头颈部肿瘤精确放疗摆位的方法与探讨

目的：测定头颈部肿瘤在调强放射治疗中的摆位偏差,分析计划设计中从临床靶区（CTV）到计划靶区（PTV）的外扩边界.方法：随机抽取76名头颈部肿瘤患者,在治疗时用电子射野影像装置（EPID）拍摄射野片,将射野片和计划系统中的数字重建射野（DRR）图像片进行误差比较.结果：在左右、头脚、腹背方向的摆位误差分别是（-0.62±1.46） mm,（-0.41±1.54） mm,（-0.31±1.67） mm,外扩边界分别是2.27 mm,1.87 mm,1.98 mm.结论：对于头颈部调强治疗的患者,CTV到PTV的外放边界在左右方向需要2.5 mm,头脚方向和腹背方向需要2 mm.并且随着治疗时间的递进,摆位误差没有规律性的变化.     

EPID在宫颈癌调强放疗中的摆位误差分析及质量控制

目的 通过电子射野影像系统(EPID)测定和分析逆向调强放疗中的摆位误差,并依此计算CTV外扩PTV边界的大小。方法 对逆向调强放疗的宫颈癌患者进行摆位误差测定。体位采用热塑成型固定膜固定,每例患者每周一次于治疗前在加速器上拍摄正、侧位等中心验证片各一张,与治疗计划系统中的DRR片比较,计算出摆位误差。结果 经计算得出放疗中心宫颈癌逆向调强放疗的PTV外扩理论边界。结论 通过对摆位误差的分析为放疗中心宫颈癌逆向调强放疗的CTV外扩边界提供了理论依据。确定了CTV到PTV外扩边界的大小,提出质量控制措施,使边界外扩数值不断减少,提高宫颈癌逆向调强治疗水平。     

发泡胶联合头颈肩膜在头颈部肿瘤放疗中的应用及其摆位误差

目的探讨发泡胶和头颈肩膜的联合使用对头颈部肿瘤放射治疗的摆位影响及应用价值。方法选择调强适形放射治疗(IMRT)的患者50例,A组采用头颈肩膜和合适头枕固定,B组采用头颈肩膜和发泡胶固定。利用电子射野影像系统(EPID)验证系统进行治疗前的误差验证,共50次摆位,获得100张验证片,通过VARIAN系统与计划系统重建所得的DRR进行图像配准得出X轴(左右)、Y轴(头脚)、Z轴(腹背)的摆位误差数据共50个数据。结果 A组:x方向(0.69±2.19)mm、y方向(0.54±2.03)mm、z方向(0.61±2.11)mm。B组:x方向(0.44±1.87)mm、y方向(0.43±1.70)mm、z方向(0.54±1.77)mm。对误差>2 mm的给予在线矫正。采用头枕+头颈肩膜组、发泡胶+头颈肩膜固定组的误差数据差异均有统计学意义(P<0.05)。结论在头颈部肿瘤固定中采用发泡胶联合头颈肩膜能够减少首次摆位误差,提高了摆位精度,增加了患者的舒适度。     

EPID在颈、胸上段食管癌调强放疗中的应用价值

目的研究电子射野影像系统（EPID）在头颈肩面罩固定下颈、胸上段食管癌调强放疗中的效果。方法放疗前先采集定位片图像为参照,与治疗过程中实时采集的验证图像对比,测量摆位误差。结果入组30例患者共进行了120次治疗重复摆位,采集验证片120张比较每次摆位的体位误差。X轴（左右方向）3 mm以内误差有29例（96.67%）,3~5 mm误差有1例（3.33%）;Y轴（头足方向）3 mm以内误差有28例（93.33%）,3~5 mm误差有2例（6.67%）;Z轴（前后方向）3 mm以内误差有27例（90%）,3~5 mm误差有3例（10%）;X轴、Y轴、Z轴3个方向误差超过5 mm者未发现,我们对误差在3~5 mm患者进行重新摆位验证。结论利用电子射野影像系统可以有效减少放疗摆位误差,提高摆位的准确性,是质量控制和质量保证的有力工具。     

应用EPID对头、胸部肿瘤放疗摆位误差的比较与分析

目的比较分析头颈部与胸部肿瘤放射治疗时的摆位误差为临床靶区勾画提供依据。方法使用电子射野影像装置（EPID）对21例头颈部肿瘤患者与23例胸部肿瘤患者放射治疗时进行前野与侧野摄片,与数字重建图像（DRR）比较,分别记录三个方向的摆位误差,对其进行统计学比较。结果头颈部肿瘤摆位的平均平移误差分别为左右（0．97±0．72）mm,头足（1．22±0．77）mm,前后（0．80±0．68）mm,胸部肿瘤分别为左右（2．10±1．38）mm,头足（1．93±1．31）mm,前后（2．40±1．64）mm。两者在三个方向上的摆位误差都存在差异（P（0．05）。结论胸部肿瘤患者的摆位误差要比头颈部肿瘤的大,故而在放疗计划PTV的设定中胸部肿瘤要比头颈部肿瘤外放范围大,而在实际投照中对腹部肿瘤患者的摆位要采用多种方法和技术来提高其摆位精确性。     

电子射野影像系统对鼻咽癌调强放疗摆位误差的测量

目的 分析鼻咽癌调强放射治疗(IMRT)的摆位误差情况,从而确定摆位扩边的大小。方法 选取采用调强放疗的鼻咽癌患者15例,放射治疗过程中每位患者前3次治疗及之后每周拍摄电子射野验证片(正侧位),共拍摄194张。应用电子射野影像系统(EPID)将验证片与数字重建射野影像(DRR)配准,分别测定左、右、头、脚、腹、背(L、R、H、F、A、P)六个方向的摆位误差。结果 六个方向的摆位误差90.21%≤ 2mm,98.63%≤ 3mm,100%≤ 5mm。总体系统误差L-0.6mm(±0.88 s),R 0.58mm(±1.02 s),H 0.08mm(±0.71 s),F 0.21mm(±0.54 s),A 0.00mm(±1.12 s),P 0.00mm(±0.97 s);随机误差的标准差分别为±0.55,±0.45,±0.56,±0.52,±0.48,±0.4mm;六个方向的摆位扩边值分别为2.59,2.85,2.17,1.72,3.15,2.72mm。结论 在EPID系统下进行实时测量和纠正摆位误差,可降低系统误差和随机误差,提高摆位精度。     

TOMO与C型臂加速器在头颈部肿瘤放疗中的摆位误差分析

目的：分析螺旋断层放疗加速器TOMO与C型臂加速器在头颈部肿瘤放疗中的摆位误差,为头颈部肿瘤治疗时的计划靶区（planning target volume,PTV）外放范围提供依据。方法：回顾性选取149例头颈部肿瘤患者的临床资料,其中采用TOMO治疗患者79例,采用C型臂加速器治疗患者70例。将治疗前获取的MV级CT或kV级锥形束CT图像分别与模拟CT定位图像进行配准,分析比较患者在X（左右）、Y（头脚）、Z（腹背）方向上的摆位误差,并计算临床靶区（clinical target volume,CTV）外扩至PTV的外放边界。采用IBM SPSS 22.0软件进行统计学分析。结果：TOMO与C型臂加速器在X、Y、Z方向上的摆位误差绝对值分别为（1.13±1.00）mm和（1.46±1.13）mm、（1.19±1.00）mm和（1.41±1.15）mm、（0.71±0.73）mm和（1.23±0.92）mm(P均<0.001);TOMO在X、Y和Z方向上CTV外扩至PTV的外放边界分别为3.55、3.33和1.91 mm,C型臂加速器在X、Y和Z方向上CTV外扩至PTV的外放边界...     

4种不同固定技术在头颈部肿瘤放疗中的摆位误差比较

目的:研究比较头颈肩塑形垫+头颈肩面罩、真空垫+头颈肩面罩、热缩枕+头颈肩面罩、单独头颈肩面罩4种固定技术在头颈部肿瘤放疗中的摆位误差.方法:选取2018年4月至2020年4月来某院放疗的头颈部肿瘤患者120例,根据固定方式分为4组,每组30人.A组采用头颈肩塑形垫+头颈肩面罩固定方式,B组采用真空垫+头颈肩面罩固定方...     

兆伏级锥形束CT在头颈部肿瘤放疗摆位中的应用

目的：采用直线加速器机载的兆伏级锥形束CT（MV-CBCT）扫描技术对头颈部肿瘤调强放疗的摆位误差进行探讨。方法：对接受调强放射治疗的头颈部肿瘤患者在首次放疗前进行MV-CBCT扫描,以后每周扫描1次,分别记录扫描图像相对于治疗计划图像靶中心点位置在左右、头脚、前后各方向上的偏移量,以判断摆位的准确性。结果：本组对101例头颈部肿瘤患者共进行MV-CBCT扫描535次,平均误差分别为：左右（1.04±0.51）mm、头脚（1.81±0.79）mm、前后（1.93±0.95）mm。结论：使用MV-CBCT扫描系统能较准确快捷地检测和修正摆位误差,从而能有效地改善和提高摆位精度,为精确放疗技术的实施提供可靠保证,并为医生勾画靶区的外放边界提供参考依据。     

EPID图像配准前的预处理方法

目的：对EPID图像进行预处理，使配准结果更加准确，由此来对临床摆位误差进行定量分析。材料与方法：在开野的情况下，根据病人的体厚选用固体水模拍摄射野片，用平滑核处理后保留处理后的图片，用于矫正EPID图像的背景不均。由于EPID透镜系统会产生几何畸变，用多项式变形技术和双线性插值对图片做了几何矫正。结果：图像背景不均用此方法得到了很好的矫正，用多项式方法做几何矫正也得到了可以接受的结果。结论：荧光型的EPID在配准前应该消除背景不均的影响，对几何畸变的修正与否要看畸变的程度，矫正时最好用三次的多项式，可以得到比较满意的结果。     

面罩固定技术在头颈部肿瘤放疗中的应用

本文介绍通过面罩固定技术使头颈部肿瘤患者摆位的精确度得到很大的提高,实践证明它是精确定位的一种行之有效的技术。     

螺旋断层放射治疗技术在头颈部肿瘤中的应用

螺旋断层放射治疗技术是近年来逐渐发展起来的一种调强适形放疗技术,目前已经初步应用于口咽癌、鼻咽癌等多种头颈部肿瘤治疗中。与传统的调强放疗比,螺旋断层放射治疗技术具有剂量更准确、分布更均匀、更好保护重要器官以及降低放疗后不良反应发生率等优点。该文就国内外螺旋断层放射治疗技术在头颈部肿瘤中的应用予以综述。     

Nutritional Support in Head and Neck Radiotherapy Patients Considering HPV Status

Malnutrition is a common problem in patients with head and neck cancer (HNC), including oropharyngeal cancer (OPC). It is caused by insufficient food intake due to dysphagia, odynophagia, and a lack of appetite caused by the tumor. It is also secondary to the oncological treatment of the basic disease, such as radiotherapy (RT) and chemoradiotherapy (CRT), as a consequence of mucositis with the dry mouth, loss of taste, and dysphagia. The severe dysphagia leads to a definitive total impossibility of eating through the mouth in 20–30% of patients. These patients usually require enteral nutritional support. Feeding tubes are a commonly used nutritional intervention during radiotherapy, most frequently percutaneous gastrostomy tube. Recently, a novel HPV-related type of OPC has been described. Patients with HPV-associated OPC are different from the HPV− ones. Typical HPV− OPC is associated with smoking and alcohol abuse. Patients with HPV+ OPC are younger and healthy (without comorbidities) at diagnosis compared to HPV− ones. Patients with OPC are at high nutritional risk, and therefore, they require nutritional support in order to improve the treatment results and quality of life. Some authors noted the high incidence of critical weight loss (CWL) in patients with HPV-related OPC. Other authors have observed the increased acute toxicities during oncological treatment in HPV+ OPC patients compared to HPV− ones. The aim of this paper is to review and discuss the indications for nutritional support and the kinds of nutrition, including immunonutrition (IN), in HNC, particularly OPC patients, undergoing RT/CRT, considering HPV status.     

头颈部立体定向适形放射治疗系统的研制

介绍一种新型头颈部适形放射治疗系统的组成和结构,可解决现有头颈部肿瘤立体定向放射治疗中的不足.     

不同图像引导方式在头颈部肿瘤中成像剂量测量

目的测量不同图像引导方式在头模中的成像剂量。方法应用UNIDOS E型剂量仪（德国PTW公司）与30013型电离室,测量Varian Clinac iX直线加速器配置的EPID、OBI和CBCT图像引导功能在圆柱形模体的成像剂量。二维图像采用0o和270o两个正交野成像,三维图像采用CBCT成像。结果二维成像时,OBI系统（KV级X线）模体内各点平均吸收剂量0.74mGy,显著低于EPID系统（MV级X线）的90.93mGy,且图像清晰度优于后者;标准CBCT（KV级X线）各点平均吸收剂量4.77mGy,而低剂量CBCT模式仅为标准模式的50%,能够完成精确匹配。结论OBI系统比EPID系统成像剂量更低,图像质量更好。CBCT作为三维图像引导方式显著优于二维图像引导方式,进行日常的摆位验证也是安全的。因此,合理选择图像引导方式和设置图像采集参数,能够有效地减少患者的额外受照剂量。     

放射治疗射野影像系统的应用

放射治疗射野影像系统EPID是治疗计划所实施的重要质量保证工具,其主要功能是射野验证和剂量验证。     

Prognostic Nutritional Index Predicts Toxicity in Head and Neck Cancer Patients Treated with Definitive Radiotherapy in Association with Chemotherapy

Background: The Prognostic Nutritional Index (PNI) is a parameter of nutritional and inflammation status related to toxicity in cancer treatment. Since data for head and neck cancer are scanty, this study aims to investigate the association between PNI and acute and late toxicity for this malignancy. Methods: A retrospective cohort of 179 head and neck cancer patients treated with definitive radiotherapy with induction/concurrent chemotherapy was followed-up (median follow-up: 38 months) for toxicity and vital status between 2010 and 2017. PNI was calculated according to Onodera formula and low/high PNI levels were defined according to median value. Odds ratio (OR) for acute toxicity were calculated through logistic regression model; hazard ratios (HR) for late toxicity and survival were calculated through the Cox proportional hazards model. Results: median PNI was 50.0 (interquartile range: 45.5–53.5). Low PNI was associated with higher risk of weight loss > 10% during treatment (OR = 4.84, 95% CI: 1.73–13.53 for PNI < 50 versus PNI ≥ 50), which was in turn significantly associated with worse overall survival, and higher risk of late mucositis (HR = 1.84; 95% CI:1.09–3.12). PNI predicts acute weight loss >10% and late mucositis. Conclusions: PNI could help clinicians to identify patients undergoing radiotherapy who are at high risk of acute and late toxicity.     

Change in Nutritional Status and Dysphagia after Resection of Head and Neck Cancer

Nutritional status is well-known to influence patient recovery after resection of head and neck cancer (HNC). The influence of preoperative nutritional status on dysphagia was assessed in patients who underwent surgical resection of HNC along with the assessment of nutritional status during the acute and subacute phases. Eighty-six patients underwent surgical resection and dysphagia assessments (repetitive saliva-swallowing test, water-swallowing test, and functional oral intake scale) and had their tongue pressure assessed five times (before surgery, after 1–2 weeks, and 1, 2, and 3 months after surgery). The nutritional status was assessed according to the body mass index, total protein, and albumin. The prognostic nutritional index was calculated from preoperative data, and the subjects were classified into three groups: Low-risk, Attention and High-risk groups. After surgery, the nutritional status index values were low, and the High-risk group showed significantly lower values in comparison to the other two groups. The water-swallowing test and functional oral intake scale findings were worse than they had been preoperatively until 2 months after surgery, and a significant correlation was noted between the postoperative nutritional status and the presence of dysphagia. The results indicated that the preoperative nutritional status of HNC patients influenced their ability to ingest/swallow, which in turn influenced their nutritional status after HNC resection.