Impact of acquisition time on image quality and quantification of F-¹⁸FDG PET/CT images

The purpose of this study was to evaluate the impact of acquisition time on image quality,lesion detection rate and standardized uptake value of F ¹⁸FDG PET images in cancer patients. 32 cancer patients over the period of 20 months were included in this study, 67 lesions were evaluated, two consecutive whole body F 18 FDG PET/CT scans using a 3 min and 1.5 min acquisition time per bed position were obtained for each patient. Lesions were visually identified and their locations were compared. SUV values of the primary tumor, lymph nodes and metastasis were determined and compared. Image quality was visually analyzed and quantified in terms of lesion to background ratio (L/B) , scored on a 5 point like rt type scale. For all parameters interobserver agreement was assessed. All relevant lesions could be identified at both acquisition times. Image quality is slightly poor in 1.5 min than 3 min. but the quality of lesion visualization was excellent regardless of the acquisition time. SUV values of the images correlated well. Although image quality is slightly poorer, reducing acquisition time to 1.5 min per bed position seems to be clinically feasible without decreasing the lesion detection rate and quality of lesion visualization even for less experienced observers. (author)