Journal Article

Dosimetry and optimal scan time of 18FSiTATE-PET/CT in patients with neuroendocrine tumours

Böning Guido, Cyran, Clemens C, Wängler Björn, Jurkschat Klaus, Schirrmacher Ralf, Auernhammer, Christoph J, Gosewisch Astrid, Unterrainer Marcus, Gildehaus, F J, Mittlmeier, Lena M, Spitzweg, Christine, Völter Friederike, Beyer, Leonie, Todica Andrei, Harun, Ilhan, Tiling Reinhold, Brendel Matthias, Wenter Vera, Wängler Carmen, Lindner, Simon, Rübenthaler Johannes, Bartenstein, Peter

2021

Overview

PurposeRadiolabelled somatostatin analogues targeting somatostatin receptors (SSR) are well established for combined positron emission tomography/computer tomography (PET/CT) imaging of neuroendocrine tumours (NET). [18F]SiTATE has recently been introduced showing high image quality, promising clinical performance and improved logistics compared to the clinical reference standard 68Ga-DOTA-TOC. Here we present the first dosimetry and optimal scan time analysis.MethodsEight NET patients received a [18F]SiTATE-PET/CT (250 ± 66 MBq) with repeated emission scans (10, 30, 60, 120, 180 min after injection). Biodistribution in normal organs and SSR-positive tumour uptake were assessed. Dosimetry estimates for risk organs were determined using a combined linear-monoexponential model, and by applying 18F S-values and reference target masses for the ICRP89 adult male or female (OLINDA 2.0). Tumour-to-background ratios were compared quantitatively and visually between different scan times.ResultsAfter 1 h, normal organs showed similar tracer uptake with only negligible changes until 3 h post-injection. In contrast, tracer uptake by tumours increased progressively for almost all types of metastases, thus increasing tumour-to-background ratios over time. Dosimetry resulted in a total effective dose of 0.015 ± 0.004 mSv/MBq. Visual evaluation revealed no clinically relevant discrepancies between later scan times, but image quality was rated highest in 60 and 120 min images.Conclusion[18F]SiTATE-PET/CT in NET shows overall high tumour-to-background ratios from 60 to 180 min after injection and an effective dose comparable to 68Ga-labelled alternatives. For clinical use of [18F]SiTATE, the best compromise between image quality and tumour-to-background contrast is reached at 120 min, followed by 60 min after injection.

• Publisher: Springer Nature B.V
• Subject: Computed tomography / Dosimeters / Dosimetry / Fluorine isotopes / Image contrast / Image quality / Injection / Logistics / Medical imaging / Metastases / Neuroendocrine tumors / Organs / Patients / Positron emission / Positron emission tomography / Somatostatin / Somatostatin receptors / Tomography / Tumors