RADIATION THERAPY WITH ACTIVE BREATHING CONTROL

外照射放射治疗癌症的成功 关键取决于对肿瘤的充分覆盖。治疗 由于每日设置变化和器官运动而引起的变化必须被记录 的理由：建筑 通常情况下，会添加一个治疗裕度， 对于这些变化。 通常希望具有小的 治疗边缘。 更高的剂量，然后可以规定没有 造成严重的失败。 但是，不适当地减少保证金 将大大增加局部失效的风险。 保证金问题 减少对于肺部肿瘤的治疗尤其重要 和上腹部 这些疾病的预后很差， 使用更高剂量进行治疗。 然而，这样做的企图是严重的， 由于覆盖肿瘤运动所需的大边缘， 病人呼吸。 申请人假设， 在胸部和腹部是更有效的呼吸运动时， 被最小化。 主动呼吸控制（ABC） 被开发用于暂时抑制呼吸运动， 可再现地。 在呼吸周期中的任何预选阶段，ABC 装置暂时限制流向和来自患者的气流， 固定呼吸运动。 主动屏气的时间是， 其可以由患者舒适地保持。 ABC，辐射 手动打开和关闭，并且仅在活动期间 屏住呼吸。 治疗机的复杂控制的需要是 从而避免。 ABC程序可以应用于三维 (3D)CT扫描和治疗，使病人的信息使用 在计划中重现了治疗过程中的情况。 在这份报告中，ABC 设备将用于获取40例肺部患者的3D CT扫描 和肝癌在呼吸周期的8个不同阶段。 的 ABC治疗的优点是通过比较 3D治疗计划，其中呼吸运动被固定在 存在具有3D器官运动的呼吸阶段，如由 8扫描 ABC治疗的临床可行性也将在 对25名接受常规治疗的患者进行了测试， 患者和患者对手术的可重复性和接受程度 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.