Application of Deep Inspiration Breath Hold Technique in Radiotherapy After Breast- Conserving Surgery for Left Breast Cancer and Its Improvement on Cardiac Dose

Objective: To analyze the application of deep inspiration breath hold technique in radiotherapy after breast-conserving surgery for left breast cancer and the improvement of cardiac dose. Methods: A total of 45 patients with left breast cancer treated in our hospital after breast-conserving surgery were selected, and the selection time was set from January 2020 to August 2022. All patients received radiotherapy. The right breast, heart, and lung volumes, and dose parameters of the heart, lungs, right breast, and left anterior descending coronary artery were compared under free breathing (FB) and deep inspiration breath hold (DIBH) technical modes. Results: The heart volume of the DIBH group was smaller than that of the FB group, and the left and right lung volumes were significantly larger than those of the FB group. In the DIBH group, the heart dose parameters V5, proper lung dose parameters, and left anterior descending coronary artery dose parameters were found lower than that of the FB group, and the differences were statistically significant (P < 0.05). Conclusion: Compared with FB, the DIBH technique can reduce the heart’s size and increase the lung volume when used for radiotherapy after breast-conserving surgery for left breast cancer. It also reduces the dose to the heart, right lung, and left anterior descending coronary artery, thus protecting the heart and lungs.