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CAPINTEC, INC. CAPTUS
®
600
MDA TEST
This is a test of Minimum Detectable Activity for the specific nuclide selected by the user.
The test can be performed for the Probe or Well. A nuclide is chosen for the test (the default
is Tc99m) and the appropriate energy range (400 keV or 1600 keV) is automatically selected.
The test measures the background in the Region of Interest that would be used to measure
the activity of the selected nuclide.
The user also selects the counting period and the precision used in the calculation.
The minimum detectable counting rate is given by:
T
counts * p
MDR
=
where p is the precision, counts is the background counts in the channels for the nuclide, and
T is the counting time.
The precision can range from 1 to 9. The default value is 3.
To get the Minimum Detectable Activity, the minimum detectable counting rate is divided by
the efficiency for the nuclide:
Eff
MDR
MDA
=
To perform the MDA Test, press the
HOME key and then TEST key. The Test menu (Figure
6-13) will appear.
1 . C A L IB R A T IO N T E S T
0 . R E T U R N T O S E T U P M E N U
1 4 :3 2
2 . M D A T E S T
Figure 6-13
Press
2 to select MDA TEST . The Well or Probe Selection Screen (Figure 6-14) will appear.
November 07 ACCEPTANCE & QUALITY ASSURANCE TESTS 6-9