Department of Radiation Oncology, Kyoto City Hospital, 1-2 Mibu Higashi Takadacho, Nakagyo-ku, Kyoto, 604-8845, Japan.
Clinical Radiology Service Division, Kyoto City Hospital, 1-2 Mibu Higashi Takadacho, Nakagyo-ku, Kyoto, 604-8845, Japan.
Breast Cancer. 2021 Sep;28(5):1154-1162. doi: 10.1007/s12282-021-01259-4. Epub 2021 Apr 28.
The deep inspiration breath hold (DIBH) technique is effective for heart dose reduction in patients with left-sided breast cancer. In deep breathing, some women breathe in thoracic respiration; and others, in abdominal respiration. This study evaluated differences in dose reduction in organs at risk (OAR) and reproducibilities of the target and OAR between thoracic DIBH (T-DIBH) and abdominal DIBH (A-DIBH).
Fourteen patients with left-sided breast cancer who had planned to receive whole-breast irradiation were included. Computed tomography (CT) was performed in free breathing (FB), T-DIBH, and A-DIBH, and the dosimetric indexes of the target and OAR for three treatment plans were compared. In T-DIBH and A-DIBH, two series CTs were taken in each breathing method and the displacements of the target and heart were calculated.
The averaged mean heart doses (MHDs) were 1.5 Gy and 1.6 Gy in T-DIBH and A-DIBH, respectively, significantly lower than 2.7 Gy in FB (p < 0.001 for both breathing methods). Between T-DIBH and A-DIBH, no significant difference in MHD was found (p = 0.95); however, the percentage increase in lung volume positively moderately correlated with the reduction in MHD (R = 0.68). The three-dimensional target displacements were 2.3 mm in T-DIBH and 2.0 mm in A-DIBH (p = 0.64). The three-dimensional heart displacements were 1.7 mm in T-DIBH and 1.8 mm in A-DIBH (p = 0.85).
The present study demonstrates that the MHD and reproducibility did not differ between T-DIBH and A-DIBH. However, the superior breathing method for increasing lung volume should be determined for each patient.
深吸气屏气（DIBH）技术可有效降低左侧乳腺癌患者心脏剂量。在深吸气时，一些女性进行胸式呼吸，而另一些女性则进行腹式呼吸。本研究旨在评估目标和危及器官（OAR）之间剂量差异以及 T-DIBH 和 A-DIBH 之间靶区和 OAR 可重复性。
纳入 14 例计划接受全乳照射的左侧乳腺癌患者。在自由呼吸（FB）、T-DIBH 和 A-DIBH 下进行 CT 扫描，并比较三种治疗计划的靶区和 OAR 的剂量学指标。在 T-DIBH 和 A-DIBH 中，每种呼吸方式各进行两次 CT 扫描，计算目标和心脏的位移。
T-DIBH 和 A-DIBH 的平均心脏剂量（MHD）分别为 1.5Gy 和 1.6Gy，明显低于 FB 的 2.7Gy（两种呼吸方式均 P<0.001）。T-DIBH 和 A-DIBH 之间的 MHD 无显著差异（P=0.95）；然而，肺容积增加的百分比与 MHD 的降低呈正中度相关（R=0.68）。T-DIBH 的三维靶区位移为 2.3mm，A-DIBH 为 2.0mm（P=0.64）。T-DIBH 的三维心脏位移为 1.7mm，A-DIBH 为 1.8mm（P=0.85）。
本研究表明 T-DIBH 和 A-DIBH 之间的 MHD 和可重复性没有差异。然而，应该为每个患者确定增加肺容积的最佳呼吸方式。
