Scintillation camera and head therefor having means for improving resolution over a limited field of view
A head for a scintillation camera has a planar scintillating crystal that responds to radiation stimuli by producing light events whose spatial distribution corresponds to the spatial distribution of the radiation stimuli, and a plurality of photomultipliers each having a photocathode facing the crystal and producing an output signal when a light event occurs. The photomultipliers are organized into a first group arranged in a cluster centrally positioned relative to the crystal and having smaller photocathodes than those in the second group which is arranged in an annular array surrounding the first group. The head of the camera is connected to signal processing circuitry for computing each of two spatial coordinates of a light event by forming analytical functions of the output signals. Such circuitry has two selective modes of operation. In the first, each spatial coordinate of a light event is computed by forming an analytic function of the output signals from only those photomultipliers in the first group. In the second mode of operation, each spatial coordinate of the light event is computed using an analytical function of the sum of the output signals of the first group of photomultipliers and the output signals from the second group. For light events falling within a first portion of the crystal defined by the envelope of the projection on the crystal of the photocathodes of the first group of photomultipliers, when the signal processing circuitry is operating in its first mode, the resolution achieved will be much better than the resolution achieved when the signal processing circuitry is operating in its second mode. 17 claims, 4 figures.
- Assignee:
- Elscint Ltd.
- Patent Number(s):
- US 4001591
- OSTI ID:
- 7317568
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
550601 -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
CAMERAS
COLLIMATORS
CONFIGURATION
DATA ACQUISITION SYSTEMS
DESIGN
GAMMA CAMERAS
MEASURING INSTRUMENTS
PHOTOMULTIPLIERS
PHOTOTUBES
RADIATION DETECTORS
SCINTILLATION COUNTERS