呼吸運動對靶區(qū)重建的影響極大,三維放療計劃設(shè)計所依賴的CT圖像,必須是腫瘤靶區(qū)處于相對靜止?fàn)顟B(tài)下掃描的圖像,否則,適形射野和劑量體積直方圖將嚴重失真。而如何正確地控制呼吸運動顯得尤為重要。 總之,在三維適形放療技術(shù)中,精確勾畫腫瘤區(qū)是優(yōu)化治療增益比的關(guān)鍵,要求既不漏掉腫瘤組織,又要最大限度保護正常組織。作者認為可以通過以下途徑來提高靶區(qū)勾畫的精確性:①提高CT機的質(zhì)量,改進掃描技術(shù);②應(yīng)用融合技術(shù)(與MRI圖像的融合、與PET或SPECT圖像的融合);③應(yīng)用增強CT掃描技術(shù),提高組織對比度;④通過對放療醫(yī)師進行臨床及影像知識的培訓(xùn),可提高GTV勾畫的一致性。放療的進步與診斷技術(shù)的提高與計算機的發(fā)展密切相關(guān)。診斷的發(fā)展已由解剖性的診斷轉(zhuǎn)向為功能性的診斷,包括PET、MRSI及準確率高于PET的基因檢測。待這些技術(shù)臨床應(yīng)用成熟,腫瘤靶區(qū)的勾畫范圍不僅要求邊界精確,而且同時要求內(nèi)部結(jié)構(gòu)勾畫的精細,可達到組織學(xué)上的腫瘤細胞GTV的勾畫,屆時勾畫的腫瘤范圍為生物靶區(qū)。
【參考文獻】
[1]BAUMANN M, APPOLD S, PETERSEN C, et al. Dose andfractionation concepts in the primary radiotherapy of non2small cell lung cancer [J]. Lung Cancer, 2001,33:35245.齊魯醫(yī)學(xué)雜志2009年2月第24卷第1期 Med J Qilu, FePuary 2009, Vol.24, No.1
[2]PEREZ C A, PAJAK T F, RUBIN P, et al. Long2termobservations of the patternsof failure in patientswith unresectable nonoat cell carcinoma of the lung treated with definitive radiotherapy: report by the RTOG [J]. Cancer, 1987,59:187421881.
[3]王旬果,孫福鑾,王建軍. 三維適形放射療法治療非小細胞肺癌的效果[J]. 齊魯醫(yī)學(xué)雜志, 2005,20(2):1122114.
[4]HARRIS K M, ADAMS H, LLOYD D C, et al. The effect on apparent size of simulated pulmonary nodules of using three standard CT window settings[J]. Clin Radiol, 1993,47(4):2412244.
[5]ROSENMAN J. Incorporating functional imaging information into radiation treatment[J]. Semin Radiat Oncol, 2001,11(1):83292. [6]夏士安,吳國華,林清,等. CT模擬定位中窗寬窗位變化對勾畫靶區(qū)的影響[J]. 上海第二醫(yī)科大學(xué)學(xué)報, 2005,25(7):7412743.
[7]姚原,吳國華,吳旭東,等. CT模擬定位中掃描層厚對腫瘤靶區(qū)體積的影響[J]. 實用癌癥雜志, 2001,16(4):4102412醫(yī)學(xué)全.在線gydjdsj.org.cn.
[8]GIRAUD P, ELLES S, HELFRE S, et al. Conformal radiotherapy for lung cancer: different delineation of the gross tumor volume (GTV) by radiologists and radiation oncologists[J]. Radiother Oncol, 2002,62(1):27236.
[9]VAN DE STEENE J, LINTHOUT N, DE MEY J, et al. Definition of gross tumor volume in lung cancer:interobserver variability[J]. Radiother Oncol, 2002,62(1):37249.
[10]BOWDEN P, FISHER R, MANUS M M, et al. Measurement of lung tumor volumes using three2dimensional computer planning software[J]. Int J Radiat Oncol Biol Phys, 2002,53(3):5662573.
[11]錢建軍,田野. 放射治療中腫瘤靶區(qū)勾畫的主觀差異性分析 [J]. 核技術(shù), 2007,30(7):6052609. [12]任克杰,申建,徐全敬. 適形放療靶區(qū)確定的影響因素分析[J]. 實用全科醫(yī)學(xué), 2005,3(1):14215.
[13]張燁,錢建軍,陸雪官.等. 大體腫瘤靶區(qū)勾畫的差異性分析[J]. 蘇州大學(xué)學(xué)報:醫(yī)學(xué)版, 2007,27(6):9592960.
[14]吳開良,蔣國梁,王鵬,等. 肺癌三維適形放射治療靶體積確定的影響因素[J]. 中華放射腫瘤學(xué)雜志, 2003,12(3):1882191.
[15]ERRIDGE S C, SEPPENWOOLDE Y, MULLER S H, et al. Portal imaging to assess set up errors, tumor motion and tumor shrinkage during conformal radiotherapy of non2small cell lung cancer[J]. Radiother Oncol, 2003,66(1):75285.
[16]SHIMIZU S, SHIRATO H, KAGEI K, et al. Impact of respiratory movement on the computed tomographic images of small lung tumors in three2dimensional (3D) radiotherapy[J].Int J Radiat Oncol Biol Phys, 2000,46(5):112721133.
[17]SEPPENWOOLDE Y, SHIRATO H, KITAMURA K, et al. Precise and real time measurement of 3D tumor motion in lung due to Peathing and heartbeat, measured during radiotherapy[J]. Int J Radiat Oncol Biol Phys, 2002,53(4):8222834. [18]張書旭,徐海榮,陳光杰,等. 呼吸運動對靶區(qū)三維重建的影響[J]. 中國醫(yī)學(xué)物理學(xué)雜志, 2006,23(6):4002404.