發(fā)布時(shí)間：2018-05-23 18:39

  本文選題：調(diào)強(qiáng)放療 + 蒙特卡羅方法��； 參考：《清華大學(xué)》2012年碩士論文

【摘要】：三維調(diào)強(qiáng)放射治療技術(shù)已經(jīng)在臨床中得到廣泛應(yīng)用。但是由于人體組織結(jié)構(gòu)的復(fù)雜性，和IMRT治療計(jì)劃的復(fù)雜性影響，，不同劑量算法的治療計(jì)劃系統(tǒng)在計(jì)算的IMRT治療計(jì)劃劑量分布時(shí)計(jì)算會(huì)有不同的誤差存在。驗(yàn)證不同算法在不同條件下的劑量精度，對選擇合適的系統(tǒng)和適應(yīng)癥，保證治療的劑量誤差沒有超出臨床允許的范圍，是IMRT治療成敗的關(guān)搖問題之一。 本課題研究了在組織不均勻條件下，商業(yè)化的治療計(jì)劃系統(tǒng)（MONACO）中的有限筆形束（FSPB）算法與快速X射線體積元蒙特卡羅（XVMC）算法的IMRT計(jì)劃計(jì)算精度差別，以及它們對臨床治療的影響和各自的應(yīng)用范圍。 課題實(shí)驗(yàn)首先對MONACO計(jì)劃系統(tǒng)兩種算法在均勻模體中輸出的二維平面劑量及絕對劑量分別用二維半導(dǎo)體陣列和指型電離室進(jìn)行了測量比對。在非均勻仿真人體模型中，對兩種算法模型計(jì)算的規(guī)則照射野及調(diào)強(qiáng)照射野的劑量精度利用經(jīng)過刻度的放射性鉻膠片（EBT2）進(jìn)行劑量測量比對。了解系統(tǒng)對6MV和15MV能量的X射線在仿真人體模型中肺、骨以及軟組織各部分結(jié)構(gòu)的劑量計(jì)算誤差。實(shí)驗(yàn)結(jié)果顯示：1、在均勻等效固體水模體中，對6MV和15MV能量的射線，XVMC算法計(jì)算結(jié)果與實(shí)際測量的值誤差均在±2%范圍內(nèi)，而FSPB算法計(jì)算結(jié)果與實(shí)際測量值的誤差均在±3%范圍內(nèi)。利用二維半導(dǎo)體陣列驗(yàn)證兩種算法在均勻模體中計(jì)算的IMRT計(jì)劃，其GAMMA通過率（3mm，3%）均大于90%，指型電離室測量絕對劑量XVMC算法偏差-0.66±1.55%，F(xiàn)SPB算法偏差1.67±1.71%。2、在非均勻仿真人體模型中，不同能量的X射線規(guī)則照射野，XVMC算法在不同介質(zhì)中的劑量計(jì)算與膠片測量的結(jié)果偏差均在±2%范圍內(nèi)，而FSPB計(jì)算的結(jié)果與測量結(jié)果的偏差除了15MV能量2cm×10cm射野情況下肺中的劑量偏差高達(dá)6.51%以外，其他條件下的結(jié)果偏差也都在±3%范圍內(nèi)。IMRT計(jì)劃的膠片驗(yàn)證測量結(jié)果中，Gamma（3%/3mm）通過率XVMC算法組大于90%；FSPB算法組小于90%大于80%，且Gamma（4%/4mm）通過率大于90%；而兩種算法的3mm等劑量距離誤差（DTA）的通過率均大于90%。 研究的結(jié)論為：當(dāng)臨床治療病例的組織密度不均勻性較大、子野數(shù)較多的情況下， XVMC算法的劑量計(jì)算精度優(yōu)于FSPB算法，采用XVMC治療設(shè)計(jì)胸腹部IMRT治療計(jì)劃可以將算法所引起的誤差控制在3%以內(nèi)。
[Abstract]:Three-dimensional intensity modulated radiotherapy has been widely used in clinical practice. However, due to the complexity of human tissue structure and the complexity of IMRT treatment plan, there are different errors in the calculation of dose distribution of IMRT treatment plan by different dose algorithms. It is one of the key problems for the success or failure of IMRT to verify the dose accuracy of different algorithms and ensure that the dose error of the treatment does not exceed the clinical allowable range for the selection of appropriate system and indications. In this paper, the difference of IMRT planning accuracy between the finite pencil beam (FSPB) algorithm and the fast X-ray volume element Monte Carlo (XVMC) algorithm in the commercialized treatment planning system (MONACOO) is studied under the condition of uneven organization. And their effects on clinical treatment and their respective application scope. Firstly, the two-dimensional plane dose and absolute dose of MONACO planning system in uniform mode are measured and compared with that of two-dimensional semiconductor array and digital ionization chamber, respectively. In the non-uniform simulated human body model, the dose accuracy of the regular irradiation field and the intensity modulated radiation field calculated by the two algorithms are compared by using the calibrated radioactive chromium film EBT2. To understand the dose calculation errors of the lung, bone and soft tissue components of 6MV and 15MV energy X-ray in the simulated human model. The experimental results show that in the homogeneous equivalent solid water mode, the error between the calculation results of 6MV and 15MV energy and the measured values is in the range of 鹵2%, while the error between the calculated results of the FSPB algorithm and the actual measured values is within 鹵3%. Two dimensional semiconductor array was used to verify the IMRT plan calculated by the two algorithms in the homogeneous mode. The GAMMA pass rate of the two algorithms was higher than 90. The deviation of the absolute dose XVMC algorithm measured by the finger ionization chamber was -0.66 鹵1.550.67 鹵1.71. 2. In the non-uniform simulation of human body model, the deviation of the two algorithms was 1.67 鹵1.71. The deviation between the dose calculation of the XVMC algorithm and the film measurement in different media is in the range of 鹵2%. The deviation between the results of FSPB calculation and that of measurement was 6.51% in the case of 15MV energy 2cm 脳 10cm field. Under other conditions, the deviation of results is also in the range of 鹵3%. IMRT plan. The result of film verification measurement is Gamma3 / 3mm) pass rate XVMC algorithm group is greater than 90% more than 90% FSPB algorithm group > 80%, and Gamma-4 / 4 mm) pass rate is greater than 90%; and the 3mm equal dose distance of both algorithms is greater than 90%. The pass rate of DTAs is more than 90%. The conclusions are as follows: when the tissue density and the number of subfields are large, the dose calculation accuracy of XVMC algorithm is better than that of FSPB algorithm. The error caused by the algorithm can be controlled within 3% by using XVMC to design the IMRT treatment plan of chest and abdomen.
【學(xué)位授予單位】：清華大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2012
【分類號】：R311

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 馬金利,蔣國梁,傅小龍,李龍根;沖洗時(shí)間因素對膠片劑量的影響[J];中華放射腫瘤學(xué)雜志;2005年06期

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