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BIOGUIDE-X: A First-in-Human Study of the Performance of Positron Emission Tomography-Guided Radiotherapy. International journal of radiation oncology, biology, physics Vitzthum, L. K., Surucu, M., Gensheimer, M. F., Kovalchuk, N., Han, B., Pham, D., Chang, D., Shirvani, S. M., Aksoy, D., Maniyedath, A., Narayanan, M., Da Silva, A. J., Mazin, S., Feghali, K. A., Iyengar, P., Dan, T., Pompos, A., Timmerman, R., Öz, O., Cai, B., Garant, A. 2023

Abstract

SCINTIX® Biology-guided radiotherapy (BgRT) is a novel tracked dose delivery modality that uses real-time positron emission tomography (PET) to guide radiotherapy beamlets. The BIOGUIDE-X study was performed with sequential cohorts of participants to (1) identify the fluorodeoxyglucose (FDG) dose for SCINTIX therapy and (2) confirm that the emulated dose distribution was consistent with a physician-approved radiotherapy plan.This prospective study included participants with at least 1 FDG-avid targetable primary or metastatic tumor (=2cm and =5cm) in the lung or bone. For Cohort I, a modified 3?+?3 design was used to determine the FDG dose that would result in adequate signal for SCINTIX therapy. For Cohort II, PET imaging data were collected on the X1 system before the first and last fractions among patients undergoing conventional stereotactic body radiotherapy. SCINTIX therapy dose distributions were modeled on the patient's CT anatomy using the collected PET data at each fraction as input to an "emulated delivery" and compared to the physician-approved plan.Cohort I demonstrated adequate FDG activity in 6/6 (100.0%) evaluable participants with the first injected dose level of 15 mCi FDG. In Cohort II, 4 patients with lung tumors and 5 with bone tumors were enrolled, and evaluable emulated delivery data points were collected for 17 treatment fractions. Sixteen of the 17 emulated deliveries resulted in SCINTIX dose distributions that were accurate with respect to the approved SCINTIX therapy plan. The 17th data point was just below the 95% threshold for accuracy (DVH Score?=?94.6%). All emulated fluences were physically deliverable. No toxicities were attributed to multiple FDG administrations.SCINTIX therapy is a novel radiotherapy modality in which a radiolabeled tumor can act as its own fiducial for radiotherapy targeting. Emulated SCINTIX therapy dose distributions calculated from continuously acquired real-time PET data were accurate and machine-deliverable in tumors that were 2-5 cm in size with adequate FDG signal characteristics.

View details for DOI 10.1016/j.ijrobp.2023.12.019

View details for PubMedID 38147912