PET detector quality assurance using /sup 137/Cs singles transmission imaging

Daily quality assurance of the detectors, to ensure accurate efficiency calibration of the system, typically requires the acquisition of coincidence data from a flood source. In order to obtain sufficient counts, long scan times, on the order of an hour, are required. The long acquisition time and necessity of an external activity source makes such a protocol impractical for daily use. The new method has been demonstrated for the KCAT ART scanner, using the two ¹³⁷Cs transmission sources. The new protocol produces a map of the counts per detector, as well as plots of the mean detector counts per block and CoV of each block. Graphical outputs allow for quick recognition of problematic areas. The factory protocol requires 90 min to obtain a 1% error on the individual detector counts. Due to the high activity of the ¹³⁷Cs sources, a 1% error is obtained with an 8 min scan with the new protocol. The new protocol provides information regarding the status of all blocks, reduces acquisition time, and alleviates the need for an external activity source. The protocol presented in this study can be implemented on other ¹³⁷Cs based scanners, and with coincidence flood sources if detector-specific singles histogramming is available