本文選題：IMRT + 逆向計(jì)劃��； 參考：《東北大學(xué)》2009年碩士論文

【摘要】：IMRT是一種先進(jìn)的三維放射治療技術(shù),近年來(lái)廣泛用于臨床腫瘤治療。它的特點(diǎn)在于能實(shí)現(xiàn)幾何形態(tài)和強(qiáng)度分布的雙重適形,從而提高治療比,降低對(duì)病人的傷害。 與傳統(tǒng)的正向計(jì)劃不同,IMRT采用逆向計(jì)劃,先由醫(yī)生確定處方劑量,然后由計(jì)算機(jī)給出實(shí)現(xiàn)該結(jié)果的方法和參數(shù),從而實(shí)現(xiàn)了治療計(jì)劃的自動(dòng)最佳優(yōu)化。 本文根據(jù)IMRT逆向計(jì)劃的研究現(xiàn)狀,結(jié)合現(xiàn)代最優(yōu)化方法,對(duì)IMRT逆向計(jì)劃的優(yōu)化作了較為深入的研究。首先介紹了規(guī)則野、不規(guī)則野的各種劑量計(jì)算模型,其中著重論述了目前常用的基于筆形束模型的劑量計(jì)算方法,用于計(jì)算由多葉準(zhǔn)直器形成的不規(guī)則野的劑量分布；然后研究了IMRT逆向計(jì)劃優(yōu)化算法,針對(duì)模擬退火算法和單純形法的特點(diǎn),將二者相結(jié)合,形成了一種改進(jìn)的模擬退火算法：SMSA算法,并用該算法實(shí)現(xiàn)了子野形狀和權(quán)重的優(yōu)化。實(shí)驗(yàn)結(jié)果表明,該算法不僅能很好的收斂于最優(yōu)值,而且相比于模擬退火算法,優(yōu)化速度大大提高。同時(shí),優(yōu)化過(guò)程中,為更好的保護(hù)靶區(qū)周圍的正常組織及減少計(jì)算量,構(gòu)建了新的優(yōu)化模型；在劑量均勻性約束和組織重要程度約束的條件下,建立了新的目標(biāo)函數(shù)。最后,進(jìn)行了實(shí)驗(yàn)測(cè)試,并用劑量一體積直方圖和等劑量線進(jìn)行了計(jì)劃評(píng)估。 臨床模擬病例結(jié)果表明,采用本文的算法及建立的目標(biāo)函數(shù),達(dá)到了臨床要求,不僅提高了計(jì)劃靶區(qū)的劑量均勻性,減少了正常組織的受照劑量,而且大大減少了逆向計(jì)劃優(yōu)化時(shí)間。本文對(duì)算法及目標(biāo)函數(shù)的改進(jìn)具有較好的實(shí)際意義和臨床應(yīng)用價(jià)值。
[Abstract]:IMRT is an advanced three-dimensional radiotherapy technique, which has been widely used in clinical tumor therapy in recent years. It is characterized by its dual conformal geometry and intensity distribution, which can improve the treatment ratio and reduce the injury to patients. Different from the traditional forward plan, IMRT adopts reverse plan. First, the prescription dose is determined by the doctor, then the method and parameters to realize the result are given by the computer, thus the automatic optimal optimization of the treatment plan is realized. According to the research status of IMRT reverse plan and modern optimization method, this paper makes a deep research on the optimization of IMRT reverse plan. In this paper, the dose calculation models of regular field and irregular field are introduced firstly, and the dose calculation methods based on pen beam model are emphatically discussed, which are used to calculate the dose distribution of irregular field formed by multi-leaf collimator. Based on the characteristics of simulated annealing algorithm and simplex method, an improved simulated annealing algorithm, called "IMRT" algorithm, is proposed to optimize the shape and weight of the subfield. Experimental results show that the proposed algorithm not only converges to the optimal value, but also improves the optimization speed compared with the simulated annealing algorithm. At the same time, in order to better protect the normal tissue around the target area and reduce the amount of calculation, a new optimization model is constructed, and a new objective function is established under the condition of dose uniformity constraint and tissue importance constraint. Finally, the experiment was carried out, and the plan was evaluated with dose-volume histogram and equal dose line. The results of clinical simulation show that the proposed algorithm and the established objective function can not only improve the dose uniformity of the planned target area, but also reduce the radiation dose of normal tissue. Moreover, the optimization time of reverse planning is greatly reduced. This paper has good practical significance and clinical application value for the improvement of algorithm and objective function.
【學(xué)位授予單位】：東北大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2009
【分類號(hào)】：TP301.6;R311;O224

【參考文獻(xiàn)】

相關(guān)博士學(xué)位論文 前1條

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本文編號(hào)：1923071