Question 1

What is the NEMA allowance parameter for an x-ray tube that has a stated focal spot size of 1.5 mm?

Accepted Answer

Stated focal spot sizes between 0.8 and 1.5 mm increase by more than 40% from this size.

Question 2

Conventional tomographic systems should produce images of tissue that lie within ____ mm of the indicated tomographic plane.

Accepted Answer

The level of the tomographic section (fulcrum level) that is indicated on the equipment and the actual level of the tomographic section that is imaged above the tabletop should be the same or within F1F1F1S1F1F1F105 mm.

Question 3

During AEC evaluation with varying kVp, the AEC system should maintain a constant film density to within ____ optical density units.

Accepted Answer

The optical density values should measure the same or be within an optical density of$\pm$0.3.

Question 4

Which of the following devices can be used as the sensor in AEC units?

Accepted Answer

Ion chambers, photocells, and solid-state detectors can all be used as AEC sensors.

Question 5

A synchronous spinning top is used on a three-phase unit with a time of 17 ms. Approximately how large of an arc should appear if the timer circuit is accurate?

Accepted Answer

0.017 s F1F1F1S1F1F1F10 360 = 6 degrees.

Question 6

The x-ray tube must be mounted inside its housing so that the central ray exits the housing to within ____ degree(s) of perpendicular.

Accepted Answer

The x-ray tube must be mounted in its housing so that the central ray of the x-ray beam is within 1 degree of perpendicular.

Question 7

Path closure in pluridirectional tomographic units should be within ____ of the path length.

Accepted Answer

Path closure in pluridirectional units should be within F1F1F1S1F1F1F1010% of the path length.

Question 8

Two common quality control tests that should be performed on grids are grid _____ and grid _____ tests.

Accepted Answer

Grids should be evaluated for uniformity and alignment.

Question 9

X-ray system mAs reciprocity has an acceptance parameter of

Accepted Answer

Any variation in reciprocity cannot exceed $\pm$10%.

Question 10

What is the acceptance criterion for a timer circuit with an exposure time shorter than 10 ms?

Accepted Answer

The variability allowed for timer accuracy is $\pm$5% for exposure times greater than 10 ms and $\pm$20% for exposures less than 10 ms.

Question 11

Collimation systems equipped with positive beam limitation must be accurate to within ____ of the SID.

Accepted Answer

Collimators with PBL systems must be accurate to within $\pm$3% of the SID.

Question 12

The maximum variation coefficient for reproducibility of x-ray generators is

Accepted Answer

The calculated variance should be less than 0.05 (5%) for a properly functioning x-ray generator.

Question 13

An exposure of 600 mA and 16 ms yields an exposure output of 240 mR. What is the mR/mAs?

Accepted Answer

240 mR ÷ 9.6 mAs = 25 mR/mAs.

Question 14

During testing for grid uniformity, films should be uniform within an optical density of

Accepted Answer

All density readings should be within an optical density value of $\pm$0.1 for proper uniformity.

Question 15

The light field and radiation field of a radiographic unit must be congruent to within ____ of the SID.

Accepted Answer

The edges of the light field and radiation field must be congruent to within $\pm$2% of the SID.

Question 16

What is the accepted half-value layer (HVL) for an x-ray unit operating at 80 kVp?

Accepted Answer

The minimum HVL for units operating at 80 kVp is 2.3 mm Al.

Question 17

The minimum filtration required for general-purpose radiographic systems is _____ mm Al.

Accepted Answer

General-purpose radiographic systems capable of operating above 70 kVp should have a minimum of 2.5 mm Al total filtration.

Question 18

The kilovolts peak (kVp) must be accurate to

Accepted Answer

Variations between the stated kVp and the x-ray beam quality must be within F1F1F1S1F1F1F105%.

Question 19

The tomographic exposure angle indicated on the equipment and the actual tomographic angle must coincide within ____ degrees for units operating at angles greater than 30 degrees.

Accepted Answer

It is important that the value indicated on the equipment and the actual angle is the same or within F1F1F1S1F1F1F105 degrees for units operating at angles greater than 30 degrees.

Question 20

Which of the following tests can be used to determine focal spot size?

Accepted Answer

Focal spot size can be evaluated using a slit resolution chart, a star pattern resolution chart, or pinhole camera.

Quiz 5: Quality Control of X-Ray Generators and Ancillary Radiographic Equipment