Mathematical Simulation of Optimal Dose Fields in Radiation Therapy of Malignant Tumors.Part 2. Contact Methods of Radiation Therapy

摘要

Introduction. The problems of formation of optimal dose fields in radiation therapy (RT) of malignant tumors can be reduced to various extremal problems of mathematical programming [1-4, 6]. The main goal of planning of RT is to select an irradiation plan that allows the main problem of RT (creation of the effective therapeutic dose field in the target lesion) to be solved with minimal radiation load on normal organs and tissues. The dose field should be sufficiently uniform and reach a specified value; whereas the dose field configuration should coincide with that of the lesion focus. The dose field in the lesion focus should be uniform to prevent the malignant disease relapse at the points of the minimal dose field (underexposure of malignant tissue) and radiation necrosis at points of the maximal dose field (overexposure of stromal and malignant tissues). The required cancericide dose, uniformity, and configuration of the dose field are usually determined on the basis of personal experience of the radiologist in planning RT and generalized experience of other physicians described in the medical literature. However, the requirements listed above are mainly applicable to remote RT. In the case of contact RT, they should be modified.