METHOD FOR RADIOTHERAPY FOR EARLY GASTRIC CANCER Russian patent published in 2023 - IPC A61N5/10 

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely radiotherapy and oncology, and can be used for stereotactic radiation therapy of early gastric cancer. Through the forceps aperture of a video gastroscope with a diameter of 2.8 mm, radiopaque tags: hemostatic clips are installed on the intact gastric mucosa along the periphery of the tumor. CT marking is carried out with delineation of the tumor of the stomach and critical organs: liver, kidneys, spinal cord, lungs. CT data is transmitted to the MultiPlan planning system with the following parameters: “Anatomy of treatment” – “Body”, “Set of trajectory templates” – “1path_body”, “Tracking method” – “Tracking coordinate labels (Fiducials)”, “Collimator type” – “Fixed collimator”; when planning, the “Contour correction” functions are enabled and, using the “Sequential Optimization (Sequential)” function, the following optimization scenario restrictions are set: maximum values of monitor units for each beam, for each manipulator position 240 IU and 360 IU, for the target and each organ of risk: PTV 42 Gy, liver 8 Gy, spinal cord 2 Gy, left lung maximum dose of 22 Gy, 30% volume 4.5 Gy, right lung 4 Gy, heart maximum dose of 10 Gy, 10% volume 5 Gy, spleen maximum dose of 10 Gy, 10% volume 4 Gy, stomach without volume PTV, the maximum dose is 35 Gy, 10 cm³ 23 Gy, dose at a distance of 3 mm from the edge of PTV 35.5 Gy, dose at a distance of 35 mm from the edge of PTV 8 Gy, target and relaxation values for each stage: optimization of PTV coverage (OCO) 36 Gy, relaxation value 0.2 Gy, optimization of the minimum dose of GTV (OMI) 39 Gy, relaxation value 0.2 Gy, upper limit of the dose volume per stomach without PTV (DVU) 18 Gy per 10% volume, relaxation value 1%, optimization of the coating for the shell at a distance of 16 mm from the edge of the PTV 13 Gy, relaxation value 0.5 Gy, optimization of the coating for the shell at a distance of 35 mm from the edge of PTV 6.5 Gy, relaxation value 0.5 Gy, the collimator size is selected according to the size of the target. The total number of beams in the Beam Reduction treatment plan is decreased to a level above 40 IU. A high-resolution dose calculation is performed and the treatment plan is saved using the “Evaluate” function. The dose is scaled to an average of 35 Gy in PTV. The treatment is carried out on a linear accelerator “Cyberknife” with TRD 35 Gy for 5 daily fractions of 7 Gy with automatic control of the target position in real time by the location of radiopaque markers.

EFFECT: method provides high accuracy of target irradiation, complete tumor resorption in early gastric cancer in an incurable patient by optimizing the dosimetric plan and monitoring the position of the target in real time by the location of radiopaque markers.

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