Shonan Kamakura General Hospital, Department of Radiation Oncology, 1370-1 Okamoto, Kamakura, Kanagawa, Japan.
Yokohama City University Graduate School of Medicine, Department of Radiation Oncology, 3-9 Fukuura, Kanazawa-ku, Yokohama, Japan.
J Radiat Res. 2019 Oct 23;60(5):694-704. doi: 10.1093/jrr/rrz052.
Intensity-modulated radiation therapy (IMRT) delivers an excellent dose distribution compared with conventional three-dimensional conformal radiation therapy (3D-CRT) for postoperative radiation including the lymph nodes in breast cancer patients. The TomoTherapy system, developed exclusively for IMRT, has two treatment modes: TomoDirect (TD) with a fixed gantry angle for beam delivery, and TomoHelical (TH) with rotational beam delivery. We compared the characteristics of TD with TH and 3D-CRT plans in the breast cancer patients. Ten consecutive women with left breast cancer received postoperative radiation therapy using TD including the chest wall/residual breast tissue and level II-III axial and supraclavicular lymph node area. Fifty percent of the planning target volume (PTV) was covered with at least 50 Gy in 25 fractions. TD, TH and 3D-CRT plans were created for each patient, with the same dosimetric constraints. TD and TH showed better dose distribution to the PTV than 3D-CRT. TD and 3D-CRT markedly suppressed low-dose spread to the lung compared with TH. Total lung V5 and V10 were significantly lower, while V20 was significantly higher in the TD and 3D-CRT plans. The mean total lung, heart and contralateral breast doses were significantly lower using TD compared with the other plans. Compared with 3D-CRT and TH, TD can provide better target dose distribution with optimal normal-organ sparing for postoperative radiation therapy including the chest wall/residual breast tissue and lymph node area in breast cancer patients. TD is thus a useful treatment modality in these patients.
调强放射治疗（IMRT）与传统的三维适形放射治疗（3D-CRT）相比，能为乳腺癌患者提供更好的术后放射治疗剂量分布，包括淋巴结。TomoTherapy 系统是专门为调强放射治疗而开发的，有两种治疗模式：TomoDirect（TD）用于固定机架角度的光束输送，以及 TomoHelical（TH）用于旋转光束输送。我们比较了乳腺癌患者中 TD 与 TH 和 3D-CRT 计划的特点。10 例连续的左侧乳腺癌患者接受了包括胸壁/残留乳腺组织和 II-III 轴位和锁骨上淋巴结区域的术后放射治疗，使用 TD。50%的计划靶区（PTV）在 25 次分割中至少接受 50Gy 的照射。为每位患者创建了 TD、TH 和 3D-CRT 计划，采用相同的剂量学限制。TD 和 TH 对 PTV 的剂量分布优于 3D-CRT。TD 和 3D-CRT 明显抑制了肺的低剂量扩散，而 TH 则不然。TD 和 3D-CRT 计划的总肺 V5 和 V10 明显较低，而 V20 明显较高。TD 计划的总肺、心脏和对侧乳腺剂量明显低于其他计划。与 3D-CRT 和 TH 相比，TD 可以为包括胸壁/残留乳腺组织和淋巴结区域的乳腺癌患者提供更好的术后放射治疗靶区剂量分布，同时最大限度地保护正常器官。因此，TD 是这些患者的一种有用的治疗方式。
