目的 比较3种体位固定术在盆腔肿瘤患者放疗中的摆位误差,探讨盆腔肿瘤患者放疗的理想体位,为临床提供参考.方法 选取2013-09-01-2014-03-31山东省肿瘤医院放疗科收治的需要进行精确放疗的盆腔肿瘤患者45例,根据固定技术不同分为真空垫、低温热塑体膜和碳纤维腹板3组,每组各15例,每组患者均行放疗前的锥形束CT(cone beam computed tomography,CBCT)扫描,进行CBCT与计划CT图像在线配准,获取摆位误差,收集数据,采用SPSS 19.0软件进行统计分析.结果 真空垫组患者摆位误差依次为X(2.9±1.64) mm,Y(3.1±1.73) mm,Z(4.5± 1.60) mm;热塑体膜组依次为X(3.4±2.10) mm,Y(3.3±2.32) mm,Z(1.8±1.08) mm;碳纤维腹板组依次为X(2.3±1.33) mm,Y(1.6±0.83) mm,Z(2.1±1.30) mm.经过单项方差分析和LSD方法多重比较发现,X方向,3组比较差异均无统计学意义,P值均＞0.05;Y方向,真空垫组和低温热塑体膜组差异无统计学意义,但两者均大于碳纤维腹板组,P值均＜0.05;Z方向,低温热塑体膜组和碳纤维腹板组差异无统计学意义,但两者均小于真空垫组,P值均＜0.05.结论 3种体位固定方式在盆腔肿瘤的放疗中尽管都能起到一定的固定作用,但从摆位误差结果分析来看,碳纤维腹板的固定效果最好,低温热塑体膜次之.

Objective To determine the positional and volumetric differences between the target volumes delineated based on three-dimensional computed tomography (3DCT),four-dimensional computed tomography (4DCT),and cone-beam computed tomography (CBCT) in non-small cell lung cancer (NSCLC).Methods Thirty-one patients with peripheral NSCLC sequentially underwent 3DCT and 4DCT simulation scans of the thorax during normal breathing.A 3D conformal treatment plan was created based on 3DCT.Before the first treatment,CBCT was performed and registered to the planning CT using bony anatomy registration.All contours were delineated by a radiation oncologist using the same contouring protocol.GTV3D and GTV4D50％ were contoured based on 3DCT and end-expiration phase (50％ phase) of 4DCT,respectively;internal GTVs (IGTVMIP and IGTVCBCT) were contoured based on maximum intensity projection (MIP) of 4DCT and CBCT,respectively.The differences in the position,size,and degree of inclusion (DI) between these volumes were determined by Wilcoxon rank-sum test and paired t-test.The Pearson test was used for the correlation analysis on 3D motion vector of GTV.Results The mean size ratio of GTV3D,GTV4D50％,and IGTVMIP to IGTVCBCT were 0.77,0.84,and 1.10(z =-2.91,P =0.004;z =-2.79,P =0.005 ;z =-1.81,P =0.070) for tumors in the upper lobe of the lung and 0.67,0.65,and 1.17(z=-3.30,P=0.001;z=-3.30,P=0.001;z=-2.32,P=0.020)fortumorsinthemiddle/ lower lobe of the lung.GTV4D50％/IGTVCBCT ratio was negatively correlated with the 3 D motion vector of GTV (r =-0.45,P =0.012) in all the patients.The mean DIs of GTV3D,GTV4D50％,and IGTVMIP in IGTVCBCT were 0.65,0.65,and 0.62,respectively,and the DI of GTV3D or GTV4D50％ in IGTVCBCT showed no significant difference from that of IGTVMIP in IGTVCBCT (t =-0.90,P =0.375 ; t =-1.42,P =0.167) ; the mean DIs of IGTVCBCT in GTV3D,GTV4D50％,and IGTVMIP were 0.47,0.49,and 0.67,respectively,and the DI of IGTVCBCT in IGTVMIP was significantly greater than that of IGTVCBCT in GTV3D or GTV4D50％ (t =-8.28,P =0.000 ; t =-5.70,P =0.000).Conclusions CBCT can help to acquire significantly more information on tumor motion than 3DCT and end-expiration phase of 4DCT,but with slightly less information than 4DCT MIP.The use of 3DCT or 4DCT registered to CBCT based on bony anatomy may still result in a serious target miss in radiotherapy,which should be focused on when we perform adaptive radiotherapy and rectify treatment planning based on CBCT.

Objective To optimize the registration template of kilovohage cone-beam CT (CBCT) guided radiotherapy in whole breast irradiation(WBI)after lumpectomy of breast cancer.Methods From April 2006 to July 2009,twelve patients undergoing WBI with intensity-modulated radiotherapy (IMRT)were recruited in this study.All patients were performed with both conventional planning CT and CBCT integrated on Varian 23 EX.Six distinguishable referenee points(the diameter 1 mm)around the lumpectomy cavity and the surrounding gland on the planning CT image were marked.The images were manually registered offline based on the breast surface,surgical clips,breast gland,contiguous rib,ipsilaterai lung and its external contours,respectively.The same six reference points were then marked on the CBCT image.The performance of the five registration templates was compared using the concept of registration error,while the registration time was taken into account.The registration error was calculated based on the six reference points'translations between the planning CT image and CBCT image,and analyzed with SPSS 13.0 software using one-way ANOVA.Results The values of the registration error for the breast surface,surgical clips,breast gland, contiguous rib,ipsilateral lung and its external contours were(0.60±0.20),(0.43±0.15),(0.49±0.19),(0.69±0.36)and(0.94±0.49)cm,respectively,and the registration time were(3.8±1.1),(3.0±0.9),(4.7±1.7),(4.3±1.3)and(4.5±1.3)min,respectively.There was no statistical difforence between the breast surface,surgical clips and breast gland registration template(t=0.48-1.36,P>0.05),the same result trend to contiguous rib compared with ipsilateral lung(t=2.00,P=0.055),however,there was significant difference between surgical clips and the last two registration methods(t=2.08-4.08,P<0.05).Conclusion In this initial study with a modest number of patients,surgical clips show a best registration template from the standpoint of accuracy and efficiency,whereas contiguous rib and ipsilateral lung are not an ideal method.

OBJECTIVE:To investigate the magnitude of the setup error using online kilo-voltage cone beam computed tomography(kV CBCT) for nasopharyngeal carcinoma,and estimate the appropriate margins for the planning target volume(PTV).METHODS:Sixteen nasopharyngeal carcinoma patients underwent 3D CRT or IMRT.Immobilization and alignment were performed by conventional head-and-neck masking and laser alignment for daily positioning.kV CBCT scans were acquired on couch before radiotherapy.The analysis of these images was performed by automatic and manual registration of the kV CBCT and planning CT images.The patient setup was then corrected by moving the couch accordingly.CBCT online-guided correction data were recorded.RESULTS:A total of 160 CBCT sets of 16 nasopharyngeal carcinoma patients were analyzed.If the goal of treatment was clinical target volumes that received the prescribed dose was 95% at least,the margins required to account for these setup errors were 4 mm in the right-left,superior-inferior,anterior-posterior directions,respectively.CONCLUSIONS:There exists some extent of setup error in nasopharyngeal carcinoma 3D CRT or IMRT.The approach based on the CBCT measurements can be used to reduce the impact of setup error obviously and to estimate the required margins for PTV.

Objective To measure the displacement of the silver clips guided by kV-plain film at state of moderate deep inspiration hold(mDIBH) assisted by active breathing control(ABC) and to explore the margin of clinical target volume(CTV) to planning target volume(PTV) for breast cancer patients treated with three-dimensional conformal external-beam partial breast irradiation (EB-PBI) assisted by ABC. Methods The patients undertook CT simulation assisted by ABC to get the CT images on the respiratory condition of mDIBH. Four selected silver clips in breast cavity were delineated and the cavity based on all of the clips were delineated as gross tumor volume (GTV). Before each irradiation, two orthogonal kV-plain films were taken for the patients in the respiratory condition of mDIBH assisted by ABC device. 2D-2D auto-matie registration was performed based on pixel between the kV-plain films and the digital reconstructed radi-ographs(DRR). Then manual registration was undertook to get the shifts of the four clips separately at LAT, LNG,and VRT directions. Based on the shift data,the margins of CTV to PTV at LAT,LNG and VRT direc-tions were calculated. Results The margins from CTV to PTV were 5.00 mm,7.78 mm and 9.30 mm at LAT,LNG and VRT directions based on the clip at cephal border of the cavity. The corresponding margins were 4.40 mm,6.43 mm and 6.73 mm based on the clip at bottom of the cavity;5.04 mm,8.63 mm and 10.54 mm based on the clip at lateral border of the cavity;5.40 mm,8.59 ram and 10.81 mm based on the clip at pedal border of the cavity. Conclusions The silver clips in breast cavity can be clearly showed on the kV-plain film. The displacement of the clips can be exactly measured by registration of kV-plain film and planning DRR in condition of mDIBH assisted by ABC. The margins from CTV to PTV for EB-PBI can be calculated based on the displacement of the clips.

OBJECTIVE: To measure planning target volume margin in cone beam CT(CBCT) guided conformal radiotherapy(IG-CRT) of brain metastases carcinoma.METHODS: Fourteen consecutive cases of brain metastases carcinoma were treated with IG-CRT.All the patients were immobilized on a head and neck support pad using a customized thermoplastic masks(ORFIT).CRT technique was performed by using the Eclipse planning system.Before the radiotherapy,3-dimentional CBCT/ planning CT was matched at every first ten fractions of each patient by using IGRT system.After CRT,3-D CBCT/ planning CT was matched again.RESULTS: The standard deviation of overall systematic error was 0.92 mm in the right-left(X axis),0.95 mm in the anterior-posterior(Y axis),1.10 mm in the superior-inferior(Z axis)directions.The corresponding SDs of the random errors were 2.19 mm(X),1.87 mm(Y),1.94 mm(Z),respectively.The estimated margins required from clinical target volume(CTV)-planning target volume(PTV) were calculated according to the Van Herk formula being 3.2 mm(X),3.5 mm(Y),4.0 mm(Z).CONCLUSION: Brain metastases carcinoma can display on KVCBCT with injecting a contrast medium into a vein.4 mm CTV-PTV margin has been adopted in IG-CRT on brain metastases carcinoma.

Objective To investigate how much the patient setup accuracy for irradiation of head and neck cancer can be improved by online setup verification and offline setup verification using cone-beam computed tomography(CBCT), and the feasibility of image-guided adaptive correction procedure to reduce the PIN margin.Methods 16 patients of head-and-neck cancer treated with three-dimensional conformal radiotherapy (3D-CRT)or intensity modulated radiotherapy(IMRT)were investigated. The first online kV CBCT scan, rigid image registration, setup correction were performed before radiotherapy. The second kV CBCT scan were acquired immediately after treatment and analysis was performed as above. CBCT scans were acquired at two or three fractions weekly during the entire course of radiotherapy and CBCT online-guided correction data were recorded. The data was used to calculate the population-based CTV-PTV margins under the condition of non-correction, correction every fraction and compensation of the systematic setup error respectively. The number of initial images required to predict systematic setup error was evaluated with the permission of 0.5 mm residue error. Results Total of 320 sets of CBCT images were analyzed for 16 patients. Under the condition of non-correction, the margins required to account for total error are 5.7 mm,5.6 mm,and 7.3 mm in the left-right(X axis),cranio-eaudal(Y axis), and anterior-posterior (Z axis)directions respectively, when the tumor was corrected every fraction, the margins required to account for intrafraetion error are 1.7 mm,1.7 mm,and 2.3 mm in X, Y,and Z axis.To correct the systematic setup error,8 sets of CBCT images are adequate. After compensation for the effect of the systematic setup error, 2.7 mm,2.5 mm, and 3.6 mm PTV margins are necessary in X, Y, and Z axis respectively. Conclusions There exists some extent of setup error in head and neck 3D-CRT or IMRT.The on-line CBCT correction and the approach based on off-line adaptive correction both can be used to reduce the impact of setup error obviously, the required margins for the PTV was reduced accordingly.

Objective To investigate the feasibility of online and offline cone-beam CT (CBCT) guided radiotherapy for lung cancer. Methods Fourteen patients with lung tumor treated by three-dimen-sional conformal radiotherapy were investigated. Online kV CBCT scan,image registration and setup correc-tion were performed before and immediately after radiotherapy. CBCT online-guided correction data were used to calculate the population-based CTV-PTV margins under the condition of non-correction and correction in every fraction respectively. The numbers of initial images and the population-based CTV-PTV margins af-ter the offline compensation of the system setup error were evaluated with the permission of 0.5 mm and 1.5 mm maximal residue error,respectively. Results Under the condition of non-correction,the required mar-gins for total error were 5.7 mm,8.0 mm and 7.8 mm in the left-right(x axis) ,cranio-caudal(y axis) and anterior-posterior(z axis) directions, respectively. When the tumor was corrected in every fraction, the re-quired margins for intra-fraction error were 2.4 mm,2.4 mm and 2.3 mm in x,y and z axes, respectively. To correct the systematic setup error,9 sets of CBCT images for 3.3 mm,3.7 mm and 3.6 mm PTV margins, and 7 sets of CBCT images for 3.9 mm,4.3 mm and 4.3 mm PTV margins in x,y and z axes were necessary when 0. 5 mm and 1.5 mm maximal residue errosr were permited respectively. Conclusions Both of the online CBCT correction and the offline adaptive correction can markedly reduce the impact of setup error and reduce the required PTV margins accordingly. It is feasible to deliver the online and offline image guided ra-diation for patients with lung tumor.

OBJECTIVE: To evaluate the effect of respiratory motion on imaging results of KV X-ray cone beam CT(CBCT) equipped on Varian 23EX linear accelerators.METHODS: A phantom system consisted of a mobile flatform and three solid acrylic balls(1,2 and 3 cm in diameter,respectively) was devised to simulate respiratory motion,while the cone-beam CT images were acquired.The peak-to-peak amplitude was 0.5,1.0,1.5 cm in X axis,and 0.5,1.0 and 2.0 cm in Z axis with a frequency of 12,20,25 per minute,respectively.RESULTS: The images of static phantom were limpid and undeformed,and its magnitudes were in accordance with real size,with measured diameters 9.8±0.66(95%CI(9.1-10.5) mm),19.9±0.75(95%CI(19.1-20.7) mm),29.7±0.69(95%CI(29.0-30.4) mm) mm vs.the real size 10,20 and 30 mm,respectively,with error 1 mm.The simulated respiratory motion had significant effects on CBCT images of the phantom in both transverse axis and long axis.Significant decrease in image legibility and increase in deform and volume were observed when the motion amplitude was increased.No significant effects on image results related to respiratory frequency change was observed.In this study,all CBCT images showed accordance with the range of phantom movement(the magnitude of the phantom plus the motion amplitude),with difference 3 mm.CONCLUSION: This phantom study indicates that CBCT image includes the data of respiratory motion.

尽管三维适形放疗(3D-CRT)以其照射野形状和剂量分布与肿瘤靶区的适形性为非小细胞肺癌(NSCLC)照射剂量的提高和正常组织的保护创造了条件,但摆位误差和器官运动等因素的影响导致了NSCLC 3D-CRT治疗计划制定时计划靶区(PTY)确定和施照过程中肿瘤位置的不确定性,而影像引导放疗(IGRT)是分析和解决摆位误差和器官运动等因素对PTV确定及其施照过程中肿瘤位置变化影响的重要途径。

> 非小细胞肺癌(NSCLC)放疗的局部控制率较低,影响较大的治疗因素包括靶区的准确定义、照射剂量及投照精确性等。由于放疗过程中肿瘤及周围解剖结构反应性变化、呼吸运动变化及体形和体重改变等因素影响,肿瘤位置、体积均存在着不同程度的变化。因此有必要监测和评价放疗过程中靶区位置和体积变化,从而提高靶区照射精度,减少正常

>作为图像引导放疗(IGRT)的主要实现方式,kV级X线锥形束CT(CBCT)主要用于各轴向摆位误差的在线和离线校正,同时也被用作放疗计划在线和离线校正。笔者自2006年6月开始使用IGRT系统于非小细胞肺癌IGRT后发现,CBCT平扫图像与治疗计划制定前CT模拟定位所获得增强CT扫描图像匹配时,因CBCT图像为平扫且CBCT扫

目的锥形束CT(CBCT)引导测定术腔中银夹位移以探讨保乳术后三维适形部分乳腺外照射(EB-PBI)临床靶体积(CTV)外扩到计划靶体积(PTV)的边界。方法自主呼吸控制(ABC)辅助行CT模拟定位扫描,获取适度深吸气呼吸控制(mDIBH)状态CT图像,分别勾画和标记术腔中4个选定银夹,并勾画所有银夹构成的术腔作为肉眼靶体积(GTV)。每次照射前获取ABC辅助mDIBH状态下2次CBCT扫描图像。每次获取CBCT图像后先与计划CT图像自动匹配,在自动匹配基础上对选定银夹进行手动匹配。获得选定银夹在左右、上下、前后各个方向的位移数据,依据获取的数据分别计算选定银夹放疗分次内和分次间群体系统误差的标准差和群体随机误差的标准差及总体系统误差和总体随机误差的标准差,依据公式M=2.5Σ_总z+0.7σ_总计算各个选定银夹在各个方向上由CTV外扩到PTV所需要边界大小。结果最上层银夹LAT、LNG、VRT方向由CTV到PTV的外扩边界分别为9.2、6.4、12.0mm,最近胸壁层银夹为8.1、8.0、11.7mm,最外侧银夹为9.8、7.7、12.5mm,最下层银夹为9.8、7.7、12.5mm。结论ABC辅助mDIBH状态下CBCT图像与计划CT图像自动加手动配准呵准确显示银夹位移,为EB-PBI的PTV边界确定提供了依据。

Objective To estimate the appropriate margins for the clinical target volume (CTV) with or without online correction using cone-beam CT(CBCT) during the processs of radiation for non-small cell lung cancer(NSCLC) patients. Methods Eight patients with NSCLC treated with three-dimensional conformal ra-diotherapy(3D-CRT) were investigated, kV CBCT scans were performed before and immediately after radio-therapy. Then analysis of these images was performed using automatic and manual registration of the CBCT and planning computed tomography images. The patient positioning and organ motion were corrected by moving the couch in the left- right (X), cranio- caudal (Y), and anterior- posterior (Z) directions accordingly, and CBCTonline-guided correction data were recorded. The clinical study performed 2-3 times per week. CBCT data ac-quired before treatment delivery were used to evaluate the positioning error and organ motion, and that acquired after treatment were used to assess intrafraction tumor displacement and organ motion. These data were used in a standard formula to calculate CTV-to-PTV(planning target volume) margin of online-guided correction and non-online-guided correction. Results Total of 143 sets of CBCT images were analyzed. On the condition of non- correction, the margins required to account for total errors were 8 mm, 9 nun, 11 mm in X, Y and Z direc-tions respectively. When the tumor was corrected every fraction, margins required to account for intrafraction errors were 2 mm in each directions. Conclusion There are some extent of errors from positioning and organ motion in 3D-CRT for NSCLC. Online correction approach based on CBCT images analysis can be used to re-duce the impact obviously and to estimate the appropriate margins for the CTV.

Objective To study the value of active breathing control(ABC) in postoperative radiotherapy for breast cancer. Methods Having breast conservative surgery, 22 early stage breast cancer patients(left-sided lesion 10, right-sided 12) were treated by whole breast radiotherapy with active breathing control(ABC)technique. All patients had CT scans at standard free breathing(FB) and 75% moderate deep inspiration breath holding(mDIBH)position. For each scan, with optimized treatment plan designed with conformal tangential field, the prescribed dose was 1.8Gy×25 fractions. For FB and ABC plan, the mean lung dose(MLD), percentage of both lungs receiving 20Gy(V 20),ipsilateral lung V 20,the percentage of heart receiving 30Gy(V 30)were compared; for left-sided breast cancer patients, the mean dose of heart(D mean) were also compared.Results For the whole group, the ipsilateral lung V 20 was 17.0% and 16.2% at FB and mDIBH,with a decrease of 0.8%(t=3.63,P=0.002); both lung V 20 was 8.7% and 8.0% at FB and mDIBH,with a decrease of 0.6%(t=2.78,P= 0.011). For 10 left-sided patients, the heart V 30 was 6.1% and 3.8% at FB and mDIBH, with a decrease of 2.3%(t=6.50,P<0.01);The heart D mean decreased from 449.58cGy to 332.79cGy(t=5.94,P<0.01). Conclusion Moderate Deep Inspiration Breath Holding (mDIBH) not only decreases the impact of respiratory motion on breast target during postoperative whole breast radiotherapy, but also significantly reduces the lung and heart irradiated volume and dose, thus lessening the radiation injury to lung and heart.

目的探讨皮肤蕈痒霉菌病全身电子线照射的技术实施及剂量测定。方法选用PRECISE ELEKTA公司直线加速器6MeV电子线,对皮肤蕈痒霉菌病患者行全身电子线照射,采用双机架角照射技术,分别于放疗前及放疗中用瑞典IBA多通道半导体探头剂量仪进行剂量监测。结果采用双机架角全身电子线照射技术,全身皮肤表面剂量分布比较均匀,放疗后达到完全缓解,且放疗不良反应轻微,可耐受。结论皮肤蕈痒霉菌病全身电子线双机架角照射技术及剂量测定方法,临床便于实施,且疗效确切。

"ABC"是英文"Active Breathing Coordinator"的缩写,它的意思是呼吸活动控制.今年来,随着精确放疗技术的发展,推动了CT、加速器的快速发展."ABC"控制器就是精确放疗中的一种辅助设备.放射治疗由原来的单一放疗,发展到现在多元化放疗,由原来的局部放疗,现在全身各个部位都可以放疗,尤其是胸部的放疗,很多放疗工作者都做出了很大的贡献.由于胸部生理解剖结构的特点,具有动态呼吸运动,导致胸廓随呼吸而变化,使得体表标志不能固定不变,给精确放疗带来了一定的不利因素.自2004年6月以来我院引进开发了"ABC"这套呼吸控制器,克服了呼吸运动带来的不利因素,它适应于乳腺癌、肺癌及胸部肿瘤的治疗.在精确放疗中具有非常高的使用价值,具体说明如下:

调强放疗是一新兴的正在发展中的放疗技术.也是我院新开展的又一治疗肿瘤的技术.调强放疗(intensity-modu-lated radiation therapy. IMRT).