Accession Number:

ADA210773

Title:

Robust Spatial Calibration of a Planar Positron Camera

Descriptive Note:

Final rept. Oct 1985-Sep 1987

Corporate Author:

NAVAL MEDICAL RESEARCH INST BETHESDA MD

Report Date:

1988-10-01

Pagination or Media Count:

29.0

Abstract:

The planar positron camera is a three-dimensional imaging device with two parallel and planar large crystal detectors. The spatial calibration problem is to define the relation between the raw digitized detector output to a physical coordinate system in the imaged space. In a calibration procedure, a positron point source is placed in a series of known emission locations during data acquisition. Data is then fit to a mathematical model to estimate spatial offsets and gains in the detector. Fitting procedures require some assumptions about error distribution, and the assumption of normally distributed error used in least-squares estimation does not appear suitable for these detectors. In simulated data sets, alternative non-normal distributions robust estimators allowed successful recovery of camera spatial parameters even with a few hundred total detected positron emissions. With experimental data, the robust procedures avoided the unreasonable camera performance parameters estimated by least squares. Keywords Positron Instrumentation Image Mathematical model Error distribution Crystal detectors.

Subject Categories:

  • Nuclear Instrumentation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE