Author: Wesley A. Belcher, Aidan Burke, Matthew Green, Taylor Stamey 👨🔬
Affiliation: ECU Health, East Carolina University Brody School of Medicine 🌍
Purpose: The purpose of this study was to determine the effect of using deep inhalation breath hold (DIBH) vs. free breathing (FB) and intensity-modulated radiation therapy (IMRT) vs. 3D for right-sided breast radiation therapy dose to normal tissue structures.
Methods: 4 patients’ data were included in this IRB-approved study. Each patient had an IMRT and a 3D plan created on their DIBH and their FB CT scan. 2 patients were receiving whole breast plus lymph nodes and the other 2 patients were receiving whole breast only. The physician contoured substructures of the heart for the study. Dose metrics were calculated for each patient and plan. A two mean t-test was used to compare DIBH vs. FB for both IMRT and 3D plnas, as well as IMRT vs. 3D on both FB and DIBH scans. The right coronary artery (RCA), right ventricle, left anterior descending aorta (LAD), and heart had the dose to 0.03 cc, mean dose, and percent of their volume getting 5 Gy were used as dose metrics. The right lung and total lung had their mean and percent of volume getting 20 Gy compared.
Results: When comparing DIBH vs. FB, all metrics that had a significant difference were better for DIBH scans for both IMRT and 3D, except for one metric that was better on the FB scan for 3D (right ventricle 0.03 cc dose). When comparing 3D and IMRT, the IMRT plan had worse dose metrics regardless of the type of scan.
Conclusion: For most constraints DIBH is better than FB. IMRT had worse dose constraints than 3D for the plans. While mean dose to the heart does not reach concerning levels for IMRT, the dose to critical cardiac substructures is worse for IMRT.