Abstract: In breast cancer radiotherapy, exposure of the heart and its substructures to radiation is one of the important risk factors for long-term cardiovascular diseases, which is particularly prominent in patients with left-sided breast cancer. The deep inspiration breath hold (DIBH) technique is an effective method to reduce cardiac radiation dose by having the patient take a deep breath and hold it, thereby moving the heart away from the target area. This article systematically reviews the principles, dosimetric advantages of the DIBH technique, and its application effects when combined with different radiotherapy techniques involving three-dimensional conformal radiation therapy (3DCRT), intensity modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT) and proton therapy technology. Studies have shown that the DIBH technique can significantly reduce the mean heart dose (MHD) and the doses to substructures such as the left anterior descending artery (LAD) and left ventricle (LV). Among them, it is found that DIBH combined with 3DCRT or proton therapy technology has the best cardioprotective effect. While when combining IMRT and VMAT with DIBH, further consideration of target dose uniformity and cardiac dose is needed to select the optimal method. In addition, regarding the correlation between cardiac substructure doses and the risk of cardiovascular events, it is necessary to combine relevant factors such as anatomical characteristics, biomarkers, and dose parameters to construct an individualized risk prediction model. In the future, we should focus on technical optimization, patient selection, and multimodal image guidance. Through these measures, maximizing the use of the DIBH technique will enable us to minimize radiotherapy-related cardiac toxicity.
Key words: breast cancer; radiation therapy; deep inspiration breath hold; cardiac protection; dosimetry
（Acta Laser Biology Sinica, 2026, 35(1): 010-018）