20.1 Introduction Intracavitary brachytherapy can be performed using low dose rate (LDR), pulsed dose rate (PDR), or high dose rate (HDR) sources. LDR implants expose the patient care team to more radiation than HDR and require longer hospitalization of the…
19.1 Introduction One of the primary goals in radiation therapy is to maximize the dose to the target while minimizing the dose to healthy tissue. For targets that exhibit significant motion (>5 to 10 mm) during the respiratory cycle this creates…
18.1 Introduction Image-guided radiotherapy (IGRT) is well established; however it is important to note that there has never been a prospective randomized trial to examine its value. There are, however, a number of retrospective series examining the impact of IGRT…
17.1 Introduction Stereotactic radiosurgery (SRS) was originally defined as fulfilling all of the following conditions: 1. Single-fraction treatment 2. High dose per fraction (>5 Gy) 3. Target with diameter of <3.5 cm in the brain 4. Delivery accuracy of <1 mm as defined…
16.1 Introduction Intensity-modulated radiotherapy (IMRT) provides exceptional control over the delivery of dose. Figure 16.1 shows an example of a 7-field IMRT plan for a patient with T3 oropharyngeal carcinoma of the head and neck. This case illustrates the ability…
15.1 Introduction Electron beams have been used in radiotherapy since the 1940s but did not gain widespread use until the 1970s with the commercial development of linear accelerators (linacs). Electrons lose energy as they traverse a medium through various elastic…
14.1 Introduction The overall goal of the treatment planning process is to produce the optimal dose distribution for the patient, taking into account the following factors: 1. Treatment intent (curative or palliative) 2. Stage of disease (extent of involvement) 3.…
13.1 Introduction Prior to the early 1990s, “simulation” for an external beam radiotherapy consisted of just that: simulating the treatment with a device that mimicked a linear accelerator (linac) in all aspects except the delivery of a therapeutic beam. These…
12.1 Introduction Watershed Accidents in Radiation Oncology One way to view the issue of quality and safety in radiotherapy is to consider the serious accidents that have garnered the attention of the community and occasionally the media. The purpose of…
11.1 Introduction Information technology (IT) in Radiation Oncology has developed into highly complex networks driving much of treatment delivery and other safety-critical tasks in the department. Based on the size of a Radiation Oncology clinic, the role of the physicist…