⁶⁴CuCl₂ PET/CT in Prostate Cancer Relapse

Area of Science:

• Nuclear Medicine
• Oncology Imaging
• Radiochemistry

Background:

• Prostate cancer (PCa) recurrence after initial treatment poses a significant clinical challenge.
• Accurate detection of recurrent PCa is crucial for timely and effective management.
• Current imaging modalities have limitations in sensitivity and specificity for detecting disease relapse, particularly at low prostate-specific antigen (PSA) levels.

Purpose of the Study:

• To evaluate the biodistribution, kinetics, and radiation dosimetry of copper-64 chloride (⁶⁴CuCl₂) in humans.
• To assess the efficacy of ⁶⁴CuCl₂ Positron Emission Tomography/Computed Tomography (PET/CT) in detecting prostate cancer recurrence in patients with biochemical relapse.
• To compare the detection rate of ⁶⁴CuCl₂ PET/CT with ¹⁸F-choline PET/CT and multiparametric MRI.

Main Methods:

• Prospective evaluation of 50 prostate cancer patients with biochemical relapse.
• All patients underwent ⁶⁴CuCl₂ PET/CT, ¹⁸F-choline PET/CT, and multiparametric MRI within a 15-day interval.
• Detection rate (DR) calculation for each modality, confirmed by histopathology, clinical response, or multidisciplinary follow-up.

Main Results:

• ⁶⁴CuCl₂ PET/CT demonstrated an 82% detection rate, significantly higher than ¹⁸F-choline PET/CT (56%) and multiparametric MRI (74%) (P < 0.001).
• ⁶⁴CuCl₂ showed favorable biodistribution, with no urinary tract excretion, allowing better pelvic imaging.
• Detection rates for ⁶⁴CuCl₂ PET/CT were notably higher than ¹⁸F-choline PET/CT in patients with PSA < 1 ng/mL.
• An administered dose of 200 MBq ⁶⁴CuCl₂ resulted in a 5.7-mSv effective dose, comparable to other PET tracers.

Conclusions:

• ⁶⁴CuCl₂ exhibits superior biodistribution for pelvic and prostatic bed imaging compared to ¹⁸F-choline.
• The radiation dosimetry of ⁶⁴CuCl₂ is within acceptable limits for clinical use.
• ⁶⁴CuCl₂ PET/CT offers a significant advantage in detecting prostate cancer recurrence, especially in biochemically relapsed patients with low PSA levels, outperforming ¹⁸F-choline PET/CT.