KEY POINTS
- This prospective clinical-trial dataset included 22 patients receiving postoperative radiotherapy after breast-conserving surgery. Treatment comprised 50 Gy in 25 fractions, followed by a 16 Gy boost in 8 fractions; 247 surface scans were analysed.
- A handheld structured-light scanner acquired torso surfaces before treatment, every five fractions, and at one and three months after radiotherapy. A functional-map framework established nonrigid correspondence between scans and the planning computed tomography surface.
- Mean treated-breast surface displacement across sessions was 1.62 ± 0.72 mm. During treatment, the highest group average occurred at fraction 25: 1.84 ± 1.05 mm.
- Mean displacement increased after treatment to 1.98 ± 0.62 mm at one month and 2.82 ± 1.56 mm at three months. Individual patients showed substantially larger localized changes.
- Average relative volume change across sessions was 3.54% ± 3.16%, increasing to 5.34% ± 6.30% at fraction 25 and 9.93% ± 6.98% at three months. The study did not evaluate dose-distribution changes or define replanning thresholds.
CLINICAL TAKEAWAY
Longitudinal surface analysis may help breast radiotherapy teams identify patients with atypical anatomical change and select cases for additional imaging or dose review. However, acquisitions were operator-dependent, the cohort was small, and no dosimetric consequences were assessed, making this technically relevant rather than practice-changing.