深呼吸屏气（DIBH）用于左乳腺癌手术后的辅助放疗，以减少对心脏的辐射剂量。在本研究中，我们确定是否应根据患者背景选择胸部DIBH（T-DIBH）或腹部DIBH（A-DIBH）。使用曾在我们医院接受治疗的患者的自由呼吸（FB）、T-DIBH和A-DIBH CT扫描，在相同条件下创建三维适形放疗计划。与FB相比，A-DIBH减少了左肺剂量。比较T-DIBH和A-DIBH，在A-DIBH中心脏的最大剂量和左肺剂量明显降低。FB、T-DIBH和A-DIBH之间的心脏均值剂量（Dmean）的差异与心胸比、心脏体积和左肺体积有关。T-DIBH和A-DIBH的心脏Dmean和左肺剂量的差异与强制呼吸容积（FVC）有关。就心脏和左肺剂量而言，A-DIBH优于T-DIBH，但在某些情况下，就心脏Dmean而言，T-DIBH在降低剂量方面更有效，并且FVC是本研究的相关因素。

Deep inspiration breath hold (DIBH) is used with adjuvant radiation therapy after left breast cancer surgery to reduce radiation dose to the heart. In this study we determined whether thoracic DIBH (T-DIBH) or abdominal DIBH (A-DIBH) should be selected based on patient background.Three-dimensional conformal radiation therapy plans were created under the same conditions using free breathing (FB), T-DIBH, and A-DIBH CT scans of patients who had previously undergone treatment at our hospital.A-DIBH decreased the left lung dose compared to FB. In comparing T-DIBH and A-DIBH, the heart maximum and left lung doses were significantly lower in A-DIBH. The differences in the heart mean dose (Dmean) between FB, and T-DIBH and A-DIBH were correlated with the cardiothoracic ratio, heart volume, and left lung volume. The difference in the heart Dmean and the left lung dose of T-DIBH and A-DIBH correlated with the forced vital capacity (FVC).A-DIBH is preferable over T-DIBH with respect to the heart and left lung doses; however, with respect to the heart Dmean, T-DIBH was more effective in reducing the dose in some cases, and the FVC was a relevant factor in this study.