METHOD OF PLANNING RADIOOSURGERIC TREATMENT OF BRAIN TUMORS LOCATED IN THE MOTOR CORTEX AND / OR ADJACENT TO THIS FIELD Russian patent published in 2018 - IPC A61B8/13 A61B6/02 A61B6/03 A61B5/05 

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely, to medical radiology. Method for planning the radiosurgical treatment of brain tumors located in the region of the motor cortex and/or adjacent to this region, includes: conducting the MRI of brain without contrast medium to obtain a series of anatomical sections images of the brain, time-weighted T1. Conducting fMRI studies to obtain a series of functional images of the motor zones of the cerebral cortex, conducting nTMS motor zones of the cerebral cortex with obtaining of appropriate images. Verify the location of the tumor relative to the motor zones and its shape which is close to the sphere or ellipsoid of rotation by the images obtained. Install the stereotaxic coordinating frame. Record MRI in the T1 sequence using a contrast agent with a localization device, obtaining an anatomical image of the brain with confidence marks designed to determine the target coordinates. Import the obtained images of MRI, fMRI, nTMS into the treatment planning program file for stereotactic radiosurgery, scale and combine them on the basis of a single system of stereotaxic coordinates to obtain a single series of images with a number of voxels, characterizing the location of the motor zones of the cerebral cortex and tumors obtained as a result of MRI, fMRI and nTMS, with the subsequent obtaining of the image of the final zone of the motor cortex at the intersection of the regions obtained with fMRI and nTMS. Contour the tumor and the final motor zone at each cut, obtaining a three-dimensional image of the motor zone, then plan the treatment of the tumor, taking into account the mutual location of the tumor and the motor zone. In this case, prescribe the prescribed dose (PD) and the prescribed isodose (PI), select the isocycles with the collimator size of 4 mm and/or 8 mm and/or 16 mm, fill the tumor volume using first larger isocenters, then the smaller ones, with guarantee of conformal filling of the entire volume of the tumor with mutual intersection of equilibrium isocenters by not more than half of their diameter and coating of the entire tumor volume by not less than 97 % by the prescribed dose; when the tumor volume is filled, locate the maxima of the isocenters within the isoline of the PI, ensuring that the isoline of the prescribed isodose corresponds to the contour of the tumor. If the pathological focus is adjacent to the area of the motor cortex or partially submerged in the motor cortex by no more than 50 %, perform the collimation of the beam of isocenters near the region of the motor cortex using the blocking of those collimator sectors, whose radiation beams pass through the region of the motor cortex, changing the shape of the individual isocenters, so that the larger diameter of the isocenter is parallel to the tangent to the contour of the tumor in the area of contact of the tumor with the motor cortex, followed by adjusting the dose distribution by changing the amount, coordinates of isocenter and/or relative weight, which characterizes the contribution of a separate isocenter to the total dose, after which irradiation is carried out according to given parameters. If the tumor is located directly inside the region of the motor cortex and has a spherical or a shape close to it, then use PI with values of 60–80 % depending on the size of the tumor when planning irradiation and repeat the step of filling the tumor volume with isocenter described above followed by irradiation without blocking the collimator beams. When detecting a tumor with the shape of an ellipsoid of rotation or close to it inside the motor cortex, perform the installation of stereotaxic coordinating frame parallel to the plane passing through the larger diameter of the tumor. When planning irradiation, use PI with values of 60–80 % depending on the size of the tumor, and block no more than three sectors of the isocenters when the tumor volume is filled with those isocenters, which are located inside the region of the motor cortex, so that the isolines of the PI to be corresponded to the contours of the tumor as much as possible.

EFFECT: invention provides the increase of treatment safety while maintaining the effectiveness of treatment by decreasing the dose load on the motor zones of the cerebral cortex and maintaining a high prescribed dose for the pathological focus.

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