Research And Implementation Of A3d Electron Beam Irradiation Planning System Based On CT Images

In recent years, radiation treatment technology such as CT, MRI, and PET image fusion technology development and the three dimensional irradiation technology (3D-CRT, IMRT, IGRT) used in3D planning system, has been injected fresh blood. On one hand, it constantly improves the radiation treatment effect and increases radiation therapy indications. On the other hand, challenging issues will be put forward for engaging in3D radiation treatment planning system theory and applied research workers. As a special external radiotherapy, electron beam irradiation has its own advantage of treating superficial or bias tumor and the invaded lymph gland applying in clinic for sixty years, which therapy effect has got the clinician’s sure.According to domestic and overseas literature,3D electron beam irradiation planning system based on CT, MRI, PET images has been adopted in developed countries at present. However, most of electron beam radiotherapy in China are limited to2D planning system based on X-ray film. The2D planning system cannot realize3D image reconstruction and precise anatomical position owing to the tissue organ image overlapping in X-ray film and simple dose calculation model. So it cannot intuitively display dose distribution of patients and is difficult to design an individual treatment plan, which lead to an unreasonable dose distribution and trigger tumor recurrence or complications.In order to change this situation, we need accurate and rigorous treatment planning design to improve electron beam radiotherapy effect. Through it, we can achieve dose distribution visualization and dose optimization of patients with tumor and evaluate the uniformity of dose distribution. It not only analyses the target dose distribution, what’s more, but also show the dose uniformity of the target area surrounding normal tissues and key organs, for the sake of reducing the side effect and increasing ratio of gains in radiation therapy. Due to little resources of most of hospital in China, few hospitals in the three dimensional planning system import3D electron beam therapy plan module. Through few researchers at home develop the3D planning system, a commercial product is not emerged. Therefore, the3d electron beam irradiation planning system based on CT images was developed by VC++. It overcame the drawback of2D treatment planning systems under using at present, fulfilled the design of individual treatment plan, finally sovled the contradiction between existing electron irradiation technology and the clinical need day by day.First of all, the history of high energy electron beam radiation therapy technology is reviewed, and field dose characteristics are briefly introduced and analysis. Furthermore, this paper details electron beam treatment planning system involving in compensation technology and block technology. All of those are important for the research in the thesis. And the writer put forward the necessity of3D electron beam irradiation planning system development. In chapter2of this dissertation, the author detailedly discusses the dose model building, implementation and calculation formula. The model considers oblique incidence and inhomogenous correction in dose calculation, which improves the dose distribution calculation accuracy of the human body. Meanwhile, the dosimetry parameters of model are analysed for subsequent measuring dose datas to furnish theory support. In the third chapter, the theoretical basis of the prescription dose calculation is analyzed and the mathematical model is established. Using MFC framework, prescribed dose calculation module of easy operation is set up. What’s more, we get the accelerator MU through querying the backend database (PDD,FF).This module simplifies the dose calculation trivial process of radiation staff, quickly and accurately gets prescription dose.The next chapter mainly has elaborated the related parameters measurement method for the above dose calculation model, analysed and discussed the datas. It provides the clinical data for using planning system, which ensure system dose calculation accuracy and reliability. In chapter5, how to develop the new3D electron beam irradiation treatment planning system based on CT images by VC++was presented, which main contents are comprise of the design of database, two-dimensional CT image preprocessing, the3D rebuilding method, the isodose curve drawing and so on. The interface interactive and friendly electron beam radiation therapy planning system is designed according to the clinical application requirements. The new system not only can display dose distribution in any transverse section and sagittal plane, but also reflect the tumor absorbed dose by intuitive and the protection of surrounding organs. At last, the dose value of an arbitrary point on the transverse section images is quantitatively calculated.Finally, chapter6of this paper summarizes the work, and points out the need of perfect content and suggests consideration for future research on the basis of the conclusions reached in the previous chapters.