Physics Department, King Abdulaziz University, Jeddah, Saudi Arabia; Medical Physics Unit, Radiology and Intervention Department, Faculty of Medicine, Alexandria University, Egypt.
Clinical Oncology Department, Faculty of Medicine, Alexandria University, Egypt.
Pract Radiat Oncol. 2018 Mar-Apr;8(2):71-80. doi: 10.1016/j.prro.2017.11.006. Epub 2017 Dec 2.
When treating breast cancer with radiation therapy, the impact of treatment position on heart and lung dose-volume parameters (DVPs) is largely dependent on the maximal heart distance (MHD) and central lung distance (CLD). We evaluate how much heart and lung sparing can be achieved using the semilateral decubitus (SLD) position without and with breath hold compared with the standard supine position for left-sided breast cancer patients. A secondary aim was to investigate the impact of MHD and CLD on heart and lung DVPs.
Thirty-five left-sided breast cancer patients were simulated in supine, free breathing SLD, and SLD with breath hold positions. A dosimetry plan was developed for each of these and 3 plans were compared for target coverage and organs at risk sparing. A correlation between CLD, MHD, and planning target volume, and heart and ipsilateral lung DVPs was tested.
SLD breath hold position showed a significant reduction in percentage of heart receiving ≥5 Gy (V), V, V V, mean dose and maximum dose (P < .001), ipsilateral lung V, and mean dose compared with supine (P < 001) and free breathing SLD (P = .003 and .006). There was also a significant reduction in the heart DVPs (P < .001) and ipsilateral lung DVPs (P < .001 and .007) with free breathing SLD compared with the supine position. SLD with or without breath hold were associated with significant reduction in MLD (P < .001) and CLD (P = .030 and .003) compared with the supine position.
Treatment plans for patients in the SLD position with or without breath hold for left-sided breast cancer patients demonstrated a superior heart and lung sparing compared with the supine position due to significant reduction in MHD and CLD. MHD and CLD are important simulation factors that affect the heart and lung DVP.
在采用放射疗法治疗乳腺癌时，治疗体位对心脏和肺剂量-体积参数（DVP）的影响在很大程度上取决于最大心脏距离（MHD）和中央肺距离（CLD）。我们评估了与标准仰卧位相比，左侧乳腺癌患者采用半侧卧位（SLD）且不屏气或屏气时，可实现多少程度的心脏和肺保护。次要目的是研究 MHD 和 CLD 对心脏和肺 DVP 的影响。
对 35 例左侧乳腺癌患者分别进行仰卧位、自由呼吸 SLD 和 SLD 屏气体位的模拟。为每个体位制定了一份剂量学计划，并对这些计划的靶区覆盖和危险器官保护进行了 3 项比较。测试了 CLD、MHD、计划靶区体积以及心脏和同侧肺 DVP 之间的相关性。
SLD 屏气体位与仰卧位（P < 0.001）和自由呼吸 SLD（P = 0.003 和 0.006）相比，显著降低了心脏接受≥5 Gy（V）、V、V V、平均剂量和最大剂量的百分比、同侧肺 V 和平均剂量（P < 0.001）。与仰卧位相比，自由呼吸 SLD 也显著降低了心脏 DVP（P < 0.001）和同侧肺 DVP（P < 0.001 和 0.007）。与仰卧位相比，SLD 体位无论是带或不带屏气呼吸均与显著降低的 MLD（P < 0.001）和 CLD（P = 0.030 和 0.003）相关。
对于左侧乳腺癌患者，SLD 体位且无论是否带屏气呼吸的治疗计划均显示出比仰卧位更好的心脏和肺保护，这归因于 MHD 和 CLD 的显著降低。MHD 和 CLD 是影响心脏和肺 DVP 的重要模拟因素。
