Biochemically recurrent prostate cancer (BCR) is the main indication to perform prostate-specific membrane antigen PET/CT. However, localizing BCR with prostate-specific membrane antigen PET/CT remains challenging in patients with low prostate-specific antigen (PSA) values. Here, we studied the impact of advanced PET image reconstruction methods on BCR localization and interobserver agreement with ¹⁸F-DCFPyL PET/CT scans in patients with BCR and low PSA values. Methods: Twenty-four patients with BCR and a PSA level of less than 2.0 ng/mL were included. PET images were reconstructed with 4-mm voxels and 2-mm voxels, both with and without point-spread function. All scans were interpreted by 4 nuclear medicine physicians. Additionally, PET examinations of 5 patients with primary prostate cancer and confirmed absence of lymph node metastases (after lymph node dissection) were included, to assess the risk of introducing false-positive findings when using advanced reconstruction. Calculation of BCR localization rates (scan positivity) was based on consensus among our readers (≥3 readers regarding a scan positive for BCR), as well as the individual scan interpretations of the readers. Results: In the consensus analysis, BCR localization rates were not higher using advanced reconstruction (62.5%–66.7%) than using 4-mm reconstruction (62.5%). On the basis of individual readings, however, more scans were positive using 2-mm reconstruction (74.0%; 95% confidence interval [CI], 65.0%–82.9%) (P = 0.027) and 2-mm reconstruction with point-spread function (75.0%; 95% CI, 66.2%–83.8%) (P = 0.014) than 4-mm reconstruction (65.6%; 95% CI, 56.0%–75.3%). A higher number of lesions was detected on the 2-mm scans (median, 2 lesions; interquartile range, 1–3) than the 4-mm scans (median, 1; interquartile range, 0–3; P = 0.008). The advanced reconstruction methods did not increase interobserver agreement (80.6%–84.7%), compared with the 4-mm scans (75.7%, P = 0.08–0.25). In the patients with primary prostate cancer, an equal number of false-positive lesions was observed among the different reconstruction methods (overall, n = 13). Conclusion: Applying advanced image reconstruction for ¹⁸F-DCFPyL PET/CT scans did not increase BCR localization in patients with BCR and low PSA values (reader consensus). Yet, the increased number of positive individual readings may imply that further development of image reconstruction methods holds potential to improve BCR localization. No improved interobserver agreement was observed with advanced reconstruction compared with standard 4-mm reconstruction.

生化复发性前列腺癌（BCR）是进行前列腺特异性膜抗原PET / CT的主要指征。但是，在前列腺特异性抗原（PSA）值较低的患者中，用前列腺特异性膜抗原PET / CT定位BCR仍然具有挑战性。在这里，我们用¹⁸ F-DCFPyL PET / CT扫描对BCR和PSA值低的患者进行了先进的PET图像重建方法对BCR定位和观察者间一致性的影响。方法：包括二十四例BCR和PSA低于2.0 ng / mL的患者。用4毫米体素和2毫米体素重建PET图像，同时具有和不具有点扩展功能。所有扫描均由4位核医学医师进行解释。此外，还包括对5例原发性前列腺癌患者的PET检查，并证实其没有淋巴结转移（淋巴结清扫后），以评估在进行晚期重建时引入假阳性结果的风险。BCR定位率（扫描阳性）的计算基于我们读者之间的共识（对于BCR的扫描阳性，≥3位读者），以及读者的个别扫描解释。结果：在共识分析中，采用先进重建（62.5％–66.7％）的BCR定位率不高于使用4-mm重建（62.5％）的BCR定位率。然而，根据个体读数，使用2-mm重建（74.0％； 95％置信区间[CI]，65.0％–82.9％）（P = 0.027）和采用点扩散的2-mm重建的更多扫描为阳性功能（75.0％; 95％CI，66.2％–83.8％）（P = 0.014）比4 mm重建（65.6％; 95％CI，56.0％–75.3％）。在2毫米扫描（中位数，2个病变；四分位间距1–3）上检测到的病灶数量比4毫米扫描（中位数，1；四分位间距0-3，P = 0.008）更高。先进的重建方法并未增加观察者之间的一致性（80.6％–84.7％），而进行4毫米扫描（75.7％，P = 0.08–0.25）。在原发性前列腺癌患者中，在不同的重建方法中观察到相同数量的假阳性病变（总体，n = 13）。结论：对^18例F-DCFPyL PET / CT扫描进行高级图像重建，不会增加BCR和PSA值低的患者的BCR定位（读者共识）。然而，阳性个体读数数量的增加可能意味着图像重建方法的进一步发展具有改善BCR定位的潜力。与标准的4 mm重建相比，高级重建未观察到改善的观察者间一致性。