PET Detector Quality Assurance Using Cs Singles Transmission Imaging

Daily quality assurance of positron emission tomography detectors, to ensure accurate efficiency calibration of the system, typically requires the acquisition of coincidence data from a flood source. 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 may make such a protocol impractical for daily use. A new protocol has been demonstrated for the ECAT ART scanner, using the two Cs transmission sources. The new protocol produces a map of the counts per detector, as well as plots of the mean and standard deviation of the detector counts in a given block. Graphical outputs allow for quick recognition of problematic areas. The factory protocol requires 90 min to obtain a 1% statistical error on the individual detector counts. Due to the high activity of the Cs sources, a 1% statistical error is obtained with an 8 min scan using 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 Cs transmission based scanners, and with coincidence flood sources if detector-specific singles histogramming is available.