Optimizing and Validating Reduced PET Volume Overlap in 18F-FDG Oncology Wholebody PET/CT to Improve Speed and Patient Comfort

Objectives To optimize and validate reducing PET acquisition volume overlap in 18F-FDG Time-of-Flight oncology wholebody PET/CT to save table time and improve patient comfort

Methods An integrated pre-clinical optimization (beagles) and clinical validation (human patients) trial was initiated to proof the feasibility of reducing PET volume overlap from established system default. In human studies, additional reduced overlap PET/CT sweeps were acquired immidiately after the default overlap standard of care imaging. Phantom evaluations were performed prior to pre-clinical studies. All imaging were acquired on a Gemini TF 64 PET/CT scanner (Philips Healthcare). Reduced PET overlaps (40%, 33%, 27%, 20%, 13% and no overlap) were investigated and compared to the system default (53%). Image quality was blindly reviewed by multiple readers using a visual scoring criteria and a quantitative SUV assessment. Patients were asked to comment on comfort

Results 20 beagle subjects were imaged. In the ongoing trial, 10 patients are currently completed and the basis this assessment. All wholebody PET exams demonstrated no impact on the visual grade with overlaps >13%. In the matched comparison, the best visual scores were found for studies using the default 53%, 40% and 27% overlaps. Reducing overlap to 27% for oncology patients saved an average of ~40% acquisition time (11min) compared to using the default overlap (18min). No significant SUV variances were found between PETs of 27% to 53% overlaps for cerebellum, lung, heart, aorta, liver, fat, muscle, bone marrow, thighs and target lesions (p>0.05), except expected variability in kidneys and bladder

Conclusions This trial demonstrates by combined pre-clinical, phantom and clinical validation that a reduction of PET volume overlap to 27% (half of the system default) can be implemented without degradation of image quality or quantification. This approach can reduce table time by 40% and additionally improves patient comfort.

Research Support Ohio Third Frontier Innovation Platform grant TECH 10-012 and 13-060