!
Biodex Medical Systems, Inc. © 2016 133
This test allows the user to put a calibrated sealed isotope into the detector and check to make
sure the system is correctly reading the activity. Expanded constancy takes and records
readings for each of the isotopes listed on your Expanded Constancy Test List. Expanded
constancy is sometimes called “channel check.” The Expanded Constancy Test List defaults to
Tc-99m and Cs-137. You should add the appropriate isotopes that you want as part of your
Expanded Constancy List before performing an Expanded Constancy Test. A maximum of 14
isotopes can be saved to the Expanded Constancy List. This includes the sealed source being
used for the test.
The Expanded Constancy Test measures and records an activity reading using the selected
sealed source for each of the isotopes selected for the Expanded Constancy Test. The system
takes a reading and records it for each isotope. Expanded constancy then compares the
readings for each isotope from one test to the next test performed, and shows the variance
when the test is performed.
Each detector must be checked individually. The Atomlab 500 allows entry of the sealed sources
into inventory and decay-corrects these sources for time. These sources are used for the testing of
the dose calibrator detectors.
Constancy means reproducibility in measuring the same source, over a period of time, with
decay correction. Assay a relatively long-lived source (such as Cs-137) each day before using
the calibrator.
NOTE: When you perform an Expanded Constancy Test, the isotope used for the isotope
constancy value is put into the Daily Constancy Test screen and shows the variance from
the calculated value.
Cs-137, 200 µCi, is strongly recommended because the 30-year half-life will assure use of the same
source throughout the life of the calibrator, and it is readily available. The Cs-137 source should be
replaced at 100 µCi,
NOTE: You can only perform one Daily Constancy Test or Expanded Constancy Test for a
specific sealed source per day. Select the desired isotope before performing the test.
To Perform An Expanded Daily Constancy Test:
1. From the QA Dose Calibrator screen touch <Expanded Daily Constancy Test>. The expanded
Daily Constancy Test screen is now displayed. The source information is shown.
2. Touch <Set Expanded Const List>. The Set Expanded Constancy List is displayed.
3. To add an isotope, touch <Add Isotope>. The isotopes list is now displayed. Touch to
highlight the isotope you wish to add to the Expanded Constancy Isotope List. Touch
<Enter> to record and return to the Set Expanded Constancy List. Repeat the add isotope
procedure for each isotope you wish to add to the list.
4. To remove an isotope from the Set Expanded Constancy List, touch to highlight the isotope
to be removed. Touch <Delete Isotope> to remove the isotope from the Expanded
Constancy List. Touch <Cancel> to discard any changes made, or <Enter> to record the
changes.
5. If more than one detector is connected, touch <Select Detector> and select the detector to
test.
To Next Page
Loading...
