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Count‐based monitoring of Anger‐camera spectra—local energy shifts due to rotation
Author(s) -
Swailem Fayez M.,
Koral Kenneth F.,
Rogers W. Leslie
Publication year - 1991
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.596660
Subject(s) - physics , rotation (mathematics) , spectral line , optics , offset (computer science) , scattering , compton scattering , energy (signal processing) , computational physics , atomic physics , mathematics , astronomy , geometry , computer science , quantum mechanics , programming language
This study reports on a spectral monitoring method in which (1) a small source fixed to the camera is used, (2) a narrow, offset window is set on the side of the photopeak, and (3) variations in count rate are measured to assess energy shifts in the vicinity of the source. For one camera model, the count rate drops from 100% to 76% over a rotation of 180°, implying a local energy shift of 1.4 keV. Also looked for are local count‐rate variations with rotation for (1) wide‐symmetric, (2) 20%‐symmetric, and (3) 10%‐asymmetric windows. The last is in limited use to partially compensate for Compton scattering. The effects of background and time stability are assessed.