X-Ray Certification Quality Control 2 — Questions and Answers
Question 1: What is the purpose of a sensitometric strip in radiographic quality control?
- To measure patient radiation dose
- To evaluate film processor performance by assessing density and contrast (Correct answer)
- To calibrate the X-ray tube output
- To test the accuracy of the collimator light field
Correct answer: To evaluate film processor performance by assessing density and contrast
A sensitometric strip is used to monitor film processor performance by measuring base plus fog, speed, and contrast index values.
Question 2: Which parameter does the 'speed index' on a sensitometric strip primarily reflect?
- Contrast of the film
- The density at a specific step near the mid-density range (Correct answer)
- The base plus fog level
- The maximum density achievable
Correct answer: The density at a specific step near the mid-density range
The speed index is the density measured at a specific mid-density step on the sensitometric strip, representing the film's sensitivity to exposure.
Question 3: What action should be taken when the base-plus-fog level of a processor QC chart exceeds control limits?
- Continue processing and recheck the next day
- Adjust the developer temperature by 5°F
- Investigate and correct the problem before processing diagnostic images (Correct answer)
- Increase the sensitometer exposure
Correct answer: Investigate and correct the problem before processing diagnostic images
Exceeding control limits indicates a processor problem; clinical imaging must be suspended until the cause is identified and corrected.
Question 4: How often should processor quality control be performed in a high-volume radiology department?
- Weekly
- Monthly
- Daily (Correct answer)
- Every 8 hours of operation
Correct answer: Daily
Daily processor QC ensures consistent film development quality and allows early detection of processor drift or malfunction.
Question 5: What does a 'contrast index' value on a processor QC chart indicate?
- The difference in density between two specific steps on the sensitometric strip (Correct answer)
- The maximum optical density on the film
- The kVp setting used during exposure
- The amount of silver halide remaining after processing
Correct answer: The difference in density between two specific steps on the sensitometric strip
The contrast index reflects the difference in optical density between two defined steps, indicating the processor's ability to produce adequate image contrast.
Question 6: Which chemical component of the developer solution most directly affects film contrast?
- Sodium sulfite (preservative)
- Hydroquinone (superadditive developing agent) (Correct answer)
- Potassium bromide (restrainer)
- Sodium carbonate (activator)
Correct answer: Hydroquinone (superadditive developing agent)
Hydroquinone is primarily responsible for building density in the high-exposure (highlight) areas, directly affecting overall film contrast.
Question 7: In digital radiography, what QC test evaluates whether the detector uniformly responds across its entire surface?
- Spatial resolution test
- Flat-field uniformity test (Correct answer)
- Modulation transfer function test
- Signal-to-noise ratio test
Correct answer: Flat-field uniformity test
The flat-field uniformity test exposes the detector to a uniform radiation field to check for pixel dropouts, artifacts, or uneven response across the imaging area.
X-Ray Certification Quality Control 2
What is the purpose of a sensitometric strip in radiographic quality control?