Head-to-head comparison between 68Ga-PSMA and 18F-FDG-PET/CT in lymphomas: a preliminary analysis

Author(s)

de Souza, Stephan Pinheiro Macedo ^[1] ; Tobar, Natalia ^[1] ; Frasson, Fernanda ^[1] ; Perini, Efrain Araujo ^[2] ; de Souza, Carmino A. ^[3] ; Delamain, Marcia T. ^[3] ; Ramos, Celso Dario ^[1]

Affiliation

^[1] Univ Campinas UNICAMP, Fac Med Sci, Dept Radiol, Div Nucl Med, Sao Paulo - Brazil

^[2] Nucl & Energy Res Inst IPEN, Sao Paulo - Brazil

^[3] Univ Campinas UNICAMP, Dept Internal Med, Div Hematol, Fac Med Sci, Sao Paulo - Brazil

• Document type: Journal article
• Source: NUCLEAR MEDICINE COMMUNICATIONS; v. 42, n. 12, p. 1355-1360, DEC 2021.
• Web of Science Citations: 0

Abstract

Purpose Isolated case reports mention the uptake of radiolabeled PSMA in lymphoma. However, it is not clear if the intensity of 68Ga-PSMA expression varies among different histological subtypes or if it correlates with 18F-FDG uptake. This study compared both tracers in patients with diverse lymphoma subtypes. Methods Ten patients with biopsy-proven-lymphoma underwent 18F-FDG and 68Ga-PSMA-PET/CT (maximum time interval: 6 days). Lymphoma subtypes included Hodgkin's lymphoma (HL, three patients) and aggressive and indolent non-Hodgkin's lymphoma (NHL, seven patients). The intensity of PSMA uptake was classified visually as low, intermediate, or high, using blood pool, liver and parotid gland uptake as references. Maximum standardized-uptake value (SUVmax) of each affected site was measured in both sets of images. Results FDG detected 59/59 involved sites in 10 patients and PSMA 47/59 sites in nine patients. PSMA uptake was generally low, regardless of the intensity of FDG uptake, but it was classified as intermediate in two patients. The median SUVmax varied from 2.0 (2.0-8.2) to 30.9 for FDG and from 1.7 (1.7-1.7) to 4.4 for PSMA, P < 0.0001. The primary lesion of one patient had a marked intralesional mismatch uptake pattern of the tracers, with areas of higher PSMA expression than FDG uptake, and vice-versa. A brain lesion was more easily identified with PSMA than with FDG images. Conclusion HL and several NHL subtypes may present PSMA uptake. The intensity of PSMA expression is generally lower than that of FDG uptake and seems to present less variation among the different histological subtypes of lymphomas. (AU)

• FAPESP's process: 18/00654-4 - Comparison between Neovascularization and Cellular Hypermetabolism in Multiple Myeloma Using 68Ga-PSMA and 18F-FDG PET/CT Imaging - A Pilot Study
• Grantee: Celso Darío Ramos
• Support Opportunities: Regular Research Grants
• FAPESP's process: 09/54065-0 - Acquisition of a PET/CT for the quantification of metabolic activity in living tissue
• Grantee: Carmino Antonio de Souza
• Support Opportunities: Multi-user Equipment Program