摘要
This study proposes a computational simulation method to calculate therapeutic outcomes in radiotherapy for head and neck carcinoma. As a tumor shrinks due to radiation exposure, it was possible to express the radiotherapeutic effects in terms of tumor volume changes and geometric distortion. The shrinking was assumed to conform to the deformation of solid body. The relationships between radiation energy and tumor deformation were estimated from solid mechanics equations. The simulation model was applied to six clinical cases of lymph node metastasis in patients with head and neck carcinoma. Three-dimensional solid models of tumors were constructed based on computed tomography (CT) images taken before the start of treatment. Follow up CT images were also taken weekly during the treatment period, to evaluate the changes in tumor volumes. The values of parameters prescribing tumor radiosensitivity or growth rates of tumor cells were identified so that the calculated results fit the clinical results. The simulated results represented the tumor decreases well in all cases. Average differences between measured and calculated tumor volume for all the cases were less than 10%. In conclusions, simulation results show that the simulation model can be applied to a variety of clinical cases by determining the tumor parameters appropriately.