Portillo Elisabet González-Del, Hernández-Rodríguez Jorge Hernández, Tenllado-Baena Enrique, Fernández-Lara Álvaro, Alonso-Rodríguez Orlanda, Matías-Pérez Ángela, Cigarral-García Cristina, García-Álvarez Graciela, Pérez-Romasanta Luis A
Department of Radiation Oncology, La Paz University Hospital, Madrid, Spain.
Department of Radiation Physics, Salamanca University Hospital, Salamanca, Spain.
Rep Pract Oncol Radiother. 2024 Mar 18;29(1):21-29. doi: 10.5603/rpor.99024. eCollection 2024.
The objective was to compare dosimetry in left-sided breast cancer (LSBC) patients receiving deep inspiration breath hold (DIBH) radiotherapy (RT) with free-breathing (FB) treatment plans.
Voluntary DIBH with a spirometer-based video-assisted system and CT-simulation were performed under FB and DIBH conditions on 40 LSBC patients, segmented according Duane's atlas. IMRT plans kept the same dosimetric goals on FB and DIBH conditions. Target, lungs and heart volumes were measured. Planning target volume (PTV) dose distribution, organs at risk (OARs) dose/volume parameters, including cardiac substructures, were calculated.
Lungs and left-lung volumes increased in DIBH conditions (ΔV = 1637.8 ml ± 555.3 and 783.5 ml ± 286.4, respectively). Heart volume slightly decreased in apnea (p = 0.04), but target volumes, CTV and PTV were similar in FB or DIBH plans. PTV dose coverage was similar irrespective of respiratory conditions (median D50% = 41.1 Gy 41.0 Gy, p = 0.665; V95% = 96.9% . 97%). Mean dose for the whole heart (MHD), left ventricle (LV), and LV segments were significantly reduced in DIBH plans. V20 values for heart subvolumes were significantly different only for those that received considerable doses (apical and anterior). DIBH plans provided significantly smaller doses (Dmax, D2%, and V20) to the LAD artery.
Important dosimetric improvements can be achieved with DIBH technique for LSBC patients, reducing the dose to the LAD artery and heart, particularly to the segments closer to the chest wall. Apical/anterior LV segments, should be considered as separate organ at risk in breast RT.
目的是比较接受深吸气屏气（DIBH）放疗（RT）的左侧乳腺癌（LSBC）患者与自由呼吸（FB）治疗计划的剂量学。
在40例LSBC患者中，在FB和DIBH条件下使用基于肺活量计的视频辅助系统进行自主DIBH和CT模拟，并根据杜安图谱进行分割。调强放疗（IMRT）计划在FB和DIBH条件下保持相同的剂量学目标。测量靶区、肺和心脏体积。计算计划靶区（PTV）剂量分布、危及器官（OARs）剂量/体积参数，包括心脏亚结构。
在DIBH条件下肺和左肺体积增加（ΔV分别为1637.8 ml±555.3和783.5 ml±286.4）。屏气时心脏体积略有减小（p = 0.04），但靶区体积、临床靶区（CTV）和PTV在FB或DIBH计划中相似。无论呼吸条件如何，PTV剂量覆盖相似（中位D50% = 41.1 Gy对41.0 Gy，p = 0.665；V95% = 96.9%对97%）。DIBH计划中全心平均剂量（MHD）、左心室（LV）和LV节段剂量显著降低。仅对于接受相当剂量的心脏亚体积（心尖和前部），V20值有显著差异。DIBH计划为左前降支动脉提供的剂量（Dmax、D2%和V20）显著更小。
DIBH技术可为LSBC患者带来重要的剂量学改善，减少左前降支动脉和心脏的剂量，尤其是靠近胸壁的节段。在乳腺癌放疗中，心尖/前部LV节段应被视为单独的危及器官。
