QC Flashcards
Dose calibrator constancy checks must be done
daily
Dose calibrator linearity checks must be performed
quarterly
Dose calibrator accuracy checks must be performed
annually
Accuracy checks must be performed, per 10 CFR 35, with ________ sources with at least one source having an energy between ___________ and ___________ keV.
two
100, 500
Dose calibrator accuracy checks must show agreement with standard source within __________
± 5%
Dose calibrator bias voltage must be __________for standard calibrators and ______________ for PET.
~150 V
~500 V
Beta emitters can’t penetrate the dose calibrator chamber, but produce a secondary signal through the production of __________________ radiation. The dipper construction can / cannot impact the measured activity.
bremstrallung
can
Fo Mo-99 concentration tests, the minimum record retention period is ____________. In addition to the measurement, the record must contain:
3 years
time and date
name of individual performing measure
Mo-99 pig thickness is roughly _________ and has a transmission factor of _________
.6 cm Pb
.497
3 reasons for a Moly test failure:
- External contimantion on outside of moly shield
- Wrong isotope selection
- Worn or dented moly shield, allowing Tc-99m photons to escape
This image is an example of
Moly shield holder and and breakthrough shield.
Mo-99 breakthrough is a _________ event
very rare
Dose calibrator linearity must be tested within this range
highest administered activity
down to 30 uCi
The two most probable modes of dose calibrator failure include
Pressure leak from the chamber
Loss of bias battery voltage on the chamber
Linearity testing can be performed via these two ways
decay or shield test
Most dose calibrator “failures” are due to
operator error
If the voltage test indicates normal chamber voltage and the daily constancy test passed, linearity failure is probably due to
operator error performing the test
With the decay method of linearity testing, 6 common errors are
- Recording time incorrectly (use the same timepiece)
- Failure to zero and background correct before each measurement
- Failure to wait for the reading to stabilize
- Record reading on the lowest possible scale and slow response.
- Failure to anticipate that the last measurement bue occur during normal work hours.
- Failure to reproduce the geometry for each measurement
Linearity testing at each measurement point must be within what acceptance limits?
± 5%
Examples of shield based linearity testing include these systems
Lineator
Calicheck
Fluctuations in the dose calibrator reading during lineator testing will occur
at low activity values as you near 30uCi
This is a _____________ used for ___________
lineator
shield based linearity dose calibrator testing
Multi energy calibration of thyroid uptake probes is done using
Eu-152 source
~.5 uCi, exempt source
Distance of sources used in thryoid probe QC
25 cm
Source used for Chi-Square testing of the thyroid probe
Cs-137
.5 uCi, exempt quantity
These devices are used for
Shield based linearity testing
These sources are used in what detection system?
thyroid probe
The source is located where in these rods?
black tip
What is the black arm used for?
flipped in front and placed against the region to be measured to ensure 25 cm distance