title: A method for determination of the timing stability of PET scanners.
abstract: We report on the timing resolution and stability of the MicroPET R4 PET scanner. Its detectors have energy resolutions in the range of 25% and previously reported timing resolutions 3.2 ns. Our preliminary evaluation of this instrument showed that artefact-free normalization sinograms could only be obtained with a timing window of 10 ns or more in spite of a timing resolution of 3.2 ns. This instrument uses high-speed electronics albeit with 2-ns timing clock. We performed sham transmission scans with nothing in the field of view, and a range of timing windows from 2 to 14 ns and used a 14-ns timing blank scan to generate effective attenuation sinograms as a function of timing window. These showed trues count-rates which fit well to a ERF (tau) function. However, the effective attenuation value, which should be 1.0, changes from block to block and becomes very high in some blocks (> 3.5 at 6 ns) suggesting the need for timing alignment. A method was devised to measure the timing stability to a precision better than the timing bin width of 2 ns.
authors.affiliation: Montreal Neurological Institute, 3801 University St. #798, Montreal, QC H3A 2B4, Canada. christopher.thompson@mcgill.ca
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Thompson
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Goertzen
mesh_terms: D000465:Algorithms; D002138:Calibration; D019544:Equipment Failure Analysis / Q000379:methods*; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D049268:Positron-Emission Tomography / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors