AUTHOR=Zhang Jiaying , Lin Zefang , Zhang Xiaojun , Lin Rong , Cui Mengchao , Miao Weibing , Yao Shaobo 

TITLE=68Ga-DOTA-DiPSMA PET/CT Imaging: Biodistribution, Dosimetry, and Preliminary Application in Prostate Cancer

JOURNAL=Frontiers in Bioengineering and Biotechnology

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2021.811972

DOI=10.3389/fbioe.2021.811972

ISSN=2296-4185

ABSTRACT=<p><bold>Purpose</bold>: This prospective trial aimed to evaluate the safety, dosimetry, and biodistribution of a novel theranostic probe <sup>68</sup>Ga-DOTA-DiPSMA. Also, we have performed the first preliminary application with <sup>68</sup>Ga-DOTA-DiPSMA in prostate cancer (PCa) patients.</p><p><bold>Methods</bold>: Five healthy volunteers and ten PCa patients were injected with an intravenous bolus of <sup>68</sup>Ga-DOTA-DiPSMA. They received serial whole-body PET scans from the time of injection up to 60 min post-injection, with a second PET/CT scanning at 120 min post-injection. In PCa patients, low-dose CT scan and whole-body PET were performed with 2 min per bed position in 40 min post-injection. Absorbed organ doses and effective doses were calculated using OLINDA/EXM. Normal organ uptake and tumor lesion uptake were measured. A lesion-by-lesion analysis was performed.</p><p><bold>Results</bold>: <sup>68</sup>Ga-DOTA-DiPSMA administration was safe and well-tolerated. The kidneys received the highest absorbed dose (114.46 ± 29.28 μSv/MBq), followed by the urinary bladder wall (100.82 ± 46.22 μSv/MBq) in accordance with the expected Prostate-Specific Membrane Antigen (PSMA) renal excretion of the tracer. The mean effective dose was 19.46 ± 1.73 μSv/MBq. The SUV<sub>max</sub> of <sup>68</sup>Ga-DOTA-DiPSMA PET/CT for PCa lesions, bone metastases, and lymph node metastases was 4.41 ± 2.72, 2.95 ± 1.11, and 3.26 ± 1.20, respectively.</p><p><bold>Conclusion</bold>: Injection of <sup>68</sup>Ga-DOTA-DiPSMA is safe and associated with low absorbed and effective doses. <sup>68</sup>Ga-DOTA-DiPSMA shows favorable kinetics and imaging characteristics in patients who warrant further head-to-head comparison to validate <sup>68</sup>Ga-DOTA-DiPSMA as an alternative for gallium-68-labeled PSMA clinical PET. Low nonspecific uptake in normal organs of <sup>68</sup>Ga-DOTA-DiPSMA indicates potential radioligand therapy (RLT) application when labeled with <sup>177</sup>Lu, <sup>90</sup>Y, or <sup>225</sup>Ac.</p>