Assessment of PET/CT: National Electrical Manufacturers Association NU2-2018 Standards versus American Association of Physicists in Medicine Task Group 126.

Abstract

The aim of this study was to perform and evaluate PET/computed tomography acceptance tests separately using American Association of Physicists in Medicine (AAPM) Task Group 126 and National Electrical Manufacturers Association (NEMA) methods. Measurements of sensitivity, spatial resolution, count rate performance and scatter fraction, the accuracy of corrections for count losses and randoms, and image quality were obtained according to NEMA NU-2018. Likewise, the performance tests were made using the AAPM Task Group 126 method, and the results were compared with NEMA NU-2018. The sensitivity at the isocenter was 8.87 cps/kBq according to NEMA and 7.60 cps/kBq by using the AAPM Task Group 126. For the spatial resolution, the full width at half maximum (FWHM) and FWTM values were 4.34 mm and 6.78 mm at 1 cm radial offset by NEMA, while AAPM Task Group 126 yielded FWHM and FWTM values of 4.42 mm and 8.14 mm, respectively. In the image quality, NEMA exhibited hot lesions contrast of 40.8, 56.7, 69.9, and 77.3 for 10, 13, 17, and 22 mm spheres, respectively. As a ratio to 25 mm, the "Hot" max standard uptake values by AAPM Task Group 126 were found to be 1, 1.1, 1.37, and 1.68 for 8, 12, 16, and 25 mm lesions, respectively. Acceptance tests using NEMA are of high relevance and convenience for the reliability of the results. Alternatively, AAPM Task Group 126 seems convenient and more economical to apply with reliable outcomes for the equivalent tests.