[18F]-rhPSMA PET-CT Imaging Performance in Patients With Prostate Cancer

Posluma (18F-rhPSMA) PET Guided Radiotherapy Planning in Prostate Cancer: A Prospective Study Evaluating POSLUMA PET Tumor Detection on Radiation Therapy Planning and on BGRT Planning on the RefleXion X1 System

This clinical trial evaluates [18F]-rh PSMA positron emission tomography (PET)-computed tomography (CT) imaging performance in patients with prostate cancer. PET is an established imaging technique that utilizes small amounts of radioactivity attached to very minimal amounts of tracer, in the case of this research, 18F-rhPSMA. Because some cancers take up [18F]-rhPSMA, cancer cells can be seen with PET. CT utilizes x-rays that traverse body from the outside. CT images provide an exact outline of organs and potential inflammatory tissue where it occurs in patient's body. Posluma (18F-rhPSMA) is an approved prostate-specific membrane antigen (PSMA) imaging agent for prostate cancer. The RefleXion Medical Radiotherapy System (RMRS) is designed to facilitate delivery of biology-guided radiotherapy (BgRT). The system uses PET emissions to guide radiotherapy delivery in real-time and has been studied for use with fludeoxyglucose (FDG) (which is an agent used in standard PET-CT scans that targets glucose). Information gathered from this study may help researchers to improve PET-CT imaging on the RefleXion system. This information will be used in the future to improve planning and delivery of radiation therapy that will target (in real time) the signal released from the [18F]-rhPSMA PET-CT tracer. Comparing the imaging from the standard of care [18F]-rh PSMA PET-CT with the imaging from RMRS may help improve the quality of the imaging captured on the RMRS for detection of imaging signals in patients with prostate cancer.

PRIMARY OBJECTIVE:

I. To evaluate the imaging performance of flotufolastat F-18 gallium ([18F]-rhPSMA) PET-CT imaging subsystem of the RefleXion Medical Radiotherapy System Device in patients with lesions detected on standard-of-care (SOC) [18F]-rhPSMA PET-CT on the same day.

SECONDARY OBJECTIVES:

I. To evaluate the frequency that SOC Posluma imaging will result in the ability to distinctly identify and separate PET activity from bladder activity to aid in the detection, lesion contouring, RT planning and RT delivery for intra-prostatic lesions, prostate bed lesions (salvage RT) or lesions near the bladder.

II. To evaluate the frequency that SOC Posluma imaging will result in a change in radiotherapy planning through either exclusion due to extra-pelvic metastatic disease or detection of disease that results in a modification of RT field coverage or dose.

III. Evaluate the potential for using the X1 RMRS PET used to generate an acceptable BgRT plan such that dosimetric parameters for the target and the nearby normal anatomy are met based on investigator assessment.

OUTLINE:

Patients receive SOC flotufolastat F-18 gallium intravenously (IV) and undergo PET-CT on study. Patients then undergo X1 RMRS PET-CT imaging-only session 120 minutes post-injection.

After completion of study intervention, patients are followed up within 72 hours of PET imaging-only session.

Inclusion Criteria:

• Documented informed consent of the participant and/or legally authorized representative
• Age: ≥ 21 years
• Patients with SOC [18F]-RhPSMA PET-CT in whom a PET avid lesion is identified
• Able to get same day X1 RMRS PET

Exclusion Criteria:

• Known psychiatric or substance abuse disorder that would interfere with conduct of the study
• Patient weight exceeding the weight limit (450 pounds) outlined per X1 RMRS specifications sheet