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CT Cross Training > ASRT Practice Exam 1 & Free Preview > Flashcards

ASRT Practice Exam 1 & Free Preview Flashcards

1
Q

Which of the following reconstruction intervals will provide overlapping data?
A. 5.0 mm; 5.0 mm.
B. 2.5 mm: 1.25 mm.
C. 2.5 mm; 5.0 mm.
D. 1.25 mm; 2.5 mm.

A

Answer: B

The reconstruction interval must be LESS than the slice thickness in order for the reconstructed images to create overlapping data.

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2
Q

The __________ of the data acquisition system converts the analog signal from the detectors to a digital signal for the computer.

A

Analog-to Digital converter (ADC).

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3
Q

If the detector width of a 64-slice scanner is set to 0.625 mm, what is the coverage area?

A

40 mm.

The formula to determine coverage area is the number of slices multiplied by the detector width.

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4
Q

When evaluating the thoracic aorta, the ROI should be placed in the ________________ above the aortic root.

A

Ascending aorta.

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5
Q

The axial plane of the body is also known as the:

A

Transverse plane of the body.

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6
Q

Indications for a high-resolution CT scan include all of the following EXCEPT:
A. Pulmonary embolism.
B. Bronchiectasis.
C. Asbestos exposure.
D. Interstitial disease.

A

A. Pulmonary Embolism.

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7
Q

A CTA chest scan to rule out a pulmonary embolism terminates at the:

A

Lung apices.

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8
Q

Post-patient collimation:
1. Maintains slice thickness.
2. Affects dose.
3. Removes scatter.

A

1 and 3 only. (POST SCAN)

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9
Q

Shaded surface display is used to create 3D reformats of the maxillofacial region, including the:

A

External surface of facial region.

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10
Q

Compared to a single-detector row image acquisition, multidetector CT image acquisition provides:

A

Increased z-axis coverage per rotation of the gantry.

MDCT provides more coverage of the z-axis per gantry rotation. This configuration covers more volume which in turn decreases the scan time.

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11
Q

Pre-patient collimation in CT:
A. Restricts the X-ray beam.
B. Prevents scatter radiation.
C. Covers areas of the detector.
D. Filters out low-energy X-rays.

A

Answer: A - restricts the X-ray beam.

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12
Q

Common indications for a brain perfusion scan is:

A

Strokes & they can be ordered to assess tumors.

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13
Q

Advantages of a dual source scanner include:
1. Increased scan speed.
2. Reduced dose.
3. Variable kVp techniques for each tube.

A

1 and 3.

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14
Q

Which of the following are symptoms of a mild allergic reaction?
1. Hives.
2. Coughing.
3. Localized swelling of the face.
4. Dyspnea.

A

1, 2, and 3.

Dyspnea is a moderate to severe reaction.

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15
Q

Computed tomography is often combined with _________ to provide both anatomical & functional data.

A

Position emission tomography.

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16
Q

Reliability of the detectors depends upon all of the following EXCEPT:
A. Stability.
B. Response time.
C. Efficiency.
D. Dynamic Speed.

A

Answer: D - Dynamic Speed.

Characteristics of reliable detectors include stability, efficiency, NO afterglow, response time, and dynamic range.
Dynamic speed is NOT a characteristic of a reliable CT detector.

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17
Q

All of the following are dose reduction techniques appropriate for pediatric patients EXCEPT:
A. reducing SFOV.
B. Avoiding repeat scans.
C. Using pediatric specific protocols.
D. Using thinner slices.

A

Answer: D - using thinner slices.

Thinner slices = more dose.

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18
Q

Spatial resolution is affected by all of all the following EXCEPT:
A. SFOV.
B. DFOV.
C. Matrix size.
D. Pixel size.

A

A - SFOV.

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19
Q

What is the purpose of a saline bonus administered immediately after contrast?

A

To reduce streaking artifact from the concentration of contrast in the vein.

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20
Q

During helical image acquisition, the X-ray tube must rotate an additional 180 degrees at the beginning and end of the scan for image reconstruction, in a process called:

A

Overhanging.

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21
Q

For a 64-slice MDCT scanner, if the pitch is 1.375 and the detector width is 0.625 mm, how far does the table travel per rotation of the X-ray tube?

A

55 mm.

The MDCT pitch formula is used to determine the distance the table moves per rotation of the X-ray tube. Pitch = the distance the table travels per rotation / (number of detector rows x detector width).

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22
Q

A water phantom is used in __________ testing to check for noise during daily calibration.

A

Standard deviation.

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23
Q

What WW and WL are optimal for a CT scan of the thoracic spine?

A

WW 1800; WL 400.

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24
Q

How much contrast is needed for a CTA chest scan to r/o pulmonary embolism?

A

120 mL.

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25
Q

High frequency generators provide power to the X-ray tube producing kV in the range of:

A

80 kV to 140 kV.

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26
Q

Which of the following factors affect pt dose?
A. DFOV.
B. Post-pt collimation.
C. Detector stability.
D. Pitch.

A

D - Pitch.

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27
Q

During daily calibration, the phantom is scanned to ensure the CT numbers of different areas correctly correlate with each material. This test confirms _____ of the equipment.

A

Linearity.

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28
Q

A key benefit of solid-state detectors is:
A. Stability under pressure.
B. Reduced cost.
C. Resistance to heat and moisture.
D. Increased absorption efficiency.

A

D. Increased absorption efficiency.

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29
Q

The hospital information system (HIS) provides _________ to the radiology information system (RIS) prior to scanning the patient.

A

Patient demographics.

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30
Q

What type of dosimeter is used to measure CTDI?

A

Pencil-beam ionization chamber.

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31
Q

CT contrast administration routes include:
1. Enteral.
2. Intrathecal.
3. Parenteral.

A

1, 2, and 3.

32
Q

__________ radiation effects, such as erythema, occur after receiving a high threshold dose of radiation.

A

Deterministic.

33
Q

For a CT abdomen of the pelvis, what is an accurate slice thickness interval for acquisition for a 64 slice MDCT?

A

2.5 mm with an interval of 1.25 mm.

34
Q

What is another name for the late or delayed phase of the abdomen, which occurs several minutes after contrast injection?

A

Equilibrium phase.

35
Q

How many pixels are generated by a 1024x1024 matrix?

A

1,048,576

Multiply 1024x1024.

36
Q

Most modern CT scanners use __________ linear interpolation

A

180-degree.

37
Q

Which of the following enhancement phases should be included for a suspected liver hemangioma?
1. Arterial phase (35 seconds)
2. Portal venous phase (65 seconds)
3. Excretory phase (10 minutes)

A

1, 2, and 3.

38
Q

The initial data acquired by the scanner is called the:

A

Raw data.

39
Q

Risk factors for contrast-induced nephrotoxicity include:
1. Dehydration.
2. Diabetes.
3. Exceeding 200 mL of IV contrast within 24 hours.

A

1, 2, and 3.

40
Q

Which algorithm produces a data set with minimized artifacts?

A

Filtered Back-Projection.

41
Q

For a CT of the right wrist, the pt should be positioned:

A

Prone, with the right arm extended above the head.

42
Q

Invasive procedures, such as biopsies, require __________ consent by the pt.

A

Informed.

43
Q

Which of the following reformats select specific voxels of the acquired image data to create the final image?
1. Shaded Surface Display.
2. Minimum Intensity Projection.
3. Maximum Intensity Projection.

A

1, 2, and 3.

44
Q

How much IV contrast should be administered for a CTA head and neck exam?

A

80 ml.

45
Q

Appropriate shielding of the pt during a CT exam includes all of the following EXCEPT:
A. using lead shielding at the level of the gonads, above & below the pt when not in the SFOV.
B. Bismuth shielding in the SFOV for radiosensitive tissues.
C. Bismuth shielding on the pt after the initial topogram.
D. Placing a lead apron over the pts gown before the scan.

A

Answer - D

46
Q

Beam width for a MDCT scan is defined by:

A

Number of detectors multiplied by slice thickness.

47
Q

What is a typical scan delay for a routine chest CT?

A

35 seconds.

48
Q

A pt receives 120 mL of IV contrast followed by 60 mL of saline, During the post contrast saline bolts, the IV catheter extravasates. What is the correct response?

A

Immediately stop the bolus, remove the catheter, and apply a warm compress.

49
Q

When image data is reformatted for a 3D reconstruction, the image is created from:

A

Voxels.

50
Q

When does retrospective reconstruction occur?

A

Occurs AFTER the scan.

51
Q

Which of the following access lines are CT technologists allowed to access for administering IV contrast?
1. Intravenous catheters.
2. Tunneled catheters.
3. Power PICC lines.

A

1 and 3.

52
Q

The amount of IV contrast administered for a routine CT abdomen Pelvis exam is:

A

125 mL.

53
Q

When starting a peripheral IV, the bevel should face upwards and the needle should be angled _____ to the skin.

A

15-30 degrees.

54
Q

The __________ factors in the type of tissue being irradiated.

A

Effective dose.

55
Q

Table movement per tube revolution divided by slice thickness is the formula that defines pitch for:

A

Single-Slice helical CT.

56
Q

The dose length product (DLP) is:

A

The scan length multiplied by the CTDI volume.

57
Q

CT colonography requires:

A

CO2 insuffiation.

58
Q

Increasing beam width _____ pt dose.

A

Increases.

59
Q

For a CT soft tissue neck exam, what can the CT technologist adjust to reduce the effect of dental artifacts?
1. Adjust the pt to ensure the OML is perpendicular to the floor.
2. Tilt the gantry away from the teeth.
3. Ask the pt to remove items from their mouth such as dentures, prior to the scan.

A

2 and 3.

60
Q

Pixel size is defined by:

A

The display field of view (DFOV) divided by the matrix size.

61
Q

To better visualize cardiac structure, __________ is administered to reduce cardiac motion.

A

Nitroglycerine.

62
Q

CT dose modulation is a compatible dose reduction technique to __________ in diagnostic radiography.

A

Automatic exposure control.

63
Q

Following intrathecal injection of contrast for a CT myelogram, the pt should:

A

Remain supine & be instructed to roll 1 to 2 times prior to scanning.

64
Q

After a phantom scan, the line pair results of different scanners are compared. The scanner that identified __________ has the best spatial resolution.

A

30 line pairs.

(More lines = better spatial resolution).

65
Q

Which of the following slice thickness is correct for a 64-slice CT chest without contrast for suspected lung mass?
A. 10 mm.
B. 5 mm.
C. 2.5 mm.
D. 1.25 mm.

A

D 1.25 mm.

66
Q

Which of the following is an indication for a CT urogram?
A. Renal Calculi.
B. Hematuria.
C. End-stage renal disease.
D. Cysistis.

A

B. Hematuria.

67
Q

Which of the following is a good alternative to CT for a pediatric pt to rule out appendicitis?

A

Ultrasonography.

68
Q

_____ enables the X-ray tube to rotate continuously while the pt travels through the gantry during a CT scan.

A

Slip-ring technology.

69
Q

The focus-to-iOS center distance is the:

A

Distance from the X-ray source to the center of gravity.

70
Q

Which of the following is a clinical indication for CT colonography?
A. Adrenal mass.
B. Incomplete colonoscopy.
C. Caron’s disease.
D. Abcess.

A

B - incomplete colonoscopy.

71
Q

Moderate reactions to contrast media include:
A. Congestion or sneezing.
B. Bronchospasm with mild or no hypoxia.
C. Diffuse edema.
D. Limited urticaria.

A

B - Bronchospasm with mild or no hypoxia.

72
Q

Which of the following best represents a typical soft-tissue window setting?
A. WW 100, WL 30.
B. WW 350, WL 50.
C. WW 1500, WL -600
D. WW 1800, WL 400.

A

B - WW 350, WL 50.

73
Q

What type of QC test evaluates ROI measurements at various locations to determine if any differ by more than 2 HU?

A

Uniformity.

74
Q

All of the following are true of the bolus phase of contrast enhancement, EXCEPT:
A. The bolus phase immediately follows an IV bolus injection.
B. The bolus phase often occurs after a specified delay following an IV bolus injection.
C. Arterial structures are filled with contrast medium and brightly displayed on the image.
D. Venous structures are not yet filled with contrast medium on the image.

A

B - the bolus phase often occurs after a specified delay following an IV bolus injection.

75
Q

A technologist performing a CT exam could choose to increase the pitch because:

A

Increasing pitch = decreases dose.

CT Cross Training (28 decks)

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