TY - JOUR T1 - Initial clinical experience with rapid high definition Na<sup>18</sup>F digital photon counting PET/CT imaging for whole-body osteoblastic disease assessment JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1387 LP - 1387 VL - 60 IS - supplement 1 AU - Chadwick Wright AU - Katherine Binzel AU - Jun Zhang AU - Edmund Folefac AU - Dayssy Diaz Pardo AU - Daniel Stover AU - Michael Knopp Y1 - 2019/05/01 UR - http://jnm.snmjournals.org/content/60/supplement_1/1387.abstract N2 - 1387Objectives: In patients undergoing routine oncologic or non-oncologic bone imaging evaluation, sodium fluoride-18 (Na18F) PET/CT is clinically useful for the detection and assessment of osteoblastic lesions. An existing clinical challenge for whole-body Na18F PET imaging are the longer than desired PET image acquisition times (60 - 120 s/bed) especially for patients with symptomatic osseous disease. New clinical PET/CT systems with digital photon counting PET (dPET) detector technology enable novel PET imaging approaches with higher definition PET images, shorter PET image acquisition times, and/or PET imaging at lower radiotracer doses. The objective is to develop and assess a high-definition whole-body Na18F dPET imaging approach with a substantially faster dPET acquisition time. Methods: In this Phase I intra-individual comparison trial, whole-body Na18F dPET/CT imaging (Vereos, Philips Healthcare) was performed in 16 oncologic patients using a target Na18F dose of 185 MBq. At 75 min post injection, investigational whole-body dPET acquisitions were performed using a faster 30 s/bed (1/3 of the standard PET acquisition time). At 90 min post injection, whole-body dPET acquisitions were performed using the standard 90 s/bed. High-definition dPET image data sets (voxel volume = 2x2x2 mm3) were reconstructed using Time-of-Flight and evaluated by matched pair comparison for overall image quality, background quality and lesion detectability by a blinded reader panel using an Intellispace Portal workstation. Results: All 32 data sets were rated as evaluable for qualitative assessment of 18F biodistribution and osteoblastic activity. Visually, there was no significant loss of 18F-avidity in either normal bone or osteoblastic lesions with faster dPET acquisitions at 30 s/bed when compared to the standard 90 s/bed. There was no impact on the detectability of 18F-avid osteoblastic lesions between the 30 s/bed and 90 s/bed acquisitions and no discordant 18F-avid osteoblastic lesions were identified. The average SUVmean values were comparable for 30 s/bed and 90 s/bed acquisitions in terms of background skeletal muscle (0.8 ± 0.1 and 0.7 ± 0.1, respectively) and normal vertebral bone (6.9 ± 1.7 and 7.4 ± 1.9, respectively). The average SUVmax values of 18F-avid osteoblastic lesions were also comparable for 30 s/bed and 90 s/bed acquisitions (31.5 ± 26.4 and 34.4 ± 29.1, respectively). There was likely physiologic clearance of 18F activity from skeletal muscles and continued 18F uptake in normal bone/osteoblastic lesions between the initial 30 s/bed and subsequent 90 s/bed acquisitions. No statistically significant differences in the average SUVmean or SUVmax values were noted between the 30 s/bed and 90 s/bed acquisitions. Conclusions: These results demonstrate that next-generation dPET detector technology enables 3x faster Na18F PET imaging without loss of image quality, osteoblastic lesion detectability or quantitative accuracy. Ultra-fast whole-body Na18F dPET imaging at &lt;10 s/bed may even be feasible in the future with further optimization of dPET image reconstruction. ER -