To optimize the radiolabeling of prostate specific membrane antigen (PSMA)-targeted probe Al¹⁸F-PSMA-BCH (Beijing Cancer Hospital) and to evaluate its potential for clinical trial and translation.

The mixture of PSMA-BCH, AlCl₃, potassium biphthalate and no-carrier loaded ¹⁸F^- was reacted at 110 ℃ for 15 min, then purified by Sep-Pak Light C18 column and filtered through 0.22 μm sterile filter to obtain Al¹⁸F-PSMA-BCH. The radiolabeled yield and radiochemical purity were determined. Al¹⁸F-PSMA-BCH PET/CT imaging was performed on 5 healthy volunteers (age: (68±7) years) for biodistribution and radiation dosimetry estimate and on 1 patient (65 years) with recurrent prostate cancer.

The non-decay-corrected radiochemical yield of Al¹⁸F-PSMA-BCH was (38.0±3.5)% with the radiochemical purity >99% and the specific activity of (16.4±4.4) MBq/nmol. Al¹⁸F-PSMA-BCH was stable in saline at room temperature. In healthy volunteers, radioactivity was mainly accumulated in the bladder, kidneys, lacrimal glands, parotid glands and submandibular glands, of which kidneys were the most critical organs with the dosimetry of (152.89±33.43) μGy/MBq, while bones showed lower uptake ((11.10±1.23) μGy/MBq) than most organs. The effective dose of whole body was (0.013 5 ±0.002 5) mSv/MBq. Multiple bone metastases were observed by Al¹⁸F-PSMA-BCH PET/CT imaging in a patient with recurrent prostate cancer.

Al¹⁸F-PSMA-BCH prepared with the pH controller of potassium biphthalate holds the potential for the diagnosis, staging and monitoring recurrence of prostate cancer.

Prostatic neoplasms; Prostate-specific membrane antigen; Isotope labeling; Fluorine radioisotopes; Positron-emission tomography; Tomography, X-ray computed