Bolus construction in proton beam radiotherapy

National Institute of Radiological Sciences initiated its proton beam radiotherapy in October, 1979. The beam energy is 70 MeV and its penetration is 38 mm. Proton beam radiotherapy has the possibilities to avoid dose to a critical organ perfectly and to concentrate dose to the target. Bolus technique is one the methods to realise the above possibilities. In recent radiotherapy CT-views are applied to institute the target and to perform treatment planning. Hence in this study facile construction methods of various boluses for proton radiotherapy and their materials are investigated employing CT-views and CT-scan nre too. As the material for it we consider water is the best, since it's perfectly clear. It helps a therapist very much in setting up a patient for irradiation. Moreover majority of physics data are obtained with water phantoms. Hence the method to apply water for bolus was studied. (author)