Start-up and application of radiotherapy technology for the body parts involved in respiratory movement

Treatment devices equipped with high-precision radiotherapy technology corresponding to the internal changes (breathing movement, peristaltic motion, etc.) of the human bodies that change with the passage of time have appeared. This paper mentioned what is necessary for the safe clinical introduction of these devices. As the methods of reducing the influence of respiratory movement, there are an abdominal pressing method and a breath holding method as physical methods. There are a respiratory synchronizing irradiation method as an efficient method and a dynamic tracking irradiation as a movement-correcting method. As the imaging method of CT for treatment planning, there are cine scan and helical scan, where the reconstruction method is different, respectively. Prior to clinical introduction, it is necessary to verify the accuracy of 4-D CT using a moving body phantom. This paper explained the target setting corresponding to the irradiation method, as well as the commissioning of radiotherapy corresponding to respiratory movement. Using a moving body phantom, E2E test (End-to-End) should be performed from CT imaging for treatment planning, through treatment planning, irradiation, and dose verification. It is also necessary to train operators, prepare protocols, and confirm the actual state of irradiation. (A.O.)