title: Quality control for system count rate performance with scatter in gamma cameras.
abstract: We aimed to analyze the optimal conditions to carry out the periodical statistical control tests of the gamma camera count rate performance. First we focused in reproducing the actual R(20) value of the gamma camera response. Second we studied the variability of this parameter in the statistical control test. We performed a reference measurement, which consisted of the determination of the complete curve relating observed and incident count rates, the counting model describing it and the reference R(20). This reference determined the conditions for the statistical control tests and the way to analyze the results obtained. Results from three different gamma cameras were studied. Each gamma camera showed a different behavior and required specific data analysis. The optimal conditions to perform the statistical control test were determined in each case. Our procedure provides the information necessary to correlate the average value of R(20) obtained in the quality control test with the reference one. The critical requirement to perform any statistical control test, that is to have a reduced variability of the control variable, can be fulfilled in this case only for relatively high activities.
authors.affiliation: Servicio de Radiofísica, Hospital Universitario San Cecilio, Avda Dr Olóriz, 16, E-18012 Granada, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Guirado
authors.forename: J C
authors.initials: JC
authors.lastname: Ramírez
authors.forename: J M
authors.initials: JM
authors.lastname: de la Vega
authors.forename: M
authors.initials: M
authors.lastname: Vilches
authors.forename: A M
authors.initials: AM
authors.lastname: Lallena
mesh_terms: D015902:Gamma Cameras / Q000592:standards*; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D011786:Quality Control; D012015:Reference Standards; D012542:Scattering, Radiation