Calculation Methods for the Prediction of the Absorbed Dose in Radiotherapy Physics.

摘要

Radiotherapy is widely used for the treatment of cancer, either as a single modality or in combination with other therapies, such as chemotherapy. Radiotherapy can be defined in general terms as the eradication of the tumor by means of ionizing radiation. When the radiation source is outside the patient one talks about external radiotherapy, and when the radiation source is placed into the patient, often by a surgical procedure, one talks about brachytherapy. In case of external radiotherapy, the ionizing radiation is most commonly high energy photons or electrons with energies in the range of 1 MeV to 50 MeV. Eradication of the cancer cells occurs by damage of the DNA of the cells. This damage indirectly causes cell death at the time of the cell division. Because both tumor and normal tissues are damaged, the success of this therapy depends on the choice of the radiation dose and the treatment schedule (i.e. fractionation scheme), resulting in the greatest damage to the tumor, but allowing repair of normal tissues.