mixed review deck 3

Question 1

For the AP axial projection of L5-S1 (Ferguson method), how is the CR angled and directed?

Answer 1

CR is directed to midline at ASIS level, 30-35 degrees cephalad (30 for males, 35 for females)

Question 2

Average lifespan of an erythrocyte

Answer 2

120 days

Question 3

For an AP knee radiograph, give approximate suggested CR angles for patients whose ASIS to tabletop measurement is …

a. less than 19 cm
b. 19 to 24 cm
c. greater than 24 cm

Answer 3

less than 19 cm: 3 to 5 degrees caudad
19 to 24: 0 degrees
greater than 24: 3 to 5 degrees cephalad

Question 4

The total electrical charge generated by an x-ray beam per unit mass of air is called:

Answer 4

exposure

Question 5

erythema has a threshold dose of ___ Gy and will occur within ___

Answer 5

2 Gy; hours to days

Question 6

epilation has a threshold dose of ____ Gy and will occur within ___

Answer 6

3 Gy; 3 weeks

Question 7

desquamation has a threshold dose of ___ Gy and will occur within ___

Answer 7

15 Gy; 4 weeks

Question 8

If an individual receives an acute dose of radiation to the forearm, in which order will desquamation, erythema and epilation occur?

Answer 8

erythema, epilation, desquamation

Question 9

ICRP dose equivalent limit for the skin

Answer 9

500 mSv

Question 10

On an axiolateral projection of the temporomandibular joints (TMJs), the patient’s head is placed in a
lateral position with the TMJ of interest closest to the image receptor. The central ray is angled caudally
about 30°. On the image, the TMJ of interest will be projected ________ to the other TMJ.
(superior, inferior, anterior or posterior?)

Answer 10

superior

Question 11

The CR entrance point for an AP oblique projection, Grashey method, of the shoulder is …

Answer 11

2 inches medial and 2 inches inferior to the superolateral border of the shoulder (some sources list this as medial/inferior to the superolateral border of the scapula!)

Question 12

During which weeks of development can exposure to an embryo or fetus to ionizing radiation result in skeletal anomalies?

Answer 12

3 weeks to 20 weeks (Lange lists this as 2 weeks to 10 weeks being MOST likely)

Question 13

The ___ tendon inserts on the lesser tubercle of the humerus

Answer 13

subscapularis

Question 14

What is the main purpose of positioning fluoroscopic equipment with the tube positioned under the table?

Answer 14

Results in less scattered and leakage radiation, and less occupational exposure

Question 15

For a lateral humerus, it is necessary to have the coronal plane passing through the humeral epicondyles aligned _____ to the IR

Answer 15

perpendicular

Question 16

What method of imaging the shoulder will show the lesser tubercle of the humerus in profile and directed anteriorly?

Answer 16

Lawrence method, inferosuperior axial projection

Question 17

How will the coracoid process appear in an inferosuperior axial shoulder (axillary shoulder, Lawrence method)?

Answer 17

in profile! (if you do a superoinferior, or a PA Bernageau, it will appear on end)

Question 18

The Rafert-Long method of imaging the scaphoid for obscure fractures, the wrist is positioned in extreme ulnar deviation and a series of ___ projections are taken with varying CR angles

Answer 18

4 PA and PA axial projections; uses 0, 10, 20 and 30 degree cephalic angles

Question 19

Range of typical grid ratios used in fluoroscopic units

Answer 19

6:1 to 10:1

Question 20

Where should the perpendicular CR enter for a lateral projection of the orbit?

Answer 20

At the outer canthus

Question 21

The base layer of a flat-panel detector is made of …

Answer 21

glass (TFT array is mounted onto a glass substrate)

Question 22

The ____ is a collection of disk drives that perform together as a single unit and improve reliability of data storage

Answer 22

RAID (redundant array of independent disks)

Question 23

What projection of the ankle is required to see an open distal tibiofibular joint?

Answer 23

An AP oblique with 45° medial rotation is required to see an open distal tibiofibular joint. On the AP
projection of the ankle, the fibula and tibia and the fibula and talus are seen slightly superimposed on the
image. The AP oblique with 15° to 20° medial rotation demonstrates the fibula free of superimposition
from the talus but not the tibia. It requires a 45° medial rotation to open the joint space between the fibula
and tibia. The AP oblique with 45° lateral rotation demonstrates the fibula, tibia, and talus superimposing
one another.

Question 24

The right kidney is placed perpendicular to the IR in the ___ position

Answer 24

RPO

Question 25

A patient is scheduled for a barium swallow. As you begin to review instructions with the patient, you notice that the patient seems lethargic. You should ...

Answer 25

reschedule the exam because the patient will not be able to swallow properly

Question 26

A total of ________ dots on the receptor is the proper number during a spinning top test of a singlephase, fully rectified generator at 0.10 seconds.

Answer 26

12: the single phase, fully rectified generator has 120 pulses per second, so with one dot per pulse, at 0.10 seconds there should be 12 dots

Question 27

One of the greatest concerns for an elderly patient is fear of ___ (this is most often the greatest fear)

Answer 27

falling

Question 28

Give the formula for the magnification factor in a fluoroscopic unit (multifield image intensifier)

Answer 28

full-size input diameter DIVIDED BY the selected input diameter

Question 29

What 3 pieces of information are necessary to use a tube rating chart to determine the maximum safe kilovoltage?

Answer 29

mA, exposure time and focal spot size

Question 30

The image intensifier may be coupled to the TV camera or CCD via 1 of what 2 devices? Name the advantage(s) of each

Answer 30

1. Fiber-optic bundle. Less fragile, more compact and easier to maneuver. 2. Lens coupling device (objective lens): can use with the (now infrequently used) auxiliary devices, like a cine camera or spot-film camera.

Question 31

What is the best way to control voluntary motion? Involuntary motion?

Answer 31

Voluntary: careful explanation of procedure Involuntary: use shortest possible exposure time (only way)

Question 32

The crista galli is part of the ___ bone and projects superiorly from the ...

Answer 32

Ethmoid; cribriform plate

Question 33

DR collection elements may be a TFT, CMOS or CCD. which is/are used in indirect and direct capture systems?

Answer 33

Indirect may use CMOS, CCD, TFT direct uses TFT

Question 34

Formula for pixel size

Answer 34

FOV / Matrix size (,1 dimension of matrix size) Ex: a 20 cm FOV and 512 x 512 matrix, do 20/512

Question 35

Where in the circuit is the MA meter found?

Answer 35

In the secondary circuit, midpoint of the secondary coil of the step up transformer

Question 36

In what portion of the xray circuit is the timer found?

Answer 36

Primary circuit

Question 37

What part of primary circuit adjusts for any fluctuations in incoming voltage supply?

Answer 37

Line voltage compensator

Question 38

kV selector: kV major refers to... kV minor ...

Answer 38

kV major, increments of 10 Minor, increments of 2

Question 39

Circuit breaker switches must be ____ to allow equipment to be energized

Answer 39

Closed

Question 40

Xray tubes with a ___ target angle and ___ actual focal spot have the greatest heat loading capacity

Answer 40

Small target angle Large actual focal spot

Question 41

What part pf the tube significantly reduces off focus radiation

Answer 41

Fixed diaphragm located just outside the port window (considered part of the collimator assembly)

Question 42

Xray tubes are rated according to allowable kilowatts; how do you calculate this?

Answer 42

kW=100 kV x (maximum mA at 100 ms, or 0.1 s)

Question 43

Xray tube focal spot and collimator light bulb must be ____ for light field and xray field to correspond accurately.

Answer 43

Equidistant from the center of the collimator mirror.

Question 44

Most xray tube cooling results from...

Answer 44

Heat diffusion to the oil surrounding the tube.

Question 45

CPR sternal compressions are made with heels of hands _____ superior to xiphoid tip

Answer 45

1.5 inches

Question 46

What bone has a trochlear sulcus?

Answer 46

Humerus

Question 47

The radiocarpal joint has what movement type?

Answer 47

Condyloid

Question 48

What projection would provide a PA of the gastroduodenal surface of a barium filled high and transverse stomach

Answer 48

Angle the CR 35 to 45 degrees cephalad

Question 49

Each time thr beam scatters its intensity is reduced by a factor of...

Answer 49

1,000 (or to about 0.1 % of original intensity)

Question 50

How would introduction of a 6 inch oid affect contrast?

Answer 50

Increase contrast due to air gap effect

Question 51

Vasomotor vs vasovagal response to contrast: Which includes nausea, emesis, flushing and heat? Which is bradycardia/hypotension

Answer 51

Vasomotor is nause, emesis, heat Vasovagal includes bradycardia and hypotension

Question 52

What projection of foot best shows interspaces between 1st and 2nd cuneiforms

Answer 52

Lateral oblique

Question 53

Assisting injured pt with dressing or undress, u should...

Answer 53

Place clothing on injured side 1st Remove clothing from uninjured side 1st

Question 54

Avg adult respiratory rate

Answer 54

10 to 20 breaths/min

Question 55

Amount of time xrays are being produced and directed toward a particular wall

Answer 55

Use factor

Question 56

When making a significant increase in collimation, what specifically should u do to technique?

Answer 56

Increase mAs

Question 57

___ involves averaging a set of images to reduce image noise

Answer 57

Temporal averaging

Question 58

During IVU, the upright post void image is generally used to demonstrate...

Answer 58

Filling of ureters

Question 59

Perforated small bowel is best diagnosed with what position?

Answer 59

Left lateral decubitus

Question 60

Soaking objects in germicidal solution causes

Answer 60

Chemical sterilization

Question 61

A grids contrast improvement factor is greatest with a ___ ratio grid with ___ lines per inch

Answer 61

High ratio Fewer lines bc if u increase the lines/inch, lead straps become thinner, allowing more scatter to pass through)

Question 62

What is the 1st arterial branch of the aorta?

Answer 62

Coronary arteries

Question 63

What is the main purpose of a falling load generator?

Answer 63

Minimize exposure time

Question 64

Scoliosis patients must have what included on a radiograph? (C ... L ... AND)

Answer 64

C7, L5 and iliac crests

Question 65

Dose limits for osl, tld and film badge dosimeter are valid for what radiation types?

Answer 65

Beta, x and gamma

Question 66

Frequency in Hz of AC generated in America

Answer 66

60 Hz (60 cps)

Question 67

Amplitude (max height of waveform) represents what component of Ohm's law?

Answer 67

V, voltage

Question 68

Define helix and solenoid

Answer 68

Helix: coil of conductive wire Solenoid: helix supplied with an electric current

Question 69

Anode target material is tungsten; what usually comprises the disk?

Answer 69

Molybdenum, graphite or both

Question 70

A type of variable resistor (besides a rheostat) that operates on self induction and may be used to regulate filament current

Answer 70

Choke coil

Question 71

Star (wye) and delta configurations are related to

Answer 71

Transformers

Question 72

If a 1 phase generator requires 100 mAs, what is required by a 3 phase 6 pulse and a 3 phase 12 pulse?

Answer 72

3 phase 6 pulse, 66 (2/3) 3 phase 12 pulse, 50 (1/2)

Question 73

Power loss formula

Answer 73

P=I^2(R)

Question 74

Only interaction between xrays and matter where no ionization occurs

Answer 74

Coherent scatter (classical, unmodified, Rayleigh)

Question 75

3 phase rectification requires ___ autotransformers and 1 high voltage transformer having ___ windings arranged in ___ or ___ configurations

Answer 75

3 (1 per current) 3 Star (wye) or delta

Question 76

Nyquist theorem: sampling frequency must be .... in order to duplicate the original signal w/o compromising resolution

Answer 76

More than twice the frequency of the input signal

Question 77

In indirect capture systems, a ____ (cesium iodide or gadolinium oxysulfide) captures xray photons and emits light, which is recorded via a ___ or ____.

Answer 77

Scintillator TFT or CCD

Question 78

Semiconductor used in direct capture systems

Answer 78

Amorphous selenium

Question 79

The heat loss formula implies that it is more efficient to carry electricity over long distances if current is (low or high)?

Answer 79

Low current (high voltage)

Question 80

When the trapped electrons in the PSP's halogen ions ate exposed to a monochromatic light source they emit polychromatic light, a process known as ___ or _____

Answer 80

Secondary excitation or photostimulated luminescence (PSL)

Question 81

To improve SNR, what must be true of the PSP's emitted light during PSL and the laser light used to activate them?

Answer 81

Must be of different wavelength/color and be physically separate Laser light is red (430 to 550 nm) PSL is bluish purple or blue green

Question 82

Process that automatically adjusts brightness and contrast to meet diagnostic requirements

Answer 82

EDR (exposure data recognition)

Question 83

In CR, there is a ____ relationship between exposure and its resulting luminescence

Answer 83

Linear

Question 84

How are CR techniques compared to analog and to DR?

Answer 84

CR is equal to or greater than analog DR can be lower than analog