Feasibility study of optimizing PET/CT acquisition protocol between image quality and radiation dose

In current combined PET/CT systems, high-quality CT images not only increase the diagnostic values by providing anatomic delineation of hyper- and hypo-metabolic tissues but also offer shorter transmission scanning times compared to standard PET imaging. However, this approach potentially introduces radiation burden due to the higher radiation exposure. Ideally operation protocols for routine PET/CT imaging take diagnostic values, image quality, clinical practicability, scanning time and radiation doses into consideration, but the question of how to reconcile all these factors is made debated topic in nuclear medicine today. In this study, the radiation doses delivered from a typical germanium-based and CT-based transmission scan were measured by means of an anthropomorphic Rando Alderson phantom with insertion of thermoluminescent dosimeters and the image effects of the attenuation correction with various CT acquisition protocols were compared. From the results, we found that image properties and attenuation correction data did not differ significantly by adjusted CT acquisition parameters in PET/CT imaging for reduced patient exposure about 1/26 compared to the currently used while maintaining the advantages of short scanning time and clinical practicability.