High-energy electron line multi-degree-of-freedom intensity modulated radiotherapy system based on longitudinal magnetic confinement

Abstract

The invention relates to a high-energy electron line multi-degree-of-freedom intensity modulated radiation therapy system based on longitudinal magnetic confinement. The system comprises longitudinal magnetic confinement high-energy electron line radiation therapy equipment and a multi-degree-of-freedom integrated optimization method for high-energy electron line intensity modulated radiation therapy. The equipment comprises a radiotherapy machine and a magnetic confinement device. The radiotherapy machine comprises a linear accelerator or a cyclotron for accelerating electrons and a multi-stage electron beam collimator, the magnetic confinement device comprises a three-stage split perforated coil, and the central axis of the coil coincides with the central axis of a high-energy electron beam. The optimization method comprises the following steps: 1, optimizing the head angle of the radiotherapy machine, and determining a beam arc section; 2, optimizing the angle of a collimator, and determining a beam dynamic track; and 3, synchronously optimizing the electron line energy and the beam intensity, and determining an optimal electron line multi-degree-of-freedom intensity modulated radiotherapy plan. Lateral scattering of high-energy electron rays in the air and in the body of a patient can be effectively reduced, multi-degree-of-freedom intensity modulated radiotherapy of the magnetic confinement high-energy electron rays is realized, and the curative effect of the patient is improved.

Description

technical field [0001] The present application belongs to the technical field of radiotherapy, and in particular relates to a high-energy electron beam multi-degree-of-freedom intensity-modulated radiotherapy system based on longitudinal magnetic confinement. Background technique [0002] Radiation therapy is an important treatment for malignant tumors. About 70% of cancer patients need radiation therapy during the treatment process, and about 40% of cancers can be cured by radiotherapy. The most commonly used indirect ionizing radiation in radiotherapy is photons, and the most commonly used direct ionizing radiation is electrons. Contrary to the characteristics of high-energy photon beam dosimetry, high-energy electron beams have almost no build-up effect, which can effectively increase the dose in the superficial area of ​​​​the tumor. At the same time, the dose of high-energy electron beams drops rapidly in the direction of the beam, which can effectively reduce the cumul...

AI Technical Summary

Problems solved by technology

[0003] However, current high-energy electron beam radiotherapy can only achieve primary conformal radiotherapy technology, and cannot achieve more advanced multi-degree-of-freedom intensity-modulated radiotherapy. The stray radiation dose of a large patient increases the risk of secondary carcinogenesis, and the lateral scattering in the patient's body will cause the dose drop gradient in the penumbra area of ​​the field of view to decrease with depth, which is not conducive to the protection of lateral normal tissues; For side scatter, clinically it is necessary to make individualized lead blocks, combined with electronic light-limiting tubes, to realize the conformity of the dose to the tumor target area. However, the distance between the lower surface of the light-limiting tubes and the patient's body surface is very small. Collision risk, the beam output angle of the high-energy electron beam radiotherapy plan must be limited; ③ Currently, there is a lack of radiotherapy plan optimization methods dedicated to high-energy electron beams, and it is difficult to fully utilize the optimization degrees of freedom such as the gantry angle, collimator angle, electron beam energy and intensity, etc. Significantly limits the ability to modulate high-energy electron beam radiotherapy plans

This radiotherapy plan with insufficient modulation capacity cannot ensure the uniformity and conformity of tumor dose distribution, which may lead to tumor underdose and subsequent recurrence

[0004] Umeå University in Sweden reduces the side scattering of high-energy electron beams by setting a helium gas pipeline in the direction of the electron beam, but this method can only reduce the side scattering in the air, but cannot reduce the side scattering in the patient's body. There is a high risk of collision between helium pipeline equipment and patients, and it is difficult to achieve multi-degree-of-freedom modulation

[0005] The University of Maryland School of Medicine and the University of Wollongong in Australia use NdFeB permanent magnets to set a magnetic field in the beam path to constrain the side scattering of high-energy electrons. side scattering, and the restricted beam aperture and patient treatment space are too small, so the clinical practical value is not high

[0006] Therefore, in order to achieve multi-degree-of-freedom intensity-modulated radiation therapy with high-energy electron beams, it is necessary to solve the problems of large inward scattering of high-energy electron beams in the air and inside the patient's body, and limited ability to plan modulation.

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