PRECISION IN PATIENT SET-UP AND TARGET LOCALIZATION

项目3的总体目标是量化，并通过 改进，最大限度地提高目标卷在 患者可以在治疗时定位。根本目标 适形放射治疗的目的是将高剂量的区域限制为 尽可能紧密地瞄准卷。目前，固定的生物 目标卷需要扩展以形成规划目标卷，以 考虑到在治疗和治疗之间患者设置的不确定性 病人体内的器官运动。然而，要将剂量安全地提高到超过 目前的标准，有必要最大限度地减少组织的体积 辐射过的。在本项目中，假设通过使用 改进了患者固定、实时诊断和超大容量 平板成像器，用于计算重新定位校正的软件 病人，和一台电脑控制的治疗机，它将是 有可能在患者就诊前和/或就诊期间准确快速地为患者做好准备 每一次治疗。进一步假设，通过使用 在诊断和诊断上可见的放射不透明标记的组合 巨电压研究，器官运动对靶区体积的影响 本地化可以在数量的基础上进行解释。因此，项目 3有两个具体目标，这两个目标将通过完成 与每个目标相关联的三个主要子任务。目标1：发展和 实施可减少“病人”设置的程序 不准确到与患者的精确度一致的水平 体位可以测量；具有与1a)患者相关的子任务 使用改进的设备和技术进行制动，1)患者 通过位于以下地点的诊断X射线源进行定位 治疗单元与创新的复合诊断- 超大电压、在线平板成像仪和1c)计算机辅助患者 使用重新设计的计算机控制的桌面系统进行重新定位。 目标2：解释患者器官运动引起的“靶”运动 其他固定的患者；通过2a)确定 治疗期间患者结构和器官定位的稳定性， 2b)直接量化目标体积在前列腺、肝脏和 使用植入的放射不透明标记的肺，以及2c)使用先进的 通过以下方式补偿日常器官运动的技术 调整处理体积或使用生理性门控技术。

The overall objective of Project 3 is to quantify, and through improvements, maximize the precision with which target volumes within patients can be localized at the time of treatment. A fundamental goal of conformal radiation therapy is to confine regions of high dose as tightly as possible to target volumes. currently, immobile biologic target volumes need to be expanded to form planning target volumes to account for uncertainties in patient setup between treatments and for organ motion within patients. However, to escalate dose safely beyond current standards, it is necessary to minimize the volume of tissue irradiated. In this project it is hypothesized that through use of improved patient immobilization, real-time diagnostic and megavoltage flat-panel imagers, software to compute corrections for repositioning patients, and a computer controlled treatment machine, it will be possible to accurately and rapidly setup a patient before and/or during each treatment session. It is further hypothesized that, through use of a combination of radio-opaque markers visible on diagnostic and megavoltage studies, the influence of organ motion on target volume localization can be accounted for on a quantitative basis. Thus, Project 3 has two specific aims, which will be addressed through completion of three major subtasks associated with each aim. Aim 1: To develop and implement procedures that enable the reduction of "patient" setup inaccuracies to a level consistent with the precision with which patient position can be measured; with subtasks related to 1a) patient immobilization utilizing improved devices and techniques, 1b) patient localization by means of diagnostic x-ray sources located at the treatment unit in conjunction with innovative composite diagnostic- megavoltage, online flat-panel imagers, and 1c) computer-assisted patient repositioning using a redesigned computer-controlled table top system. Aim 2: To account for "target" motion due to patient organ motion in an otherwise immobilized patient; through subtasks which 2a) determine the stability of inter-treatment patient structure and organ localization, 2b) directly quantify target volume motion in the prostate, liver and lung using implanted radio-opaque markers, and 2c) employ advanced techniques to compensate for organ motion on a daily basis through adjustment of treated volumes or use of physiological gating techniques.