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3.3 Tube Voltage Measurement and Reproducibility
Chapter 3
4
Make an exposure. (On some units, a cassette must be placed in the cassette holder to enable
exposure.)
5
Record the results for the measured and displayed values in the correct elds on the Table
MP-2 (Tube Voltage Measurement and Reproducibility).
6
Set the next exposure to the most commonly used kVp settings for the site. Make 4 exposures
at this setting.
7
Record the measured results in the correct elds on the Table MP-2. Also record the displayed
kVp setting in the correct eld on the Table MP-2.
8
Set the mammography X-ray unit to the highest available clinical kVp for the site and make an
exposure.
9
Record the results for the measured and displayed values in the correct elds on the Table
MP-2.
3.3.5 Performance Criteria and Corrective Action
Performance Criteria: The displayed kVp on the modality should be accurate (within +/- 5% of the indicated kVp) and
that the kVp is reproducible, having a coecient of variation equal to or less than 0.02.
Corrective Action: If the test fails, please repeat the above procedure. If results exceed the criteria the mammography
X-ray unit must be serviced to correct the condition.
The source of the problem shall be identied and corrective action shall be taken within 30 days of the test date. Pa-
tient examination may continue during this period.
3.3.6 Documentation
Record the results in the Table MP-2 (Tube Voltage Measurement and Reproducibility) and the Table MP-S (MEDICAL
PHYSICIST'S MAMMOGRAPHY QC TEST SUMMARY).
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