Facing the NEMA challenge to testing gamma cameras

Abstract

Nuclear medicine is dependent on the accurate and reproducible performance of the gamma camera. There are various guidelines for acceptance testing and performance characterisation, such as IPEM, IAEA and NEMA. Gamma camera manufacturers usually quote system performance in terms of NEMA test results allowing users to compare the performance of different systems. This study outlines how the NEMA test protocol [NEMA NU1-2012] was implemented at the acceptance testing of a dual headed SPECT system and highlights the challenges encountered. The NEMA standard defines the required test phantoms, acquisition parameters and method of analysis in detail. Some test phantoms had to be produced in-house using commonly available materials and the analysis was performed using commonly available software (ImageJ and Microsoft Excel). The NEMA standard was successfully implemented and results were obtained which indicated a performance as good if not better than specified by the manufacturer. Any deviations from the standard during testing are outlined. Although IPEM recommends NEMA for acceptance testing and IPEM Report 111 for commissioning and routine Quality Assurance, it is the intention to continue NEMA testing routinely as it has the advantages of available performance criteria from the manufacturers, a set of baseline values established at acceptance testing, and not having to implement an additional set of tests.