PerkinElmer QuantaSmart 1694267

CHAPTER 11
194 PerkinElmer Life and Analytical Sciences
Priostat
This is a set of capabilities on the TriCarb instrument which allows for the
interruption of a current protocol to count a set of high priority samples or
perform specialized counting functions.
Pulse
A pulse is an electrical signal resulting when photons are detected by a PMT.
Pulse Decay Analysis (PDA)
PDA is a technique by which nuclide pulses are sorted into separate multichannel
analyzers for analysis and quantitation. Pulse Decay Analysis relies on the
differences in pulse duration to classify the types of radioactive emissions (alpha,
beta or gamma) from a nuclide.
Quench
Quench results in the reduction in the scintillation intensity seen by the
photomultiplier tubes of a liquid scintillation counter as a result of materials
present in the scintillation solution that interfere with the processes leading to the
production or detection of light. The result is fewer photons per keV of beta
particle energy and usually a reduction in counting efficiency.
Quench Curve
A quench curve is a mathematical graph which correlates the counting efficiency
to a quench indicating parameter (QIP). The QIP for a sample is determined
during sample counting. This value is used to interpolate the counting efficiency
for a sample from the quench curve (where %Efficiency is plotted vs. the QIP).
The interpolated efficiency value is used to calculate the DPM (Disintegrations Per
Minute, where DPM=CPM/Efficiency).
Quench Indicating Parameter (QIP)
A QIP is a numerical value used to express the level of quench in a sample. SIS,
tSIE and tSIE are quench indicating parameters used in the TriCarb system.
Reference Date
This is the date on which a radio-labeled material has the specified amount of
activity.
Reference Time
This is the time at which a radio-labeled material has the specified amount of
activity. Typically, this parameter is described only for radionuclides with very
short half-lives.
Region
This is the range of energy over which counts are measured for a nuclide in a
liquid scintillation counter. Also referred to as “window” or “channel”.