What information must be included on an x-ray image for it to be considered as legitimate legal evidence?

Answer 64

1. Name of facility where exam performed
2. Examination date

EXPLANATION: X-ray images are often subpoenaed as court evidence in cases of medical litigation. In order to be considered as legitimate legal evidence, each x-ray image must contain certain essential and specific patient information. Essential information that must be included on each image is patient identification, the identity of the facility where the x-ray study was performed, the date that the study was performed, and a right- or left-side marker.
Other useful information that may be included, but that is not considered essential, is additional patient demographics such as their date of birth, the identity of the referring physician, the time of day that the study was performed, and the identity/initials of the radiographer performing the examination.

Question 65

Which of the following conditions describes a patient who is unable to breathe easily while in the recumbent position?

Answer 65

Orthopnea

EXPLANATION: A patient with orthopnea is unable to breathe while lying down. When the body is recumbent, the diaphragm and abdominal viscera move to a more superior position. It is therefore more difficult to breathe deeply. Patients with orthopnea must be examined in an erect or semierect position. Dyspnea refers to difficulty breathing in any body position. Apnea describes cessation of breathing for short intervals. Oligopnea is infrequent breathing—as slow as 6 to 10 respirations per minute. (Ehrlich, McCloskey, & Daly, p 127)

Question 66

Which of the following expresses the gonadal dose that, if received by every member of the population, would be expected to produce the same total genetic effect on that population as the actual doses received by each of the individuals?

Answer 66

Genetically significant dose

EXPLANATION: The genetically significant dose (GSD) illustrates that large exposures to a few people are cause for little concern when diluted by the total population. On the other hand, we all share the burden of the radiation that is received by the total population, and especially as the use of medical radiation increases, each individual’s share of the total exposure increases. (Bushong, 8th ed., p. 589)

Question 67

Tracheotomy is an effective technique most commonly used to restore breathing when there is

Answer 67

respiratory pathway obstruction above the larynx

EXPLANATION: The respiratory passageways include the nose, pharynx, larynx (upper respiratory structures), trachea, bronchi, and lungs (lower structures). If obstruction of the breathing passageways occurs in the upper respiratory tract, above the larynx (i.e., in the nose or pharynx), tracheotomy may be performed to restore breathing. Intubation can be done into the lower structures, larynx, and trachea, moving aside any soft obstruction and restoring the breathing passageway. (Tortora and Derrickson, 11th ed., p. 856)

Question 68

If extravasation occurs during an IV injection of contrast media, correct treatment includes which of the following?

Answer 68

Apply pressure, cold compress, then apply warm, moist heat.

Question 69

To be suitable for use in intensifying screens, a phosphor should have which of the following characteristics?

High conversion efficiency
High x-ray absorption
High atomic number

Answer 69

1, 2, and 3

EXPLANATION: Intensifying-screen phosphors that have a high atomic number are more likely to absorb a high percentage of the incident x-ray photons and convert x-ray photon energy to fluorescent light energy. How efficiently the phosphors detect and interact with the x-ray photons is termed quantum detection efficiency. How effectively the phosphors make this energy conversion is termed conversion efficiency. (Shephard, p. 65)

Question 70

The most frequent site of hospital-acquired infection is the

Answer 70

urinary tract.

EXPLANATION: Hospital-acquired infections (HAIs) are also referred to as nosocomial. Despite the efforts of infectious disease departments, HAIs continue to be a problem in hospitals today. This is at least partly due to there being a greater number of older, more vulnerable patients and an increase in the number of invasive procedures performed today (i.e., needles and catheters). The most frequent site of HAI is the urinary tract, followed by wounds, the respiratory tract, and blood. (Torres et al., 6th ed., p. 47)

Question 71

Which of the following are methods of limiting the production of scattered radiation?

Using moderate ratio grids

Using the prone position for abdominal examinations

Restricting the field size to the smallest practical size

Answer 71

2 and 3 only

EXPLANATION: If a fairly large patient is turned prone, the abdominal measurement will be significantly different from the AP measurement as a result of the effect of compression. Thus, the part is essentially “thinner,” and less scattered radiation will be produced. If the patient remains supine and a compression band is applied, a similar effect will be produced. Beam restriction is probably the single most effective means of reducing the production of scattered radiation. Grid ratio affects the cleanup of scattered radiation; it has no effect on the production of scattered radiation. (Shephard, p. 203)

Question 72

The largest dose to the male gonads is most likely to result from which of the following exposures?

Answer 72

Cross-table lateral hip

EXPLANATION: The cross-table lateral hip will bring the primary beam in closest proximity to the male reproductive organs. A grid is required, and gonadal shielding is most likely not possible. Close, accurate collimation is recommended to keep exposure to a minimum, but the cross-table lateral hip will deliver the greatest dose to the male reproductive organs. (Bontrager, p 267)

Question 73

The interaction between x-ray photons and tissue that is responsible for radiographic contrast but that also contributes significantly to patient dose is

Answer 73

the photoelectric effect

EXPLANATION: In the photoelectric effect, the incident (low-energy) photon is completely absorbed and thus is responsible for producing contrast and contributing to patient dose. The photoelectric effect is the interaction between x-ray and tissue that predominates in the diagnostic range. In Compton scatter, only partial absorption occurs, and most energy emerges as scattered photons. In coherent scatter, no energy is absorbed by the part; it all emerges as scattered photons. Pair production occurs only at very high energy levels, at least 1.02 MeV. (Bushong, 8th ed., p. 176)

Question 74

Which of the following would be considered an advantage of using photospot camera film instead of cassette-loaded spot film to record conventional fluoroscopic images?

Answer 74

Reduced patient dosage

EXPLANATION: When using photospot camera film, there is reduced patient dosage (A). In fact, dosage is at least half of that which occurs with cassette-loaded spot film (A). A smaller anatomical image size (B) is produced with photospot camera film, when compared to cassette-loaded spot film. The photospot camera provides adequate image quality without interruption of the fluoroscopic examination and an increased rate of exposures (C) of up to 12 images per second. With cassette-loaded spot films, the fluoroscopic examination must be interrupted while the film moves into position within a lead-lined compartment, the mA is switched from low to high mA, and the rotor speed is increased, which can delay the exposure for a couple of seconds. Both photospot camera film and cassette-loaded spot film must be chemically processed (D) in a darkroom. (Bushong, 10th ed., p. 413).

Question 75

Exposure factors of 90 kV and 3 mAs are used for a particular nongrid exposure. What should be the new milliampere-seconds (mAs) value if a 12:1 grid is added?

Answer 75

15

EXPLANATION: To change nongrid to grid exposure or to adjust exposure when changing from one grid ratio to another, it is necessary to recall the factor for each grid ratio:

no grid = 1x Orig. mAs

5: 1 grid = 2x Orig. mAs
6: 1 grid = 3x Orig. mAs
8: 1 grid = 4x Orig. mAs
10: 1 grid =5x Orig. mAs
12: 1 grid = 5x Orig. mAs
16: 1 grid = 6x Orig. mAs

EXPLANATION: Therefore, to change from nongrid to a 12:1 grid, multiply the original milliampere-seconds value by a factor of 5. A new milliampere-seconds value of 15 is required. (Shephard, pp. 247–248)

Question 76

Examples of late effects of ionizing radiation on humans include
leukemia
local tissue damage
malignant disease

Answer 76

1, 2, and 3

EXPLANATION: Occupationally exposed individuals are concerned principally with late (i.e., long-term or delayed) effects of ionizing radiation such as radiation-induced genetic effects, leukemia, and cancers (e.g., bone, lung, thyroid, and breast), as well as local effects, such as skin erythema, infertility, and cataracts—these can occur many years following initial exposure to low levels of ionizing radiation. The long-term/delayed effects usually are chronic, and many are represented by the linear, nonthreshold dose–response curve. (Bushong, 10th ed., pp. 507 and 519)

Question 77

Which of the following is (are) required for a lateral projection of the skull?
The IOML is parallel to the IR.
The MSP is parallel to the IR.
The CR enters ¾ inch superior and anterior to the EAM.

Answer 77

1 and 2 only

EXPLANATION: In the lateral position of the skull, the midsagittal plane must be parallel to the IR and the interpupillary line vertical. Flexion of the head is adjusted until the IOML is parallel to the IR. The CR should enter about 2 inches superior to the EAM. The centering point for a lateral sella turcica is ¾ inch anterior and superior to the EAM. (Frank, Long, and Smith, 11th ed., vol. 2, p. 306)

Question 78

An increase in total filtration of the x-ray beam will increase

Answer 78

beam HVL

EXPLANATION: Aluminum filters are used to decrease patient skin dose by absorbing the low-energy photons (therefore, decreased milliroentgen output) that do not contribute to the image but do contribute to patient skin dose. HVL is defined as that thickness of any absorber that will decrease the intensity of a particular beam to one-half its original value. As filtration of an x-ray beam is increased, the overall average energy of the resulting beam is greater (because the low-energy photons have been removed)—and, therefore, the HVL thickness required would be greater. (Bushong, 8th ed., p. 165)

Question 79

Techniques that function to reduce the spread of microbes are termed

Answer 79

medical asepsis.

EXPLANATION: Medical asepsis refers to practices that reduce the spread of microbes, and therefore the chance of spreading disease or infection. Washing your hands is an example of medical asepsis. It reduces the spread of infection, but it does not eliminate all microorganisms. Disinfection involves the use of chemicals to either inactivate or inhibit the growth of microbes. The complete killing of all microorganisms is termed sterilization. Surgical asepsis refers to the technique used when performing procedures to prevent contamination. (Adler & Carlton, p 211)

Question 80

Which of the following is most likely to permit the greatest decrease in patient exposure?

Answer 80

Changing from an 8:1 grid technique to nongrid

EXPLANATION: Converting from an 8:1 grid to nongrid requires about a fourfold decrease in milliampere-seconds. Increasing the kilovoltage by 15% and cutting the milliampere-seconds in half would reduce patient dose by half. Changing from a 200-speed system to a 400-speed system also would require the milliampere-seconds to be halved. Therefore, the largest decrease will occur with removal of a grid. (Bushong, 8th ed., p. 252)

Question 81

Which of the following drugs is used to treat dysrhythmias?

Answer 81

Lidocaine

EXPLANATION: Lidocaine (Xylocaine) is an antiarrhythmic used to prevent or treat cardiac arrhythmias (dysrhythmia). Epinephrine (Adrenalin) is a bronchodilator. Bronchodilators may be administered in a spray mister, such as for asthma, or by injection to relieve severe bronchospasm. Nitroglycerin and verapamil are vasodilators. Vasodilators permit increased blood flow by relaxing the walls of the blood vessels. (Adler and Carlton, 4th ed., p. 304)

Question 82

To demonstrate the glenoid fossa in profile, the patient is positioned

Answer 82

45 degrees oblique, affected side down.

EXPLANATION: When viewing the glenoid fossa from the anterior, it is seen to angle posteriorly and laterally approximately 45 degrees. To view it in profile, then, it must be placed so that its surface is perpendicular to the IR. The patient is positioned in a 45-degree oblique, affected-side-down position, which places the glenoid fossa approximately perpendicular to the IR. The arm is abducted slightly, the elbow is flexed, and the hand and forearm are placed over the abdomen. The CR is directed perpendicular to the glenohumeral joint. (Frank, Long, and Smith, 11th ed., vol. 1, pp. 192–193)

Question 83

All of the following statements regarding the inferosuperior axial (nontrauma, Lawrence method) projection of the shoulder are true, except

Answer 83

the arm should be in internal rotation.

EXPLANATION: The inferosuperior axial (nontrauma, Lawrence method) projection of the shoulder demonstrates the glenohumeral joint and adjacent structures. The patient is supine with arm abducted 90°, and in external rotation. The (horizontal) CR is directed medially 25° to 30° through the axilla. The coracoid process and lesser tubercle are seen in profile. (Bontrager, p 179)

Question 84

A particular radiograph was produced using 6 mAs and 110 kVp with an 8:1 ratio grid. The radiograph is to be repeated using a 16:1 ratio grid. What should be the new mAs?

Answer 84

9

EXPLANATION: To change nongrid exposures to grid exposures, or to adjust exposure when changing from one grid ratio to another, you must remember the factor for each grid ratio:
No grid = 1 x the original mAs
5:1 grid = 2 x the original mAs
6:1 grid = 3 x the original mAs
8:1 grid = 4 x the original mAs
12:1 grid = 5 x the original mAs
16:1 grid = 6 x the original mAs
To adjust exposure factors, you simply compare the old with the new:
x = 9 mAs using 16:1 grid.
(Shepard, pp. 247–248)

Question 85

Use your mouse to drag the following structures into anatomic order (A–D), that is, the order in which an oral administration of barium sulfate would pass through them.

D. Duodenum

B. Pylorus

A. Ileum

C. Sigmoid

Answer 85

(A) Pylorus
(B) Duodenum
(C) Ileum
(D) Sigmoid

EXPLANATION: (A) Pylorus
(B) Duodenum
(C) Ileum
(D) Sigmoid
With oral administration, barium sulfate suspension would first pass through the upper gastrointestinal (GI) tract—mouth, pharynx, esophagus, stomach (fundus, body, pylorus), small bowel (duodenum, jejunum, ileum), large bowel (cecum, ascending colon, right colic/hepatic flexure), transverse colon, left colic/splenic flexure, and descending colon, sigmoid colon, rectum). (Tortora and Derrickson, 11th ed., pp. 911–932)

Question 86

To demonstrate the first two cervical vertebrae in the AP projection, the patient is positioned so that

Answer 86

a line between the maxillary occlusal plane and the mastoid tip is vertical.

EXPLANATION: To clearly demonstrate the atlas and axis without superimposition of the teeth or the base of the skull, a line between the maxillary occlusal plane (edge of upper teeth) and mastoid tip must be vertical. If the head is flexed too much, the teeth will be superimposed. If the head is extended too much, the cranial base will be superimposed on the area of interest. A line between the mentum and the mastoid tip is used to demonstrate the odontoid process only through the foramen magnum (Fuchs method). (Frank, Long, and Smith, 11th ed., vol. 1, p. 393)

Question 87

What portion of the humerus articulates with the ulna to help form the elbow joint?

Answer 87

Trochlea

EXPLANATION: The distal humerus articulates with the proximal radius and ulna to form the elbow joint. Specifically, the semilunar/trochlear notch of the proximal ulna articulates with the trochlea of the distal medial humerus. The capitulum is lateral to the trochlea and articulates with the radial head (Figure 2–50). (Frank, Long, and Smith, 11th ed., vol. 1, p. 99)

Question 88

An advantage of coupling the image intensifier to the TV camera or CCD via a fiber-optic coupling device is its

compact size

durability

ability to accommodate auxilary imaging devices

Answer 88

1 and 2 only

EXPLANATION: The image intensifier can be coupled to the TV camera via a fiber-optic bundle or via a lens coupling device. The fiber-optic connection offers less fragility, more compactness, and ease of maneuverability. The big advantage of the objective lens is that it allows the use of auxiliary imaging devices such as a cine camera or spot-film camera.(Bushong, 8th ed., p. 366)

Question 89

Which of the following examinations require(s) restriction of a patient’s diet?

Barium enema

Pyelogram

Metastatic survey

Answer 89

1 and 2 only

EXPLANATION: A patient who is having a BE generally is required to have a low-residue diet for 1 or 2 days, followed by cathartics and cleansing enemas prior to the examination. Any retained fecal material can simulate or obscure pathology. A patient who is scheduled for a pyelogram must have the preceding meal withheld to avoid the possibility of aspirating vomitus in case of an allergic reaction. A metastatic survey does not require the use of contrast media, and no patient preparation is necessary. (Torres et al., 6th ed., p. 234)

Question 90

All the following are forms of mechanical obstruction seen in neonates or infants except

Answer 90

paralytic ileus.

EXPLANATION: Volvulus and intussusception both involve a mechanical “closure” or obstruction of the intestinal lumen by a change in the continuous pathway of the GI tract—volvulus by a twisting of the bowel on itself causing obstruction and intussusception by “telescoping” of the bowel causing obstruction. Meconium ileus is another form of mechanical obstruction where meconium (first feces of a newborn) becomes hardened and impacted, causing obstruction. Paralytic (or adynamic) ileus, however, is an obstruction caused by loss of peristaltic movement of the intestine. (Bontrager and Lampignano, 6th ed., p. 660)

Question 91

When caring for a patient with an IV line, the radiographer should keep the medication

Answer 91

18 to 20 inches above the level of the vein.

EXPLANATION: It is generally recommended that the IV bottle/bag be kept 18 to 20 inches above the level of the vein. If the container is too high, the pressure of the IV fluid can cause it to pass through the vein into surrounding tissues, causing a painful and potentially harmful condition. If the IV container is too low, blood may return through the needle into the tubing, form a clot, and obstruct the flow of IV fluid. (Torres et al., 6th ed., p. 323)

Question 92

An increase in kilovoltage will have which of the following effects?
More scattered radiation will be produced.
The exposure rate will increase.
Radiographic contrast will increase.

Answer 92

1 and 2 only

EXPLANATION: An increase in kilovoltage (photon energy) will result in a greater number (i.e., exposure rate) of scattered photons (Compton interaction). These scattered photons carry no useful information and contribute to radiation fog, thus decreasing radiographic contrast. (Selman, 9th ed., p. 117)

Question 93

The radiographer must perform which of the following procedures prior to entering a contact isolation room with a mobile x-ray unit?

Put on gown and gloves only.

Put on gown, gloves, mask, and cap.

Clean the mobile x-ray unit.

Answer 93

1 only

EXPLANATION: When performing bedside radiography in a contact isolation room, the radiographer should wear a gown and gloves. The cassettes are prepared for the examination by placing a pillowcase over them to protect them from contamination. Whenever possible, one person should manipulate the mobile unit and remain “clean,” whereas the other handles the patient. The mobile unit should be cleaned with a disinfectant on exiting the patient’s room, not prior to entering. (Torres et al., 6th ed., p. 69)

Question 94

According to the NCRP, the total gestational dose equivalent limit for the pregnant radiographer is

Answer 94

5 mSv

EXPLANATION: According to the NCRP, the annual occupational whole-body dose equivalent limit is 50 mSv (5 rem or 5000 mrem). The total gestational dose equivalent limit for embryo/fetus of a pregnant radiographer is 5 mSv (500 mrem or 0.5 rem); the monthly dose equivalent limit is 0.5 mSv (50 mrem or 0.05rem). The annual occupational whole-body dose equivalent limit for students under the age of 18 years is 1 mSv (100 mrem or 0.1 rem). The annual occupational dose equivalent limit for the lens of the eye, a particularly radiosensitive organ, is 150 mSv (15,000 mrem or 15 rem). The annual occupational dose equivalent limit for the skin and extremities is 500 mSv (50,000 mrem or 50 rem). (Bushong, 9th ed, p 619)

Question 95

The term effective dose refers to

Answer 95

whole-body dose

EXPLANATION: Every radiographic examination involves an ESE, which can be determined fairly easily. It also involves a gonadal dose and a marrow dose, which, if needed, can be calculated by the radiation physicist. If the ESE of a particular examination were calculated to determine the equivalent whole-body dose, this would be termed the effective dose. For example, the ESE of a PA chest radiograph is approximately 70 mrem, whereas the effective dose is 10 mrem. The effective (whole body) dose is much less because much of the body is not included in the primary beam. (Fosbinder and Kelsey, p. 390)

Question 96

What is the approximate entrance skin exposure (ESE) for the average anteroposterior (AP) supine abdomen radiograph?

Answer 96

300 mrad

EXPLANATION: Patients occasionally will question the radiographer regarding the amount of radiation they are receiving during their examination. Most of these patients are merely curious because they have heard a recent news report about x-rays or have perhaps studied about x-rays in school recently. It is a good idea for radiographers to have some knowledge of average exposure doses for patients who desire this information. The curious patient also can be referred to the medical physicist for more detailed information. The average anteroposterior (AP) supine lumbar spine radiograph delivers an ESE of about 350 mrad (0.35 rad). The average AP supine abdomen radiograph delivers about 300 mrad; the average AP cervical spine radiograph delivers about 80 mrad. (Dowd and Tilson, 2nd ed., p. 247)

Question 97

Geometric unsharpness will be least obvious
at long SIDs.
with small focal spots.
at the anode end of the image.

Answer 97

1, 2, and 3

EXPLANATION: The x-ray tube anode is designed according to the line-focus principle, that is, with the focal track beveled (Figure 6–24). This allows a larger actual focal spot to project a smaller effective focal spot, resulting in improved recorded detail with less blur. However, because of the target angle, penumbral blur varies along the longitudinal tube axis, being greater at the cathode end of the image and less at the anode end of the image. Therefore, better detail will be appreciated using small focal spots at the anode end of the x-ray beam and at longer SIDs. (Bushong, 8th ed., p. 287)

Question 98

If the exposure rate at 3 ft from the fluoroscopic table is 40 mR/h, what will be the exposure rate for 30 minutes at a distance of 5 ft from the table?

Answer 98

7 mR

EXPLANATION: The intensity/exposure rate of radiation at a given distance from a point source is inversely proportional to the square of the distance. This is the inverse-square law of radiation, and it is expressed in the following equation:

EXPLANATION: Substituting known values:

EXPLANATION: Thus, x = 14.4 mR/h and, therefore, 7.2 mR in 30 minutes. (Bushong, 8th ed., pp. 68–70)

Question 99

Which of the following anomalies is (are) possible if an exposure dose of 40 rad (400 mGy) were delivered to a pregnant uterus in the third week of pregnancy?

Skeletal anomaly
Organ anomaly
Neurologic anomaly

Answer 99

1 and 2 only

EXPLANATION: Irradiation during pregnancy, especially in early pregnancy, must be avoided. The fetus is particularly radiosensitive during the first trimester, during much of which time pregnancy may not even be suspected. High-risk examinations include pelvis, hip, femur, lumbar spine, cystograms and urograms, and upper and lower gastrointestinal (GI) series. During the first trimester, specifically the 2nd to 10th weeks of pregnancy (i.e., during major organogenesis), if the radiation dose is sufficient, fetal anomalies can be produced. Skeletal and/or organ anomalies can appear if irradiation occurs in the early part of this time period, and neurologic anomalies can be formed in the latter part; mental retardation and childhood malignant diseases, such as cancers or leukemia, and retarded growth/development also can result from irradiation during the first trimester. Fetal irradiation during the second and third trimesters is not likely to produce anomalies but rather, with sufficient dose, some type of childhood malignant disease. Fetal irradiation during the first 2 weeks of gestation can result in embryonic resorption or spontaneous abortion. It must be emphasized, however, that the likelihood of producing fetal anomalies at doses below 20 rad is exceedingly small and that most general diagnostic examinations are likely to deliver fetal doses of less than 1 to 2 rad. (Bushong, 8th ed., pp. 544–546)

Question 100

A compression fracture of the posterolateral humeral head and associated with an anterior dislocation of the glenohumeral joint is called a(an)

Answer 100

Hill-Sachs defect.

EXPLANATION: A Hill-Sachs defect is a compression fracture of the posterolateral humeral head, usually associated with anterior dislocation of the shoulder joint. It can involve the cartilage of the humeral head, causing instability and predisposing the shoulder to subsequent dislocations. A Bankart lesion is a fracture of the anteroinferior portion of the rim of the glenoid fossa. A rotator cuff tear involves injury to one or more of the muscles participating in formation of that muscular structure. The supraspinatus, infraspinatus, subscapularis, and teres minor are the major muscles of the rotator cuff. Adhesive capsulitis, or “frozen shoulder,” causes very diminished shoulder movement as a result of chronic joint inflammation. (Bontrager and Lampignano, 6th ed., p 189)

Question 101

A radiograph made using 300 mA, 0.1 second, and 75 kV exhibits motion unsharpness but otherwise satisfactory technical quality. The radiograph will be repeated using a shorter exposure time. Using 86 kV and 400 mA, what should be the new exposure time?

Answer 101

37 ms

EXPLANATION: The milliampere-seconds (mAs) formula is milliamperage x time = mAs. With two of the factors known, the third can be determined. To find the milliampere-seconds value that was used originally, substitute the known values:

EXPLANATION: We have increased the kilovoltage to 86 kV, an increase of 15%, which has an effect similar to that of doubling the milliampere-seconds. Therefore, only 15 mAs is now required as a result of the kilovoltage increase:

EXPLANATION: Thus, x = 0.0375-s exposure = 37.5 ms. (Selman, 9th ed., p. 214)

Question 102

In which of the following positions can the sesamoid bones of the foot be demonstrated to be free of superimposition with the metatarsals or phalanges?

Answer 102

Tangential metatarsals/toes

EXPLANATION: The tangential projection projects the sesamoid bones separate from adjacent structures. The patient is best examined in the prone position because this places the parts of interest closest to the IR. The affected foot is dorsiflexed so as to place its plantar surface 15 to 20 degrees with the vertical. The CR is directed perpendicular to the posterior surface of the foot (near the metatarsophalangeal joints). The dorsoplantar and oblique projections of the foot will demonstrate the sesamoid bones superimposed on adjacent bony structures. (Bontrager and Lampignano, 6th ed., p. 231)

Question 103

Inherent and added filtration in the x-ray tube functions to

Answer 103

reduce patient skin dose.

EXPLANATION: The x-ray tube’s glass envelope and oil coolant are considered inherent filtration. Thin sheets of aluminum are added to make a total of 2.5 mm Al equivalent filtration in equipment operated above 70 kVp. The function of aluminum filtration is to remove from the x-ray beam the soft (long-wavelength) x-ray photons that do not contribute to image formation but simply contribute to patient dose. These soft x-rays penetrate only a small thickness of tissue before being absorbed. (Selman, p 411)

Question 104

Evaluation criteria for a lateral projection of the humerus include

epicondyles parallel to the IR

lesser tubercle in profile

superimposed epicondyles

Answer 104

2 and 3 only

EXPLANATION: The greater and lesser tubercles are prominences on the proximal humerus separated by the intertubercular (bicipital) groove. The lateral projection of the humerus places the shoulder in extreme internal rotation with the epicondyles perpendicular to the IR and superimposed. The lateral projection of the humerus should demonstrate the lesser tubercle in profile. The AP projection of the humerus/shoulder places the epicondyles parallel to the IR and the shoulder in external rotation and demonstrates the greater tubercle in profile. (Frank, Long, and Smith, 11th ed., vol. 1, p. 176)

Question 105

The articular facets of L5-S1 are best demonstrated in a(n)

Answer 105

30-degree oblique

EXPLANATION: Lumbar articular facets, forming the apophyseal joints, are demonstrated in the oblique position. L1 through L4 are best demonstrated in a 45-degree oblique, while L5-S1 are best seen in the 30-degree oblique (up to 60° oblique could be required). The AP axial projection is used to demonstrate an AP projection of L5-S1. (Bontrager and Lampignano, 7th ed., p. 334)

Question 106

Which of the following projection(s) require(s) that the shoulder be placed in internal rotation?

1. AP humerus
2. Lateral forearm
3. Lateral humerus

Answer 106

3 only

EXPLANATION: When the arm is placed in the AP position, the epicondyles are parallel to the plane of the cassette and the shoulder is placed in external rotation. In this position, an AP projection of the humerus, elbow, and forearm can be obtained; it places the greater tubercle of the humerus in profile. For the lateral projection of the humerus, the arm is internally rotated, elbow somewhat flexed, with the back of the hand against the thigh and the epicondyles superimposed and perpendicular to the IR. The lateral projections of the humerus, elbow, and forearm all require that the epicondyles be perpendicular to the plane of the cassette. (Ballinger & Frank, pp 161, 164)

Question 107

If the exposure rate at 2.0 m from a source of radiation is 18 mR/min, what will be the exposure rate at 5 m from the source?

Answer 107

2.8 mR/min

EXPLANATION: The relationship between x-ray intensity and distance from the source is expressed in the inverse-square law of radiation. The formula is

EXPLANATION: Substituting known values:

EXPLANATION: Thus, x = 2.88 mR/min at 5 m. Distance has a profound effect on dose received and, therefore, is one of the cardinal factors considered in radiation protection. As distance from the source increases, dose received decreases. (Bushong, 8th ed., pp. 68–70)

Question 108

What is the best position/projection to demonstrate the longitudinal arch of the foot?

Answer 108

Lateromedial weight-bearing lateral

EXPLANATION: Weight-bearing lateral projections of the foot are requested often to evaluate the longitudinal arch structure of the foot. The patient stands on a small platform. The x-ray cassette is placed between the feet, in a slot provided on the platform, with the top of the cassette against the medial aspect of the foot. The CR is directed to enter the lateral aspect of the foot perpendicular to the base of the fifth metatarsal and to exit the medial side of the foot. (Frank, Long, and Smith, 11th ed., vol. 1, pp. 268–269)

Question 109

For which of the following can a radiographer be found liable for a negligent tort?

Radiographer images the wrong forearm.

Patient is injured while being positioned on the x-ray table.

Radiographer fails to question patient about possible pregnancy before performing x-ray examination.

Answer 109

1, 2, and 3

EXPLANATION: For negligent tort liability, four elements must be present—duty (what should have been done), breach (deviation from duty), injury sustained, and cause (as a result of breach). The assessment of duty is determined by the professional standard of care. Examples of negligent torts include patient injury as a result of a fall while unattended on an x-ray table, in a radiographic room, or on a stretcher without side rails or safety belt. Radiographing the wrong patient and radiographing the opposite limb are other examples of negligence. If patient injury results from misperformance of a duty in the routine scope of practice of the radiographer, most courts will apply res ipsa loquitur; that is, “the thing speaks for itself.” If the patient is obviously injured as a result of the radiographer’s actions, it becomes the radiographer’s burden to disprove negligence. In many instances, the hospital and/or radiologist also will be held responsible according to respondeat superior, or “the master speaks for the servant.” (Adler and Carlton, 4th ed., p. 374)

Question 110

What lies immediately under the phosphor layer of a PSP storage plate?

Answer 110

Reflective layer

EXPLANATION: The PSP storage plate within the IP has a layer of europium-activated barium fluorohalide (BaFX: Eu2+; X = halogen) mixed with a binder substance. This layer serves as the image receptor when exposed in the traditional manner; it looks very much like an x-ray cassette intensifying screen.
The barium fluorohalide is usually granular or turbid phosphors. Other examples of turbid phosphors are gadolinium oxysulfide and rubidium chloride. “Needle”-shaped, or columnar phosphors (usually cesium iodide), have the advantage of better x-ray absorption and less light diffusion.
Just under the barium fluorohalide layer is a reflective layer that helps direct emitted light up toward the CR reader. Below the reflective layer is the base, behind that is an antistatic layer, and then the lead foil to absorb backscatter. Over the top of the barium fluorohalide is a protective layer.

Question 111

Symptoms associated with a respiratory reaction to contrast media include

sneezing.
hoarseness.
wheezing.

Answer 111

1, 2, and 3

EXPLANATION: All these symptoms are related to a respiratory reaction. There also may be dyspnea, asthma attack, or cyanosis. The patient who has received contrast media should be watched closely. If any symptoms arise, the radiologist should be notified immediately. (Adler and Carlton, 4th ed., p. 331)

Question 112

Which of the following modes of a trifield image intensifier will result in the highest patient dose?

Answer 112

Its 12-cm. mode

EXPLANATION: Most image-intensifier tubes are either dual-field or trifield, indicating the diameter of the input phosphor. When a change to a smaller-diameter mode is made, the voltage on the electrostatic focusing lenses is increased, and the result is a magnified but dimmer image. The milliamperage will be increased automatically to compensate for the loss in brightness with a magnified image, resulting in higher patient dose in the smaller-diameter modes. (Bushong, 10th ed., p. 407)

Question 113

Causes of grid cutoff, when using focused reciprocating grids, include the following?

Inadequate SID

X-ray tube off-center with the long axis of the lead strips

Angling the beam in the direction of the lead strips

Answer 113

1 only

EXPLANATION: If the SID is above or below the recommended focusing distance, the primary beam will not coincide with the angled lead strips at their lateral edges. Consequently, there will be absorption of the primary beam termed grid cutoff. If the central ray is off-center longitudinally, there will be no ill effects. If the central ray is off-center side to side, the lead strips are no longer parallel with the divergent x-ray beam, and there will be loss of density owing to grid cutoff. Central ray angulation in the direction of the lead strips is appropriate and will not cause grid cutoff. Central ray angulation against the direction of the lead strips will cause grid cutoff. (Selman, 9th ed., pp. 239–242)

Question 114

Characteristics of low ratio focused grids include the following:

1. they have a greater focal range
2. they are less efficient in collecting SR
3. they can be used inverted

Answer 114

1 and 2 only

EXPLANATION: Grid ratio compares the height of the lead strip to the distance between the lead strips. Focused grids have their lead strips angled so as to parallel the divergent x-ray beam. The higher the grid ratio, the greater the grid’s efficiency in absorbing scattered radiation before it reaches the image receptor—but the more critical the centering and distance specifications. Although higher ratio focused grids absorb more SR they have a narrower focal range (focusing distance) and grid/tube centering becomes much more critical. Focused grids must not be accidentally inverted—to do so would cause the lead strips to be placed exactly in the path of the lead strips (grid cutoff), everywhere but in the center of the grid. (Ballinger & Frank, vol 3, p 235)

Question 115

Which of the following positions is used to demonstrate vertical patellar fractures and the patellofemoral articulation?

Answer 115

Tangential patella

EXPLANATION: In the tangential (sunrise) projection of the patella, the CR is directed parallel to the longitudinal plane of the patella, thereby demonstrating a vertical fracture and providing the best view of the patellofemoral articulation. The AP knee projection could demonstrate a vertical fracture through the superimposed femur, but it does not demonstrate the patellofemoral articulation. The tunnel view of the knee is used to demonstrate the intercondyloid fossa. (Frank, Long, and Smith, 11th ed., vol. 1, pp. 324–325)

Question 116

If a patient’s zygomatic arch has been traumatically depressed or the patient has flat cheekbones, the arch may be demonstrated by modifying the SMV projection and rotating the patient’s head

Answer 116

15 degrees toward the side being examined

EXPLANATION: When one cheekbone is depressed, a tangential projection is required to “open up” the zygomatic arch and draw it away from the overlying cranial bones. This is accomplished by placing the patient in the SMV position, rotating the head 15 degrees toward the affected side, and centering to the zygomatic arch. A 30-degree rotation places the mandibular shadow over the zygomatic arch. (Frank, Long, and Smith, 11th ed., vol. 2, pp. 364–365)

Question 117

Biologic material is least sensitive to irradiation under which of the following conditions?

Answer 117

Anoxic

EXPLANATION: Tissue is most sensitive to radiation when it is oxygenated and least sensitive when it is devoid of oxygen. Anoxic refers to tissue without oxygen; hypoxic refers to tissue with little oxygen. Anoxic and hypoxic tumors typically are avascular (with little or no blood supply) and, therefore, more radioresistant. Oxygen at a higher level than atmospheric pressure (hyperbaric) can be used to treat infections and promote healing, as well as treat carbon monoxide poisoning. (Bushong, 10th ed., p. 481)

Question 118

The articulation between the first metacarpal and the trapezium is what joint type?

Answer 118

Diarthrotic joint

EXPLANATION: The radiograph is a PA projection of the hand and wrist; an oblique projection of the thumb is obtained. The letter T is pointing out the first carpometacarpal joint, formed by the base of the first metacarpal and the trapezium. This is classified as a saddle-type diarthrotic joint. Diarthrotic joints are freely movable joints and the most plentiful type of joint in the human body. Amphiarthrotic joints are partially movable; synarthrotic joints are immovable. (Frank, Long, and Smith, 11th ed., vol. 1, p. 73)

Question 119

Structures involved in blowout fractures include the

orbital floor
inferior rectus muscle
zygoma

Answer 119

1 and 2 only

EXPLANATION: Blowout fractures of the orbital floor are caused by a direct blow to the eye. The orbital floor is caused to collapse; this carries the inferior rectus muscle through the fracture site and into the maxillary sinus. Diplopia (double vision) often results. Blowout fractures are well demonstrated with the modified Waters method (modified parietoacanthal projection) and with CT studies. A modified parietoacanthal projection with the lips-meatal line (LML) perpendicular and the OML 55degrees to the IR will demonstrate the orbital floor. The zygoma usually is not involved with a blowout fracture but rather with a tripod fracture. (Bontrager and Lampignano, 7th ed., p. 422)

Question 120

Adverse reactions to high osmolality water-soluble contrast media that are classified as mild, include

1. nausea.
2. pallor.
3. dyspnea.

Answer 120

1 and 2 only

EXPLANATION: Use of high osmolality (ionic) water-soluble contrast media can result in adverse physiological effects. These effects are usually classified as mild, moderate, or severe. Mild effects include warmth, itching, flushing, nausea, pallor, hives, anxiety, chills. Mild reactions are usually temporary and transient. The radiographer should reassure the patient and should observe and communicate with the patient to be certain that the mild reaction is resolved. Treatment is usually not necessary for mild reactions. Moderate adverse effects include hypertension, dyspnea, hypotension, bronchospasm. Patients must be closely observed for possible worsening of reaction; treatment might be required depending on progression of the reaction. Severe reactions include arrhythmia, cardiopulmonary arrest, laryngeal edema. Clearly, severe reactions require immediate recognition and treatment. (Adler and Carlton, 3rd ed, pp 297-298)

Question 121

A patient is usually required to drink barium sulfate suspension to demonstrate which of the following structures?

1. Esophagus
2. Pylorus
3. Ilium

Answer 121

1 and 2 only

EXPLANATION: Oral administration of barium sulfate is used to demonstrate the upper digestive tract: the esophagus; the fundus, body, and pylorus of the stomach; and the small bowel, consisting of duodenum, jejunum, and ileum. Consistent care must be taken to read and record patient information accurately and correctly. The large bowel is usually demonstrated via rectal administration of barium. (Bontrager, pp 442-443)

Question 122

To evaluate a digital receptor for debris that may cause image artifacts, which of the following should be done?

Answer 122

The receptor field should be exposed to a uniform X-ray exposure field, followed by visual inspection of the image

EXPLANATION: Because digital receptors are re-used, artifacts arising from debris and contaminants such as barium contrast media will show up on subsequent images from the receptor until the problem is corrected. By exposing the receptor to an X-ray exposure field (A) that covers the entire receptor, the resultant image can be inspected for artifacts. Maintenance checks should be conducted by technologists on a regular basis to ensure the production of diagnostic images free from artifacts and maintain patient throughput. If the artifacts cannot be corrected, then the manufacturer or a medical physicist should be contacted to evaluate the equipment (B). Regular maintenance checks should be conducted to proactively detect artifacts prior to exposing patients. Otherwise, potential artifacts may interfere with correct diagnoses (C). Cleaning the surrounding environment (D) to reduce collection of debris that may find its way to the receptor is a good practice. However, detector artifacts caused by debris (or contaminants) cannot be detected prior to patient exposure unless an exposure is made on the receptor and the resultant image is visually inspected. (Seeram, p. 231).

Question 123

The exposure rate to a body 4 ft from a source of radiation is 16 R/h. What distance from the source would be necessary to decrease the exposure to 6 R/h?

Answer 123

7 ft

EXPLANATION: The relationship between x-ray intensity and distance from the source is expressed by the inverse-square law of radiation. The formula is

EXPLANATION: Substituting known values:

EXPLANATION: Thus, x = 6.5 ft (necessary to decrease the exposure to 6 R/h). Note that in order for the exposure rate to decrease, the distance from the source of radiation must increase. (Bushong, 8th ed., p. 68)

Question 124

Which of the following terms is used to describe unsharp edges of tiny radiographic details?

Answer 124

Blur

EXPLANATION: Recorded detail is evaluated by how sharply tiny anatomic details are imaged on the radiograph. The area of blurriness that may be associated with small image details is termed geometric blur. The blurriness can be produced by using a large focal spot or by diffused fluorescent light from intensifying screens. The image proper (i.e., without blur) is termed the umbra. Mottle is a grainy appearance caused by fast imaging systems. (Selman, 9th ed., pp. 206–207)

Question 125

Handwashing is the easiest way of preventing spread of microorganisms, and health care professionals should wash their hands before and after every patient. Additionally, it is particularly essential that the radiographer wash his/her hands after contact with

1. patients who are at risk of infection.
2. blood/body fluids.
3. patients with known communicable diseases.

Answer 125

2 and 3 only

EXPLANATION: Handwashing remains the single most effective way to prevent spread of microorganisms. Health care workers should wash their hands before and after each patient. Radiographers must wash their hands after contact with patients with known communicable diseases, after contact with blood/body fluids, and before starting any procedure on patients who are at risk of infection (i.e., immunosuppressed). (Ballinger and Frank 10th ed Vol 1, p 15)

Question 126

Which unit of exposure is described as 100 ergs of energy per gram of irradiated absorber?

Answer 126

rad

EXPLANATION: Rad is an acronym for radiation absorbed dose; it measures the energy deposited in any material; that is, it is equal to 100 ergs of energy per gram of any absorber. Roentgen is the unit of exposure; it measures the quantity of ionizations in air. Rem is an acronym for radiation equivalent man; it includes the RBE specific to the tissue irradiated and therefore is a valid unit of measurement for the dose to biologic tissue. (Bushong, p 24)

Question 127

What is likely to occur if 25 rad is accidentally delivered to a recently fertilized ovum?

Answer 127

Spontaneous abortion

EXPLANATION: Irradiation during pregnancy, especially in early pregnancy, is avoided because the fetus is particularly radiosensitive during the first trimester. Especially high-risk examinations include pelvis, hip, femur, lumbar spine, cystograms and urograms, upper gastrointestinal (GI) series, and barium enema examinations. During the 2nd to 10th week of pregnancy (ie, during major organogenesis), fetal anomalies can be produced. Skeletal and/or organ anomalies can appear if irradiation occurs early on, and neurologic anomalies can be formed in the latter part; mental retardation childhood malignant diseases can also result from irradiation during the first trimester. Fetal irradiation during the second and third trimester, with sufficient dose, can cause some type of childhood malignant disease. Fetal irradiation during the first 2 weeks of gestation will most likely result in embryonic resorption or spontaneous abortion.
It must be emphasized that the likelihood of producing fetal anomalies at doses below 20 rad is exceedingly small and that most general diagnostic examinations are likely to deliver fetal doses of less than 1 to 2 rad. (Bushong, p 561)

Question 128

An advantage of using photospot camera film instead of cassette-loaded spot film to record conventional fluoroscopic images is:

Answer 128

Reduced patient dosage

EXPLANATION: When using photospot camera film, there is reduced patient dosage (C). In fact, dosage is at least half that used with cassette-loaded spot film (C). A smaller anatomical image size (A) is produced with photospot camera film when compared to cassette-loaded spot film. The photospot camera provides adequate image quality without interruption of the fluoroscopic examination and an increased rate of exposures (B) of up to 12 images per second. With cassette-loaded spot films, the fluoroscopic examination must be interrupted while the film moves into position, the mA is switched from low to high mA, and the rotor speed is increased, which can delay the exposure for a couple of seconds. Both photospot camera film and cassette-loaded spot film must be chemically processed in a darkroom (D). (Bushong, 9th ed., p. 358).

Question 129

All of the following statements regarding dual x-ray absorptiometry are true, except

1. radiation dose is considerable.
2. two x-ray photon energies are used.
3. photon attenuation by bone is calculated.

Answer 129

1 only

EXPLANATION: Dual x-ray absorptiometry (DXA) imaging is used to evaluate bone mineral density (BMD). It is the most widely used method of bone densitometry—it is low dose, precise, and uncomplicated to use/perform. DXA uses two photon energies—one for soft tissue and one for bone. Since bone is more dense and attenuates x-ray photons more readily, their attenuation is calculated to represent the degree of bone density. Bone densitometry, DXA, can be used to evaluate bone mineral content of the body, or part of it, to diagnose osteoporosis or to evaluate the effectiveness of treatments for osteoporosis. (Ballinger & Frank, vol 3, pp 488–489)

Question 130

Compared with that of the hypersthenic and sthenic body types, the gallbladder of an asthenic patient is most likely to be located

Answer 130

lower and more medial

EXPLANATION: The four types of body habitus describe differences in visceral shape, position, tone, and motility. One body type is hypersthenic, the very large individual with short, wide heart and lungs, high transverse stomach and gallbladder, and peripheral colon. The sthenic individual is the average, athletic, most predominant type. The hyposthenic patient is somewhat thinner and a little more frail, with organs positioned somewhat lower. The asthenic type is smaller in the extreme, with a long thorax, a very long, almost pelvic stomach, and a low medial gallbladder. The asthenic colon is medial and redundant. (Frank, Long, and Smith, 11th ed., vol. 1, p. 64)

Question 131

Which of the following can affect radiographic contrast?

1. Processing
2. Pathology
3. OID

Answer 131

1, 2, and 3

EXPLANATION: All three factors can affect radiographic contrast. The type of chemistry used in the automatic processor and especially the temperature of the solution can have a big impact on the resulting image contrast. As temperature increases, contrast decreases. Since pathology can alter the degree of attenuation of the x-ray beam, it can affect contrast. The type of pathology will determine how contrast is affected. An additive pathology such as Paget’s disease will increase contrast, while a destructive disease such as osteoporosis will decrease contrast. OID can affect contrast when it is used as an air gap. If a 6-inch air gap (OID) is introduced between the part and the IR, much of the scattered radiation emitted from the body will not reach the IR; the air gap thus acts as a grid and increases image contrast. (Carlton & Adler, pp 397–398)

Question 132

You have encountered a person who is apparently unconscious. Although you open his airway, there is no rise and fall of the chest, and you can hear no breath sounds. You should

Answer 132

begin external chest compressions at a rate of at least 100 compressions/min.

EXPLANATION: The long tradition of ABC’c (airway, breathing, chest compressions) has been changed to CAB (chest compressions, airway, breathing). If the victim is unable to be roused, the rescuer should start with 30 compressions, at a rate of 100 compressions per minute. The victim’s airway should then be opened and rescue breathing begun. This is accomplished by tilting back the head and lifting the chin. However, if the victim may have suffered a spinal cord injury, the spine should not be moved, and the airway should be opened using the jaw-thrust method. The rescuer next listens to breathing sounds and watches for the rise and fall of the chest to indicate breathing. If there is no breathing, the rescuer pinches the victim’s nose and delivers two full breaths via mouth-to-mouth rescue breathing. (Adler and Carlton, 5th ed., p. 256)

Question 133

Which of the following is (are) used to account for the differences in tissue characteristics when determining effective dose to biologic material?

Tissue weighting factors (Wt)
Radiation weighting factors (Wr)
Absorbed dose

Answer 133

1 only

EXPLANATION: The tissue weighting factor (Wt) represents the relative tissue radiosensitivity of irradiated material (e.g., muscle vs. intestinal epithelium vs. bone). The radiation weighting factor (Wr) is a number assigned to different types of ionizing radiations in order to better determine their effect on tissue (e.g., x-ray vs. alpha particles). The Wr of different ionizing radiations depends on the LET of that particular radiation. The following formula is used to determine effective dose E:

EXPLANATION: (Bushong, 8th ed., p. 556)