Multi-timepoint imaging with PSMA-targeted [¹⁸F]F-Florastamin PET/CT: lesion detection and comparison to conventional imaging

Objective: The aims of this study were to investigate the utility of [¹⁸F]F-Florastamin, a novel prostate-specific membrane antigen (PSMA)-targeted PET radiotracer with facile radiochemistry, relative to the conventional imaging for the detection of sties of disease and evaluate the effect of multi-timepoint imaging with [¹⁸F]F-Florastamin PET on lesion detectability. Methods: Eight prostate cancer patients with known or suspected recurrence who underwent [¹⁸F]F-Florastamin PET/CT at 1-h and 2-h imaging time-points were included in this prospective pilot study. [¹⁸F]F-Florastamin PET images were interpreted visually and quantitatively at both time points and compared with CIM. Results: [¹⁸F]F-Florastamin PET was superior to CT in the detection of active osseous metastases and small-sized metastatic lymph nodes that do not fall under the anatomic imaging size criteria for metastasis. Multi-timepoint imaging showed a significant reduction in the blood pool, bone marrow and muscular uptake, and increase in liver uptake over time. There is a significant improvement in tumor-to-background ratio (TBR) at the 2-h imaging time-point (P = 0.04). The mean percentage change in TBR at 2-h was 21% (SD = 0.31). Conclusions: [¹⁸F]F-Florastamin is a promising new radioligand for PSMA-targeted PET with suitable lesion detectability and high TBR at both time points.