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Updated: Apr 11, 2026
Voluntary Breath-hold Technique for Reducing Heart Dose in Left Breast Radiotherapy
Published on: July 3, 2014
Using deformable registration to assess dosimetric impact of variability in deep inspiration breath hold (DIBH)
Venketesh Thrithamara Ranganathan1, Amy Gouthro1, Tynan Stevens1
1Department of Radiation Oncology, Cape Breton Cancer Center, Sydney, Nova Scotia, Canada.
Background:
In deep inspiration breath hold (DIBH) left breast radiation treatment, dosimetric impact of variation within breath hold (BH) tolerances has not been precisely quantified.
Purpose:
Estimate target and organs at risk (OAR) dose variations due to patient movements within BH target tolerances, and assess impacts on 3DCRT, VMAT and pseudo skin flash planning.
Methods:
Twenty patients who underwent left breast DIBH treatment with 4000 cGy in 15 fractions using 3DCRT or VMAT were retrospectively selected. A combination of deformable registration and breathing traces from CT simulation were used to generate CT volumes corresponding to ± 5 mm about the BH target. 3DCRT clinical treatment plans were applied directly to the generated CT volumes. For VMAT, new optimizations were performed on the target BH CT scan to achieve target dose within ± 0.5 % of the treated plan. The re-optimized plan was applied to the generated CT volumes to estimate the organ doses. Pseudo skin flash treatment plans were created for the VMAT patients using the same optimization parameters, and applied to the generated CT volumes. Target coverage (D95), heart, lung, and breast mean doses, and heart hotspot (D1cc) were evaluated at each deviation.
Results:
Deformable registration demonstrated relative motion of the target and OARs not previously observed with simple rigid registration methods. Target coverage in 3DCRT plans were more robust against BH target variation compared to VMAT and pseudo skin flash. However, pseudo skin flash show comparable target coverage to 3DCRT for BH target overshoot. With 3DCRT, the heart hot spot shows significant individual variations in the undershoot regime.
Conclusion:
Deformable registration-based dose estimation reveals complex organ motion with significant individual variability in plan robustness. 3DCRT is less sensitive to BH variability than VMAT. Our protocol potentially enables individualized approach to selecting technique and tolerances based on patients' DIBH movements.
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