利用DVH圖比較鼻咽癌兩種放療方法對(duì)正常組織受量的影響

1、利用DVH圖比較鼻咽癌兩種放療方法對(duì)正常組織受量的影響         07-08-27 10:07:00     編輯：studa20         作者：原錦，程惠華，傅志超，林貴山，朱錦鋒 【關(guān)鍵詞】  鼻咽腫瘤    DVH comparison of threedimensional conformal and conventional radi

2、otherapies in normal tissues of patients with nasopharyngeal carcinoma【Abstract】 AIM: To investigate the effect of threedimensional conformal radiotherapies (3DCRT) and conventional radiotherapies on normal tissues in patients with nasopharyngeal carcinoma by comparing the dose distribution in norma

3、l tissues so as to pick out the better method. METHODS:  Forty cases of nasopharyngeal carcinoma (18 cases at stage T1 and 22 at stage T2, according to 92 Fuzhou staging) underwent conventional radiotherapy and 3DCRT respectively. Treatment planning system (TPS) was used to mark the dose distri

4、bution and quantity in normal tissues (bilateral lens, optic nerves, brain stem, spinal cord, parotid glands and temporomandibular joints) and the data obtained were analyzed with dosevolume histogram (DVH). The major fields in conventional radiotherapy were bilateral neckconjoined horizontal field

5、and preauricular field, the prenasal. The tophead fields were respectively added in the first and second phases in 3DCRT and 3 to 5 conplane or nonconplane fields were designed in the third phase. The prescribed dose of the two groups was 70Gy respectively. RESULTS:  3DCRT had satisfactory dose

6、 coverage of target volume of nasopharyngeal carcinoma compared with conventional radiotherapy. 3DCRT plans spared more parotid glands and twoside lens than conventional treatment （P<0.05）, the conventional treatment spared a little more brain stem and bilateral optic nerves than 3DCRT（P<0.05）

7、 and the received dose in other organs was similar in the two plans（P>0.05）. CONCLUSION:  3DCRT not only satisfies the dose coverage of target volume, especially in subclinical lesion region, but also spares more normal tissues compared with conventional radiotherapy.【Keywords】 nasopharyngea

8、l neoplasms; radiotherapy; dosevolume histogram【摘要】 目的：兩種鼻咽癌放療方法對(duì)比，應(yīng)用劑量體積直方圖(DVH)對(duì)正常組織的受量進(jìn)行分析，確定最佳治療方案. 方法：鼻咽癌40例，按92福州分期法確定為T(mén)1期18例和T2期22例，分別采用常規(guī)放療法和三維適形放療(3DCRT)法，通過(guò)治療計(jì)劃系統(tǒng)(TPS)進(jìn)行布野、給量、優(yōu)化并計(jì)算，最后用DVH圖對(duì)正常組織（兩側(cè)晶體、視神經(jīng)、腦干、脊髓、腮腺及顳頜關(guān)節(jié)）進(jìn)行受量分析，兩種方法均分三階段進(jìn)行. 常規(guī)放療法以?xún)蓚?cè)水平面頸聯(lián)合野和耳前野為主（2野照射），3DCRT法第一階段加設(shè)鼻前野（3野照射），第二階

9、段加設(shè)一頭頂野（3野照射），第三階段設(shè)35個(gè)共面或非共面野. 兩種放療方法總劑量DT 70 Gy. 結(jié)果： 三維適形法腦干、兩側(cè)視神經(jīng)受量略高于常規(guī)方法，脊髓劑量相仿，而雙側(cè)晶體及腮腺受量明顯低于常規(guī)方法（P<0.05）. 結(jié)論： 用3DCRT治療鼻咽癌靶區(qū)適合度更好，能更好地保護(hù)正常組織或器官.【關(guān)鍵詞】 鼻咽腫瘤；放射療法；劑量體積直方圖0引言鼻咽癌的首選治療手段為放射治療，但正常組織或器官的損傷較重. 我們對(duì)T1T2期鼻咽癌進(jìn)行三維適形放療（threedimensional conformal radiotherapies, 3DCRT）的同時(shí)用治療計(jì)劃系統(tǒng)(treatment p

10、lanning system, TPS)進(jìn)行常規(guī)方法布野，劑量計(jì)算，劑量體積直方圖（dosevolume histogram, DVH）分析兩種方法治療后的正常組織受量變化.1對(duì)象和方法1.1對(duì)象200307/200406收治鼻咽癌患者40（男32，女8）例，按福州分期法（1992），確定為T(mén)1T2期，其中T1期18例，T2期22例，年齡2868歲. 儀器采用以色列進(jìn)口雙螺旋CT（包括可移動(dòng)三維激光定位系統(tǒng)一套），美國(guó)CMS進(jìn)口治療計(jì)劃系統(tǒng)，美國(guó)瓦里安公司進(jìn)口600C/D直線加速器.1.2方法患者仰臥于治療床上，進(jìn)行體模制作，用頭頸肩固定，同時(shí)在體模上進(jìn)行皮膚標(biāo)記，確定參考點(diǎn)，然后進(jìn)行CT掃描

11、，范圍從頭頂至胸骨切跡，病灶區(qū)層厚2.5 mm，其余為5 mm，通過(guò)網(wǎng)絡(luò)將CT圖像傳輸至治療計(jì)劃系統(tǒng)，進(jìn)行三維重建，確定靶區(qū)及重要器官，在BEV窗口下進(jìn)行布野、設(shè)定劑量，通過(guò)優(yōu)化最后確定治療方案，兩種方法均分三階段進(jìn)行. 常規(guī)放療方案：設(shè)左右兩側(cè)對(duì)穿照射，第一階段以CTV為中心，設(shè)面頸聯(lián)合野+頸切野（DT 36 Gy/2.0 Gy/3+W），第二階段復(fù)查CT根據(jù)腫瘤消退情況，確定CTV，避開(kāi)脊髓，頸部改電子線，DT 20 Gy/2.0 Gy/2 W，第三階段：再查CT，針對(duì)鼻咽部腫瘤大小縮野加量，DT 14 Gy/2.0 Gy/1+W. 3DCRT方案：第一階段以CTV為中心，設(shè)面頸聯(lián)合野+鼻前野+頸切野，DT 36 Gy/2.0 Gy/3+W，第二階段復(fù)查CT確定新的CTV，避開(kāi)脊髓，頸部改用電子線，設(shè)兩水平野+頭頂野，DT 20 Gy/2.0 Gy/2 W，第三階段再查CT，以鼻咽部腫瘤為中心，設(shè)非共面4野照射，DT 14 Gy/2