TY - JOUR T1 - Delayed Imaging Improves Lesion Detectability in [<sup>99m</sup>Tc]Tc-PSMA-I&amp;S SPECT/CT in Recurrent Prostate Cancer JF - Journal of Nuclear Medicine JO - J Nucl Med DO - 10.2967/jnumed.122.265252 SP - 265252 AU - Christoph Berliner AU - Lisa Steinhelfer AU - Maythinee Chantadisai AU - Markus Kroenke AU - Daniel Koehler AU - Randi Pose AU - Peter Bannas AU - Sophie Knipper AU - Matthias Eiber AU - Tobias Maurer Y1 - 2023/05/25 UR - http://jnm.snmjournals.org/content/early/2023/05/25/jnumed.122.265252.abstract N2 - Our objective was to compare the ability to detect histopathologically confirmed lymph node metastases by early and delayed [99mTc]Tc-PSMA-I&amp;S SPECT/CT in early biochemically recurrent prostate cancer. Methods: We retrospectively analyzed 222 patients selected for radioguided surgery using [99mTc]Tc-PSMA-I&amp;S SPECT/CT at different time points after injection (≤4 h and &gt;15 h). In total, 386 prostate-specific membrane antigen (PSMA) PET predetermined lesions were analyzed on SPECT/CT using a 4-point scale, and the results were compared between early and late imaging groups, with uni- and multivariate analyses performed including prostate-specific antigen, injected [99mTc]Tc-PSMA-I&amp;S activity, Gleason grade group, initial TNM stage, and, stratified by size, PSMA PET/CT–positive lymph nodes. PSMA PET/CT findings served as the standard of reference. Results: [99mTc]Tc-PSMA-I&amp;S SPECT/CT had a significantly higher positivity rate for detecting lesions in the late than the early imaging group (79%, n = 140/178, vs. 27%, n = 12/44 [P &lt; 0.05] on a patient basis; 60%, n = 195/324, vs. 21%, n = 13/62 [P &lt; 0.05] on a lesion basis). Similar positivity rates were found when lesions were stratified by size. Multivariate analysis found that SUVmax on PSMA PET/CT and the uptake time of [99mTc]Tc-PSMA-I&amp;S were independent predictors for lesion detectability on SPECT/CT. Conclusion: Late imaging (&gt;15 h after injection) should be preferred when [99mTc]Tc-PSMA-I&amp;S SPECT/CT is used for lesion detection in early biochemical recurrence of prostate cancer. However, the performance of PSMA SPECT/CT is clearly inferior to that of PSMA PET/CT. ER -