Benefit of Improved Scanner Performance on Monitoring Therapy Response in Oncology

Quantitative positron emission tomography (PET) is increasingly employed for cancer therapy response assessment. We conducted a virtual clinical trial (VCT) using patient data from the PennPET Explorer to monitor therapy-induced changes in standardized uptake value (SUV). Two patients with high and low BMI were studied, each with 20 small lesions (1 cm diameter) embedded in lung and liver organs. Multiple scans were generated via bootstrapping and reconstructed using list-mode time of flight ordered subset expectation maximization (TOF-OSEM) for varied scan durations and SUV changes. The resulting SUVs were utilized to construct receiver operating characteristic (ROC) curves, enabling the quantification of the system’s capability to assess response. The area under the ROC curve (AUC) was used as a metric to assess our ability to accurately measure changes in SUV. Our results demonstrate that long axial field of view (LAFOV) PET scanners with high sensitivity can effectively detect early tumor response to therapy, even with very brief scan durations. Moreover, our findings suggest that extending the imaging times, while remaining practical, enhances sensitivity to measuring smaller changes in tumor uptake, making it feasible to detect patient therapy response at an earlier time point.