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Updated: Oct 25, 2026

Voluntary Breath-hold Technique for Reducing Heart Dose in Left Breast Radiotherapy
Published on: July 3, 2014
Respiratory Instability-driven Cardiac Dose Deviation in Postmastectomy Deep Inspiration Breath-hold Volumetric
1Department of Radiation Oncology, Amrita School of Medicine, Amrita Vishwa Vidyapeetham, Faridabad, Haryana, India.
Aims:
Deep inspiration breath-hold (DIBH) reduces cardiac exposure during left-sided breast radiotherapy; however, treatment-day cardiac dose may differ from the planned dose because of variations in respiratory reproducibility and anatomy. The aim of this study was to develop and validate a framework for predicting fraction-level cardiac dose variation using routinely acquired respiratory, anatomical, and dosimetric information.
Materials And Methods:
A retrospective cohort of 150 patients treated with postmastectomy DIBH VMAT (volumetric modulated arc therapy) was analyzed. Models were developed using a 30-patient development cohort with patient-wise-nested cross-validation, externally validated in 20 independent patients using cone-beam CT-derived synthetic CT dose recalculation, and applied to a 100-patient deployment cohort. Separate models predicted deviation from planned per-fraction mean heart dose (ΔMHD) and left anterior descending coronary artery dose (ΔLADCA D0.03 cc) using treatment-day real-time position management (RPM)--derived respiratory features, planning computed tomography (CT)-derived geometric variables, and plan-derived dosimetric parameters. SHAP-based analysis was performed to identify influential predictors.
Results:
The final Gradient Boosting model for ΔMHD achieved an internal validation mean absolute error (MAE) of 0.541 ± 0.035 centigray (cGy) and coefficient of determination (R2) of 0.642 ± 0.069. The Ridge Regression model for left anterior descending coronary artery (ΔLADCA) achieved an MAE of 23.413 ± 1.617 cGy and R2 of 0.413 ± 0.082. External validation demonstrated good agreement for ΔMHD (MAE 0.58 cGy, R2 = 0.641), whereas ΔLADCA showed lower performance (MAE 24.14 cGy, R2 = 0.435). Stability index and baseline drift were key predictors.
Conclusion:
Treatment-day-respiratory characteristics combined with anatomical and dosimetric variables can estimate fraction-level cardiac dose variation during DIBH radiotherapy. The framework may support verification-based clinical review, with further validation required before implementation.
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