METHOD FOR RECONSTRUCTIVE DOSIMETRIC CONTROL OF PROTON THERAPY BY SCANNING BEAM

摘要

FIELD: medicine.;SUBSTANCE: invention refers to medicine, namely to radiology and medical biophysics, and can be used for reconstructive dosimetric monitoring in a proton therapy by a scanning beam. Radiochromic film is placed on the patient's body surface. Proton focus therapy is performed. In the interactive viewing mode of the accepted treatment plan with the prescribed dose (D_Plan), scanning by layers a patient's tomogram with one constant dose line, which value is changed during viewing, determining maximum dose on surface (D^sur_Plan) at the scanning beam input point. Further, in therapy, maximum dose on surface is measured (D^sur_Film) in the same place with a radiochromic film fixed on the patient's body. That is followed by reconstructing the dose in the lesion by the formula: D=D^sur_Film/(D^sur_Plan/D_Plan), where D^sur_Plan is design maximum surface dose, D^sur_Film is the measured maximum surface dose, D_Plan is a prescribed dose. Cross-section of the secant planes on the edge of the image of the surface is established, at least in the coronary and sagittal sections at the point of entry of the scanning beam. Indicator values are varied so that some part of the isodose line, at least in the coronary and sagittal sections, passes along the edge of the image of the surface at the point of entry of the scanning beam. Irradiated film is scanned using a scanning device and an image of optical density is obtained. Image of optical density is processed with a software package for obtaining an image which contains a pixel value with a maximum dose on the surface at the point of entry of the scanning beam, the value of which is found in the title by an indicator.;EFFECT: method provides fast, immediately after irradiation, reconstructive control of the dose supplied to the lesion and evaluation of possible reactions from the skin by calculating the dose supplied using the values of the prescribed dose, as well as calculated and measured maximum doses on surface.;5 cl, 2 dwg, 1 ex