To evaluate the biodistribution, kinetics and radiation dosimetry of (64)CuCl2 in humans and to assess the ability of (64)CuCl2-PoPET/CT to detect prostate cancer (PCa) recurrence in patients with biochemical relapse. Methods: we prospectively evaluated 50 PCa patients with biochemical relapse after surgery or external-beam radiation therapy. All patients underwent (64)CuCl2-PET/CT, (18)F-Choline-PET/CT and multiparametric magnetic resonance imaging (mpMRI) within 15 days of each other. Experienced readers interpreted the images, and the detection rate (DR) of each imaging modality was calculated. Histopathology, when available, clinical or laboratory response and multidisciplinary follow-up were used to confirm the site of disease. In parallel, biodistribution, kinetics of the lesions and radiation dosimetry of (64)CuCl2 were evaluated. Results: From a dosimetric point-of view, an administered dose of 200 MBq for (64)CuCl2 translates into 5.7mSv of effective dose. Unlike (18)F-Choline, (64)CuCl2 is not excreted nor accumulated in the urinary tract, thus allowing thorough pelvic exploration. The maximum (64)CuCl2 uptake at the sites of PCa relapse was observed one hour after tracer injection. In our cohort, (64)CuCl2-PET/CT proved positive in 41 of 50 patients, with an overall DR of 82%. The DRs of (18)F-Choline-PET/CT and mpMRI were 56% and 74% respectively. The difference between the DRs of (64)CuCl2-PET/CT and (18)F-Choline-PET/CT was statistically significant (p<0.001). Interestingly, on considering PSA value, (64)CuCl2-PET/CT had a higher DR than (18)F-Choline-PET/CT in patients with PSA <1 ng/ml . Conclusion: The biodistribution of (64)CuCl2 is more suitable than that of (18)F-Choline for exploring the pelvis and prostatic bed. The (64)CuCl2 effective dose is similar to those of other established PET tracers. In patients with biochemical relapse and a low PSA level, (64)CuCl2-PET/CT shows a significantly higher DR than (18)F-Choline-PET/CT.
- Journal Article