光影之外：攝護腺癌骨掃描解剖盲點之探索——與正子造影影像之回顧性比較

王伯皓¹林益聖¹ 許兆畬¹ 歐宴泉¹ 童敏哲¹

¹童綜合醫療社團法人童綜合醫院 外科部 泌尿科

Anatomical Blind Spots of Whole-Body Bone scan Compared to PET/CT in Prostate Cancer: A Retrospective Cohort Study

Po-Hao Wang¹, Yi-Sheng Lin¹, Chao-Yu Hsu¹, Yen-Chuan Ou¹, Min-Che Tung¹

¹Division of Urology, Department of Surgery, Tungs' Taichung Metroharbor Hospital

Introduction

Accurate bone metastasis detection is essential for prostate cancer staging. While Whole-Body Bone Scan (WBBS) is the conventional standard, it lacks the sensitivity of advanced PET imaging (NaF, Axumin, PSMA). This study compares these modalities to identify anatomical "blind spots" where WBBS frequently fails to detect metastatic disease.

Material and Methods

We conducted a retrospective analysis of 124 imaging pairs from 107 unique patients diagnosed with prostate cancer (mean age at diagnosis: 65.5 years). The cohort was characterized by aggressive disease, with a median initial PSA of 27.24 ng/mL and 68% patients possessing a Gleason score above 8. Imaging was performed at an average interval of 2.63 years post-diagnosis. WBBS findings (Scores 1–4) were cross-referenced with PET/CT (NaF, Axumin, or PSMA) results within a 3-month interval. "Blind spots" were defined as anatomical locations where PET/CT identified definitive malignancy (Score 3–4) while WBBS recorded non-suspicious findings (Score ≤2).

Results

Advanced imaging demonstrated significantly higher sensitivity for detecting metastatic lesions compared to WBBS. The primary "blind spots" of WBBS were predominantly concentrated in the axial and proximal appendicular skeleton, with the ribs identified as the most frequent site of missed detection, followed by the scapulae, pelvic girdle, and skull/facial bones. Subgroup analysis of high-risk patients (Gleason score > 8, Stage ≥ T3, or initial PSA > 20 ng/mL) revealed that the frequency and distribution of these anatomical blind spots were consistent with the overall cohort. Furthermore, these blind spots were prevalent across all PSA ranges, and no significant correlation was found between the initial PSA level and the occurrence of missed metastatic lesions.

Conclusion

WBBS frequently under-stages prostate cancer due to significant blind spots in the scapulae, pelvis, and rib fragments. We mapped the anatomical distribution of WBBS false-negative sites ("blind spots") in a paired-imaging cohort, providing practical guidance on where to be cautious when WBBS is negative but high metastatic suspicion, early PET-based imaging is recommended.