Scintillation camera uniformity correction
A two-stage system for enhancing the imaging uniformity of a scintillation camera is disclosed. The camera includes means for detecting radiation events and for producing radiation count signals indicating the location and energy level of individual detected radiation events. The uniformity correction system compensates for imprecision in the camera's indication of both radiation event regional image count density and event energy level. Compensation for energy indication errors is done by a first stage, prior to a second stage correction for residual nonuniformity in regional image count density. The operations of both stages are carried out in real time for each individual radiation count, independently of the production of other counts. The first stage location and stores a representation of the respective peaks of the detected energy pulse height distribution for each of a plurality of regions in the camera's field of view. This regional profile of the camera's energy response characteristic is used to successively realign for each count the pulse height energy window defined by the camera imaging circuitry, to align the window over the respective energy peak for each count as a function of the count's location indication. The second uniformity correction stage, a flood correction circuit, produces and stores a profile of regional variation in the image count density indicated by the camera in response to a uniform radiation flood over its field. This stored information is used for calculating regional count density correction factors for different regions of the camera field. The correction factors are used for controlling the ratio of radiation counts corresponding to each region which are actually imaged, thus eliminating residual nonuniformity caused by nonuniform regional image count density produced by the camera.
- Assignee:
- Picker Corp
- Patent Number(s):
- US 4223221
- OSTI ID:
- 6932197
- Resource Relation:
- Patent File Date: Filed date 19 Jun 1978
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effects of asymmetric photopeak windows on flood field uniformity and spatial resolution of scintillation cameras
Ideal flood field images for SPECT uniformity correction
Related Subjects
SCINTISCANNING
IMAGE PROCESSING
CAMERAS
SCINTILLATION COUNTERS
SENSITIVITY
COUNTING TECHNIQUES
DIAGNOSTIC TECHNIQUES
MEASURING INSTRUMENTS
PROCESSING
RADIATION DETECTORS
RADIOISOTOPE SCANNING
440101* - Radiation Instrumentation- General Detectors or Monitors & Radiometric Instruments