本文選題：CBCT + 宮頸癌��； 參考：《北京協(xié)和醫(yī)學(xué)院》2014年博士論文

【摘要】：背景：腔內(nèi)放療(intracavitary brachytherapy, ICBT)是局部進(jìn)展期宮頸癌根治性放療的重要組成部分。傳統(tǒng)的二維腔內(nèi)放療以正交X片為基礎(chǔ),通過參考點(diǎn)的劑量估計(jì)靶區(qū)和危及器官的劑量。三維腔內(nèi)放療則以MRI或CT等掃描技術(shù)為基礎(chǔ),可以充分了解靶區(qū)和危及器官的位置和空間形狀,能更加精確地評(píng)估這些組織和結(jié)構(gòu)的劑量,從而提高靶區(qū)劑量和降低危及器官劑量,以獲得更加理想的局部控制率并降低并發(fā)癥的發(fā)生率。CT是三維腔內(nèi)放療常用的影像學(xué)手段,依據(jù)CT圖像能夠進(jìn)行高危臨床靶區(qū)(high-risk clinical target volume, HR CTV)和危及器官(organs at risk, OARs)的勾畫并制定計(jì)劃和實(shí)現(xiàn)劑量?jī)?yōu)化過程。相比于二維腔內(nèi)放療,這一過程耗時(shí)明顯延長(zhǎng),通常需要數(shù)小時(shí)時(shí)間。在這一時(shí)間內(nèi)存在著HR CTV和OARs空間位置和形態(tài)變化,因此依據(jù)CT圖像所制定的治療計(jì)劃并不能真實(shí)地反映劑量傳遞過程中HR CTV和危及器官的實(shí)際受照劑量,二者之間存在一定程度的差異。研究這一分次內(nèi)劑量學(xué)差異的大小和可能導(dǎo)致的結(jié)果可以對(duì)臨床實(shí)踐提供有意義的指導(dǎo)。 材料和方法：本研究納入2013年12月至2014年6月之間9位在北京協(xié)和醫(yī)院放療科進(jìn)行根治性放療的宮頸癌病人進(jìn)行CT引導(dǎo)下的腔內(nèi)放療,分割次數(shù)為5次,單次分割處方劑量為6Gy。在完成施源器放置后進(jìn)行CT掃描,并以此圖像勾畫HRCTV和危及器官,隨后制定計(jì)劃并完成劑量?jī)?yōu)化。在開始治療之前數(shù)分鐘內(nèi)完成錐形束CT(cone beam computed tomography, CBCT)掃描,在CBCT圖像上重新勾畫HRCTV和危及器官,將實(shí)際治療所依據(jù)的CT計(jì)劃中放射性源的駐留位置和駐留時(shí)間模擬至CBCT圖像。對(duì)這9位病人完成了38次高劑量率(high-dose-rate, HDR)三維腔內(nèi)放療,一共獲取了76個(gè)圖像系列,包括38個(gè)CT圖像系列和38個(gè)CBCT圖像系列。運(yùn)用統(tǒng)計(jì)學(xué)方法比較著兩種圖像系列下HR CTV和OARs相關(guān)DVH(dose-volume histogram,劑量體積直方圖)參數(shù)變化,并分析這種劑量變化對(duì)整個(gè)腔內(nèi)治療帶來的影響。 結(jié)果：在平均間隔時(shí)間為55±10min的情況下,HR CTV的體積、D90、D50和V100在兩組圖像系列中變化(平均值士標(biāo)準(zhǔn)差)分別為-2.00±3.26%、-1.18±4.47%、-0.02±4.51%、-3.83±8.23%和-9.0±2.77%,其中HR CTV的體積和D100發(fā)生了顯著統(tǒng)計(jì)學(xué)減小(p值分別為0.000和0.006)。各個(gè)危及器官包括膀胱、直腸、乙狀結(jié)腸和小腸的D2cc變化分別為-0.6±17.05%、9.34±14.59%、7.15%±20.49%和1.52±12.57%,直腸D2cc發(fā)生了顯著統(tǒng)計(jì)學(xué)增加(p=0.001)。 結(jié)論：平均不到1小時(shí)的時(shí)間間隔內(nèi),單次分割內(nèi)HR CTV的劑量學(xué)變化很小,D90的不確定性水平(1個(gè)標(biāo)準(zhǔn)差)約為5%,大約70%的單次治療內(nèi)HR CTV D90(EQD2)變化不超過±0.5Gy。但對(duì)某一次的治療而言這一變化可以到達(dá)1.5Gy。這種單次分割內(nèi)的劑量不確定水平在6Gy×5f的HDR分割模式下,可使某一病人的實(shí)際總EQD2最大減少3Gy。危及器官的劑量變化更加明顯,大部分危及器官的D2cc變化無統(tǒng)計(jì)學(xué)差異,其系統(tǒng)性變化(平均值)10%,而隨機(jī)變化(標(biāo)準(zhǔn)差)可達(dá)到15～20%水平。大部分治療中至少有1個(gè)危及器官的劑量變化超過10%,可能會(huì)引起某一次治療的劑量超過單次限量或者使其在整個(gè)治療中(含外照射)的受照劑量超過累計(jì)限量。通過方法上的改進(jìn)可能會(huì)減少這種不確定性并降低臨床并發(fā)癥的風(fēng)險(xiǎn)。
[Abstract]:Background: intracavitary radiotherapy (intracavitary brachytherapy ICBT) is an important part of radical radiotherapy for locally advanced cervical carcinoma. The traditional two-dimensional intracavitary radiotherapy based on orthogonal X, through reference point dose estimation of the target area and oar dose. Radiotherapy with intracavitary three-dimensional scanning technology based MRI or CT etc. and we can fully understand the target and organs at the location and spatial shape, can be more accurate assessment of the organization and structure of the dose, so as to improve target dose and reduce the doses to the organs at risk, to obtain the local control rate is more ideal and reduce the incidence of complications of.CT is commonly used means of 3D radiotherapy, on the basis of CT images can be high-risk clinical target (high-risk clinical target volume, HR CTV) and organs at risk (organs at risk, OARs) the outline and plan and achieve optimized dose . compared to the two-dimensional radiotherapy, the process takes significantly longer, usually takes a few hours. At this time in the memory of HR CTV and OARs spatial location and morphological changes, so the basis for the formulation of the CT image treatment plan can not reflect the actual dose in the transfer process of HR CTV and organs under actual dose, there is a difference between the two. This study dosimetric differences in two times the size and that the results can provide meaningful guidance for clinical practice.
Materials and methods: the study included between December 2013 and June 2014 9 in Peking Union Medical College Hospital Department of radiotherapy for cervical cancer patients with radical radiotherapy for brachytherapy guided by CT, division 5 times, a single partition, the prescription dose was 6Gy. CT scan in finish applicator after placement, and the images HRCTV and organs then, make a plan to do the optimal dose before beginning treatment. The number of minutes to complete the cone beam CT (cone beam computed tomography, CBCT) scan in the CBCT image to draw the outline of HRCTV and organs, the dwell time to simulate the actual treatment of radioactive source CBCT image will be based on the CT plan on. The 9 patients who completed the 38 high dose rate (high-dose-rate, HDR) 3D brachytherapy, a total of 76 series of image acquisition, including 38 CT and 38 CBCT image image series A statistical method is used to compare the changes in parameters of HR CTV and OARs related DVH (dose-volume histogram, dose volume histogram) under two kinds of image series, and analyze the effect of this dose change on the whole endovascular treatment.
Results: the average interval was 55 + 10min, HR CTV D90, D50 V100 and volume changes in the two groups of image series (mean + standard deviation) were -2.00 + 3.26%, -1.18 + 4.47%, -0.02 + 4.51%, -3.83 + 8.23% and -9.0 + 2.77%, the volume and D100 HR CTV had a significant decrease (P = 0 and 0.006). Various organs including bladder, rectum, sigmoid colon and small intestine D2cc changes were -0.6 + 17.05%, 9.34 + 14.59%, 7.15% + 20.49% and 1.52 + 12.57%, rectal D2cc had significant statistically increased (p=0.001).
Conclusion: the average less than 1 hours interval, single dose variation in HR CTV segmentation is very small, the level of uncertainty in D90 (1 standard deviation) is about 5%, about 70% of the single treatment of HR CTV D90 (EQD2) of less than 0.5Gy. but for a this change can reach 1.5Gy. this single dose in the segmentation uncertainty level segmentation in 6Gy * 5F HDR mode, can make a patient's actual total EQD2 maximum reduction of 3Gy. organs dose change is more obvious, there was no significant difference in most organs of D2cc changes, the system changes (average 10%), and random variation (standard deviation) can reach 15 to 20% levels. Most of the treatments in at least 1 oars dose changes more than 10%, may cause a dose more than a single limit or in the entire treatment (including external radiation exposure) The dose exceeds the cumulative limit. Improvement through methods may reduce this uncertainty and reduce the risk of clinical complications.

【學(xué)位授予單位】：北京協(xié)和醫(yī)學(xué)院
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：R737.33

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