biostudies-literatureArmstrong WRNCI NIH HHS1244-1251https://www.ebi.ac.uk/biostudies/studies/S-EPMC9364769biostudies-literatureUnknown62(9)The prostate-specific membrane antigen (PSMA) has been targeted for PET imaging and radioligand therapy (RLT) in patients with prostate cancer. Xerostomia is a common side effect of RLT because of the high salivary gland uptake of PSMA radioligands. Here, we aimed to determine the impact of monosodium glutamate (MSG) administration on PSMA-radioligand biodistribution within healthy organs and tumor lesions by using ⁶⁸Ga-PSMA-11 PET imaging. <b>Methods:</b> Sixteen men with prostate cancer were randomized (1:1) into oral ingestion and oral topical application ("swishing") arms. Each subject underwent 2 ⁶⁸Ga-PSMA-11 PET/CT scans within 14 d under baseline and MSG conditions. The salivary glands and whole-body tumor lesions were segmented using qPSMA software. We quantified tracer uptake via SUV_mean and SUV_max and compared parameters within each patient. <b>Results:</b> For the oral ingestion arm, salivary gland SUV_mean and SUV_max decreased on average from the control scan to the MSG scan by 45% ± 15% (<i>P</i> = 0.004) and 53% ± 11% (<i>P</i> < 0.001), respectively. Tumor lesion SUV_mean and SUV_max also decreased by 38% (interquartile range, -67% to -33%) and -52% (interquartile range, -70% to -49%), respectively (<i>P</i> = 0.018). Swishing had no significant effect on ⁶⁸Ga-PSMA-11 accumulation in normal organs or tumor lesions. <b>Conclusion:</b> Oral ingestion but not topical application of MSG reduced ⁶⁸Ga-PSMA-11 uptake in salivary glands. Tumor uptake also declined; therefore, the clinical application of MSG is unlikely to be useful in the framework of RLT.Journal of nuclear medicine : official publication, Society of Nuclear MedicineThe Impact of Monosodium Glutamate on ⁶⁸Ga-PSMA-11 Biodistribution in Men with Prostate Cancer: A Prospective Randomized, Controlled Imaging Study.PMC9364769P30 CA016042P50 CA092131Dahlbom MArmstrong WRAlano RThin PElashoff DNguyen KCzernin JGardner LLira SGafita AGrogan TCalais JAllen-Auerbach MZhu SBooker KfalseThe Impact of Monosodium Glutamate on ⁶⁸Ga-PSMA-11 Biodistribution in Men with Prostate Cancer: A Prospective Randomized, Controlled Imaging Study.The prostate-specific membrane antigen (PSMA) has been targeted for PET imaging and radioligand therapy (RLT) in patients with prostate cancer. Xerostomia is a common side effect of RLT because of the high salivary gland uptake of PSMA radioligands. Here, we aimed to determine the impact of monosodium glutamate (MSG) administration on PSMA-radioligand biodistribution within healthy organs and tumor lesions by using ⁶⁸Ga-PSMA-11 PET imaging. <b>Methods:</b> Sixteen men with prostate cancer were randomized (1:1) into oral ingestion and oral topical application ("swishing") arms. Each subject underwent 2 ⁶⁸Ga-PSMA-11 PET/CT scans within 14 d under baseline and MSG conditions. The salivary glands and whole-body tumor lesions were segmented using qPSMA software. We quantified tracer uptake via SUV_mean and SUV_max and compared parameters within each patient. <b>Results:</b> For the oral ingestion arm, salivary gland SUV_mean and SUV_max decreased on average from the control scan to the MSG scan by 45% ± 15% (<i>P</i> = 0.004) and 53% ± 11% (<i>P</i> < 0.001), respectively. Tumor lesion SUV_mean and SUV_max also decreased by 38% (interquartile range, -67% to -33%) and -52% (interquartile range, -70% to -49%), respectively (<i>P</i> = 0.018). Swishing had no significant effect on ⁶⁸Ga-PSMA-11 accumulation in normal organs or tumor lesions. <b>Conclusion:</b> Oral ingestion but not topical application of MSG reduced ⁶⁸Ga-PSMA-11 uptake in salivary glands. Tumor uptake also declined; therefore, the clinical application of MSG is unlikely to be useful in the framework of RLT.2021-01-01T00:00:00Z2021 Sep2024-11-08T14:32:54.524Z2024-11-08T14:32:54.524ZS-EPMC93647693350997410.2967/jnumed.120.257931