Chapter 1 and 2 Image Analysis

1. The patient demographic requirements for radiographic images include all of the following except

a. patient and facility identification.

b. time and date.

c. birth date.

d. technologist's identification.

D

The correct patient’s name and age or birth date, patient identification number, facility name, and examination time and date should be displayed on projections.

P. 8

2. Which of the following is true about image markers?

1. They are radiopaque.

2. They should be reversed before being placed on the IR.

3. They should be positioned as close to the median plane as possible.

4. They will be magnified if positioned on the imaging table or patient.

a. 1 only

b. 1 and 4 only

c. 2 and 3 only

d. 4 only

B.

• 1. They are radiopaque

• 4. They will be magnified if positioned on the imaging table or patient

P. 10

3. What is the marker placement for the projection of lateral vertebrae?

a. Laterally on the side being identified

b. Anteriorly, identifying the side positioned closer to the IR

c. Anywhere within exposure field

d. Laterally, identifying the side situated closer to the IR

B

Pg. 10: Table 1.3

Lateral Projections of torso, vertebrae, and cranium

-Whether the marker is placed anteriorly to the torso or vertebrae does not affect the accuracy of the marking, although projections of markers placed posteriorly are often obscured by scatter.

P. 10 | Box 1-3

4. What is the marker placement for the projection of PA cranium?

a. Laterally on the side being identified

b. Anteriorly, identifying the side positioned closer to the IR

c. Anywhere within the exposure field

d. Laterally, identifying the side situated closer to the IR

A

Pg. 10 Table 1.3

Place the R or L marker laterally on the side being marked

P. 10 | Box 1-3

5. What is the marker placement for the projection of PA oblique vertebrae?

a. Laterally on the side being identified

b. Anteriorly, identifying the side positioned closer to the IR

c. Anywhere within the exposure field

d. Laterally, identifying the side situated closer to the IR

D

pg. 10 Table 1.3

Marker identifies the side of the patient positioned closer to the IR and is placed on the correct side of the patient

P. 10 | Box 1-3

6. What is the marker placement of the projection of lateral hand.

a. Laterally on the side being identified

b. Anteriorly, identifying the side positioned closer to the IR

c. Anywhere within the exposure field

d. Laterally, identifying the side situated closer to the IR

C

P. 10 | Box 1-3

7. Which guideline should be used to position the identification (ID) plate?

a. Place the ID plate within the collimated field whenever possible.

b. Position the ID plate toward the direction in which the central ray was angled.

c. Position the ID plate next to the narrowest anatomic structure.

C.

P. 12

8. Good collimation practices will do all of the following except

a. decrease the radiation dosage.

b. affect the amount of scatter radiation that reaches the IR.

c. reduce the visibility of recorded details.

d. reduce digital radiography histogram analysis errors.

C

Pg.12

Good collimation practices

• clearly delineate the values of VOI

• Decrease radiation dosage by limiting the amount of patient tissue exposed

• Improve the visibility of recorded details by reducing the amount of scatter radiation that is produced

• Reduce histogram analysis

• Histogram analysis- The process the computer uses to identify the useful exposure values in the image receptor—> Values of interests (VOI)

P. 14

9. Elongation occurs in all of the following situations except when the

a. part is off center.

b. central ray is angled with the part.

c. central ray and part are perpendicular but the IR is angled.

d. central ray and IR are perpendicular and the part is angled.

D

Pg.22

Elongation has occurred when one of the structure’s axes appears disproportionally longer on the projection than the opposite axis

The least amount of elongation occurs when the CR is aligned perpendicular to the part and IR

Pg. 25

Causes of anatomic distortion

1. CR is perpendicular to the part, and the IR is parallel with the part (B), but the part is not centered to the CR (off centered). The greater off centering, the greater the elongation

2. The CR is angled is not aligned perpendicular to the part, nut the IR and the part is parallel with each other (C). The greater the angulation, the greater the elongation

3. The CR and part are aligned perpendicular to each other, but IR is not aligned parallel with the part (D)

4. Foreshortening occurs when the CR and IR are perpendicular to each other, but the part is inclined (E)

PP. 22-23

10. For an open joint space to be obtained, the central ray must be aligned _____ to the joint.

a. perpendicular

b. parallel

c. 5 degrees cephalic for each 4 inches of tissue thickness

d. 5 degrees caudal for each 4 inches of tissue thickness

B

Pg. 23 Table 1.5

For an open joint space or fracture to be demonstrated, the CR or diverged rays regarding the joint or fracture line must be aligned parallel with it.

Failure to accomplish alignment will result in closed joint .

P. 25

11. When the central ray is angled, the structure situated _____ is projected the most.

a. farther away from the IR

b. closer to the IR

c. proximal to the tube

d. distal to the tube

A

Pg. 22 Table 1.5

When an angled CR or diverged x-rays are used the anatomy will move in the direction that the x-ray beams travel. Anatomy positioned farthest from the IR will move at greater distances than those positioned closer to the IR.

AS CR angulation increases, the degree of anatomy movement also increases

PG 24. Fig 1.45 demonstrates

PP. 22-23

14. A small focal spot should be used for each of the following situations except when

a. fine detail demonstration is important.

b. extremities are imaged.

c. the milliamperage setting is above 300.

d. the patient can control motion.

C

Pg. 31 Table 1.8

• Smaller focal spot produces better spatial resolution

• Use the small focal spot for extremity projections

• A detail that is smaller than the focal spot size used to produce the projection will be entirely blurred and blend with the surrounding details

• Using a small focal spot is only feasible when imaging structures that can be obtained using a milliamperage (mA) setting of 300 mA or less

• If the thickness measurement is larger or of the patient’s ability to hold still is not reliable, a large focal spot is recommended. These two factors will require a linger exposure time to obtain the needed IR exposure, and if a small focal spot is used, patient motion may result.

PP. 30-31

16. Anatomical relationships are affected by

1. varying degrees of patient obliquity and flexion.

2. off centering.

3. geometrical factors of magnification, elongation, and foreshortening.

4. similar structures of shape and size.

a. 1 and 4 only

b. 1, 2, and 4 only

c. 1, 3, and 4 only

d. None of the above

D

Pg. 22 Table 1.5

PP. 18-19

17. Good collimation practices result in which of the following?

1. Reduces histogram analysis errors

2. Clearly delineates the VOI

3. Improves the visibility of recorded details by reducing the amount of scatter radiation that reaches the IR

4. Decreases the radiation dosage by limiting the amount of scatter from the patient

a. 2 and 3 only

b. 1, 2, and 3 only

c. 1, 2, and 4 only

d. 1, 2, 3, and 4

B

Good collimation practices

• clearly delineate the values of VOI

• Decrease radiation dosage by limiting the amount of patient tissue exposed

• Improve the visibility of recorded details by reducing the amount of scatter radiation that is produced

• Reduce histogram analysis

PP. 14-15

18. Minimizing size distortion is accomplished by which of the following?

1. Using the longest feasible SID

2. Using the shortest possible OID

3. Decreasing the angle of the CR

4. Placing the part as close to the IR as possible

a. 2 and 3 only

b. 1, 2, and 3 only

c. 1, 2, and 4 only

d. 1, 2, 3, and 4

C

Pg.31 Table 1.8

-Longer SID produces better spatial resolution

-Shorter OID produces better spatial resolution

PP. 22-23

19. Collimation guidelines include all of the following except for

1. chest and abdomen projections, collimate to within 1 inch (2.5 cm) of the patient's skin line.

2. extremity projections, collimate to within 0.5 inch (1.25 cm) of the skin line of the thickest VOI.

3. chest and abdomen projections, collimate to within 0.50 inch (1.25 cm) of the IR edge.

4. collimating structures within the torso, bring the collimated borders to within 1 inch (2.5 cm) of the VOI.

a. 1 and 3

b. 2 and 4

c. 3 only

d. 4 only

A

Pg. 14 Table 1.4

• To allow for even collimation on all sides, obtain the tightest collimation and provide the best positioning for good exposure field recognition, align the long axis of the part to the long axis of the IR, center the CR to the center of VOI, and narrow the radiation beam on all sides to include only the required VOI amd 0.5-1 inch (1.25 cm - 2.25 cm) pf the surrounding anatomies

• When the structure being image is smaller than the IR, collimation is brought to within 0.5 - 1 inch of the closest skin line

• VOI fills the display screen demonstrating tight collimation

• Each projection should demonstrate a small, collimated border around the entire VOI unless the entire IR is covered

P. 16 | Box 1-4

20. The medial and lateral femoral condyles are not superimposed on a lateral knee projection. The larger, lateral condyle is 1 inch (2.5 cm) anterior to the medial condyle. The best way to correct this error is to

a. rotate the medial condyle 1 inch (2.5 cm) anteriorly.

b. rotate the medial condyle 0.5 inch (1.25 cm) anteriorly.

c. increase the CR angle to accommodate for the larger condyle. (WRONG)

d. increase the CR angle to magnify the smaller condyle.

b. rotate the medial condyle 0.5 inch (1.25 cm) anteriorly.

Pg. 28 Figure 1.59

P. 25

21. When imaging long bones, which of the following is (are) correct statements?

1. Choose a large enough IR so that one or both joints are included on the projection.

2. Extend the collimation field so it extends 1 to 2 inches (2.5 cm to 5 cm) beyond the joints spaces as required.

3. Histogram errors may occur if the system algorithm does not recognize a diagonal exposure field.

4. Align the long bone parallel to the IR to prevent a histogram analysis error.

a. 1 only

b. 4 only

c. 1, 2, and 4 only

d. 1, 2, 3, and 4

D

Pg. 14 Table 1.4

• When imaging long bones that require both joints to be included on the projection choose a large enough IR and open the collimation field, so it extends 1-2 inches (2.5 cm - 5 cm) beyond each joint space. This prevents the off centered joints from being projected off the IR when they are projected in the direction of the x-ray diverged beams that are used to record them

P. 14

22. The greatest detail sharpness is obtained by using

1. a small focal spot.

2. the longest SID.

3. the smallest OID.

4. longer exposure times.

a. 1 only

b. 4 only

c. 1, 2, and 3 only

d. 1, 2, 3, and 4

C

Pg. 27 The greatest edge sharpness is obtained by using a small focal spot, the longest possible source-image receptor distance (SID), shortest OID, and controlling motion.l;wqs

P. 29

23. To correctly mark a cross-table lateral hip projection,

1. place the marker anteriorly to prevent it from obscuring posterior structures.

2. place the marker to indicate the side closest to the IR.

3. place the marker toward the edge of the IR outside the exposure field.

4. include an arrow to indicate the side positioned away from the table or cart.

a. 1 and 2 only

b. 1, 2, and 3 only

c. 1, 2, and 4 only

d. 1, 2, 3, and 4

A

Pg. 11 Table 1.3

Marker used indicate the R/L side of the patient when the hip, extremities is imaged and the side of the pt positioned closer to the IR

-Placed marker anteriorly to prevent superimposition of structures that are at the posterior edge of the IR

P. 14

24. The off-centered diverged beams of a perpendicular CR will affect structures in the same manner as an angled CR. Which of the following statements best describes this relationship?

1. At a 40-inch SID, the divergence of x-rays is 1 degree for every inch off-centered in any direction from the CR.

2. At a 48-inch SID, beam divergence is off-centered about 2 degrees for every inch in any direction from the CR.

3. At a 40-inch SID, the divergence of x-rays is 2 degrees for every inch off-centered in any direction from the CR.

4. At a 72-inch SID, beam divergence is off-centered about 1 degree for every inch.

a. 1 and 2 only

b. 3 and 4 only

c. 1 and 4 only

d. 2 and 4 only

B

Pg. 22: table 1.5

At 40” SID, the divergence x-ray is 2 degrees per inch the anatomy off centered in any direction of CR; at 72” SID, it one degree per inch

PP. 20-21

25. An image analysis form

1. provides a systematic approach to evaluate a projection for positioning and technical accuracy.

2. is a structured pattern for use in a stressful situation.

3. will determine whether the projection is optimal, acceptable, or needs repeating.

4. is used to verify validity of the order and indication.

a. 1 and 3 only

b. 2 and 4 only

c. 1, 2, and 3 only

d. 1, 2, 3, and 4

C

PP. 7-8

26. When displaying images acquired on a direct-indirect capture digital radiography system (DR), which of the following statements are true?

1. Patient orientation must be considered.

2. Diagonally obtained projections will be displayed vertically.

3. IR orientation must be considered.

4. The correct examination must be selected before exposing the IR.

a. 1 and 2 only

b. 2 and 4 only

c. 1, 2, and 4 only

d. 1, 3, and 4 only

D Pg. 6- 2. Projection us accurately displayed on the workstation screen

P. 6

27. All of the following statements about display stations are true except

1. if the digital system matrix size is smaller than the display station's matrix size, the values of surrounding pixels will be averaged to display the whole image.

2. to display images at full resolution, the display monitor must be able to display the same number of pixels as those at which the digital system acquired the image.

3. display station resolution refers to the maximum number of pixels that the screen can demonstrate.

4. the technologist's workstation display monitors typically demonstrate resolution as high as that of the radiologist's display monitor.

a. 1 and 2 only

b. 2 and 4 only

c. 1, 2, and 3 only

d. None of the above

C

PP. 7-8

28. To properly display extremity projections, display

1. finger, wrist, and forearm projections as if the patient were hanging from the fingertips.

2. elbow and humeral projections as if they were hanging from the patient's shoulder.

3. toe and AP and PA oblique foot projections as if the patient were hanging from the toes.

4. lateral foot, ankle, lower leg, knee, and femur projections as if they were hanging from the patient's hip.

a. 1 and 2 only

b. 2 and 4 only

c. 1, 2, and 3 only

d. 1, 2, 3, and 4

D

Pg. 7

Table 1.2

P. 4 | Box 1-1

29. Placing a marker directly on the tabletop

1. avoids marker distortion and magnification.

2. prevents scatter radiation from undercutting the marker.

3. ensures the marker will not be projected off the IR.

4. attenuates most but not all of the incident x-rays.

a. 1 and 2 only

b. 2 and 4 only

c. 1, 2, and 3 only

d. 1, 2, 3, and 4

C

Pg. 10 Table 1.3 Guidelines

P. 10 | Box 1-3

30. A postprocessing manipulation that can be added to digital projections as a means of helping the viewer to better evaluate contrast resolution in the selected area is a

a. collimation.

b. contrast mask.

c. dimensional annotation.

d. projection mask.

B

Pg. 15 Table 1.4

PP. 20-21

32. The most common shape distortion is

a. shape/size distortion.

b. magnification.

c. foreshortening.

d. elongation.

D

PP. 22-23

33. The quality of spatial resolution of a digital imaging system is mainly defined by

1. the size of the matrix.

2. the size of the pixel within the matrix.

3. the spatial frequency.

4. line pairs per millimeter (lp/mm).

a. 1 and 2 only

b. 2 only

c. 3 only

d. 4 only

A

PP. 30-31

35. To shield the female gonads properly,

1. use a flat contact shield made from at least 0.5 mm of lead.

2. use a flat contact shield cut to the shape of the inlet pelvis.

3. the dimensions of the shield used are determined by the OID and SID and by the size of the patient's pelvis.

4. the entire inlet pelvis should be shielded.

a. 1 only

b. 1 and 2 only

c. 2, 3, and 4 only

d. 1, 2, 3, and 4

C

P. 33

36. Gonadal shielding is recommended in which of the following situations?

1. When the gonads are within 2 inches (5 cm) of the primary x-ray beam

2. If the patient is of reproductive age

3. When the gonadal shield does not cover the VOI

4. When any radiosensitive cells are in the primary beam

a. 1 only

b. 1 and 2 only

c. 1, 2, and 3 only

d. 1, 2, and 4 only

C. 1,2, 3

P. 34

37. Effective radiation protection practices include all of the following except

1. effective communication and immobilization devices.

2. maintaining minimum source to skin distances (SSD).

3. oscillating grids and contact shields.

4. collimation and minimizing technical factors.

a. 1 only

b. 1 and 2 only

c. 1, 2, and 3 only

d. 1, 2, and 4 only

D

38. The following statements with regard to the spatial resolution in a DR system are true except

1. DR systems have spatial resolution capabilities of approximately 3.7 lp/mm.

2. spatial resolution is affected by the size of the DELs and the spacing between them.

3. changing the size of the exposure field (collimation) does not affect spatial resolution.

4. as the DELs become larger, the spatial resolution capability increases.

a. 1 only

b. 1 and 2 only

c. 3 and 4 only

d. 1, 2, and 4 only

C. 3 and 4

Pg. 31

Table 1.8 Spatial resolution

• TRUE — DR systems have spatial resolution capabilities around 3.7 lp/mm.

• TRUE — Spatial resolution is affected by the size of the DELs (detector elements) and the spacing between them.

• FALSE — Changing the exposure field/collimation can affect spatial resolution because of changes in the area of the detector being used and processing considerations.

• FALSE — As DELs become larger, spatial resolution decreases, not increases. Smaller DELs = better spatial resolution.

The more DELs in a matrix= higher resolution

Smaller DELS = more spatial resolution

P. 31

39. Diagnostic imaging professionals have a responsibility to adhere to effective radiation protection practices for which of the following reasons?

1. The risk of cancer from radiologic examinations accumulates over a lifetime.

2. To limit the risk of nonstochastic effects to a reasonable level compared with nonradiation risks and in relation to society's needs, benefits gained, and economic factors.

3. Good patient care standards dictate the use of effective radiation protection practices.

4. Continually evaluating one's radiation protection practices is necessary because radiation protection guidelines for diagnostic radiology assume a linear, nonthreshold, dose-risk relationship.

a. 1 and 2 only

b. 1, 2, and 3 only

c. 1, 2, and 4 only

d. 1, 2, 3, and 4

C. 1,2,4

pg. 29-34

A rotating collimator head
1. can be rotated without rotating the entire tube column on DR systems.
2. does not affect the alignment of the beam with the grid.
3. allows the technologist to increase collimation on projections when the longitudinal axis of the anatomical structure is not aligned with the longitudinal or transverse axis of the IR.
4. should be avoided when using computed radiography because it may affect the exposure field recognition process.
a. 1 and 2 only
b. 1, 2, and 3 only
c. 1, 2, and 4 only
d. 1, 2, 3, and 4

1. can be rotated without rotating the entire tube column on DR systems.

2. does not affect the alignment of the beam with the grid.

3. allows the technologist to increase collimation on projections when the longitudinal axis of the anatomical structure is not aligned with the longitudinal or transverse axis of the IR.

4. should be avoided when using computed radiography because it may affect the exposure field recognition process.

a. 1 and 2 only

b. 1, 2, and 3 only

c. 1, 2, and 4 only

d. 1, 2, 3, and 4

D. All of the above

Pg. 14 Table 1.4

acronym for keeping radiation exposure; as low as reasonably achievable

ALARA

Maximum time that the xray AEC will be allowed to continue before shutting off automatically

backup timer

a post processing manipulation that adds a black background over the areas outside the VOI to eliminate them and provide a perceived enhancement of image contrast

contrast mask.

element in the DR image receptor containing the electronic components that store the detected energy

Detector element (DEL).

misrepresentation of the size or shape of the stricture being examined

Distortion

when techniques values (mAs, kV) are elevated more than necessary owing to fear of producing images with quantum noise

Dose creep

maximum permissible radiation does limits; used for radiation protections purposes

Dose equivalent limit

to make one axis of an anatomic structure appear longer on the image that the opposite axis

Elongation

formula used to adjust the mAs the needed amount to maintain the rerquired IR exposure and prevent quantum noise; (new mAs)/(old mAs) = (new distance squared)/(old distances squared)

exposure maintenance formula

area of the image receptor from which the image data are collected; For computed radiography, the area is the entire imaging plate; for direct or indirect capture radiography, it is the detectors that are included in the exposure field as determined by collimation

Field of view (FOV)

small area on the x-ray tube's anode target where the electrons hit and x-rays are produced.

Focal spot

to make one axis of an anatomic structure appear shorter on the image than opposite axis

Foreshortening

things related to the position and distance of the x-ray tube, patient, and image receptor (IR) that affect how sharp, magnified, or distorted the image looks

Geometric factors.

device consisting of lead strips between the patient and IR to reduce the amount of scatter radiation reaching the receptor

Grid

reduction in the amount of primary radiation reaching the IR because of grid misalignment

Grid cutoff

Graph generated from the raw data that has the pixel brightness value on the x-axis and the number of pixels with that brightness value on the y-axis

Histogram

device that receives the radiation leaving the patient. Computed radiography uses an imaging plate and DR system uses detector elements

Image receptor (IR)

law that states that radiation intensity is inversely proportional to the square of its distance from the xray source

Inverse square law.

increasing or enlarging both axes of a structure

Magnification.

columns and rows of pixels that divide a digital pixel

Matrix.

the lack of detail and sharpness on a projection caused by the patients movement during the exposure

Motion unsharpness

biologic response of radiation exposure that can be directly related to the dose received

Nonstochastic effects.

🎲 Stochastic = "Could it happen?"

Radiation increases the chance of cancer.

More radiation → more chance

💥 Nonstochastic = "Did it cause damage?"

Radiation reaches a certain level → tissue damage happens.

distance from the object being imaged to the IR

Object-image receptor distance (OID)

system whereby the digitized images from all the different modalities in a facility (RT, CT, MRI) are stored and can be retrieved, displayed, and transmitted to computers on local area network

Picture archival and communication system (PACS).

single cell within a matrix

Pixel.

outline of an anatomic structure

Profile

act of throwing the image of an anatomic structure forward

Project

allowing the passage of x - radiation; appear dark in images

Radiolucent

preventing the passage of x - radiation; appear white in images

Radiopaque

sharpness of structures that have been included on the image

Recorded detail.

radiation that has changed in direction from the primary beam because of an interaction with the patient or another structure

Scatter radiation

distance from the anodes focal spot to the IR

Source-image receptor distance (SID)

distance from the sources radiation to the patients skin: good radiation practice says stay 12 inches away to prevent unacceptable entrance skin exposure

Source-skin distance (SSD).

Used to define spatial resolution; refers to how often the number of details change in a set amount of space. It is expressed as line pairs per millimeter (lp/mm).

Spatial frequency.

Ability of an imaging system to distinguish small adjacent details from each other in the image

Spatial resolution.

Biologic response to radiation in which the chance of occurrence of the effect, rather than the severity of the effect, is proportional to the dose of radiation received.

Stochastic effects

🎲 Stochastic = "Could it happen?"

Radiation increases the chance of cancer.

More radiation → more chance

💥 Nonstochastic = "Did it cause damage?"

Radiation reaches a certain level → tissue damage happens.

• Nonstochastic = damage now/after a certain dose 💥 → HAS a threshold

  • Example: skin burns, cataracts, hair loss

  • Below the threshold → generally no effect

  • Above the threshold → damage can occur

• Stochastic = risk later 🎲 → NO threshold

  • Example: cancer

  • More radiation → greater chance of it happening later

Brightness values (raw data) that represent only the anatomic structures of interest in digital radiography

values of interest (VOI).

P. 38

2. What is the location on a histogram graph of air/gas?

a. Center

b. Far right

c. Left

d. Right

D. Right

P. 39 | Figure 2-1

3. What is the location on a histogram graph of background brightness?

a. Center

b. Far right

c. Left

d. Right

B. Far right

PP. 38-39

4. What is the location on a histogram graph of bone?

a. Center

b. Far right

c. Left

d. Right

C. left

PP. 38-39

5. What is the location on a histogram graph of contrast/metal?

a. Center

b. Far right

c. Left

d. Right

C. Left

PP. 38-39

6. What is the location on a histogram graph of fat?

a. Center

b. Far right

c. Left

d. Right

D. right

PP. 38-39

7. What is the location on a histogram graph of soft tissue?

a. Center

b. Far right

c. Left

d. Right

A. center

PP. 38-39

8. All of the following may result in histogram analysis errors except

a. unusual pathologic conditions.

b. poor positioning.

c. motion.

d. alignment of the anatomic part with the IR.

C. motion

P. 42

9. All of the following are guidelines for producing optimal image histograms except

a. choose the correct body part and projection from the workstation menu.

b. leave minimal background in the exposure field through tight collimation.

c. use the smallest possible IR and cover at least 50% of it.

d. erase the imaging plate if the IR has not been used for a few days.

C. use the smallest possible IR and cover at least 50% of it.

P. 39 | Box 2-1

10. The exposure indicator number represents all of the following except the

a. amount of light given off by the imaging plate.

b. amount of exposure to the patient.

c. amount of exposure to the imaging plate.

d. measure of dose to the patient.

D. measure of dose to patient

PP. 39-40

11. At what level is the exposure indicator reading taken on the VOI?

a. At S1

b. At S2

c. One fourth of the distance between S1 and S2

d. Halfway between S1 and S2

D. Halfway between S1 and S2

PP. 39-40

12. When is the examination or body part selected when using the DR system?

a. After the radiation exposure

b. Before the radiation exposure

c. At any time during the radiation exposure

d. This is not a required procedure.

B. Before the radiation exposure

P. 38

13. All of the following are true about display station resolution, except that

a. it refers to the maximum number of pixels that the screen can demonstrate.

b. full display resolution is only possible if the digital and display systems have equal pixel capability.

c. the technologist's display monitor has superior resolution compared with that used by the radiologist's.

d. large matrix sizes produce better resolution than small matrix sizes.

C. the technologist's display monitor has superior resolution compared with that used by the radiologist's.

P. 62

15. How many shades of gray can each pixel in a digital matrix display?

a. One

b. Two

c. Five

d. Ten

A. one

P. 38

16. Which of the following is not part of the electronic components located in the DEL?

a. Capacitor

b. Conductor

c. Matrix

d. TFT

C

DELs are made up of a capture area, a storage capacitor, and TFT gate

The capture area has three layers

-Top electrode

-Sensitive detection layer composed of either Amorphous selenium or amorphous silicon

-Bottom electrode

P. 38

17. All of the following are true about quantum noise except

a. quantum noise results in excessive patient dose when present on the image.

b. quantum noise is demonstrated as a blotchy appearance on the image.

c. when present, quantum noise requires an increase in exposure factors to reduce its visualization on the image.

d. quantum noise is visualized when the exposure indicator number is higher than the ideal exposure values.

D. quantum noise is visualized when the exposure indicator number is higher than the ideal exposure values.

PP. 48-49

18. All of the following are true about histogram analysis errors except

a. histogram analysis errors result in erroneous exposure indicator numbers.

b. histogram analysis errors may occur as a result of poor central ray centering.

c. fog values outside the exposure field, but included in the VOI, do not cause widening of the histogram.

d. selecting the wrong body part or projection in the workstation menu will cause a histogram analysis error.

C

P. 42

19. All of the following are true about windowing except

a. windowing occurs after the image is displayed on the monitor.

b. window level adjustments change the contrast of the image.

c. saving adjusted windowing settings to the PACS system narrows the dynamic range for future viewers.

d. windowing is referred to as a postprocessing manipulation procedure.

B

B/c window level changes brightness

PP. 45-47

20. An exposure recognition field algorithm is applied to the image data to

1. distinguish the gray shade values inside the exposure field from those on the outside.

2. ensure the histogram has the correct shape.

3. identify the volume of interest before rescaling.

4. identify the volume of interest after rescaling.

5. reshape the histogram.

a. 1, 2, and 4 only

b. 2 and 3 only

c. 1, 2, and 3 only

d. 1, 3, and 5 only

C

1. Distinguish gray values inside vs. outside the exposure field

✅ TRUE
It separates the actual exposed area from areas outside the exposure field.

2. Ensure the histogram has the correct shape

✅ TRUE
It helps the computer create the proper histogram for processing.

3. Identify the VOI before rescaling

✅ TRUE
The computer needs to find the VOI (Value of Interest) before it rescales/processes the image.

4. Identify the VOI after rescaling

❌ FALSE
The VOI is identified before rescaling.

5. Reshape the histogram

❌ FALSE
The algorithm analyzes/identifies the histogram; it doesn't simply "reshape" it.

P. 38

21. Saturation indicates

a. underexposure of the IR.

b. overexposure of the IR.

c. quantum mottle.

d. histogram analysis error.

B.

Saturation is demonstrated on a projection as a loss of contrast resolution where some or all structures in the VOI demonstrate pitch black shade. It is caused by overwhelming the digital system with electronic signals due to extreme exposure.

PP. 49-50

22. If the image histogram is wider than the LUT's histogram, all of the following are true except the algorithm would

a. narrow the histogram.

b. increase the degree of difference between the gray shades.

c. increase contrast.

d. widen the histogram.

A

IN the book it said to narrow it if the histogram is wider than LUT

P. 39

23. Examples of artifacts that must be accepted include all of the following except

1. pacemakers.

2. dental bridges.

3. pleural drainage tubes secured with safety pins.

4. endotracheal tubes.

5. heart monitoring lines.

a. 1, 2, and 4 only

b. 1 and 5 only

c. 1 and 4 only

d. 2 and 3 only

C

PP. 59-60

24. Appropriate scatter radiation control methods include which of the following?

1. Tight collimation

2. Lead masking at the edge of the exposure field

3. Appropriate use of a grid

4. Lower kV settings

5. Using an air gap method

a. 1, 2, and 4 only

b. 2, 3, and 5 only

c. 1, 2, 3, and 4 only

d. 1, 2, 3, 4, and 5

C

P. 43 | P. 73

25. Histogram analysis errors for digital systems include all of the following except

a. off-centered CR.

b. wrong part selection from the workstation menu.

c. collimation within 0.5 inch (2.5 cm) of the skin line.

d. exposure of less than 30% of the IR.

D

PP. 42-43

26. To demonstrate long bones with the least amount of distortion and obtain optimal anatomical alignment,

1. align the CR perpendicular to the IR and the long axis of the bone.

2. align the IR parallel to long axis of the bone.

3. use the law of isometry when the long bone is parallel to the IR.

4. use the law of isometry to minimize foreshortening.

a. 1 and 2 only

b. 2 only

c. 1, 2, and 4 only

d. 2 and 4 only

C

PP. 70-72

27. When an image resembles a double exposure, the type of artifact demonstrated is a(n) _____ artifact.

a. aliasing

b. grid cutoff

c. phantom image

d. background fog

C

P. 62

28. All of the following statements are true except

1. the movement of an image histogram, left to right, will adjust image brightness.

2. the movement of an image histogram, left to right, will adjust the gray scale.

3. changing the shape of the histogram will affect image contrast.

4. changing the shape of the histogram will change the subject contrast.

a. 2 only

b. 1 and 3 only

c. 3 only

d. 2 and 4 only

B

P. 39

29. In a cassette-less imaging system,

1. the correct examination is chosen before the exposure.

2. thin film transistors collect the electrical charge created in the LUT.

3. thin film transistors contain detector elements.

a. 1 only

b. 2 and 3 only

c. 1 and 2 only

d. 1, 2, and 3

A

P. 38

30. If a projection does not differentiate the densest and thickest structures in the VOI, adjusting the _____ is necessitated.

a. kVp

b. kVp and mAs

c. histogram

d. mAs and collimation

A