METHOD FOR MODELING TOPOMETRIC PARAMETERS OF CLINICAL BRAIN IRRADIATION

摘要

FIELD: medicine. ^ SUBSTANCE: method involves applying computer tomography and topometry on X-ray simulator device. Three radio-contrasting marks are set on patient head skin with reference to light centering spot of computer tomograph along single light horizontal line. The marks are determined as reference points and brain scanning is carried out with the computer tomography in a way that one of scanning planes passes through those three radio-contrasting marks. Next to it, two topometric stages are carried out. Geometric irradiation parameters are determined in three-dimensional coordinate system from a series of tomograms with abscissa X-axis belonging to the scanning plane passing through said three radio-contrasting marks. Ordinate Y-axis belongs to medial sagittal head plane. Z-axis belongs to a plane drawn in perpendicular to both above mentioned axes and passes through anteroposterior irradiation zone size isocentre. The patient is placed on working table of the simulator at the second stage in a way that three reference marks belong to the plane controlling the body position with laser-centering members. Working table position and spatial irradiation zone isocentre position is determined using navigation system from data obtain at the first stage. Skin projection of the irradiation zone isocentre is found and skin projection of the irradiation zone boundary is determined with simulator light-centering unit. ^ EFFECT: high accuracy in building brain irradiation fields external projections.