To evaluate the clinical value of thermo-optical surface monitoring + X-ray guidance system (ExacTrac Dynamic, ETD) in assessing inter-fraction setup accuracy and intra-fraction motion monitoring during deep inspiration breath-hold (DIBH) radiotherapy after breast-conserving surgery for breast cancer.
Approach:
Statistical Analysis: Linear mixed-effects models were applied to analyze inter-fraction setup errors from CBCT and intra-fraction errors from X-ray imaging.
Key Findings:
Calculated planning target volume (PTV) margins were 5.10 mm (lateral), 5.22 mm (longitudinal), and 5.78 mm (vertical) based on the van Herk formula.
Interpretation:
ETD provides setup accuracy comparable to CBCT with a lower radiation dose, allowing stable real-time intra-fraction monitoring and enhancing treatment precision.
Limitations:
The study was limited to a small sample size of 31 patients.
Data were collected from a single center, which may affect generalizability.
Conclusion:
ETD enhances treatment precision in DIBH radiotherapy for breast cancer by providing accurate setup verification and intra-fraction monitoring.
Harold Burstein, MD, PhD, and Ana C. Garrido-Castro, MD discuss results from the Saci-IO HR+ trial, which were presented at the 2026 ESMO Breast Cancer Congress.
