本文選題：靶區(qū)運(yùn)動(dòng)　切入點(diǎn)：實(shí)時(shí)定位　出處：《北京協(xié)和醫(yī)學(xué)院》2013年碩士論文

【摘要】：由于人體解剖結(jié)構(gòu)的動(dòng)態(tài)特性,病人胸腹部的器官和腫瘤靶區(qū)在治療過(guò)程中常會(huì)發(fā)生運(yùn)動(dòng),計(jì)劃設(shè)計(jì)時(shí)適形的劑量分布在治療時(shí)可能會(huì)偏離靶區(qū),從而影響靶區(qū)劑量分布的適形性。 為了降低放射治療過(guò)程中靶區(qū)運(yùn)動(dòng)所帶來(lái)的劑量不確定性,需要實(shí)施一定的靶區(qū)運(yùn)動(dòng)管理方法。目前提出的多種運(yùn)動(dòng)管理方法包括PTV包含運(yùn)動(dòng)范圍、呼吸屏氣治療、門控治療和實(shí)時(shí)跟蹤治療等等。但是前三種運(yùn)動(dòng)管理方法都有其一定的局限性；而實(shí)時(shí)跟蹤治療作為一種最精確的運(yùn)動(dòng)管理方法,如何精確地實(shí)時(shí)定位腫瘤靶區(qū)運(yùn)動(dòng)是這種方法最大的挑戰(zhàn)。 目前已提出了多種腫瘤靶區(qū)實(shí)時(shí)定位方法,主要可分為直接定位法、間接定位法和混合定位法三大類。直接定位法中,根據(jù)是否使用X射線成像的情況又分為X射線成像定位(包括立體X射線成像和單方向X射線成像等)和非X射線成像定位(包括電磁定位、超聲定位和核磁加速器在機(jī)MRI定位等)；間接定位法主要包括了利用體外標(biāo)記物、體外壓力傳感器、體表輪廓變化等進(jìn)行體表運(yùn)動(dòng)監(jiān)測(cè)和利用肺活量計(jì)等測(cè)量呼吸容量來(lái)進(jìn)行輔助定位的方法；混合定位法則將前兩種方法結(jié)合應(yīng)用,典型產(chǎn)品是射波刀(CyberKnife)和ExacTrac同步跟蹤定位系統(tǒng)。相比較而言,單方向X射線成像定位法應(yīng)用簡(jiǎn)單,而且能夠有效降低對(duì)病人曝光的成像劑量,如果使用合適的定位算法,則能夠方便有效地應(yīng)用于臨床。因此,本研究選取了4種典型的單方向X射線成像定位算法,使用模擬的呼吸運(yùn)動(dòng)軌跡和前列腺腫瘤病人的Calypso跟蹤數(shù)據(jù)來(lái)比較它們的定位結(jié)果。這四種定位算法分別是α分布圖法、兩種基于高斯概率密度分布的算法和貝葉斯概率密度分布法。 在連續(xù)15分次對(duì)模擬的呼吸運(yùn)動(dòng)軌跡的模擬結(jié)果中,α分布圖法的均方根誤差范圍約為2.8-4.6mm,而最大誤差的范圍為12.9-42.3mm；高斯概率密度法1的均方根誤差范圍約為6.5-8.2mm,最大誤差范圍為12.8-15.3mm；高斯概率密度分布法2的均方根誤差范圍約為1.6-3mm,在絕大多數(shù)分次中最大誤差范圍為4.4-6.1mm,但也出現(xiàn)了超過(guò)30mm的異常值；貝葉斯概率密度分布法的均方根誤差范圍約為1.8-2mm,而最大誤差范圍為4.8-6.5mm。 在對(duì)10位前列腺腫瘤病人的Calypso跟蹤數(shù)據(jù)的模擬結(jié)果中,α分布圖法的均方根誤差范圍約為0.2-5.1mm,而最大誤差的范圍為0.7-55.7mm；高斯概率密度法1的均方根誤差范圍約為0.2-2.6mm,最大誤差范圍為0.7-5.9mm；對(duì)于絕大多數(shù)病人,高斯概率密度分布法2的均方根誤差范圍約為0.15-1.4mm,最大誤差范圍為0.5-7mm,但有少數(shù)病人的均方根誤差為4.5-8.4mm,最大誤差超過(guò)了30mm；貝葉斯概率密度分布法的均方根誤差范圍約為0.15-2.5mm,而最大誤差范圍為0.5-8.8mm。 相比較而言,貝葉斯概率密度分布法能夠最好地適用于呼吸運(yùn)動(dòng)引起的腫瘤運(yùn)動(dòng)和多種類型的前列腺腫瘤運(yùn)動(dòng)的實(shí)時(shí)定位。
[Abstract]:Because of the dynamic characteristics of the anatomical structure of the human body, the organs and tumor targets of the patient's chest and abdomen often move during the course of treatment, and the conformal dose distribution of the planned design may deviate from the target area during the treatment. Thus the conformability of dose distribution in target area is affected. In order to reduce the dose uncertainty caused by target motion during radiotherapy, a certain method of target motion management should be implemented. At present, a variety of motion management methods, including PTV, including range of motion, breath-holding therapy, are proposed. But the first three methods of motion management have some limitations, while real-time tracking therapy is the most accurate method of motion management. How to accurately locate tumor target motion in real-time is the biggest challenge of this method. At present, a variety of real-time localization methods for tumor target have been proposed, which can be divided into three categories: direct localization method, indirect localization method and mixed localization method. Depending on whether X-ray imaging is used, it is subdivided into X-ray imaging positioning (including stereoscopic X-ray imaging and unidirectional X-ray imaging, etc.) and non-X-ray imaging positioning (including electromagnetic positioning). Ultrasonic localization and nuclear magnetic accelerator positioning in the machine MRI; indirect localization mainly includes the use of external markers, in vitro pressure sensor, The methods of surface motion monitoring and breathing volume measurement such as vital capacity meter are used to locate the body surface contour, and the hybrid localization method combines the first two methods. The typical products are CyberKnifeand ExacTrac synchronous tracking and positioning system. In comparison, the single direction X-ray imaging localization method is simple to use and can effectively reduce the imaging dose of patient exposure, if the appropriate localization algorithm is used, Therefore, four typical single-direction X-ray imaging localization algorithms are selected in this study. The simulated respiratory track and Calypso tracking data of prostate cancer patients were used to compare their localization results. The four localization algorithms are alpha distribution method. Two algorithms based on Gao Si probability density distribution and Bayesian probability density distribution method. The mean square error range of 偽 distribution map method is about 2.8-4.6mm, and the maximum error range is 12.9-42.3mm, and that of Gao Si's probability density method 1 is about 6.5-8.2mm, the maximum error range is about 6.5-8.2mm. The error range is 12.8-15.3mm, the root mean square error range of Gao Si probability density distribution method 2 is about 1.6-3mm, and the maximum error range is 4.4-6.1mm in most grades, but there are outliers over 30mm. The root mean square error range of Bayesian probability density distribution method is about 1.8-2mm and the maximum error range is 4.8-6.5mm. In the simulation of Calypso tracking data of 10 prostate cancer patients, the root mean square error range of 偽 distribution map method is about 0.2-5.1mm, while the maximum error range is 0.7-55.7mm, and the RMS error range of Gao Si's probability density method 1 is about 0.2-2.6mm, the maximum error range is 0.7-55.7mm, and the maximum RMS error range is about 0.2-2.6mm for Gao Si's probability density method 1. The wide error ranges from 0.7 to 5.9 mm; for the vast majority of patients, The root-mean-square error range of Gao Si probability density distribution method 2 is about 0.15-1.4mm, the maximum error range is 0.5-7mm, but the RMS error of a few patients is 4.5-8.4mm, the maximum error is more than 30mm, and the RMS error range of Bayesian probability density distribution method is about 30mm. The maximum error range is 0.5-8.8mm. In contrast, Bayesian probabilistic density distribution method is the best method for real-time localization of tumor movements caused by respiratory movement and various types of prostate tumor movements.
【學(xué)位授予單位】：北京協(xié)和醫(yī)學(xué)院
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：R730.44;TP391.41

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相關(guān)期刊論文 前1條

1 鄭超;戴建榮;;單方向X射線成像定位算法的比較[J];中國(guó)醫(yī)學(xué)物理學(xué)雜志;2012年06期

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本文編號(hào)：1683240