RADIATION THERAPY WITH ACTIVE BREATHING CONTROL

外照射治疗癌症的成功经验 这在很大程度上取决于肿瘤的覆盖范围。治疗 由于日常设置变化和器官运动而引起的变化必须采取 考虑到了。通常情况下，会增加治疗保证金以作补偿。 对于这些变化。通常情况下，人们希望有一个小的 治疗边际。然后可以开出更高的剂量，而不是 造成严重的失败。然而，不适当地降低保证金 将极大地增加局部失败的风险。边际问题 复位术对肺部肿瘤的治疗尤为重要。 和上腹部。这些疾病惨淡的预后迫使 使用较大剂量进行治疗。然而，这样做的尝试是严重的 受阻于覆盖肿瘤运动所需的大边缘，而 病人呼吸。申请人假设肿瘤的治疗 在呼吸运动时，胸部和腹部的运动更有效 是最小化的。为此，主动呼吸控制(ABC)的方法 是为了暂时停止呼吸运动而开发的 可重复性的。在呼吸周期的任何预先选择的阶段，ABC 该装置暂时限制进出患者的气流，从而 不能呼吸的动作。主动屏气的时间段是 它可以由患者舒适地维持。使用ABC，辐射 手动打开和关闭，并且仅在活动期间 屏住呼吸。需要对处理机进行复杂的控制 这样就避免了。ABC法可应用于三维 (3D)CT扫描和治疗，使患者信息使用 在计划中复制在治疗过程中。在这份提案中，ABC 将使用该设备获取40名肺部患者的三维CT扫描 以及在呼吸周期的8个不同阶段的肝癌。这个 ABC治疗的优点是通过比较以下剂量学来评价的 一种将呼吸运动固定在一处的3D治疗计划 存在具有3D器官运动的呼吸期，如由 这8次扫描。使用ABC治疗的临床可行性也将是 对25例接受常规治疗的患者进行了测试，通过研究 患者和患者对该程序的可重复性和接受性 治疗人员。

The success of cancer treatment with external beam radiation therapy depends critically on the adequate coverage of the tumor. Treatment variation due to daily setup variation and organ motion must be taken into account. Typically, a treatment margin is added to make allowance for these variations. It is generally desirable to have a small treatment margin. A higher dose can then be prescribed without inflicting serious failure. However, improper reduction of the margin will greatly increase the risk of local failure. The problem of margin reduction is particularly important for treatment of tumors in the lungs and upper abdomen. The dismal prognosis of these diseases compels the use of higher dose for treatment. Yet, attempt to do so is severely hampered by the large margin needed to cover the tumor motion while the patient breathes. The applicants hypothesize that treatment of tumors in the thorax and abdomen is much more effective when breathing motion is minimized. To do so, the approach of active breathing control (ABC) is developed to immobilize breathing motion temporarily and reproducibly. At any pre-selected phase in the breathing cycle, an ABC apparatus temporarily restricts airflow to and from the patient, thereby immobilizing breathing motion. The period of active breath hold is that which can by comfortably maintained by the patient. With ABC, radiation is turned on and off manually, and only, during the period of active breath hold. The need of complex control of the treatment machine is thus avoided. The ABC procedure can be applied for three dimensional (3D) CT scanning and treatment such that the patient information used in planning reproduces that during treatment. In this proposal, an ABC apparatus will be used to acquire 3D CT scans of 40 patients with lung and liver cancer at 8 different phases in the breathing cycle. The merit of treatment with ABC is evaluated by comparing the dosimetry of a 3D treatment plan where breathing motion is immobilized at one respiratory phase with that were 3D organ motion exists, as modeled by the 8 scans. Clinical feasibility of treatment with ABC will also be tested on 25 patients undergoing conventional treatment by studying the reproducibility and acceptance of the procedure by the patients and the treatment personnel.