Compartmental modeling and absorbed dose assessment of 188-Re-HYNIC-PSMA according to the rats’ biodistribution data

PSMA is known as a suitable marker for imaging and targeted therapy of malignant tumors, especially prostate cancer. While; 177Lu-labeled PSMA is recognized as a promising compound for the treatment of metastatic castration-resistant prostate cancer patients, deployment of radionuclides with higher beta energy, including 188Re, can be useful for larger-sized tumors. However, the absorbed dose of the PSMA radiolabeled compound is substantial according to the considerable accumulation in the kidney.

In this study; the biodistribution of 188Re-HYNIC-PSMA was studied in Wistar rats. ANACOMP software was utilized for compartmental modeling. The human absorbed dose of this new agent was assessed according to the rats’ biodistribution data using the RADAR method.

The highest accumulation of activity in Wistar rats’ organs were observed in the kidney. The human organs that received the highest absorbed dose were the kidneys and bladder wall with 0.69 and 0.46 mSv/MBq, respectively.

The absorbed dose of 188Re-PSMA-617 in critical organs is comparable to the values of 177Lu-PSMA-617. 188Re-HYNIC-PSMA can be considered a safe compound for the treatment of PSMA expressing tumors.