等中心放疗技术的临床推广意义

近年来，随着放射治疗及其配套设备的不断更新完善，等中心照射技术在外照射领域开始受到青睐，1995年来，青岛市肿瘤医院采用该技术作固定野照射。与以固定源皮距（SSIj）为特征的传统照射方式相比，等中心照射技术至少存在下面四个优势：一、为放疗医生设野提供了可靠的手段等中心技术摒弃了源皮距（SSD）概念，而采用源瘤距（STD）或源轴距（SAD）。每次定位时，放疗医生首先要将靶区中心置于等中心点上，然后只需遥控机架、小机头和准直器，即可找到一个或一组兼顾靶区和周围脏器的最佳人射野。由于这一特点，该技术首先在成角照射…     

真空袋体位固定技术临床应用价值的研究

目的分析体部恶性肿瘤在放射治疗中，真空袋体位固定技术的临床应用价值及存在的问题。方法随机抽取实施体部放疗患者714例(野)，其中使用真空袋固定体位的582例(野)，使用非真空袋固定体位(指用沙袋、胶带等简易固定体位，网膜固定体位除外)的132例(野)，在放疗摆位投照实施前、后用直尺测量灯光野与照射野各点的移动情况进行比较。另抽取56例(野)使用二次抽真空的复形真空袋固定体位的患者，同样用上述方法进行比较。结果用真空袋体位固定者灯光野与照射野的偏差率为6．7％，而用非真空袋体位固定者的为26．5％，用复形真空袋体位固定者的为32．1％。结论真空袋固定体位技术的偏差率明显少于用非真空袋体位固定和二次抽真空复形袋固定的患者，对于半软状态的真空袋须重新制作及到模拟定位机下透视复位方可供临床使用。     

乳腺癌四分之一切线野结合虚拟楔形板照射技术

采用乳腺托架固定体位，等中心1／4野结合虚似楔形板切线照射乳腺癌。结果使1／4野照射90％剂量曲线贴近胸壁，比全野照射的90％剂量曲线要少照肺0．9cm，放射性肺炎发生率低；半影宽度小，放射性皮炎发生率低；半野衔接避免了相邻野的剂量重叠或靶区遗漏，减少正常组织的损伤。表明等中心1／4野切线照射技术，能提高乳腺癌放射治疗的效果，减少并发症的发生．采用托架辅助治疗乳腺癌显著提高了治疗体位的精确度和重复率。     

大鼠全脑照射后脑内一氧化氮含量的变化

[目的]观察大鼠全脑照射后脑组织中一氧化氮（NO）含量的变化，探讨放射性脑损伤中NO所起的作用。[方法]对SD大鼠用4MeV电子线单次全脑5Gy、15Gy和30Gy照射后，于照射后6h、1d、2d和3d检测大大脑皮层中NO的含量．[结果]5Gy、15Gy和30Gy照射后1d、2d．脑内NO随照射剂量递增而增加（P〈0．05）．在6h和3d各剂量组无差异。各剂量组在1d时脑内NO达峰值，2d时逐渐下降．3d时恢复对照组水平。[结论]大鼠全脑照射后脑组织中NO升高，它在放射性脑损伤的发病机制中可能有重要的作用。     

食管癌放射治疗摆位

食管癌放射治疗包括单纯体外放射与体外放射加腔内后装放射的配合治疗。本文主要介绍体外照射有关问题。体外照射设野一般采用前正中野与两个后斜角野。伴有锁骨上淋巴结转移时,加照下颈锁骨上野。放射线以4—8Mev高能X线、~(60)钴γ线为首选。 一、照射技术 体外照射技术常用①固定源皮距技术,其要点是机架角一定要准确,病人体位要固定;②等中心技术,要求机器性能有良好的等中心精度;③旋转技术,因容积计量大,很少使用。目前我院采用固定源皮距技术对食管癌进行体外照射。     

全腹腔常规放射治疗技术的剂量学三维评价

目的：通过在三维治疗计划系统中模拟常规全腹照射来观察靶区和正常组织的剂量学分布，寻求较佳的常规放疗方法。方法：在三维治疗计划系统中模拟常规全腹照射，全腹放疗野分上腹野和盆腔野，两野间衔接方法分为常规和转床转臂架，上腹侧野后界分为椎体前1／4和PTV后缘，采用6MV高能X射线模拟照射，全腹照射总剂量30Gy／20次。结果：上腹野和盆腔野常规野间衔接处最大，最小剂量分别为36．2、26．9Gy，转床转臂架后野间衔接处最大、最小剂量分别为34．1、28．3Gy。衔接点每周移动1次，衔接处剂量分布更均匀。射野后界在椎体前1／4时95％等剂量曲线包括的PTV体积仅有82．3％，大部分脾脏在射野外，射野后界在PTV后缘时95％等剂量曲线包括的PTV体积为98．4％。射野后界应根据病变的侵犯范围而定，可以挡铅保护肾脏，漏照部分可用小野补量照射。结论：全腹放疗时，野间衔接可通过常规衔接和转床转臂架衔接实现，射野后界应个体化。     

全胸膜混合射线照射方法

目的介绍光子和电子线混合应用照射全胸腔方法。方法利用钴－６０（６０Ｃｏ）（或高能Ｘ线）与电子线，配合铸模、屏蔽技术照射全胸腔，以ＴＰＳ了解剂量分布。结果在达到全胸壁照射同时，明显降低肺照射容量，一半肺组织受量＜３０％。结论本方法对全胸膜照射达到较好剂量分布，方法可行，重复性好。     

螺旋断层治疗用于全骨髓照射的初步结果

目的：评估全骨髓照射作为异基因外周血干细胞移植（ Allo－PBSCT）前预处理方式的疗效及安全性。方法2014—2015年6例患者Allo－PBSCT前均采用HT联合环磷酰胺（60 mg／kg1次／d共2 d）的预处理方式。采用HT技术实施。结果6例患者中位年龄18．5岁。处方剂量（12 Gy分3次3 d完成）精确覆盖全部骨骼区域,OAR受量较全身照射降低13％～60％。头颈、胸腹、盆腔部位剂量验证通过率分别为（95．8±1．2）％、（96．2±1．1）％、（98．9±0．8）％。上、下部分的HI和平均治疗时间分别为1．18、1．17和39．2、14．3 min。放疗期间5例患者出现1—2级恶心、呕吐,2例患者出现1—2级疼痛,1例患者出现1级腹泻,1例患者出现2级肠炎。所有患者均未出现3—4级非血液学不良反应,并且成功植入骨髓。结论 HT技术应用于全骨髓照射是可行的,靶区适形度高,剂量均匀性好,安全性高且不良反应较传统TBI明显减低,可作为新的骨髓移植前预处理方式。     

全腹移动条形照射技术在卵巢癌治疗中的应用—39例治疗分析

移动条形照射技术是40年代从英国曼彻斯特开始,后经Delclos等在技术上做了改进并用于全腹照射及治疗卵巢癌,到目前为止已有不少报道。我院应用此照射技术治疗卵巢癌术后病人39例,现将本组病人的照射方法、结果及其适应症报道如下:     

基于VMAT的乳腺癌保乳术后全乳混合调强技术的建立与评价

目的 建立基于VMAT的乳腺癌保乳术后全乳混合调强技术并评价其临床应用价值。方法 选取10例乳腺癌保乳术后患者,分别基于固定角度IMRT的混合调强技术和基于VMAT的混合调强技术设计两组放疗计划。第1组仅以全乳作为放疗靶区,处方剂量50 Gy分25次完成;第2组以全乳及瘤床同步加量区为放疗靶区,处方剂量全乳50 Gy、瘤床同步加量区60 Gy,分25次同步完成。分别比较两组计划的剂量学参数及计划执行效率。配对t检验差异。结果 与基于固定角度IMRT的混合调强技术相比,基于VMAT的混合调强技术未能提高单纯全乳照射者靶区CI、HI值(P=0.866、0.056),反而全面增加了OAR受量和调强野机器跳数(P=0.000~0.050和P=0.002);但对全乳加瘤床同步加量照射患者,能减少肺受量、脊髓受量、调强野机器跳数、计划执行时间(P=0.004、0.001、0.000、0.000)。结论 对全乳加瘤床同步加量照射患者,基于VMAT的混合调强技术能更好保护OAR,提高计划执行效率,具有较高的临床应用潜力。     

鼻咽癌常规放疗中电子线L形野照射技术应用研究

 目的　探索一种能更好地解决鼻咽癌常规放疗中射野之间衔接问题的新方法。方法　使用三维计划系统模拟鼻咽癌2D-适形放疗（CRT）或3D-CRT治疗中电子线L形野照射技术与常规放疗颈后电子线野照射技术的布野方法,进行剂量学分布比较。结果　电子线L形野照射技术与颈后电子线野照射技术的靶区剂量超过6000 cGy的包绕体积都达到95 %以上,满足临床上肿瘤治疗的剂量需要,但颈后电子线野照射技术出现明显的剂量热点,最高剂量可达8900 cGy,电子线L形野照射技术的最高剂量达7200 cGy。电子线L形野照射技术的喉部高剂量范围比颈后电子线野照射技术小,前者喉部剂量超过6500 cGy的体积为19.64 %,后者为31.95 %。结论　电子线L形野照射技术在照射野之间衔接和剂量分布方面都具有较好的优势,值得临床推广应用。     

Double Hemibody Irradiation with GM-CSF Salvage Therapy for Refractory Chronic Lymphocytic Leukemia

We describe a new and original therapy with total body irradiation in two separate 4 gy single courses (double hemibody irradiation) combined with GM-CSF support, 5ug/day on days 1-15 after each hemibody irradiation, for refractory patients with B-chronic lymphocytic leukemia (CLL). A complete response was observed in a patient with a B-CLL resistant to CAP and FAMP therapy. Overall tolerance was good. The major points of interest in this technique are the combination of the antitumor effect of irradiation, limited bone marrow toxicity and a potential specific anti-leukemia effect of GM-CSF.     

Blockade of SOX4 mediated DNA repair by SPARC enhances radioresponse in medulloblastoma

SPARC is a matricellular glycoprotein and a putative radioresistance-reversal-gene. We therefore explored the possibility of SPARC expression on medulloblastoma radiosensitivity in vitro and in vivo. The combined treatment of the SPARC and irradiation resulted in increased cell death when compared to cells treated with irradiation alone in vitro and in vivo. SPARC expression prior to irradiation suppressed checkpoints-1,-2 and p53 phosphorylation and DNA repair gene XRCC1. We also demonstrate that SPARC expression suppressed irradiation induced SOX-4 mediated DNA repair. These results provide evidence of the anti-tumor effect of combining SPARC with irradiation as a new therapeutic strategy for the treatment of medulloblastoma.     

全中枢神经系统放射治疗新技术探讨

目的:探讨全中枢神经系统放射治疗更加合理、实用的新技术。方法:应用放疗计划系统针对成人和儿童患者分别制定四种不同照射方法的放疗计划,并比较各放疗计划的剂量分布指标。结果:经对比观察分析,几种计划方法在成人和儿童患者各有优缺点。结论:根据患者个体情况采用CT模拟定位、放疗计划系统、三维适形调强放疗技术为基础的多种全中枢系统照射技术方法,结合计划验证和图像引导技术指导治疗计划实施,都具有一定的实用性和较强的准确性、安全性。     

Opto-electronic sensing of body surface topology changes during radiotherapy for rectal cancer

PURPOSE: The CT body surface underpins millimeter scale dose computation in radical radiotherapy. A lack of technology has prevented measurement of surface topology changes during irradiation. Consequently, body changes are incorporated into plans statistically. We describe the technology for dynamic measurement of continuous surface topology at submillimeter resolution and suggest appropriately modified planning. MATERIALS AND METHODS: An interferometer casts cosinusoidal fringes across the surface of a patient on a treatment couch. Motion-induced changes to the spatial phase of the fringes are used to generate dynamic sequences of body height maps. Volume-conserving CT warping, guided by height change, is used to illustrate potential planning perturbations. RESULTS: We present the results for a prone patient with rectal carcinoma. At most of the simultaneously measured 440 x 440 points in each of the 898 body height maps in a dynamic sequence, the standard deviations were <1-2 mm, with occasional points of 6 mm. Surface motion predominantly occurred along the small of the back. This motion was periodic and could take the spine and bladder across the 95% isodose contour. CONCLUSIONS: Surface changes are most likely to be within 3 mm during irradiation, despite the effects of breathing and the discomfort of lying prone. The dosimetric effects are acceptable.     

New tools in adjuvant breast cancer radiotherapy

During the last century management of breast cancer became increasingly less aggressive for small tumors. Randomized trials demonstrated similar overall survival between mastectomy and breast-conservative surgery (BCS) followed by adjuvant radiation therapy (RT). BCS plus adjuvant RT +/- systemic therapy has become the standard of care for women with early breast cancer. Advances in modern RT technology allowed significant increase in high precision of target definition. Intensity modulated radiation therapy (IMRT) and gating, under investigation in miscellaneous cancers, are also in development for breast-cancer patients. These techniques decrease radiation toxicities and could be useful in the setting of concurrent use of RT and new systemic therapies such as trastuzumab. Another advance in RT is the development of accelerated partial breast irradiation (APBI) as a new concept in the adjuvant setting for early-stage breast cancer. Intraoperative RT (IORT), immediate postoperative RT (interstitial brachytherapy or Mammosite device implantation) and delayed postoperative RT (external beam of photons or protons with 3D conformation) are under investigation. In this review, the role of modern whole breast irradiation is discussed, the rational of partial breast irradiation is argued and the different techniques are detailed.     

Recent developments in radiotherapy.

Radiation oncology is a dynamic discipline. The radiobiologic basis for understanding and anticipating treatment effects continues to grow. Improved understanding is permitting study of altered fractionation regimens and safer integration into the clinic of high-dose-rate brachytherapy. A new agent, SR 4233, may completely revise clinical approaches to tumor hypoxia, especially intermittent (or "dynamic") hypoxia. The availability of computer technology that permits three-dimensional treatment planning with unusual beam and treatment table orientations should result in isodose lines that conform very tightly to desired treatment volumes, permitting higher doses of treatment with acceptable normal-tissue risk. The biology of cytotoxic drug and irradiation interactions and of cytokine and irradiation interactions is an area of growing promise. Combined chemotherapy and radiotherapy treatments have, in the past year, suggested major improvements in the management of esophageal and laryngeal cancer. The importance of local and regional tumor control in contributing to clinical disease course is being understood with increasing clarity, validating the development of technically demanding new approaches to administering irradiation and the use of adjunctive radiotherapy following chemotherapy for selected neoplastic diseases.     

What is new in brachytherapy?

The brachytherapy was used as of the discovery of the radioactivity and became a modern method of conformational irradiation using high technology. Every year, 8-10,000 treatments are delivered, which represents 5% of the total number of irradiations in France. Its revival comes from its increasing use in the treatment of localised cancers of the prostate of favourable prognosis, because of its effectiveness comparable with that of the surgery or the external radiotherapy, its very good immediate tolerance and its better preservation of the erectile function. In 2005, more of 1000 patients were treated in France, number that should quickly rise. The gynecological brachytherapy remains essential in the treatment of the invasive cancers of the uterine cervix. It profits of the progress of the imagery and in the optimisation of the calculation of the dose distribution allowing the optimisation of the irradiation by means of stepping source afterloaders (pulsed brachytherapy). The brachytherapy in head and neck keeps its indications, especially in the exclusive or postoperative irradiation of the cancers of the oral cavity or of the oropharynx. In the treatment of the breast cancer, a new position for the modern brachytherapy should be occur with the concepts of brachytherapy boost. Lastly, many precise indications are always of topicality. Thus, the brachytherapy by permanent implants, at low dose rate, high dose rate or pulsed dose rate, associated to the tools of imagery, of optimisation and technologies of stepping source afterloaders is competing or complementary with new 3D or 4D techniques of three or four dimensional irradiation.     

乳腺癌根治术后胸壁电子束旋转照射的临床应用

放射治疗是高危乳腺癌根治术后综合治疗的重要组成部分。胸壁和锁骨上区是最重要的术后辅助放疗部位。目前有多种胸壁照射方式,由于胸廓特殊的几何形状,传统的照射方法难以达到合理的剂量分布。电子束旋转照射技术利用电子束的剂量分布特点,根据胸壁的形状和靶区的深度选择不同的能量,能使靶区达到理想的剂量分布,同时降低心、肺晚期放射损伤,在胸壁照射中具有较大的优势及其较高的临床应用价值。本文就乳腺癌根治术后胸壁电子束旋转照射的临床应用作一综述。     

A review of treatment planning for precision image-guided photon beam pre-clinical animal radiation studies

Recently, precision irradiators integrated with a high-resolution CT imaging device became available for pre-clinical studies. These research platforms offer significant advantages over older generations of animal irradiators in terms of precision and accuracy of image-guided radiation targeting. These platforms are expected to play a significant role in defining experiments that will allow translation of research findings to the human clinical setting. In the field of radiotherapy, but also others such as neurology, the platforms create unique opportunities to explore e.g. the synergy between radiation and drugs or other agents.To fully exploit the advantages of this new technology, accurate methods are needed to plan the irradiation and to calculate the three-dimensional radiation dose distribution in the specimen. To this end, dedicated treatment planning systems are needed. In this review we will discuss specific issues for precision irradiation of small animals, we will describe the workflow of animal treatment planning, and we will examine several dose calculation algorithms (factorization, superposition-convolution, Monte Carlo simulation) used for animal irradiation with kilovolt photon beams. Issues such as dose reporting methods, photon scatter, tissue segmentation and motion will also be discussed briefly.