Compensation for the response function of medium energy collimator in 67Ga planar and SPECT imaging

C. Tocharoenchai, B. M.W. Tsui, D. P. Lewis, E. C. Frey, X. Zhao

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

This preliminary study is to improve 67Ga planar and SPECT images by compensating for the response function of a medium energy (ME) collimator. The point response functions (PRFs) of a GE ME collimator for the 93, 185 and 300 keV photons of 67Ga at 5, 10, 15 and 20 cm from the collimator face were experimentally determined. For small pixel sizes, the PRFs for all distances showed hole pattern effects. Images from the higher energy photopeaks showed increased penetration fractions. For a specified source distance, a Butterworth filter can be designed to eliminate the collimator hole pattern with minimal degradation of the spatial resolution. Compensation for the distance-dependent collimator-detector response was accomplished using iterative reconstruction methods. To evaluate the compensation methods, planar images and SPECT projection data were acquired from a phantom consisting of 3 hot spheres with diameters of 1, 1.3 and 1.6 cm inside a cylindrical phantom. The iterative reconstruction-based compensation method provided improved resolution and fewer artifacts than in images reconstructed with filtered backprojection. We conclude that degradation caused by ME collimator in 67Ga imaging can be effectively compensated for using these techniques.

Original languageEnglish (US)
Title of host publicationIEEE Nuclear Science Symposium and Medical Imaging Conference
PublisherIEEE
Pages1405-1408
Number of pages4
ISBN (Print)0780350227
StatePublished - 1999
Externally publishedYes
EventProceedings of the 1998 IEEE Nuclear Science Symposium Conference Record - Toronto, Que, Can
Duration: Nov 8 1998Nov 14 1998

Publication series

NameIEEE Nuclear Science Symposium and Medical Imaging Conference
Volume3

Other

OtherProceedings of the 1998 IEEE Nuclear Science Symposium Conference Record
CityToronto, Que, Can
Period11/8/9811/14/98

ASJC Scopus subject areas

  • Radiation
  • Nuclear and High Energy Physics
  • Radiology Nuclear Medicine and imaging

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