Real-time phase-dependent occupational radiation exposure analysis in full-endoscopic spine surgery

Full-endoscopic spine surgery performed under local anesthesia offers clinical advantages, particularly for elderly patients. However, its reliance on fluoroscopy raises concerns about occupational radiation exposure. Although several studies have evaluated cumulative radiation dose, real-time data identifying specific high-risk phases of surgery remain limited. This study aimed to clarify phase-dependent scatter radiation patterns and identify targets for effective protection. We analyzed real-time personal dose equivalent, Hp(10), measured over the protective apron (over-apron Hp(10)) in 28 FESS cases using RaySafe i3 dosimeters across four staff roles: operator, assistant, supervisor, and scrub nurse. Surgical procedures were divided into three phases: Phase 1 (Marking), Phase 2 (Setup), and Phase 3 (Check). The operator showed the highest median total over-apron Hp(10) per case (0.244 mSv), significantly exceeding other staff (p < 0.001), with an operator-to-nurse over-apron Hp(10) ratio of approximately 51.9:1. Phase-based analysis demonstrated that the operator's over-apron Hp(10) was heavily concentrated in Phase 2 (Setup) (median 0.194 mSv), significantly higher than Phase 1 and Phase 3 (p < 0.001). No significant difference in total over-apron Hp(10) was found among surgical approaches. In conclusion, although FESS is minimally invasive for patients, the Setup phase represents a critical target for radiation safety. These anatomical and spatial observations suggest that further investigation into behavioral modifications, such as the use of single-shot fluoroscopy and maximizing operator distance during sheath placement, is warranted to reduce occupational radiation risk.