biodex ATOMLAB 960 - Edit an Isotope; Delete an Isotope; How Is ROI Determined

4-20 UTILITIES Biodex Medical Systems, Inc. © 2014
Edit An Isotope:
The <Edit> function on the Select An Isotope List allows the user to change information
associated with the currently selected isotope. For factory isotopes, you can adjust only
detector efficiency or whether to use it for Bioassay or Wipe. For custom isotopes editing allows
for adjustment of area readings, half-life range, ROI settings, as well as the isotope name.
1. At the Select An Isotope screen, highlight the isotope to edit and select <Edit>. The Isotope
Management Screen is now displayed.
2. Edit any field as appropriate.
3. Select <Accept> to save the edited values and return to the Select An Isotope screen.
NOTE: For factory defined isotopes, some fields cannot be edited.
Delete An Isotope:
1. At the Select An Isotope screen, highlight the isotope to delete and select <Delete>. A
confirmation message warns that you are about to delete the currently selected isotope.
NOTE: Only custom isotopes can be deleted from the Isotope Editing screen. Factory set
isotopes cannot be deleted.
2. Select <Accept> to delete the currently selected isotope. A warning screen notes that you are
about to delete the selected isotope. Select <Accept> to delete the isotope and return to the
Select An Isotope screen, or <Cancel> to return to the Select An Isotope screen with no
deletion. If you deleted the isotope, it will no longer appear in the Select An Isotope list.
How Roi Is Determined
How is ROI Determined?
Most isotopes preset ROI energy window values do not change as the user switches between well or
probe, regardless of the mode selected (i.e., Uptake, manual, etc.). The ROI is defined in units of
energy (keV) and then converted to channel numbers with the keV/channel slope value that is
measured during calibration. The channel number for the ROI values can and will change from probe
to well if the calibration keV/channel is different between probe and well.
NOTE: Certain isotopes have a separate isotope name listed for the Well for that specific
isotope. The different ROI’s are required because in the Well there may be a second peak which
is the summation peak.
Example:
Tc-99m has a peak energy of 140 keV according to the radionuclide decay scheme. The
Atomlab 960 uses a default of +/- 15% energy window around the peak energy. These values
calculate to be 119 keV to 162 keV and are displayed on the Isotope Editing page. When either
the probe or well is selected, the ROI channels are calculated based upon the Cs-137 calibration
results for that particular detector. If the calculation of the probe results in a .3775
keV/channel on range 0-375 keV, the TC-99m default range, the channel ROI will be 119
keV/.3775 keV channel = channel 315 and 162/.3775 = channel 429. For the well detector, we
might have a calibration of .3325 keV/channel. In this case, the ROI channels will calculate
channel 358 to 487. Even though the ROI channels are different, the energy windows are the
same. This will become apparent when the spectrum for each detector is printed.