Journal Article

DKFZ-2025-00262

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png One-day dual-tracer examination in neuroendocrine neoplasms: a real advantage of low activity LAFOV PET imaging.

Calderón, E. ; Kiefer, L. S. ; Schmidt, F. P. ; Lan, W. ; Brendlin, A. S. ; Reinert, C. P. ; Singer, S. ; Reischl, G. ; Hinterleitner, M. ; Dittmann, H. ; la Fougère, C.DKFZ* ; Trautwein, N. F.

2025
Springer-Verl. Heidelberg [u.a.]

Abstract: Somatostatin receptor (SSTR)-PET is crucial for effective treatment stratification of neuroendocrine neoplasms (NENs). In highly proliferating or poorly differentiated NENs, dual-tracer approaches using additional [18F]FDG PET can effectively identify SSTR-negative disease, usually requiring separate imaging sessions. We evaluated the feasibility of a one-day dual-tracer imaging protocol with a low activity [18F]FDG PET followed by an SSTR-PET using the recently introduced [18F]SiFAlin-TATE tracer in a long axial field-of-view (LAFOV) PET/CT scanner and its implications in patient management.Twenty NEN patients were included in this study. Initially, a low activity [18F]FDG PET was performed (0.5 ± 0.01 MBq/kg; PET scan 60 min p.i.). After 4.2 ± 0.09 h after completion of the [18F]FDG PET, a standard activity of [18F]SiFAlin-TATE was administered (3.0 MBq/kg; PET scan 90 min p.i.). To ensure the quantification accuracy of the second scan, we evaluated the potential impact of residual [18F]FDG activity by segmenting organs with minimal physiological SSTR-tracer uptake, such as the brain and myocardium, and assessing the activity concentrations (ACTs) of tumor lesions. Residual tumor lesion ACTs of [18F]FDG were calculated by factoring fluorine-18 decay, identifying a maximum residual ACT of 15% (R15%). To account for increased [18F]FDG trapping over time, higher residual ACTs of 20% (R20%) were considered. These simulated [18F]FDG ACTs were compared with those measured in the second PET scan with [18F]SiFAlin-TATE. The influence of the dual-tracer PET/CT results on therapeutic strategies was evaluated.[18F]FDG cerebral uptake significantly decreased in the subsequent SSTR-PET (mean uptake [18F]FDG: SUVmean 6.0 ± 0.4; mean uptake in [18F]SiFAlin-TATE PET: SUVmean 0.2 ± 0.01; p < 0.0001); with similar results recorded for the myocardium. Simulated residual [18F]FDG ACTs represented only a minimal percentage of ACTs measured in the tumor lesions from the second PET scan (R15%: mean 5.2 ± 0.9% and R20%: mean 6.8 ± 1.2%), indicating only minimal residual activity of [18F]FDG that might interfere with the second PET scan using [18F]SiFAlin-TATE and preserved semi-quantification of the latter. Dual-tracer PET/CT findings directly influenced changes in therapy plans in eleven (55%) of the examined patients.LAFOV PET scanners enable a one-day dual-tracer protocol, providing diagnostic image quality while preserving the semi-quantification of two 18F-labeled radiotracers, potentially simplifying the assessment of tumor biology and improving the clinical patient management while reducing logistical challenges. Additionally, low-activity PET imaging facilitates one-day dual-tracer PET examinations.

Keyword(s): Dual-tracer PET ; LAFOV PET/CT ; Low activity [18F]FDG PET ; Neuroendocrine neoplasms

Note: 2025 Jun;52(7):2463-2476

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Contributing Institute(s):

1. DKTK Koordinierungsstelle Tübingen (TU01)

Research Program(s):

1. 899 - ohne Topic (POF4-899) (POF4-899)

Appears in the scientific report 2025

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Clinical Medicine ; Current Contents - Life Sciences ; DEAL Springer ; Ebsco Academic Search ; Essential Science Indicators ; IF >= 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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