MOCK questions Flashcards by khunkasem phattaharawittakorn

Which interaction between x-ray photons and matter involves the greatest patient dose?

Photoelectric

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The NCRP-recommended annual dose limit for the gonads of occupationally-exposed adults is

50mSv

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What is the term used to describe restriction of patient movement to ensure safety?

Restraint

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What weighting factor(s) is/are used to determine the Sievert?

Wt and Wr

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A device that measures, in candelas per square meter, the luminescence of image display monitors and their uniformity is knows as a(n)

Photometer

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what best function to reduce the amount of scattered radiation reaching the IR?

Grids, Collimator, and compression

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Radiographers use monitoring devices to record their monthly exposure to radiation. The types of devices suited for this purpose include the

TLD and OSL

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Which of the following is primarily responsible for occupational exposure?

Compton and scatter radiation

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What is the exposure indicator in digital (cassetteless) systems termed

Dose Area Product

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Which interaction between x-ray photons and matter involves a low-energy (low kV) incident photon?

Photoelectric

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What unit is used to describe ionization in air?

Gya

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If a lateral lumbar spine were performed with the center detector selected and the spinous processes centered to the sensor, the resulting image is likely to be

Underexposed

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When using an AEC system, the amount of preset radiation detection values can be adjusted by the

Density control

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Which of the following types of fracture occurs when the skin is not penetrated?

Closed and Simple

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Which of the following are the synarthrodial sutures of the skull?

Sagittal, Coronal, Lambdoidal, and Squamosoal

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Which term refers to the smallest dose of radiation that will produce a specific effect?

Threshold

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When struck by light photons emitted by the input phosphor, the photocathode emits

Electrons

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The NCRP-recommended annual occupational dose limit for localized areas of the skin, hands, and feet is

500 mSv

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A direct relationship exists between image brightness and

density

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In what type of interaction does the incident photon lose up to one-third of its energy?

Compton

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Fluoroscopic magnification mode

increases patient dose

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In what type of interaction is the average energy of the photon one-third of the kVp selected at the control counsel?

Bremstrahlung

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What is the process of transmitting and viewing images remotely termed?

Teleradiography

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X-rays are electrically

Neutral

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Which projection of the elbow will cause superimposition of the proximal ulna by the radial head and neck?

AP oblique with Medial rotation

Which type of shielding should be used during an examination that requires a sterile field?

Shadow shield

What postprocessing function manipulates image contrast?

Window width

The term that defines the number of shades of gray that can be displayed within a pixel is

bit depth

Which of the following is a disease that is most often a complication of thrombus formation in one or both lower extremities?

During CR image extraction, what is the device used to collect light emitted by storage plate phosphors?

photodetector

The advantages of coupling a CCD with the image intensifier output phosphor include

less spatial distortion and higher DQE

Arrange the cycle of infection components in their correct order following the recognized reservoir of infection:

Portal of exit; susceptible host; portal of entry; transmission of disease

Occupational radiation is

low energy and low LET.

The SMV projection requires that the IOML baseline be parallel to the IR, and demonstrates which of the following paranasal sinuses?

Maxillary, Ethmoid, and sphenoid

Which of the following is the term used to describe episodes of chest pain that occur when coronary arteries are unable to supply the heart with sufficient oxygenated blood?

Angina Pectoris

The x-ray tube most efficiently operates on

unidirectional/dc.

When a 1-mm Pb flat contact shield is used to shield female reproductive organs, their dose is reduced by about

50%

What must be the lead equivalent of the fluoroscopic image intensifier assembly?

2.0 mm Pb equiv

What is the name of the exposure system that uses an established, optimum kV for each anatomical part?

Fixed Kilovoltage system

With AEC, the area of interest must be placed directly over the selected detectors in order to avoid

Under and over exposure

Fluoroscopic magniﬁcation is associated with

improved spatial resolution, improved contrast resolution

Which of the following is the prominence on the squamosal portion of the frontal bone that may be used as a positioning landmark?

Glabella

20 CFR states that radiation monitoring must be provided for occupationally exposed individuals who are likely to receive more than what portion of the annual dose equivalent limit?

1/10

What angulation is required for the PA axial projection of the mandible in order to demonstrate the condyles and TMJ area?

Cephalad

The portion of fluoroscopic equipment that functions to adjust the kVp and/or mA automatically to adjust for differences in anatomic thickness or density is known as

Automatic brightness control

How is the minimum wavelength of the x-ray beam affected with added filtration?

it is unaffected

Radiologic examinations that do not demonstrate function include

retrograde urography and retrograde cystography

When x-ray exposure to the digital image receptor is too low

Quantum noise is increased and brightness is acceptable

Compared to film-screen imaging, digital systems are

more sensitive to lower energy radiation and scatter radiation

Of the three tools used to measure the focal spot size—the slit camera, the pinhole camera, and the star pattern—which is the most commonly used?

Slit Camera

The feature(s) of digital fluoroscopy that function to reduce patient dose are

last image hold, pulsed fluoroscopy

From the following list, select the factor(s) having an impact on image distortion

part thickness, Tube angle, IR placement

What type of technique chart is based on the concept that kVp should be increased as anatomic part size increases?

Variable kVp-fixed mAs

What radiation exposure dose to the ovaries will result in temporary infertility?

2Gy

When changing from half-wave to full-wave rectification

Both X-ray quantity and quality double

A 0.5-mm Pb equivalent apron will attenuate what percentage of the scattered beam at 100 kV?

75%

The NCRP recommends an annual lens of eye EfD limit to the occupationally exposed of

150 mSv

What is the normal respiratory rate for adults?

12-18 breaths/ min

Advantages of flat-panel digital fluoroscopy system include:

1. better contrast resolution 2. uniformly distortion-free images 3. high DQE

Characteristics of the primary x-ray beam include:

lower intensity at the anode end

The NCRP-recommended annual dose limit for the thyroid is

500 mSv

The length of the latent period portion of acute radiation syndrome decreases as radiation exposure

increases

The coronoid process should be visualized in profile in which of the following positions?

Medial oblique view

What kV range is recommended for chest radiography?

110-125 kV

the factor(s) that are most likely to impact image spatial resolution/image sharpness

Focal Spot Size, SID, and OID

The annual effective dose (EfD) limit for radiography students participating in clinical education before the age of 18 is

1 mSv

If a lateral lumbar spine were performed with the center detector selected and the spinous processes centered to the sensor, the resulting image is likely to be

Underexposed

In an AP external rotation projection of the shoulder, the greater tubercle should be seen in profile

Laterally

Of the four categories of mobile units, which type needs to be plugged into the wall yet produces the most consistent radiation output?

High Frequency

Within the x-ray circuit, the electrical device that operates on the principle of mutual induction and serves to increase voltage and decrease current is known as the

Step up transformer

T/F | The storage screens typically used in CR contain cesium iodide.

False

Which is the most frequently occurring interaction between x-ray photons and tissue in diagnostic x-ray imaging?

Compton scatter

If patient entrance skin exposure (ESE) is 225 mR for a particular projection, the intensity of scatter 1 m from the patient will be

.225 mR

Which of the following terms is used for ionizing radiation-induced hair loss?

Aloepecia and Epilation

Which interaction between x-ray photons and matter involves a low-energy (low kV) incident photon?

Photoelectric effect

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

hypotension

What pixel size has a 512 × 512 matrix with a 20-cm field of view (FOV)?

0.40 mm/pixel

What pixel size has a 14" FOV and a 1250 matrix size?

0.284 mm

Factors influencing image contrast in digital imaging include

both lookup table and windowing.

Causes of grid cutoff, when using focused moving grids?

Inadequate SID

As the anode angle decreases,

1. image sharpness improves 2. the effective focal spot is smaller than the actual focal spot 3. the anode heel effect is emphasized

Which fat pad(s) will be visualized in a normal and accurately positioned lateral elbow?

1. Anterior fat pads | 2. Supinator fat pad

The bilateral AP oblique/frog-leg projection/modiﬁed Cleaves method of the pelvis requires that the CR be directed to the midline at a level 1-inch superior to the

Pubic symphysis

Protective or “reverse” isolation is required in which of the following conditions?

burns and leukemia

The first through fourth lumbar zygapophyseal articulations are how many degrees to the MSP?

Consistent output in radiation intensity, at a particular kV selection, and using various combinations of mA and time to produce the same mAs value is termed

exposure linearity

How do changes in pixel density and pixel pitch impact spatial resolution?

Increased pixel density increases spatial resolution; decreased pixel pitch increases spatial resolution

The National Council on Radiation Protection and Measurements (NCRP) has recommended what total gestational equivalent dose limit to the embryo/fetus?

5 mSv

what can affect radiographic contrast?

Lookup Table, Pathology, and OID

Too much edge enhancement of the image in digital systems can cause an unwanted artifact called the

Halo effect artifact

What is the position of the gallbladder in an asthenic patient?

inferior and medial

Which of the following anatomical structures is best demonstrated in an axiolateral oblique projection of the mandible when a 30° rotation toward the IR is utilized?

The Body

Which of the following projections are typically included in a rib series to rule out pneumothorax?

PA chest and Lateral Chest

Contraindications for performing a myelogram include:

presence of blood in the CSF, increased cranial pressure, recent lumbar puncture

The types of secondary radiation include

Leakage and Scatter radiation

possible complications of barium escaping from the gastrointestinal tract in to the peritoneum or vascular system?

Peritonitis, Formation of a barium granuloma, Embolus production

what happens when the kVp is increased?

Decreased absorbed dose, Increased scatter radiation, Decreased contrast

When helping a patient into/out of a wheelchair, the wheelchair should be locked and how many degrees to the x-ray table/bed?

45 degrees