IMAGE ARTIFACTS AT HIGH PHOTON FLUENCE RATES IN SINGLE-CRYSTAL NAL(TL) SCINTILLATION CAMERAS

  • 1 January 1978
    • journal article
    • research article
    • Vol. 19  (4) , 407-413
Abstract
A method that simulated a clinically relevant situation was used to measure the amount of pulse pileup in the .gamma. image by distinguishing between correctly and incorrectly positioned events. Comparison was then made between responses from different cameras. The influence of pileup rejection on counting rate was found. Pileup effects were determined for some cameras at such low count rates as about 10,000/s with a 30% energy window. Parameters affecting total count rate of the scintillation camera, such as scattering media, source geometry, collimator and energy window, were investigated. The energy distribution of the photon fluence striking the crystal apparently determines the counting losses and image distortion, rather than the counting rate in the energy window. The approach described here may fulfill the requirements for a new method to compare scintillation cameras. Measurements without scattering medium yielded results irrelevant for clinical situations.

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