调强（IMRT）放疗复发性鼻咽癌初期报道

目的观察调强放疗复发性鼻咽癌剂量分布及可行性.方法1999年6月-2000年8月,10例病理确诊局部复发的鼻咽癌接受了调强放疗.复发距初次治疗中位时间25(14-50)个月.首程放疗均采用单纯外放射,中位剂量52天共69Gy/35次.调强放疗通过NOMOS公司PEACOCK系统完成.再程放疗处方剂量4周共57Gy/19次.结果除部分患者有体重下降和轻度口腔粘膜反应外,所有患者均能耐受这一治疗.即期疗效完全缓解6例,部分缓解4例.2例局部再次复发,1例肺转移,2例病人死亡.全组中位生存时间14个月.全组中位计划靶体积(PTV)95.8(60-134)cm3.PTV剂量分布平均25-28天59.65±2.47Gy/19次;均匀指数(最大剂量/处方剂量)1.18±O.06,95%PTV的接受剂量为53.2±1.36Gy以上,低于95%处方剂量的体积(5.4±1.2)%.危险组织器官(OAR)平均剂量均值脊髓(9.46±5.23)Gy;脑干(20.24±3.55)Gy;腮腺(18.53±5.30)Gy(左),(19.68±6.21)Gy(右);晶体(2.11±0.65)GY(左),(2.94±O.57)Gy(右);视交叉(12.34±2.47)Gy;视神经(13.14±3.65)Gy(左),(17.65±3.21)Gv(右).结论该治疗能被患者耐受,即期疗效理想,有较好物理剂量分布.     

螺旋断层放疗在肿瘤治疗中的应用

螺旋断层放疗是CT和直线加速器结合的放疗设备,具有360度照射、兆伏级螺旋CT(MVCT)影像引导、自适应计划等技术,可进行调强放疗、自适应放疗、立体定向外科等多种功能,适应证广泛.     

体部肿瘤的立体定向放疗

目的：体部肿瘤立体定向放疗的研究。方法：１９９７年５月－１９９８年１２月期间治疗３２例共３５个病灶，根据病变大小进行适形立体定向放疗，射野一般５－７个，治疗次数３－７次，治疗间隔１－３天，每次治疗周边剂量４５０－１０００ｃＧｙ，总量１８９０－３４２０Ｇｙ。结果：３２例３５个病灶根据ＣＴ复查肿瘤退缩情况确定ＣＲ为２８．６％，ＰＲ为３１．４％，总有效率为６０％。１年以上生存率为５８．３％。结论：立体定     

三维适形放疗和调强放疗

自居里夫妇发现镭并用于肿瘤治疗以来 ,肿瘤的放疗已超过了一个世纪的历程。在这一百余年的历史中 ,放射肿瘤学有了明显的发展。目前放射治疗已是恶性肿瘤的根治手段之一。据世界卫生组织估计 ,在全部恶性肿瘤中 ,4 5 %的病人可以被目前的治疗方法治愈 ,其中 2 2 %被手术治愈 ,18%被放射治疗治愈 ,余下 5 %被药物治愈。若以全部肿瘤病人计算 ,其中的三分之二在其病程的某一阶段可接受根治性或姑息性的放疗。可见放疗已被广泛应用于肿瘤的治疗。然而 ,近 2 0多年以来 ,随着各种肿瘤治疗技术的发展 ,新的抗癌药物和生物治疗的不断出现 ,使肿瘤…     

直肠癌五野调强放疗与传统适形放疗剂量学研究

Objective  

The aim of the study was to compare the difference of dose distribution in clinical target volume and organ at risk (OAR) between five-field intensity-modulated radiotherapy (IMRT) and conventional three-dimensional conformal radiotherapy (3DCRT) in the radiotherapy of rectal cancer.     

肿瘤浸润淋巴细胞对直肠癌术前放疗预后的影响

目的 探讨直肠痛肿瘤组织内术前放疗后浸润淋巴细胞(TIL)数量改变对预后的影响.方法 搜集近8年余接受30 Gy分10次12 d完成的术前放疗的直肠癌患者107例,分析TIL分级与术前放疗后病理消退程度及预后关系.结果 直肠癌放疗前TIL 1级75例,2级16例,3级16例,4级0例,术前放疗后TIL 1级19例,2级43例,3级35例,4级10例.放疗后病理消退分级1级36例,2级57例,3级14例.单因素分析发现放疗前及放疗后TIL对局部病理消退影响有统计学意义(X2=36.80,P<0.01;X2=14.00,P<0.01);术前放疗后癌巢内TIL及病理消退对预后影响显著(X2=24.00,P<0.01;X2=12.17,P<0.01).Logistic多元分析提示放疗后TIL与病理消退关系密切(X2=8.05,P<0.01).结论 放疗前及放疗后TIL与直肠癌术前放疗局部病理消退相关.直肠癌术前放疗后癌巢TIL是影响生存预后的因素之一.     

鼻咽癌患者调强放疗对早期认知功能的影响

目的 探讨调强放疗对鼻咽癌患者放疗后早期认知功能的影响。方法 前瞻性分析2012年12月至2013年5月经病理活检确诊为鼻咽癌并接受调强放疗的初治患者52例,在CT定位图像上分别勾画左右侧颞叶,从剂量体积直方图（DVH）获取其受照射的剂量。采用DN-认知评估系统（DN-cognitive assessment system,DN-CAS）评价患者放疗前后的认知功能,并用配对t检验进行分析和比较。结果 患者左侧颞叶、右侧颞叶的平均受照射剂量分别为（17.5±7.3） Gy、（18.2±6.8） Gy。鼻咽癌患者放疗后在DN-CAS量表中的计划、同时性加工、注意、继时性加工分量表的标准分与放疗前相似（P＞0.05）。结论 鼻咽癌患者调强放疗后早期的认知功能并未发生明显改变,但放疗后的长期影响值得关注。     

IMRT在老年宫颈癌治疗中的应用价值

目的 探讨IMRT在老年宫颈癌初治患者治疗中的临床应用价值。方法 选择2008年1月—2009年1月在我院收治的老年宫颈癌患者60例,其中常规放疗(CRT)组30例,IMRT组30例,比较两组患者的疗效和放疗并发症。结果IMRT组和CRT组近期有效率分别为86.7%和90.0%,差异无统计学意义(P＞0.05);IMRT组1、2年生存率分别为86.7%、73.3%,CRT组1、2年生存率分别为80.0%、63.3%,差异无统计学意义(P＞0.05);IMRT组较CRT组小肠、直肠、膀胱的受照射剂量和体积均明显减少(P＜0.05);近期胃肠道及泌尿系放疗反应IMRT组发生率明显低于CRT组(P＜0.05);远期放射性直肠炎、膀胱炎发生率明显低于CRT组,差异有统计学意义(P＜0.05)。结论 IMRT技术与常规放疗方法相比对老年宫颈癌初治患者是一种更为有效的治疗手段,临床近期疗效满意,放疗并发症明显降低。     

肿瘤浸润淋巴细胞对直肠癌术前放疗预后的影响

目的 探讨直肠痛肿瘤组织内术前放疗后浸润淋巴细胞(TIL)数量改变对预后的影响.方法 搜集近8年余接受30 Gy分10次12 d完成的术前放疗的直肠癌患者107例,分析TIL分级与术前放疗后病理消退程度及预后关系.结果 直肠癌放疗前TIL 1级75例,2级16例,3级16例,4级0例,术前放疗后TIL 1级19例,2级43例,3级35例,4级10例.放疗后病理消退分级1级36例,2级57例,3级14例.单因素分析发现放疗前及放疗后TIL对局部病理消退影响有统计学意义(X2=36.80,P<0.01;X2=14.00,P<0.01);术前放疗后癌巢内TIL及病理消退对预后影响显著(X2=24.00,P<0.01;X2=12.17,P<0.01).Logistic多元分析提示放疗后TIL与病理消退关系密切(X2=8.05,P<0.01).结论 放疗前及放疗后TIL与直肠癌术前放疗局部病理消退相关.直肠癌术前放疗后癌巢TIL是影响生存预后的因素之一.     

肿瘤浸润淋巴细胞对直肠癌术前放疗预后的影响

目的 探讨直肠痛肿瘤组织内术前放疗后浸润淋巴细胞(TIL)数量改变对预后的影响.方法 搜集近8年余接受30 Gy分10次12 d完成的术前放疗的直肠癌患者107例,分析TIL分级与术前放疗后病理消退程度及预后关系.结果 直肠癌放疗前TIL 1级75例,2级16例,3级16例,4级0例,术前放疗后TIL 1级19例,2级43例,3级35例,4级10例.放疗后病理消退分级1级36例,2级57例,3级14例.单因素分析发现放疗前及放疗后TIL对局部病理消退影响有统计学意义(X2=36.80,P<0.01;X2=14.00,P<0.01);术前放疗后癌巢内TIL及病理消退对预后影响显著(X2=24.00,P<0.01;X2=12.17,P<0.01).Logistic多元分析提示放疗后TIL与病理消退关系密切(X2=8.05,P<0.01).结论 放疗前及放疗后TIL与直肠癌术前放疗局部病理消退相关.直肠癌术前放疗后癌巢TIL是影响生存预后的因素之一.     

调强放疗中剂量验证方法的探究

[目的]探究调强放疗计划的剂量验证方法.[方法]利用Varian Clinal CX 4994号医用电子直线加速器出束的6MV能量X射线,对通过Eclipse 8.6治疗计划系统设计的调强放疗计划,采用PTW二维电离室矩阵进行平面剂量验证,采用Gamma分析.[结果]86.1％(292/339)的调强放疗计划绝对剂量通过率≥90.0％.[结论]使用二维电离室矩阵,进行调强放疗患者的个体化剂量验证,简单可靠,完善了调强放疗剂量验证体系.     

肿瘤中TGFβ1/Smads信号通路的研究进展

引言转化生长因子β(transforminggrowthfactorβ)是一个多功能的生长因子超家族,其主要作用包括调节细胞增殖和分化,参与胚胎发育调节,促进细胞外基质(ECM)形成和抑制免疫反应等。TGFβ至少有5种异构体(TGFβ1～5),另外激活素(ac tivin)、抑制素(inhibin)、骨形态发生蛋白(bone morphogenesisprotein,BMP)也属于该家族。其中TGFβ1最为常见,几乎参与了所有的病理和生理过程,并与多种临床疾病有着密切的关系[1]。TGFβ1生物学活性的发挥有赖于正常的信号传导途径,TGFβ1首先被细胞表面的受体TβRⅡ识别并结合,使其构象发生改变,然后被另一受体TβRⅠ识别形成三者的复合物。此时,TβRⅡ的胞内丝氨酸/苏氨酸蛋白激酶结构域可将TβRⅠ的胞内丝氨酸/苏氨酸磷酸化,TβRⅠ被激活,磷酸化的Smad2或Smad3进入细胞核,与Smad4结合,形成复合物,然后再与核内的各类转录因子结合,调控靶基因的转录。I Smad能够阻碍受体介导的Smad4磷酸化,启动受体复合物的泛素化降解,抑制信号传导,从而起到负调控的作用[2]。1TGFβ1/Smads信号...     

A national dosimetric audit of IMRT

Background and purpose

A dosimetric audit of IMRT has been carried out within the UK between June 2009 and March 2010 in order to provide an independent check of safe implementation and to identify problems in the modelling and delivery of IMRT.

Methods and materials

A mail based audit involving film and alanine dosimeters was utilized. Measurements were made for each individual field in an IMRT plan isocentrically in a flat water-equivalent phantom at a depth of 5 cm. The films and alanine dosimeters were processed and analysed centrally; additional ion chamber measurements were made by each participating centre.

Results

57 of 62 centres participated, with a total of 78 plans submitted. For the film measurements, all 176 fields from the less complex IMRT plans (including prostate and breast plans) achieved over 95% pixels passing a gamma criterion of 3%/3 mm within the 20% isodose. For the more complex IMRT plans (mainly head and neck) 8/245 fields (3.3%) achieved less than 95% pixels passing a 4%/4 mm gamma criterion. Of the alanine measurements, 4/78 (5.1%) of the measurements differed by >5% from the dose predicted by the treatment planning system. Three of these were large deviations of −77.1%, −29.1% and 14.1% respectively. Excluding the three measurements outside 10%, the mean difference was 0.05% with a standard deviation of 1.5%. The out of tolerance results have been subjected to further investigations.

Conclusions

A dosimetric audit has been successfully carried out of IMRT implementation by over 90% of UK radiotherapy departments. The audit shows that modelling and delivery of IMRT is accurate, suggesting that the implementation of IMRT has been carried out safely.     

动态调强和静态调强技术治疗中晚期宫颈癌剂量学比较

目的宫颈癌严重威胁着妇女的健康,调强放射治疗(intensity modulated radiotherapy,IMRT)联合后装放疗成为中晚期(ⅡB~ⅢB期)宫颈癌治疗的主要方法。本研究旨在比较动态调强放射治疗(dynamic intensity modulated radiotherapy,dIMRT)技术和强度等级不同的静态调强放射治疗(static intensity modulated radiotherapy,sIMRT)技术治疗中晚期宫颈癌时的剂量学特点,为临床应用提供参考。方法回顾性选取玉林市红十字会医院2017-10-09-2019-03-24收治的中晚期(ⅡB~ⅢB期)宫颈癌患者50例(其中ⅡB期17例,ⅢA期15例,ⅢB期18例),在增强定位CT影像上勾画靶区和危及器官。在Eclipse 10.0计划系统中基于同一套CT图像设计5野调强计划,选取dIMRT技术中的滑窗技术(Sliding Window,SW)和强度等级分别为13(Ec13),10(Ec10),7(Ec7)和5(Ec5)的sIMRT技术,处方剂量均为50Gy/25次,要求计划靶区95%的体积达到处方剂量。通过分析剂量-体积直方图(dose volume histogram,DVH)及传输参数,比较5种调强放射治疗方式中计划靶区的靶区适形指数(conformity index,CI)、均匀指数(homogeneity index,HI)、危及器官(膀胱、小肠和直肠)剂量分布和机器参数的差异。数据经Shapiro-Wilk法检验符合正态分布后,组间均值差异进行单因素方差分析,两两多重比较采用LSD法。用Pearson法分析sIMRT强度等级与子野数量的关系。结果5种计划的靶区最大剂量Dmax、平均剂量Dmean、HI值和CI值差异有统计学意义。其中,对于SW、Ec13、Ec10、Ec7和Ec5计划,Dmax值分别为(55.27±1.29)、(55.54±1.18)、(55.83±1.10)、(57.51±1.05)和(59.90±1.08)Gy,差异有统计学意义,F=154.844,P<0.01;HI值分别为1.06±0.01、1.06±0.01、1.07±0.01、1.09±0.01和1.12±0.02,差异有统计学意义,F=452.442,P<0.01;CI值分别为0.89±0.01、0.88±0.01、0.88±0.01、0.86±0.01和0.83±0.01,差异有统计学意义,F=107.928,P<0.01。相对于sIMRT,SW组的Dmean、HI值和CI值差异有统计学意义,均P<0.05。对于膀胱、小肠和直肠,5组计划中剂量体积V20、V30和V40差异无统计学意义,而最大剂量Dmax则差异有统计学意义,均P<0.01。Ec5计划中膀胱、小肠和直肠V50值的均值比SW计划中均值分别为13.58%、45.14%和36.20%。SW计划中传输时间为(6.82±0.55)min,机器跳数(monitor units,MUs)为(1090.9±88.7)MUs,比sIMRT技术数值大,差异有统计学意义,均P<0.01。对于sIMRT,强度等级越高,子野数量越多,治疗的实施时间越长。子野数量与强度等级呈线性关系。结论对于中晚期宫颈癌,dIMRT技术与强度等级≥10的sIMRT技术剂量分布相当。综合考虑,临床应用中优先选取dIMRT或者强度等级等于或接近于10的sIMRT。     

Tomotherapy and other innovative IMRT delivery systems

Fixed-field treatments, delivered using conventional clinical linear accelerators fitted with multileaf collimators, have rapidly become the standard form of intensity-modulated radiotherapy (IMRT). Several innovative nonstandard alternatives also exist, for which delivery and treatment planning systems are now commercially available. Three of these nonstandard IMRT approaches are reviewed here: tomotherapy, robotic linear accelerators (CyberKnife, Accuray Inc., Sunnyvale, CA), and standard linear accelerators modulated by jaws alone or by their jaws acting together with a tertiary beam-masking device. Rationales for the nonstandard IMRT approaches are discussed, and elements of their delivery system designs are briefly described. Differences between fixed-field IMRT dose distributions and the distributions that can be delivered by using the nonstandard technologies are outlined. Because conventional linear accelerators are finely honed machines, innovative design enhancement of one aspect of system performance often limits another facet of machine capability. Consequently the various delivery systems may prove optimal for different types of treatment, with specific machine designs excelling for disease sites with specific target volume and normal structure topologies. However it is likely that the delivery systems will be distinguished not just by the optimality of the dose distributions they deliver, but also by factors such as the efficiency of their treatment process, the integration of their onboard imaging systems into that process, and their ability to measure and minimize or compensate for target movement, including the effects of respiratory motion.     

Restricted field IMRT dramatically enhances IMRT planning for mesothelioma

PURPOSE: To improve the target coverage and normal tissue sparing of intensity-modulated radiotherapy (IMRT) for mesothelioma after extrapleural pneumonectomy. METHODS AND MATERIALS: Thirteen plans from patients previously treated with IMRT for mesothelioma were replanned using a restricted field technique. This technique was novel in two ways. It limited the entrance beams to 200 degrees around the target and three to four beams per case had their field apertures restricted down to the level of the heart or liver to further limit the contralateral lung dose. New constraints were added that included a mean lung dose of <9.5 Gy and volume receiving >or=5 Gy of <55%. RESULTS: In all cases, the planning target volume coverage was excellent, with an average of 97% coverage of the planning target volume by the target dose. No change was seen in the target coverage with the new technique. The heart, kidneys, and esophagus were all kept under tolerance in all cases. The average mean lung dose, volume receiving >or=20 Gy, and volume receiving >or=5 Gy with the new technique was 6.6 Gy, 3.0%, and 50.8%, respectively, compared with 13.8 Gy, 15%, and 90% with the previous technique (p < 0.0001 for all three comparisons). The maximal value for any case in the cohort was 8.0 Gy, 7.3%, and 57.5% for the mean lung dose, volume receiving >or=20 Gy, and volume receiving >or=5 Gy, respectively. CONCLUSION: Restricted field IMRT provides an improved method to deliver IMRT to a complex target after extrapleural pneumonectomy. An upcoming Phase I trial will provide validation of these results.     

Dose verification in clinical IMRT prostate incidents

PURPOSE: In view of the need for dose-validation procedures on each individual intensity-modulated radiation therapy (IMRT) plan, dose-verification measurements by film, by ionization chamber, and by polymer gel-MRI dosimetry were performed for a prostate-treatment plan configuration. Treatment planning system (TPS) calculations were evaluated against dose measurements. METHODS AND MATERIALS: Intensity-modulated radiation therapy (IMRT) treatments were planned on a commercial TPS. Kodak EDR-2 films were used for the verification of two-dimensional (2D) dose distributions at 1 coronal and 5 axial planes in a water-equivalent phantom. Full three-dimensional (3D) dose distributions were measured by use of a novel polymer gel formulation and a 3D magnetic resonance imaging (MRI) readout technique. Calculations were compared against measurements by means of isocontour maps, gamma-index maps (3% dose difference, 3-mm distance to agreement) and dose-volume histograms. RESULTS: A good agreement was found between film measurements and TPS predictions for points within the 60% isocontour, for all the examined plans (gamma-index <1 for 96% of pixels). Three-dimensional dose distributions obtained with the polymer gel-MRI method were adequately matched with corresponding TPS calculations, for measurements in a gel phantom covering the planning-target volume (PTV). CONCLUSIONS: Measured 2D and 3D dose distributions suggest that, for the investigated prostate IMRT plan configuration, TPS calculations provide clinically acceptable accuracy.     

A significant decrease in rectal volume and diameter during prostate IMRT

Purpose

To record changes in rectal volume (RV) and diameter (RD) of patients with prostate adenocarcinoma prior to and at an interim period during radiotherapy, which could potentially affect treatment toxicity and tumor control.

Methods

Three hundred and fifteen patients treated with intensity modulated radiotherapy (IMRT) underwent planning CT scans before radiation and after 45 Gy. For each scan, RV and RD were recorded and compared using a two-tailed paired t-test. Robust linear regression analysis assessed correlation between initial RV and percent RV change.

Results

The mean change in RV was −8.62 cm³ and in RD was −0.19 cm³, (p < 0.05). A decrease ?10% in RV and RD was seen in 159 patients (50.5%) and 117 patients (37.1%), respectively. Patients with ?10% volume change had larger initial RVs than those with <10% decrease, (78.1 vs. 50.8 cm³, p < 0.0001).

Conclusions

A significant decrease in RV and RD occurs during prostate IMRT delivery. More than half of patients had decreased RV and over a third had decreased RD. This observation is pertinent to prostate localization, planning margins, and implies that dose-volume histogram (DVH) analysis of rectal irradiation based on pre-treatment CT scanning may inaccurately estimate the risk of rectal toxicity when the initial RV is larger than 70 cm³.     

Comparing step-and-shoot IMRT with dynamic helical tomotherapy IMRT plans for head-and-neck cancer

PURPOSE: The goal of this planning study was to compare step-and-shoot intensity-modulated radiotherapy (IMRT) plans with helical dynamic IMRT plans for oropharynx patients on the basis of dose distribution. METHODS AND MATERIALS: Five patients with oropharynx cancer had been previously treated by step-and-shoot IMRT at the University Medical Centre Utrecht, The Netherlands, applying five fields and approximately 60-90 segments. Inverse planning was carried out using Plato, version 2.6.2. For each patient, an inverse IMRT plan was also made using Tomotherapy Hi-Art System, version 2.0, and using the same targets and optimization goals. Statistical analysis was performed by a paired t test. RESULTS: All tomotherapy plans compared favorably with the step-and-shoot plans regarding sparing of the organs at risk and keeping an equivalent target dose homogeneity. Tomotherapy plans in particular realized sharper dose gradients compared with the step-and-shoot plans. The mean dose to all parotid glands (n = 10) decreased on average 6.5 Gy (range, -4 to 14; p = 0.002). The theoretical reduction in normal tissue complication probabilities in favor of the tomotherapy plans depended on the parotid normal tissue complication probability model used (range, -3% to 32%). CONCLUSION: Helical tomotherapy IMRT plans realized sharper dose gradients compared with the clinically applied step-and shoot plans. They are expected to be able to reduce the parotid normal tissue complication probability further, keeping a similar target dose homogeneity.     

调强放射治疗IMRT计划临床剂量验证298例

目的：探讨调强放射治疗（IMRT）剂量验证方法的改进方向。方法：298例IMRT计划（NOMOSPeacock系统）靶区剂量计算值与验证实测值比较，得出相对误差结果。结果：298例验证计划中91．3％在平均误差±1．63％范围内，与实测剂量相符合。讨论：验证计划中电离室位置设置、测量模体、电离室体积的选用等，都需要进一步探讨和改进。