homework review 2

Question 1

According to ACR Mammography Accreditation standards, what is the minimum frequency for evaluating the compression thickness indicator by the technologist?

Answer 1

monthly

Question 2

During ACR phantom scoring, what will result in a full point being awarded when viewing the fibers?

Answer 2

> = 8 mm long

Question 3

During ACR phantom scoring, what will result in a full point being awarded when viewing the specks?

Answer 3

4-6 specks

Question 4

During ACR phantom scoring, what will result in a full point being awarded when viewing the masses?

Answer 4

≤½ & >¾ border

Question 5

Mammographers must perform phantom image evaluation at least

Answer 5

weekly

Question 6

The MQSA does not require facilities to have

Answer 6

ACR accreditation

Question 7

The average glandular dose delivered during a single craniocaudal view of an FDA-accepted phantom simulating a standard breast shall not exceed ____ mGy per exposure.

Answer 7

3

Question 8

The mAs recorded during phantom image testing of mammographic equipment should not vary by more than ____ from the initial control value.

Answer 8

±15%

Question 9

The maximum allowable dose per exposure for mammographic images is ____ rad.

Answer 9

0.3

Question 10

The recommended maximum tolerance of kVp variance for mammographic x-ray generators is

Answer 10

5%

Question 11

A visual inspection of a CT unit should be evaluated at least _____ for ACR accreditation programs.

Answer 11

monthly

Question 12

For ACR CT accreditation, the Water CT Number and Standard Deviation (Noise) should be evaluated by the CT technologist

Answer 12

daily

Question 13

For a slice thickness of 5 mm or less, the slice thickness should not vary by more than ____ mm.

Answer 13

0.5

Question 14

Patient dose values for CT scans should remain within ____ of the manufacturer’s specifications.

Answer 14

±10%

Question 15

Section thickness should not vary by more than ____ mm for sections greater than 5 mm.

Answer 15

±1.0

Question 16

The CT number of water should not deviate by more than ____ CT numbers from 0.

Answer 16

3

Question 17

The CTDIvol pass/fail criterion for an adult abdomen is ____ mGy.

Answer 17

30

Question 18

The laser light field and radiation field should coincide to within ____ mm.

Answer 18

2.0

Question 19

The minimum distance between two objects that allows them to be seen as separate and distinct would define what CT imaging parameter?

Answer 19

high contrast resolution

Question 20

The uniformity of the CT number of water should not vary by more than ____ HU from the center of the phantom to the periphery

Answer 20

5

Question 21

A change in the strength of the main magnetic field can be caused by

a. All are correct.
b. external ferromagnetic materials.
c. cryogen boiloff.
d. shim coil failure.

Answer 21

a. All are correct

Question 22

An acquisition with a 200-mm field of view and 256 x and y encodes yields a pixel size of ____ mm2.

Answer 22

0.78

Question 23

Luminance uniformity of soft-copy displays used in MRI systems should be within ____ of the maximum brightness measured in the center of the screen.

Answer 23

30%

Question 24

Nonuniformity in the magnetic field can be caused by

a. All are correct.
b. the presence of ferromagnetic material within the bore of the magnet.
c. uniformity in the RF coil.
d. a homogenous main magnetic field.

Answer 24

b. the presence of ferromagnetic material within the bore of the magnet.

Question 25

The ACR slice position deviation in MR scanners should not exceed ____ mm.

Answer 25

5

Question 26

The ability of an MR scanner to resolve small objects is known as

Answer 26

high contrast resolution

Question 27

The ability of the MR system to differentiate between adjacent tissues having minimal differences in signal intensities is known as

Answer 27

low contrast resolution

Question 28

The amount of geometric distortion in the image is the

Answer 28

spatial linearity

Question 29

What is the maximum luminance for soft-copy display devices as suggested by the ACR?

Answer 29

greater than 90 nit

Question 30

What is the resonant frequency in a unit with a 1.0-T magnet and a gyromagnetic ratio of 42.57 MHz/T?

Answer 30

42.57 MHz

Question 31

A chemical fog artifact a. appears as streaks. b. results in lower contrast. c. results in lower optical density. d. is an exposure artifact.

Answer 31

b. results in lower contrast.

Question 32

Data for determining repeat rates should include at least ____ patients to obtain a statistical sample large enough for valid results.

Answer 32

250

Question 33

If residual thiosulfate is not properly removed during washing, the radiograph will

Answer 33

turn brown

Question 34

Patient motion during exposure results in _____ artifact. a. a handling b. no c. a processing d. an exposure

Answer 34

d. an exposure

Question 35

Pi lines are so named because they a. occur at regular intervals. b. appear as a section of pie. c. None are correct. d. occur on the finished radiograph.

Answer 35

a. occur at regular intervals

Question 36

Wet pressure sensitization would be classified as _____ artifact. a. an exposure b. no c. a processing d. a handling

Answer 36

c. a processing

Question 37

Which of the following artifacts can occur in both CR and film/screen radiography? a. Moiré pattern b. Water spots c. Static electricity d. Wet-pressure sensitization

Answer 37

a. Moiré pattern

Question 38

Which of the following can occur as a result of a double set of grid lines? a. Grid misalignment b. Film fog c. Static artifacts d. Moiré effect

Answer 38

d. Moiré effect

Question 39

Which of the following will run in the same direction as that of film travel? a. Guide shoe marks b. All are correct c. Pi lines d. Hesitation lines

Answer 39

a. Guide shoe marks

Question 40

_______ can appear as dark bands at the interfaces of structures that differ widely in brightness level such as barium examinations or metal prosthesis.

Answer 40

Halo artifacts