Prostate cancer detection with [^99mTc]Tc-HYNIC-iPSMA SPECT: The Australian experience

^99mTc-HYNIC-iPSMA SPECT or SPECT/CT has potential to improve detection and staging of prostate cancer (PrCa) patients, and better direct appropriate therapies in those patients where cost or availability of PET/CT is prohibitive. Furthermore, without the targeted molecular imaging afforded by ^99mTc-HYNIC-iPSMA, rural patients are also disadvantaged with respect to access to theranostic treatment options. The primary objective of this prospective investigation was to assess the safety and clinical impact of ^99mTc-HYNIC-iPSMA SPECT imaging among PrCa patients in remote Western Australia.

Twenty-seven rural Western Australian patients with confirmed PrCa were enrolled in this prospective observational study. Imaging was performed 2-4 h after intravenous administration of 650-800 MBq ^99mTc-HYNIC-iPSMA. Planar whole-body images, static images and SPECT/CT acquisitions (chest, abdomen and pelvis) were performed. Treatment-related adverse events were collected, and patients' follow-up data were collected from medical records.

No adverse reactions or events were observed in any patient. Normal physiologic biodistribution of ^99mTc-HYNIC-iPSMA was observed in 26 (96.3 %) patients. The mean radiochemical purity was 92.5 % (±1.7) with a range of 90 %-96 % and median of 92. At least one PSMA-positive lesion was detected in 81.5 % (n = 22) of patients. The ^99mTc-HYNIC-iPSMA findings altered patient management in 11 (40.7 %) patients.

These findings support ^99mTc-HYNIC-iPSMA as a reliable alternative to existing imaging modalities, enhancing the diagnostic pipeline and informing patient management. Beyond detection rate, patient management was changed based on the ^99mTc-HYNIC-iPSMA findings in 41 % of patients who would otherwise not have had access to molecular imaging.

SPECT may extend advantage where PET is not accessible due to geographic and socioeconomic factors. ^99mTc-HYNIC-iPSMA provides reliable imaging, narrowing the equity gap among PrCa patients.