1、利用DVH圖比較鼻咽癌兩種放療方法對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比，應用劑量體積直方圖(DVH)對正常組織的受量進行分析，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T1期18例和T2期22例，分別采用常規放療法和三維適形放療(3DCRT)法，通過治療計劃系統(TPS)進行布野、給量、優化并計算，最后用DVH圖對正常組織（兩側晶體、視神經、腦干、脊髓、腮腺及顳頜關節）進行受量分析，兩種方法均分三階段進行. 常規放療法以兩側水平面頸聯合野和耳前野為主（2野照射），3DCRT法第一階段加設鼻前野（3野照射），第二階

9、段加設一頭頂野（3野照射），第三階段設35個共面或非共面野. 兩種放療方法總劑量DT 70 Gy. 結果： 三維適形法腦干、兩側視神經受量略高于常規方法，脊髓劑量相仿，而雙側晶體及腮腺受量明顯低于常規方法（P<0.05）. 結論： 用3DCRT治療鼻咽癌靶區適合度更好，能更好地保護正常組織或器官.【關鍵詞】 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T1T2期鼻咽癌進行三維適形放療（threedimensional conformal radiotherapies, 3DCRT）的同時用治療計劃系統(treatment p

10、lanning system, TPS)進行常規方法布野，劑量計算，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對象和方法1.1對象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T1T2期，其中T1期18例，T2期22例，年齡2868歲. 儀器采用以色列進口雙螺旋CT（包括可移動三維激光定位系統一套），美國CMS進口治療計劃系統，美國瓦里安公司進口600C/D直線加速器.1.2方法患者仰臥于治療床上，進行體模制作，用頭頸肩固定，同時在體模上進行皮膚標記，確定參考點，然后進行CT掃描

11、，范圍從頭頂至胸骨切跡，病灶區層厚2.5 mm，其余為5 mm，通過網絡將CT圖像傳輸至治療計劃系統，進行三維重建，確定靶區及重要器官，在BEV窗口下進行布野、設定劑量，通過優化最后確定治療方案，兩種方法均分三階段進行. 常規放療方案：設左右兩側對穿照射，第一階段以CTV為中心，設面頸聯合野+頸切野（DT 36 Gy/2.0 Gy/3+W），第二階段復查CT根據腫瘤消退情況，確定CTV，避開脊髓，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，設面頸聯合野+鼻前野+頸切野，DT 36 Gy/2.0 Gy/3+W，第二階段復查CT確定新的CTV，避開脊髓，頸部改用電子線，設兩水平野+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，設非共面4野照射，DT 14 Gy/2