An European consensus on [123I]Ioflupane acquisition and reconstruction using 3D CZT SPECT/CT

Abstract Introduction The introduction of hybrid SPECT/CT systems with 3D multi-head gantries and CZT crystal detectors offers significant clinical potential, especially for brain imaging. These advancements allow for reduced activity/time requirements, improved spatial resolution, contrast, and the ability to study early perfusion phases and enable 4D acquisitions. Approximately 200 systems have been installed worldwide, prompting individual centers to optimize acquisition and reconstruction protocols. A European effort was attempted in this paper to separately harmonize protocols for each system, facilitating multicentric clinical studies and the development of a standardized database. Materials and methods To harmonize the protocols for StarGuide (GE HealthCare) system, four online meetings were held involving nuclear medicine experts from seven European centers. These meetings focused on standardizing acquisition and reconstruction parameters based on experts’ opinion and phantom testing. To harmonize the protocols for Veriton (Spectrum Dynamics Medical) results of a prospective study (VERIDAT) were used. Specific acquisition and reconstruction parameters have been detailed for both systems. Results Significant heterogeneity was found in the initial acquisition/reconstruction protocols among the participating centers. After discussions and phantom testing, standard parameters were established for both systems. For the StarGuide, a scan time of 20 min with an energy window of 159 keV (−6.5%/+5%) and relatively wide striatum focus were suggested. For the Veriton, 15 min scan time with a symmetrical energy window (± 7.5%) and adjustable focus were recommended. Reconstruction algorithms for the Veriton used OSEM with kernel inter-iteration filter (factor of 0.125) and a median post-filter (3 × 3 × 3 voxels), while the StarGuide employed a BSREM Q.Clear algorithm with RDP mode. Both systems achieved a central SPECT spatial resolution of around 4 mm. Conclusion This initiative to standardize acquisition and reconstruction parameters for the new CZT SPECT systems (StarGuide and Veriton) represents an important step towards improving multicenter research and clinical data consistency. The proposed parameters are a preliminary foundation for further optimization and multicentric studies, allowing for more reliable quantitative and qualitative assessments. This work will also aid in updating clinical guidelines and creating a harmonized database for CZT SPECT systems.