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.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DEVICE_FEASIBILITY
Masking
NONE
Enrollment
20
Undergo PET-CT
Given IV
Undergo X1 RMRS PET-CT
Undergo PET-CT
City of Hope Medical Center
Duarte, California, United States
Comparison of imaging performance of the [18F]-rhPSMA positron emission tomography (PET)-computed tomography (CT) on the X1 RefleXion Medical Radiotherapy System (RMRS)
Will compare the performance of the \[18F\]-RhPSMA PET-CT subsystem on the RefleXion X1 system to detect selected lesions in patients with prostate cancer with the SOC diagnostic \[18F\]- RhPSMA PET-CT. One key metric will be the percent of patients with lesions identified on SOC PET-CT that are not identified on X1 (false negatives if considering SOC the true standard). With 25 patients with lesions detected by SOC Posluma PET who undergo X1 scanning, there is at least 93% chance of finding a false negative on X1 if the true false negative rate is 10%. With 25 patients, if there are no false negatives, a false negative rate of 11.3% or above can be ruled out with a type I error \<5%. Any discordances will be documented, and the final disposition recorded after a discussion between the radiation oncologist and the nuclear medicine radiologist. Graphical presentations will be provided to compare SOC positive lesions and X1 positive lesions, and SOC positive lesions and X1 neg
Time frame: Up to 72 hours after completion of imagining session
Incidence of change in treatment planning based on SOC Posluma
Will be assessed in a descriptive manner.
Time frame: Up to 72 hours after imaging session
Percent of cases where X1 RMRS PET data can be used to generate an acceptable biology-guided radiotherapy (BgRT) plan
The true positive lesions identified on the X1 PET images will be identified and used for BgRT planning. Simulated planning using the RefleXion treatment planning software will be performed, and the radiation dose to organs at risk calculated. Principal investigator will determine whether this plan is acceptable or not. The percent of cases in which RefleXion \[18F\]-RhPSMAcPET data led to an acceptable plan will be recorded (descriptive statistics). Descriptive statistics will be utilized to quantify results. Mean, standard deviation, IQR, and range will be reported for each continuous variable. Frequency and percentage will be reported for categorical variables.
Time frame: Up to 72 hours after imaging session
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