Equipment Operation and Quality Control I

To determine how quickly an x-ray tube will disperse its accumulated heat, the radiographer uses a(n)



A
 
technique chart. 


B
 
radiographic rating chart. 


C
 
anode cooling curve. 


D
 
spinning top test.

The ability of an x-ray unit to produce constant radiation output, at a given mA, using various combinations of mAs and time is called



A
 
linearity. 


B
 
reproducibility. 


C
 
densitometry. 


D
 
sensitometry.

In digital imaging, artifacts arise from a number of sources, including which of the following?



A
 
Imaging hardware 


B
 
Image processing software 


C
 
Operator error artifacts 


D
 
All of these may be sources of image artifacts

All of the following are daily quality control (QC) steps to ensure optimal diagnostic images on a digital display monitor, except:



A
 
Turn on the monitor and allow it to warm up 


B
 
Evaluate luminance, reflection, noise and glare 


C
 
Make sure that the monitor is dust-free on the viewing surface 


D
 
Evaluate the QC patterns at the periphery and verify that all letters and numbers appear

The x-ray beam and collimator light field must coincide to within



A
 
10% of the OID 


B
 
2% of the OID 


C
 
10% of the SID 


D
 
2% of the SID

To compensate for variations in gain across a digital receptor, which of the following maintenance steps should be taken?



A
 
Conduct a calibration correction for image nonuniformity 


B
 
Increase or decrease the exposure factors to compensate 


C
 
Install a variable resistor to adjust the electrical supply to the unit 


D
 
Keep a log for at least 30 days to confirm consistent variations before making any adjustments

A device used to measure the luminance response and uniformity of monitors used in digital imaging is called a



A
 
Penetrometer 


B
 
Densitometer 


C
 
Sensitometer 


D
 
Photometer

Environmental background radiation can contribute to a



A
 
Ghost artifact 


B
 
Moiré artifact 


C
 
Static artifact 


D
 
Grid cutoff artifact

Too much edge enhancement of the image in digital systems can cause an unwanted artifact called the:



A
 
Photoelectric effect artifact 


B
 
Scaling artifact 


C
 
Hounsfield artifact 


D
 
Halo effect artifact

All of the following are steps that should be used to accomplish quality control (QC) in digital radiography, except:



A
 
Acceptance testing 


B
 
Establishment of baseline performance 


C
 
Monitoring patient size to evaluate variations in equipment performance 


D
 
Diagnosis of changes in performance

An exposed image plate will retain its original image quality for about



A
 
2 hours 


B
 
8 hours 


C
 
24 hours 


D
 
48 hours

The device used to test the accuracy of the x-ray timer is the



A
 
densitometer 


B
 
sensitometer 


C
 
penetrometer 


D
 
spinning top

To ensure proper operation of the digital image display monitor, all of the following are important in order to develop a quality control (QC) program,except:



A
 
Routine quality control tests by the QC technologist 


B
 
Disassembly and cleaning of the internal monitor control devices by the QC technologist 


C
 
Periodic review of the QC program by a qualified medical physicist 


D
 
Annual and post-repair medical physics performance evaluations

The image in Figure 6–6 was obtained while testing







A
 
rectifier operation in a single-phase x-ray machine. 


B
 
rectifier operation in a three-phase x-ray machine. 


C
 
timer accuracy in a single-phase x-ray machine. 


D
 
timer accuracy in a three-phase x-ray machine.

Which of the following may occur if the X-ray exposure field is not properly collimated, positioned, and sized?



A
 
Modulation transfer function failure 


B
 
Moiré artifact 


C
 
Exposure field recognition errors may occur 


D
 
Ghost artifact

Quality control testing of digital display monitors should be conducted



A
 
Daily 


B
 
Weekly 


C
 
Monthly 


D
 
Annually

Inadequate collimation in CR imaging can result in an image that is too

1. light


2. dark


3. noisy

A
 
1 only 


B
 
1 and 2 only 


C
 
2 and 3 only 


D
 
1, 2, and 3

Which of the following is (are) tested as part of a QC program?

1. Beam alignment


2. Reproducibility


3. Linearity

A
 
1 only 


B
 
1 and 2 only 


C
 
1 and 3 only 


D
 
1, 2, and 3

QA was being performed on a three-phase, full-wave-rectified x-ray unit. A synchronous spinning-top test was performed using 300 mA, 60 ms, and 70 kVp, and a 22-degree arc is observed on the test film. Which of the following statements regarding these results is most correct?



A
 
The timer is inaccurate. 


B
 
The milliamperage station is inaccurate. 


C
 
One rectifier is malfunctioning. 


D
 
The test results are satisfactory.

Quality Control (QC) testing is used to evaluate digital display monitors in all of the following ways, except



A
 
Display luminance response 


B
 
Display resolution 


C
 
Display matrix size 


D
 
Display noise

In order to avoid background radiation artifacts when using CR, it is important to:



A
 
Erase all image plates that have not been used for 48 hours 


B
 
Erase all image plates if there is any question about how long it has been since the plate has been erased 


C
 
Erase an image plate if there is any doubt as to when it was last erased, especially in the case of pediatric radiography 


D
 
All of these are correct actions

Radiographs from a particular three-phase, full-wave-rectified x-ray unit, made using known correct exposures, were underexposed. A synchronous spinning top test was performed using 200 mA, 1/12 second, and 70 kVp, and a 20° arc is observed on the test film. Which of the following is mostlikely the problem?



A
 
The 1/12-second time station is inaccurate. 


B
 
The 200-mA station is inaccurate. 


C
 
A rectifier is not functioning. 


D
 
The processor needs servicing.