Comprehensive acceptance testing and quality control of Single Photon Emission Computed Tomography/Computed Tomography systems

BACKGROUND: Single photon emission computed tomography/computed tomography (SPECT/CT) systems play a crucial role in nuclear medicine for accurate diagnosis and treatment planning. Ensuring high image quality through rigorous acceptance testing and quality control is essential to maintain diagnostic reliability and patient safety. OBJECTIVE: This study evaluated the performance of SPECT/CT systems at NORI Hospital Islamabad against National Electrical Manufacturers Association (NEMA) and International Atomic Energy Agency standards and developed a structured quality control program based on acceptance testing results. METHODS: Acceptance tests were carried out using Tc-99m, I-131, and Co-57 radioactive sources, in conjunction with quadrant bar and Jaszczak phantoms. Parameters assessed included spatial resolution, intrinsic and extrinsic uniformity, energy resolution, sensitivity, center of rotation (COR), detector shielding, background counts, leakage, CT number accuracy, and nuclear medicine/CT registration. Data were compared with manufacturer specifications and NEMA standards to evaluate system performance and inform quality control strategies. RESULTS: Both detectors exhibited intrinsic and extrinsic uniformity within NEMA limits, ensuring consistent image quality. Spatial resolution testing confirmed sharp and precise imaging, while energy resolution was within manufacturer-specified values. Sensitivity measurements showed minor differences between detectors but remained within acceptable ranges. COR values were precise (<±0.55 mm), confirming proper mechanical and software alignment. CT number accuracy and nuclear medicine/CT registration tests confirmed precise anatomical-functional image overlay. Detector shielding and leakage tests showed minimal interference, supporting reliable imaging. CONCLUSION: The SPECT/CT systems at NORI Hospital Islamabad met established NEMA standards for image quality. Acceptance testing validated detector performance and highlighted minor areas for improvement, such as periodic sensitivity calibration. Implementation of a structured quality control program ensures consistent equipment performance, optimal image quality, improved diagnostic accuracy, and superior patient care. Routine adherence to international standards is essential for maintaining high-quality nuclear medicine imaging practices.