PT - JOURNAL ARTICLE AU - Trautwein, Nils F. AU - Mattern, Sven AU - Hinterleitner, Martina AU - Reischl, Gerald AU - Schirrmacher, Ralf AU - Steger, Volker AU - Nadalin, Silvio AU - Nikolaou, Konstantin AU - Schwenck, Johannes AU - Singer, Stephan AU - la Fougère, Christian TI - Histologic Ex Vivo Validation of the [<sup>18</sup>F]SITATE Somatostatin Receptor PET Tracer AID - 10.2967/jnumed.125.269619 DP - 2025 May 22 TA - Journal of Nuclear Medicine PG - jnumed.125.269619 4099 - http://jnm.snmjournals.org/content/early/2025/05/22/jnumed.125.269619.short 4100 - http://jnm.snmjournals.org/content/early/2025/05/22/jnumed.125.269619.full AB - Radiolabeled somatostatin analogs (SSAs), such as [68Ga]Ga-DOTA SSAs, have transformed imaging and therapeutic strategies. However, their use is constrained by the high cost of generators and their short half-life. In contrast, [18F]SITATE presents a promising alternative, offering the advantage of a longer half-life than 68Ga, along with the cost-effectiveness of cyclotron-based production. This study evaluated the first histologic ex vivo validation of [18F]SITATE. Methods: This study retrospectively included 47 patients (57% male; mean age, 66.9 ± 14.9 y) with histologically confirmed well-differentiated neuroendocrine neoplasms who underwent [18F]SITATE PET followed by surgery within 4 mo. Lesion uptake was quantified using SUVmean, SUVpeak, SUVmax, and tumor-to-liver ratio (TLR). Histologic somatostatin receptor (SSTR) type 2 expression was determined using histological scores (H-scores), with thresholds defining SSTR scores 1–3. The accuracy of PET imaging for preoperative metastatic detection was evaluated against surgical histology. Results: PET imaging demonstrated a significant correlation between [18F]SITATE uptake (SUVmean and TLR) and SSTR type 2 H-scores (r = 0.618 and 0.622, respectively; P &lt; 0.0001). SSTR score 3 correlated with increased SUVmean and TLR (P &lt; 0.0001). Among 35 patients with primary resection and lymphadenectomy, PET achieved a sensitivity of 73.9% and specificity of 100%. Conclusion: [18F]SITATE PET imaging strongly correlates with histologic SSTR expression, demonstrating utility in staging and guiding therapeutic decisions in neuroendocrine neoplasms. This 18F-labeled tracer shows specificity comparable to historical [68Ga]Ga-DOTA SSA data, whereas an increase in sensitivity for the detection of locoregional metastases appears possible. Further head-to-head comparisons of [18F]SITATE with traditional [68Ga]Ga-DOTA SSA and histologic validation are warranted to optimize its diagnostic accuracy and clinical impact.