Safety Flashcards

1
Q

The quantity of radiation dose received by the patient from a series of CT scans is referred to as the:

A

MSAD

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2
Q

Which of the following technical characteristics of a CT system does NOT directly affect patient dose?

A. Source-to-detector distance
B. Filtration
C. Detector efficiency
D. Filament size

A

D

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3
Q

Which of the following statements most accurately describes the relationship between slice sensitivity profile (SSP) and dose profile?

A

The dose profile is always wider than the SSP

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4
Q

The approximate radiation dose measured during a scan of a 100-mm-long pencil ionization chamber is termed the:

A

CTDI 100

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5
Q

The calculation of the average cumulative dose to each section within an acquisition of multiple sections is termed the:

A

MSAD

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6
Q

The multiple-scan average dose (MSAD) is used to describe the:

A

average dose to a single section within a scan of multiple sections.

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7
Q

Which of the following units is used to quantify effective dose?

A

Sievert (Sv)

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8
Q

If you increase detector pitch you will ——- pt dose

A

Decrease pt dose

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9
Q

The interaction between x-radiation and tissue that results in the complete loss of all x-ray photon energy is called:

A

photoelectric absorption

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10
Q

If you decrease pitch you will —— pt dose

A

Increase pt dose

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11
Q

A best practice for the use of in-plane bismuth shielding requires the:

A

placement of shield after the acquisition of scout (localizer) images.

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12
Q

Which of the following is the unit of radiation exposure?

A

Roentgen (R)

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13
Q

A dose check system features which of the following?

  1. Dose notification
  2. Dose alert
  3. Dose report
A

1 and 2

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14
Q

Current CT systems employ which of the following image reconstruction methods to reduce patient radiation dose?

A

Iterative reconstruction

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15
Q

As a patient size decreases, noise ———

A

Image noise is directly related to patient size. As a patient size decreases, noise decreases

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16
Q

Which of the following describes the system that adjusts the mA setting according to part size variations along the z-axis?

A

Longitudinal tube current modulation

17
Q

Which of the following descriptors accounts for the dose effects of image spacing during axial acquisition?

A

MSAD

18
Q

Because of the bow-tie filter employed in the CT x-ray system, positioning the patient at isocenter is critical to avoid:

A

increased patient exposure

19
Q

The CT dose index (CTDI) is calculated for the central slice in a series that is surrounded by ______ slices on each side.

A

7

20
Q

Which of the following technical factor adjustments would result in a decrease in the CTDIvol for a given acquisition?

A

Increased pitch

Side note to remember
As the pitch increases, the dose per section (CTDIvol) decreases.

21
Q

A CT system may employ a focal spot tracking system to precisely direct the x-ray beam toward the detector array in an effort to reduce:

A

overbeaming

22
Q

During helical CT acquisition, there is a small amount of x-ray exposure just before and immediately following the anatomical volume of interest. This may be referred to as:

A

overranging

23
Q

When employing ECG-triggered tube current modulation during a cardiac CT, as the patient heart rate increases, the radiation dose savings:

A

Decreases