肿瘤放射治疗常用英文缩写RTRadiotherapy,Radiation Therapy放疗，放射治疗放射治疗是利用放射线治疗肿瘤的一种方法，是当今治疗肿瘤的三大手段之一。
据统计，大约有60～70%恶性肿瘤患者需要接受放射治疗。
有些恶性肿瘤通过放疗可以得到根治，并可能获得同类同期肿瘤的手术治疗的疗效，且可保存所在的器官及其功能。
IMRTIntensity Modulated Radiation Therapy调强放射治疗调强放射治疗与以往放射治疗技术不同，它通过调节各个方向照射野的野内射线的强度产生非均匀照射野，达到肿瘤的高剂量三维适形分布和危及器官的低剂量分布，从而提高肿瘤的照射剂量，尽可能地减少危及器官和正常组织的受量，最终提高肿瘤局部的控制率，改善肿瘤患者的生存质量。
MLCMultiLeaf Collimator多叶准直器，多叶光栅MLC最初设计主要是用于替代射野挡铅，后来发展成了IMRT的基础，控制叶片运动可实现静态MLC和动态MLC调强。
QA & QCQuality Assurance & Quality Control质量保证和质量控制放射治疗的QA是指经过周密计划而采取的一系列必要的措施，保证放射治疗的整个服务过程中的各个环节按国际标准准确安全的执行。
这个简单的定义意味着质量保证有两个重要内容：质量评定，即按一定标准度量和评价整个治疗过程中的服务质量和治疗效果；质量控制，即采取必要的措施保证QA的执行，并不断修改服务过程中的某些环节，达到新的QA级水平。
－－摘自胡逸民主编《肿瘤放射物理学》p612。
AAPMAmerican Association of Physicists in Medicine美国医学物理学家协会AAPM FACT SHEETThe AAPM:A scientific, educational, and professional organization of more than 4,700 medical physicists. Headquarters are located at the American Center for Physics inCollege Park, MD, with a staff of 20, Annual budget is over $5M. Publications include a scientific journal ("Medical Physics"), technical reports, and symposium proceedings.Medical Physics:An applied branch of physics concerned with the application of the concepts and methods of physics to the diagnosis and treatment of human disease. It is allied with medical electronics, bioengineering, and health physics.Medical Physicists:Most have an MS or Ph.D. in medical physics, physics, radiation biology, or a related discipline, and training in clinical medical physics. Clinical training may be obtained through a residency traineeship or a postdoctoral program of one or two years in a hospital. Clinical medical physicists are employed in medical schools, hospitals or clinics, or are in private practice. These physicists divide their time between clinical service and consultation, research and development, and teaching. Some medical physicists work in industrial or research positions, and have no clinical responsibilities.Medical Physicist's Role:Medical physicists contribute to the effectiveness of radiological imaging procedures by assuring radiation safety and helping to develop improved imaging techniques (e.g., mammography CT, MR, ultrasound). They contribute to development of therapeutic techniques (e.g., prostate implants, stereotactic radiosurgery), collaborate with radiation oncologists to design treatment plans, and monitor equipment and procedures to insure that cancer patients receive the prescribed dose of radiation to the correct location.Medical physicists are responsible for ensuring that imaging and treatment facilities meet the rules and regulations of the Nuclear Regulatory Commission and various State Health Departments.Medical Physicist Credentials:The American Board of Radiology certifies medical physicists, as does the American Board of Medical Physics. Medical physicists contribute to the education and certification of radiologists and radiation oncologists. Many are members of physician organizations such as the American College of Radiology, the Radiological Society of North America, and the American Society for Therapeutic Radiology and Oncology.Salaries for clinical medical physicists are derived from technical payments to hospitals and sharing of physicians' professional reimbursement, or through fee-for-service in private practice.-------FromSADSource to Axis Distance源轴距放射源到机架旋转或机器等中心的距离。
SSDSource to Surface Distance源皮距放射源到模体表面照射野中心的距离。
3DCRT、X刀、IMRT等技术都采用SAD技术，国内常规放疗正在普及SAD等中心照射技术，希望大家能尽早放弃SSD技术，只在某些特定情况下采用SSD技术。
PDDPercentage Depth Dose百分深度剂量定义为射野中心轴上某一深度处的吸收剂量率与参考点深度处剂量率的百分比。
对于高能X（γ）射线，参考深度一般取在射野中心轴上最大剂量点深度处。
TMRTissue Maximum Ratio组织最大剂量比定义为模体中射野中心轴上任意一点的剂量率与空间同一点模体中射野中心轴上最大剂量点深度处同一射野的剂量率之比。
两者书写格式不同，如：PDD为92%，TMR为0.87。
两者的转换关系请参见胡逸民主编《肿瘤放射物理学》p171。
一般来说，PDD用于SSD技术剂量计算，TMR用于SAD技术剂量计算。
而一般输入TPS的加速器数据是PDD，TMR由PDD转换而得。
LALinear Accelerator直线加速器直线加速器是加速器家族中使用量最大的一种。
其工作原理主要是通过一个微波功率源（磁控管或速调管）把电子加速到设计要求的很高的能量，然后撞击靶物质（产生高能X射线）或直接由电子窗引出（形成β射线）。
医用直线加速器的主要作用是用于肿瘤的放射治疗。
加速器的诞生源于二战时期用于雷达通讯的磁控管技术的发展。
自1953年用加速器治疗第一例患者以来，加速器的临床应用已达整整半个世纪。
随着科学技术特别是计算机技术的不断进步，加速器在工艺、功能、精度等方面的发展已经日趋成熟，目前已经成为肿瘤放射治疗领域最重要的设备之一。
用于肿瘤放射治疗的加速器还有电子感应加速器、电子回旋加速器、亚质子和质子加速器等。
DVHDose Volume Histogram剂量体积直方图三维治疗计划系统中用DVH表示某感兴趣区域如靶区或OAR的体积内有多少体积受到多高剂量的照射。
DVH是评估计划设计方案的最有力的工具，根据DVH图可以直接评估高剂量区与靶区的适合度。
但是，考虑到串型器官的耐受剂量特性，DVH应该与相应计划的等剂量分布图结合来综合评估。
DVH又包括积分DVH和微分DVH，一般常说和常用的DVH指积分DVH。
可参考胡逸民主编《肿瘤放射物理学》p451。
SRSStereotactic RadioSugery立体定向放射手术X（γ）-刀的最初定义，其特征是小野三维集束单次大剂量照射。