EPID辅助头颈肩热塑膜在喉癌调强放疗中的摆位误差

[目的]探讨电子射野影像装置（EPID）辅助下头颈肩热塑膜在喉癌调强放疗（IMRT）中的摆位误差。[方法]选取喉癌患者40例,使用头颈肩热塑膜加以固定,在放射治疗过程中每周摄取电子射野影像片（EPI）1次,正侧位片各1张。在直线加速器的电子射野影像系统下将电子射野影像片与数字重建射线影像（DRR）进行匹配,测得在X轴（左右方向）、Y轴（头脚方向）和Z轴（前后方向）的摆位误差并加以记录。[结果]选取的40例患者在各个方向上的总体摆位误差分别为X轴左右方向（0.45±0.36）mm,Y轴头脚方向（0.56±0.47）mm,Z轴前后方向（0.40±0.33）mm,各周差异相比没有统计学意义（P〉0.05）。[结论]头颈肩热塑膜应用于喉癌调强放射治疗,体位移动少,重复性及固定性好,准确度高,在EPID的辅助下可以纠正摆位误差,提高摆位精确度。     

乳腺癌改良根治术后放疗体位固定技术探讨

目的 探讨2种不同体位固定技术对乳腺癌患者改良根治术后放疗重复摆位精度的影响.方法 50例乳腺癌改良根治术后需行辅助放疗的患者按随机数字法分为翼形板+真空垫组(25例)和头颈肩热塑体膜组(25例)采取相应固定体位.在治疗过程中每例通过锥形束CT(cone beam computer tomography,CBCT)测量5次摆位误差,共获取250组CT数据,利用X线容积成像(X-ray volume image,XVI)软件将CBCT扫描图像与计划CT图像进行自动骨性配准,比较两组三维平移方向(X轴、Y轴、Z轴)和旋转方向(ROLL、PITCH、YAW)的摆位误差值.结果 翼形板+真空垫组射野中心点在X轴(左右)、Y轴(头足)和Z轴(前后)方向上摆位误差分别为(2.20±1.65)mm、(2.95±2.10) mm和(2.37±2.14) mm;在ROLL、PITCH和YAW方向上摆位误差值分别为(1.25±0.96)°、(0.45 ±0.53)°和(0.61±0.52)°.头颈肩热塑体膜组射野中心点在X轴(左右)、Y轴(头足)和Z轴(前后)方向上摆位误差分别为(2.29±1.89)mm、(2.49±1.79)mm和(1.67±0.95) mm;在ROLL、PITCH和YAW方向上摆位误差值分别为(0.81±0.92)°、(0.43±0.51)°和(0.53±0.64)°.两组在Z轴及ROLL方向的摆位误差比较差异均具有统计学意义(均P＜0.05).结论 乳腺癌改良根治术后患者放疗时采用热塑头颈肩体膜固定技术可以改善摆位的重复性,有助于体位的固定,减少摆位误差,提高患者治疗定摆位的精度.     

研究体板结合真空垫及热塑膜技术与传统臂部支撑固定技术在胸部肿瘤放疗摆位中的误差

背景与目的:放射治疗已进入了精确放疗的时代,摆位误差成为影响放疗效果的重要因素.通过采用两种不同体位固定方式,即自行改装后的体板结合真空垫及热塑膜的固定装置和臂部支撑装置,讨论分析胸部肿瘤放疗中的摆位误差.方法:选择肺及食管胸部肿瘤患者19例,随机分成两组,分别采用体板+真空垫+体部热塑膜固定(A组)、臂部支撑装置固定(B组)进行摆位和治疗.A组利用二次摆位技术,即先使患者头脚方向的激光线与真空垫上的定位标记一致,再根据患者体表定位标记进行摆位(第一次摆位),最后覆上热塑膜固定,再根据热塑膜上的定位标记移床至治疗位置(第二次摆位);B组利用一次摆位技术,即直接根据体表标记进行摆位.A、B组均利用千伏级锥形束CT(kilo-voltage cone beam computed tomography,KV-CBCT)采集治疗前﹑后的图像,并与计划CT图像配准,得到治疗前及治疗后的体位误差并进行统计分析.结果:对于两种不同固定方式,A组和B组治疗前误差分别为:X轴(左右方向)(1.06±0.58)和(1.82±0.82)mm,Y轴(头脚方向)(1.31±0.40)和(2.18±1.20)mm,Z轴(腹背方向)(1.28±0.66)和(2.94±1.81)mm.治疗后误差分别为:X轴(0.86±0.54)和(1.29±0.58)mm,Y轴(1.07±0.58)和(1.08±0.45)mm,Z轴(0.98±0.53)和(1.56±0.63)mm.结论:A组误差均小于B组,采用体板结合真空垫及热塑膜固定装置并应用二次摆位技术的患者,在放疗过程中不仅摆位的精确度得以提高,同时也保证了体位的重复性及稳定性.     

不同体位固定技术在胸腹部肿瘤放射治疗中的应用比较

[目的]比较研究体表画线、体表纹身、热塑体膜及真空垫4种体位固定技术在胸腹部肿瘤放射治疗中的摆位误差,探讨其应用价值。[方法]对总共176例胸腹部肿瘤患者实施不同体位固定技术,通过电子射野影像装置（electronic portal imaging device,EPID）对患者左右、头足及前后3个方向的重复摆位误差进行测量计算。[结果]胸腹部肿瘤放射治疗的4种体位固定技术中,体表画线组的摆位误差最大,应用热塑体膜固定技术的摆位误差最小,在左右、头足及前后3个方向上误差均小于其他三组,与体表画线组比较均有统计学意义（P〈0.05）。[结论]在胸腹部肿瘤放射治疗过程中,应用热塑体膜固定技术可明显减小摆位误差,提高放疗精度。     

130例放疗病人摆位误差分析

目的:利用MV级电子射野影像系统（EPID）对130例放疗病人摆位误差进行分析。方法:选取头颈部肿瘤放疗患者30例,胸部肿瘤放疗患者50例,盆腔肿瘤放疗患者50例,使用6MV X线通过EPID获得0°和 90°两射野的实时位置验证片,并与计划系统产生的数字化重建影像的验证片进行对照,计算并分析所测定的摆位误差。结果:3%的头颈部患者摆位误差超过3mm,20%的胸部患者摆位误差超过5mm,10%的盆腔患者摆位误差超过5mm,对这些超过误差范围的患者重新调整位置,达到治疗要求。各部位在X轴（左右方向）、Y轴(头脚方向)、Z轴（前后方向）三个方向的平均摆位误差分别为头颈部1.59mm、1.38mm、1.42mm,胸部2.40mm、2.52mm、2.01mm,盆腔2.11mm、2.35mm、1.98mm。结论:利用EPID可以有效检测放射治疗中的摆位误差,提高摆位的准确性和重复性,是放射治疗质量保证的重要手段。     

鼻咽癌调强放疗中的摆位误差

[目的]用电子射野图像器件(EPID)拍摄的射野片研究调强放疗治疗鼻咽癌过程中的摆位误差。[方法]比较8例接受调强放疗的初治鼻咽癌患者的数字重建影像(DRR)和EPID图像,得到各个骨性标志间各个方向的偏差,分别以左右、前后和头脚方向上的最大偏差代表该方向的摆位误差。[结果]3个方向的摆位误差范围是-5mm到5.5mm,平均值是(-0.87±1.3)mm,(-0.28±1.5)mm和(-0.55±1.6)mm,大于2mm的误差分别占17.3%、14.3%和17.3%,且各次治疗的摆位误差之间无显著性差异。[结论]鼻咽癌调强放疗的误差在可以接受的范围,而且各次治疗间也没有显著差异,首次治疗时拍摄射野片验证是非常重要的。     

改良式体位固定技术在胸腹部肿瘤放疗中的应用

目的:探讨两种不同体位固定技术对胸腹部肿瘤放疗重复摆位精度的影响。方法:60例需行放疗的胸腹部肿瘤患者按随机数字法分为对照组:翼形板+真空垫固定体位(30 例);观察组:改良式体位固定技术即热塑体膜联合体板+真空垫组(30 例)。所有患者首次放疗前行CBCT扫描,以后每周扫描一次,比较两组X轴(左右)、Y轴(头脚)和Z轴(腹背)方向的摆位误差值。结果:对照组X轴、Y轴和Z 轴方向上摆位误差分别为(4.03±0.15)mm、(3.62±0.23)mm和(3.74±0.31)mm。观察组X 轴、Y 轴和Z轴方向上摆位误差分别为(3.91±0.29)mm、(3.54±0.34)mm 和(2.86±0.20)mm。两组在Z轴方向的摆位误差比较差异具有统计学意义(P<0.05)。结论:改良式体位固定技术可以改善胸腹部肿瘤患者放疗时摆位的舒适度,利于体位的固定,提高患者治疗时摆位的重复性和精度。     

胸腹部肿瘤放射治疗中两种摆位方式的误差分析

目的探讨胸腹部肿瘤放射治疗中两种摆位方式的误差。方法选取2017年1月至2019年3月间湖南省湘南学院附属医院收治的80例胸腹部肿瘤患者,根据摆位方法的不同分为两组,采用体膜和激光灯加体部皮肤及膜表面辅助线配合的摆位方式的40例患者纳入试验组。采用体膜和激光灯无体部辅助线的摆位方式的40例患者纳入对照组。两组患者均采用常规增强扫描定位及行锥形束CT图像引导得到各次治疗的摆位误差(前后、左右和头脚)并进行比较。结果试验组前后方向(1. 25±0. 63) mm,左右方向(1. 83±0. 97) mm,上下方向(0. 86±0. 34) mm;对照组后方向(2. 64±1. 14) mm,左右方向(3. 56±1. 74) mm,上下方向(1. 91±0. 87) mm。试验组在前后和左右方向上摆位误差数值均优于对照组,差异均有统计学意义(均P <0. 05)。结论用热塑膜加画相关辅助线进行胸腹部放射治疗体位固定及摆位的方法,通过研究发现能够很好的提高体位的重复性和降低摆位误差,起到精确放疗的目的从而提高放疗的疗效。     

鼻咽癌常规放疗摆位重复性的研究

[目的]测量鼻咽癌常规放疗患者改野前后的摆位误差，了解摆位的准确性和重复性。[方法]对68例鼻咽癌常规放疗病人采用U型塑料面网固定，使用射野影像验证系统（EPID）在缩野前后各拍摄射野验证片2次，通过模拟定位片与验证片上照射野边框及骨性标志进行比较，分别测量改野前后的摆位误差。[结果]68例患者共摄取272张射野验证片，缩野前X轴（前后方向）、Y轴（上下方向）和Z轴（旋转方向）各方向的系统误差分别为1.46mm、1.44mm、0.29度，随机误差分别为0.97mm、0.98mm、0.51度；缩野后各方向的系统误差分别为1.51mm、1.39mm、0.26度，随机误差分别为0.96mm、1.08mm、0.53度（P〉0.05）。[结论]鼻咽癌常规放疗时采用U型塑料面网同定技术同定所发生的误差在允许范围内,绝大部分患者缩野时不需要重新制作面罩。     

48例脊柱轻度畸形肿瘤患者放疗摆位误差

目的:采用锥形束CT(CBCT)研究脊柱轻度畸形肿瘤患者调强放疗中两种固定方式对摆位精度的影响.方法:随机选取48例脊柱畸形轻度的患者,平均分成A、B两组.A组定位时采用热塑体膜固定,B组采用热塑体膜和负压真空垫协同固定.利用CBCT对每位患者前4次治疗前和第4次治疗后的摆位误差进行测量,SPSS 17.0软件统计分析.结果:A组在左右(X)、头脚(Y)、前后(Z)方向上测量的摆位误差分别为(0.23±0.47)cm、(0.36±0.08)cm、(0.27±0.07)cm,而B组为(0.16±0.06)cm、(0.23±0.12)cm、(0.17±0.04)cm,B组误差数据小于A组,并且差异有统计学意义(P<0.05),其中Y轴误差最大、Z轴次之、X轴最小.第四次治疗后的CBCT数据显示病人在治疗过程中存在位置移动,A组病人移动量大于2mm的占27.5%,B组为8.5%,B组好于A组.结论:热塑体膜协同真空垫固定技术能减少脊柱轻度畸形患者在放疗中的摆位误差.     

肋骨原发性骨肿瘤的诊断及治疗

目的探讨肋骨原发性骨肿瘤的诊断及手术方式。方法回顾性分析6例（7根肋骨）肋骨原发性骨肿瘤患者的临床特点及手术治疗效果。6例均行手术切除,切除范围：超过肿瘤边缘2 cm离断肋骨,延上一肋骨下缘、下一肋骨上缘切除周围组织。1例用聚丙烯材料行胸廓重建术。结果随访时间1~7年,无1例复发。结论肋骨原发性骨肿瘤手术治疗效果明确,复发率低。     

Electron arc therapy: chest wall irradiation of breast cancer patients

From 1980 to October 1985 we treated 45 breast cancer patients with electron arc therapy. This technique was used in situations where optimal treatment with fixed photon or electron beams was technically difficult: long scars, recurrent tumor extending across midline or to the posterior thorax, or marked variation in depth of target tissue. Forty-four patients were treated following mastectomy: 35 electively because of high risk of local failure, and 9 following local recurrence. One patient with advanced local regional disease was treated primarily. The target volume boundaries on the chest wall were defined by a foam lined cerrobend cast which rested on the patient during treatment, functioning as a tertiary collimator. A variable width secondary collimator was used to account for changes in the radius of the thorax from superior to inferior border. All patients had computerized tomography performed to determine Internal Mammary Chain depth and chest wall thickness. Electron energies were selected based on these thicknesses and often variable energies over different segments of the arc were used. The chest wall and regional node areas were irradiated to 45 Gy-50 Gy in 5-6 weeks by this technique. The supraclavicular and upper axillary nodes were treated by a direct anterior photon field abutted to the superior edge of the electron arc field. Follow-up is from 10-73 months with a median of 50 months. No major complications were observed. Acute and late effects and local control are comparable to standard chest wall irradiation. The disadvantages of this technique are that the preparation of the tertiary field defining cast and CT treatment planning are labor intensive and expensive. The advantage is that for specific clinical situations large areas of chest wall with marked topographical variation can be optimally, homogeneously irradiated while sparing normal uninvolved tissues.     

体部恶性肿瘤的立体定向放射治疗(附21例近期疗效)

目的：报道立体定向放射治疗体部恶性肿瘤的近期疗效。方法：对原采用放射治疗的病变,如肺癌,分次立体定向放射作为追加剂量,每次５￣７Ｇｙ,共４￣７次;对原不适合放射治疗的病变,如胰腺癌,则单用立体定向放射治疗,每次５￣７Ｇｙ,共６￣７次。结果：总有效率为６６．７％,４例死亡。３例胰腺癌均于治疗后５￣６个月死于肿瘤未控。６例脊椎转移瘤疼痛症状均完全缓解。结论：立体定向放射治疗可得到良好的姑息甚至根治的疗     

颈动脉三角区肿瘤术前准备的研究

目的:对81例颈动脉三角区肿瘤术前准备情况进行统计、归纳和分析,就其临床意义进行探讨.方法:对资料就性别、年龄、病理、手术情况进行统计,归纳出术前准备各种方法.结果:B超在颈动脉三角区肿瘤术前应用率为100%(81/81),CDFI为88%(71/81),瘤腔造影为39%(28/81),选择性颈动脉造影为25%(18/81),CT为15%;在选择性颈动脉造影组中,颈动脉体瘤、神经鞘膜瘤与血管瘤之间差异显著(P<0.01);瘤腔造影组中,腮裂囊肿占68%,血管瘤占32%;CT组中,恶性肿瘤占67%,良性肿瘤占33%;Matas试验组中,应用于颈动脉体瘤为80%.结论:(1)B超因其价廉、检查方便而成为常规特检手段;(2)CDFI临床应用效果明显优于B超,原因是B超不能显示血流情况.但其较B超应用率低的原因是价格较贵;(3)在B超、CDFI应用基础上,选择性颈动脉造影、瘤腔造影、CT成为一种特异性检查手段:(4)Matas试验以颈动脉体瘤为 主,时间以30天为宜,指压更为可靠.     

Noninvasive patient fixation for extracranial stereotactic radiotherapy.

PURPOSE: To evaluate the setup accuracy that can be achieved with a novel noninvasive patient fixation technique based on a body cast attached to a recently developed stereotactic body frame during fractionated extracranial stereotactic radiotherapy. METHODS AND MATERIALS: Thirty-one CT studies (> or = 20 slices, thickness: 3 mm) from 5 patients who were immobilized in a body cast attached to a stereotactic body frame for treatment of paramedullary tumors in the thoracic or lumbar spine were evaluated with respect to setup accuracy. The immobilization device consisted of a custom-made wrap-around body cast that extended from the neck to the thighs and a separate head mask, both made from Scotchcast. Each CT study was performed immediately before or after every second or third actual treatment fraction without repositioning the patient between CT and treatment. The stereotactic localization system was mounted and the isocenter as initially located stereotactically was marked with fiducials for each CT study. Deviation of the treated isocenter as compared to the planned position was measured in all three dimensions. RESULTS: The immobilization device can be easily handled, attached to and removed from the stereotactic frame and thus enables treatment of multiple patients with the same stereotactic frame each day. Mean patient movements of 1.6 mm+/-1.2 mm (laterolateral [LL]), 1.4 mm+/-1.0 mm (anterior-posterior [AP]), 2.3 mm+/-1.3 mm (transversal vectorial error [VE]) and < slice thickness = 3 mm (craniocaudal [CC]) were recorded for the targets in the thoracic spine and 1.4 mm+/-1.0 mm (LL), 1.2 mm+/-0.7 mm (AP), 1.8 mm+/-1.2 mm (VE), and < 3 mm (CC) for the lumbar spine. The worst case deviation was 3.9 mm for the first patient with the target in the thoracic spine (in the LL direction). Combining those numbers (mean transversal VE for both locations and maximum CC error of 3 mm), the mean three-dimensional vectorial patient movement and thus the mean overall accuracy can be safely estimated to be < or = 3.6 mm. CONCLUSION: The presented combination of a body cast and head mask system in a rigid stereotactic body frame ensures reliable noninvasive patient fixation for fractionated extracranial stereotactic radiotherapy and may enable dose escalation for less radioresponsive tumors that are near the spinal cord or otherwise critically located while minimizing the risk of late sequelae.     

CT image fusion as a tool for measuring in 3D the setup errors during conformal radiotherapy for prostate cancer

AIMS AND BACKGROUND: The importance of optimal daily patient positioning has been stressed in order to ensure treatment reproducibility and gain in accuracy and precision. We report our data on the 3D setup uncertainty during radiation therapy for prostate cancer using the CT image fusion technique. METHODS: Ten consecutive patients scheduled for radiation therapy for prostate cancer underwent 5 prone position CT scans using an individualized immobilization cast. These different setups were analyzed using the image fusion module of the ERGO 3D-Line Medical System (Milan, Italy) treatment planning system. The isocenter and the body marker displacements were measured. RESULTS: The 3D isocenter dislocations were quantified: systematic error was sigma(3D) = 3.9 mm, whereas random error was sigma(3D) = 1 mm. The mean of the minimum displacements was 0.2 +/- 1 mm showing that the immobilization device used allows an accurate setup to be obtained. Single direction errors were also measured showing systematic errors, sigma(AP), = 2.6 mm, sigma(LL) = 0.6 mm, SigmaSI = 3 mm in the anterior-posterior, latero-lateral, superior-inferior direction, respectively. Related random errors were sigma(AP), = 1 mm, sigma(LL) = 0.6 mm, sigma(SI) = 1.2 mm. In terms of accuracy, our uncertainties are similar to those reported in the literature. CONCLUSIONS: By applying the CT image fusion technique, a 3D study on setup accuracy was performed. We demonstrated that the use of an individualized immobilization system for prostate treatment is adequate to obtain good setup accuracy, as long as a high-quality positioning control method, such as the stereoscopic X-ray-based positioning system, is used.     

Dose distribution of narrow beam irradiation for small lung tumor

: To aid in the selection of incident X-ray energy for stereotactic irradiation (STI) of lung tumor, dose distribution was investigated in a model of a thorax embedded with a tumor.

: The dose distribution in a thorax model was calculated using the EGS4 Monte Carlo simulation; it was also measured with dosimetric film of a tentative thorax phantom. Uniformity of dose distribution in a tumor region was compared among the results of irradiation for several X-ray energies, and optimal X-ray energy for STI of a lung tumor was discussed.

: Dose distributions in the thorax were obtained. An increase in X-ray energy led not only to an increased dose delivered to the tumor, but also to an increased dose to surrounding normal lung tissue.

: The flat range in dose distribution along the beam axis and in the beam profiles of the tumor increases with decreasing X-ray energy. Consequently, lower energy, rather than higher energy, is recommended for STI of a lung tumor in terms of higher uniformity in the target volume.     

原发性骨胸壁肿瘤的外科治疗

为了提高原发性骨胸壁肿瘤的手术成功率，回顾性分析２５ 例原发性骨胸壁肿瘤的治疗情况，对手术方法进行了讨论。结果表明，对良性肿瘤局部切除，对恶性肿瘤行胸壁大块切除并胸壁重建术，疗效满意。无论良、恶性骨胸壁肿瘤均首选手术治疗，但２ 者手术方式不同。     

A novel support system for patient immobilization and transportation for daily computed tomographic localization of target prior to radiation therapy

PURPOSE: To develop a method for quick and smooth transportation of patients from a computed tomography (CT) table to a linear accelerator (linac) table for confirming tumor center before radiation therapy. MATERIALS AND METHODS: We developed a system using a subtable for patient immobilization that is transported via a customized stretcher. The patient lies on the subtable and is immobilized by a vacuum cushion and thermoplastic body cast. The subtable stretcher is used to carry the subtable from the CT table to the linac table. During transportation, the subtable is kept flat and shock to the subtable is carefully avoided. Between August 2001 and September 2002, a total of 9 patients with solitary upper lung tumors (superior to carina) were treated using this system. RESULTS: Intrafractional tumor motion along the x (left-right), y (anterior-posterior), and z axis (superior-inferior) ranged from -2 mm to 2 mm, -2 mm to 2 mm, and -5 mm to 3 mm, respectively. The standard deviation of intrafractional tumor motion along the x, y, and z axis ranged from 0.5 mm to 1.5 mm, 0 mm to 1.7 mm, and 0.6 mm to 3.5 mm, respectively. Interfractional setup errors along the x, y, and z axis ranged from -5 mm to 4 mm, -6 mm to 8 mm, and -6 mm to 6 mm, respectively, and we could reduce interfractional setup errors in the majority of treatment sessions. CONCLUSIONS: We developed a system that allows patients to be immobilized and transported to verify tumor location on a daily basis. This system is highly useful for reducing setup errors.