Capintec CAPTUS 600 - Chapter 7 Thyroid Uptake Setup; Counting Methods

CAPINTEC, INC. CAPTUS
®
600
CHAPTER 7
THYROID UPTAKE SETUP
COUNTING METHODS
Counting Methods refer to the Counting Time Base and Regions of Interest for each nuclide.
The values are the same for all entered protocols.
The CAPTUS
®
600 offers two counting time bases: REAL time and LIVE time. The
Multichannel Analyzer (MCA) in the CAPTUS
®
600 measures each pulse that comes out of
the Sodium Iodide/Photomultiplier tube detector. To process each pulse requires a finite
amount of time. During the time the MCA is busy, it cannot accept another pulse. Any other
pulse that occurs during this time is not measured, and is lost. During this time, the MCA is
said to be DEAD.
Live Time is defined as the time during which the MCA can actually accept and process a
pulse.
Real Time is defined as the actual clock interval.
If LIVE time is chosen, the CAPTUS
®
600 counts until the MCA's Live Time reaches the
specified counting period. The actual counting time is always greater than or equal to the
requested Live Time.
If REAL time is chosen, the CAPTUS
®
600 counts until the Real Time reaches the specified
count period. The count rate is calculated from measured Live Time.
To view or change the Counting Method, press the HOME key, then the UTIL key. The main
Utilities menu (
Figure 7-1) will appear.
UTILITIES
1. MULTICHANNEL ANALYZER
2. STAFF BIO ASSAY RESULTS
3. SETUP
4. DIAGNOSTICS
0. RETURN TO PROBE SCREEN
14:32
Figure 7-1
November 07 THYROID UPTAKE SETUP 7-1