The Impact of Peptide Amount on Tumor Uptake to Assess PSMA Receptor Saturation on 68 Ga-PSMA-11 PET/CT in Patients with Primary Prostate Cancer.

Autor: Siebinga H; Department of Nuclear Medicine, Netherlands Cancer Institute, Amsterdam, The Netherlands.; Department of Pharmacy and Pharmacology, Netherlands Cancer Institute, Amsterdam, The Netherlands; and., Heuvel JO; Department of Nuclear Medicine, Netherlands Cancer Institute, Amsterdam, The Netherlands., Rijkhorst EJ; Department of Medical Physics and Technology, Netherlands Cancer Institute, Amsterdam, The Netherlands., Hendrikx JJMA; Department of Nuclear Medicine, Netherlands Cancer Institute, Amsterdam, The Netherlands.; Department of Pharmacy and Pharmacology, Netherlands Cancer Institute, Amsterdam, The Netherlands; and., de Wit-van der Veen BJ; Department of Nuclear Medicine, Netherlands Cancer Institute, Amsterdam, The Netherlands; l.vd.veen@nki.nl.
Jazyk: angličtina
Zdroj: Journal of nuclear medicine : official publication, Society of Nuclear Medicine [J Nucl Med] 2023 Jan; Vol. 64 (1), pp. 63-68. Date of Electronic Publication: 2022 Jun 09.
DOI: 10.2967/jnumed.122.264101
Abstrakt: 68 Ga-labeled prostate-specific membrane antigen (PSMA) is often produced on-site, where usually a fixed amount of peptide is conjugated to the generator eluate. However, fluctuations in specific activity might influence tracer distribution and tumor accumulation. Therefore, our aim was to investigate the potential effect of varying the administered peptide amount on 68 Ga-PSMA-11 uptake in tumors using PET/CT in patients with primary prostate cancer (PCa). Additionally, the impact of tumor volume on this potential effect and on accumulation in reference organs was assessed. Methods: The imaging data of 362 men with primary PCa who underwent 68 Ga-PSMA-11 PET/CT were retrospectively included. Scans were quantified for normal tissue and primary tumors. Patients were divided into 3 groups based on their tumor volume. Correlation and multivariable linear regression analyses were performed. Results: The median index lesion volume was 9.50 cm 3 (range, 0.064-174 cm 3 ). Groups were based on quartiles of prostatic lesion volume: ≤4.11 cm 3 (group 1), 4.11-20.6 cm 3 (group 2), and ≥20.6 cm 3 (group 3). No correlation was found between administered peptide amount and tumor uptake (SUV mean or SUV peak ) for any group, except for a significant correlation for SUV mean in the first group ( P = 0.008). Linear regression analysis supported these findings. Conclusion: The amount of administered peptide had no evident effect on 68 Ga-PSMA-11 uptake in tumors, except for a significant positive correlation between administered peptide amount and tumor SUV mean for group 1. The findings imply that no receptor saturation occurs in men with primary PCa at peptide levels of about 2.5 μg.
(© 2023 by the Society of Nuclear Medicine and Molecular Imaging.)
Databáze: MEDLINE
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