Department of Radiation Oncology, Medical Physics Division, Kimmel Cancer Center (NCI-designated), Thomas Jefferson University, Philadelphia, PA 19107, USA.
Phys Med Biol. 2011 Mar 7;56(5):1299-318. doi: 10.1088/0031-9155/56/5/005. Epub 2011 Feb 1.
Respiratory and cardiac motions induce displacement and deformation of the tumor volumes in various internal organs. To accommodate this undesired movement and other errors, physicians incorporate a large margin around the tumor to delineate the planning target volume, so that the clinical target volume receives the prescribed radiation dose under any scenario. Consequently, a large volume of healthy tissue is irradiated and sometimes it is difficult to spare critical organs adjacent to the tumor. In this study we have proposed a novel approach to the 4D active tracking and dynamic delivery incorporating the tumor motion prediction technique. This method has been applied to the two commercially available robotic treatment couches. The proposed algorithm can predict the tumor position and the robotic systems are able to continuously track the tumor during radiation dose delivery. Therefore a precise dose is given to a moving target while the dose to the nearby critical organs is reduced to improve the patient treatment outcome. The efficacy of the proposed method has been investigated by extensive computer simulation. The tumor tracking method is simulated for two couches: HexaPOD robotic couch and ELEKTA Precise Table. The comparison results have been presented in this paper. In order to assess the clinical significance, dosimetric effects of the proposed method have been analyzed.
呼吸和心跳运动会导致体内各种器官肿瘤体积的位移和变形。为了适应这种不期望的运动和其他误差，医生会在肿瘤周围留出一个较大的边界来勾画计划靶区，以确保在任何情况下临床靶区都能接收到规定的辐射剂量。因此，大量健康组织会受到辐射，有时很难避开肿瘤附近的关键器官。在这项研究中，我们提出了一种新的方法，即结合肿瘤运动预测技术的 4D 主动跟踪和动态治疗。该方法已应用于两种商用机器人治疗床。所提出的算法可以预测肿瘤的位置，机器人系统能够在辐射剂量输送过程中持续跟踪肿瘤。因此，在将精确的剂量给到移动的目标的同时，还可以减少附近关键器官的剂量，以提高患者的治疗效果。本文介绍了该方法的有效性，通过广泛的计算机模拟进行了研究。对两种治疗床（HexaPOD 机器人床和 ELEKTA Precise 治疗床）进行了肿瘤跟踪方法的模拟。本文还给出了比较结果。为了评估其临床意义，分析了该方法的剂量学效果。
