利用3D打印颅脑辐射等效体模进行个性化适形放疗的剂量验证

目的 建立利用3D打印颅脑辐射等效体模对患者进行个性化放疗剂量验证的方法,为三维适形放射治疗安全提供一种可靠的剂量保证手段。方法 采集两例患者（患者1和患者2）的CT图像数据,基于患者1的图像数据,重建其颅骨与脑组织,制作颅脑体模,验证颅骨与脑组织的等效材料。基于患者2的图像数据,根据3D图像重建并选用组织等效材料重建完全的头颅结构,采用3D打印技术制作全头颅体模。通过对目标区域插入电离室剂量仪并行放射治疗方案,获得头颅体模病灶部的剂量,验证和校准实际放疗计划的安全性。结果 对所获两个体模分别进行DR、CT成像,颅脑体模的等效骨骼与患者1骨骼的X射线灰度值差异为13 721,颅脑体模的等效脑组织与患者1的脑组织的CT值差异为35~40 HU,全头颅体模等效颞肌与患者2的颞肌组织的CT值差异为18~28 HU,影像数据表明体模材质的辐射等效性与人体组织近似,并且等效剂量分布符合常规治疗范围,体模的剂量验证可以有效验证放疗计划系统的准确性。结论 基于3D打印和组织等效技术所设计的个性化放疗体模,可应用于个性化放射治疗验证。体模制作方法简单快速,个性化程度高,为三维适形放射治疗安全提供一种可靠的剂量保证手段。     

热释光探测器测量颈部热塑面罩对照射剂量的影响

热塑面罩与头颈部固定体架组成头颈部体位固定系统，目前在头颈部肿瘤的放射治疗中逐步推广应用。人体头颈部因解剖的特点决定了头颈部的活动度较大，不宜固定，放疗摆位时体位重复性差。采用头颈部的固定装置结合热塑面罩固定技术，使头颈部肿瘤的放射治疗质量得到了保证。但使用热塑面罩后，可能对病人的治疗剂量造成影响。为研究放射物理剂量的变化可能对正常组织的影响。使用石蜡浇注制成人体颈部体模，代替正常的人体颈部。选用热释光材料制成直径1mm、长3mm的热释光探测器，置入石蜡人体颈部体模中，按照实际治疗的靶区分布测量受照剂量。     

3D打印技术在颅颌面创伤应用的相关技术与发展趋势

3D打印作为新兴技术首次应用于工业领域,目前在医疗领域的潜在价值也受到诸多关注。自从20世纪80年代后期引入医学领域以来,利用这一技术,医学数字成像和通信(DICOM)文件可以转化为立体光刻(STL)文件,打印出血管、肿瘤和头盖骨等三维解剖结构,使外科医生能够改进术前规划。由于该领域起步晚,技术种类繁多且各有利弊,目前尚无标准的3D打印模式用于临床和医学研究。为了使创伤外科临床医生能正确使用3D打印技术,笔者对各种3D打印和计算机辅助设计(CAD)软件的临床应用特别是颅颌面创伤的应用作一综述。     

应用放射治疗模拟机对二次复形真空袋体位固定精度的验证研究

目的:探讨半软状态二次复形真空袋体位固定误差,为立体定向放射治疗中能否使用其提供依据。方法:抽取无漏气真空袋120例为对照组,抽取半软状态二次抽真空复形真空袋45例为实验组,应用模拟定位机对照射前、后测量灯光野与照射野X、Y、Z方向的移动情况进行比较,并进行统计学处理。结果:无漏气真空袋体位固定患者的X、Y、Z坐标的偏差率为5.83%,而半软状态二次复形真空袋体位固定患者X、Y、Z坐标的偏差率为35.65%,二者比较差异有显著性意义(P<0.01),故提示不能使用二次复形真空袋作为立体定向放射治疗的体位固定。结论:本研究结果表明在X-刀治疗中,使用真空袋体位偏差率及偏差幅度低,具有较好的体位固定效果,能保证良好的体位重复性。半软状态二次复形真空袋则有较大偏差率及偏差幅度,不宜在立体定向放射治疗中继续应用,应当重新制作真空袋进行CT定位。     

3D打印技术在关节置换中的应用与进展

人工关节置换术已有近百年历史,而3D打印技术30年前开始兴起的技术,是基于先进的3D设计、计算机辅助设计、离散/堆积成型原理、制造技术、数控技术、三维CT技术、快速成型技术。随着3D打印技术的发展,其在关节置换得到了广泛的应用,又相互促进发展。目前,它包括但不限于以下方面：术前规划、医学教学中、医生和病人之间的医患沟通、降低学习曲线、个性化的假体、生产个性化的模板、大规模生产的3D打印假体等。应用并不困难,然而,仍有一些局限性有待解决。因此,最新的全膝关节置换仍然依靠传统的工具。相信在3 d打印技术的发展及其临床应用的普及,相关的问题都将会逐渐得到解决,推动联合手术的发展。     

3D打印技术在放疗中的应用与进展

随着3D打印技术的发展和成熟,其在医学领域被广泛应用,尤其在骨科、口腔颌面外科等方面取得了突破性进展。而在肿瘤的放疗领域,创新性地将3D打印技术与放疗技术相结合并应用于临床,可大大提高放疗的精确度和临床疗效,为肿瘤的精确放疗提供有力保障。     

3D生物打印技术在组织工程支架构建与再生中的应用进展

具备个性化、精准化的3D生物打印技术构建优良生物相容性的组织工程支架,替换或修复人体中病变的组织和/或器官,在组织工程研究中极具广泛的应用前景。而作为3D打印技术的基材,如金属、生物陶瓷、高分子材料和细胞生物材料等,也因此得到了研究者的重视和研发。由金属和生物陶瓷制备的支架具有高强度和耐腐蚀性,已在骨科中得到广泛应用,而高分子材料由于其和细胞/组织的良好生物相容性及可塑性使其在软骨、矫形外科、心血管系统等组织/器官中被广泛研究。相信在不久的将来,以上述材料为基材结合3D生物打印技术构建的组织和器官,在临床上会得到应用和推广。本文就用于3D打印的生物材料及其打印技术在组织工程支架构建及组织再生中的应用进行综述。     

3D打印技术在医疗救援中的应用

目的通过3D打印技术制作实物模型或医疗辅助器械,使医疗救援过程中的诊治方法更加直观化、便捷化、精确化。方法利用车载式磁共振成像系统配套装备的3D打印设备,借助熔融沉积制造（fused deposition modeling,FDM）技术,使用热塑性材料在计算机的控制下,快速制作各种实物模具和医疗辅助器械。结果利用车载式MRI系统配备的3D打印设备不仅能够制作射频接收线圈模具,还可应用于医疗救援中术前策划、术中导航、定制手术辅助器械,以及定制假体等,满足救援现场需求。结论 3D打印技术作为车载式MRI的配套设备在救援现场诊断及治疗方面可发挥重要作用。     

封面故事

3D打印自20世纪80年代诞生以来,该技术飞速发展,已广泛应用于骨科的各个领域,如脊柱骨科、创伤骨科、关节骨科等等,其带来的多孔支架、个体化内植物、个性化导板、术前实体解剖模型在临床工作中有着独特的优势。本期南京医科大学第一附属医院骨科方加虎教授团队论文《3D打印在骨科畸形矫正中的应用》回顾近年来应用3D打印技术对四肢畸形进行矫形的病例,并结合多年来在矫形骨科领域的临床经验,对3D打印技术在骨科领域,尤其是矫形骨科领域中的应用进行分析。     

将3D打印技术应用到颅颌面战创伤救治中

颅颌面部战创伤是战伤减员的重要组成部分,加强对颅颌面部战创伤救治的教学是提高我军战场急救水平的迫切需求.随着3D打印技术的发展,3D打印技术已经广泛应用到口腔种植、口腔修复、口腔颌面外科等临床及教学多个领域中.将低成本的3D打印模型引入到颅面部战创伤救治的教学,可以提高颅面部战创伤相关的解剖结构及救治方法的教学效果.颅颌面部战创伤模型的3D打印主要是在标准或损伤后颅颌面部立体光刻(stereolithography,STL)文件上创建模拟出战创伤的损伤形态,利用计算机辅助设计和制造(CAD/CAM)及3D打印技术制作出损伤模型,再将其用于颅面部战创伤救治的教学中.     

Comparison of the effectiveness of different immobilization systems in different body regions using daily megavoltage CT in helical tomotherapy

Objective:

Effective immobilization is crucial for the accurate delivery of radiotherapy. This study aimed to compare the effectiveness of the commonly used immobilization systems for different body regions using megavoltage CT (MVCT).

Methods:

Daily treatment set-up data from 212 patients treated by helical tomotherapy (Accuray, Sunnyvale, CA) in 6 body regions (52 head and neck, 41 chest, 38 abdomen, 36 pelvis, 18 breast and 27 cranium) were obtained. Based on a verification tool using the pre-treatment MVCT, set-up corrections for each patient were recorded. Mean systematic and random errors of lateral, longitudinal, vertical and roll directions and three-dimensional vectors were compared between immobilization systems of each region.

Results:

Smaller set-up deviations were observed in the Orfit system (Orfit Industries NV, Wijnegem, Belgium) of the head and neck region, while the performance of immobilization systems for the chest, abdomen and pelvis regions was similar. Larger differences were noted in the breast group, where the prone BodyFIX® system (Medical Intelligence, Medizintechnik GmbH, Schwabmünchen, Germany) was less stable than the supine VacLok® system (CIVCO Medical Solutions, Orange City, IA).

Conclusion:

Differences were found between the immobilization systems in the head and neck region, in which the Orfit system was relatively more effective, whereas the VacLok and BodyFIX systems performed similarly in the chest, abdomen and pelvis regions. For the breast case, the supine position with VacLok was much more stable than the prone breast technique. The results provided references for the estimation of clinical target volume–planning target volume margins.

Advances in knowledge:

This is the first article on comprehensive comparisons performed in immobilization systems for main body regions that provides some practical recommendations.The goal of radiotherapy is to maximize tumour control and minimize complications in the surrounding normal tissue. The success of radiotherapy depends mostly on the accuracy and the reproducibility of daily treatment delivery.^1,2 Many studies have shown that an effective immobilization system can reduce positioning variations^3–6 and improve the outcome of radiotherapy treatment. With the introduction of many commercially available immobilization accessories, oncology departments have developed their own immobilization systems for specific cancer patients and radiotherapy techniques based on their available resources and treatment protocols. As many choices of immobilization devices are now available in the market, more than one immobilization system may have been developed for the treatment of a specific disease. It is the interest of the clinicians to understand the effectiveness of individual immobilization devices and come up with an optimal system that offers the least set-up deviation during treatment.Because of this, many studies have been performed in the past to investigate the effectiveness of different immobilization systems, most of which used portal imaging as the verification method. Since portal images can only provide two-dimensional (2D) information, it is difficult to detect rotational set-up errors. The recent integration of CT in radiotherapy treatment machines has solved this problem and provides a three-dimensional (3D) verification application. Such systems include the integration of cone beam CT in a linear accelerator and the megavoltage (MV) CT in helical tomotherapy (Accuray, Sunnyvale, CA). Many previous studies, including the one by Li et al,⁷ have already demonstrated that the 3D approach in cone beam CT was superior to the 2D radiographic portal images used in the verification of patients treated at the head and neck region.MVCT is inherent in the helical tomotherapy unit, which is used for the daily set-up and verification of the patient position. Such a system provides more detailed set-up data and is more reliable in assessing positional deviations compared with the portal imaging method. Furthermore, the data collected from the MVCT verification system can be used to generate the systematic and random errors of each treatment, which are useful for the evaluation of set-up accuracy. The systematic error is the average error over all treatment fractions, whereas the random error is the average magnitude of errors that are expected to be distributed as a gaussian function about a mean.The aim of this study was to evaluate the effectiveness of different immobilization systems by assessing the systematic and random errors generated from MVCT data of helical tomotherapy for different body regions. The results would provide reference information for the choice of immobilization devices and establish an optimal system for specific treatment conditions, as it is expected that an optimal immobilization system would lead to more accurate treatment and better treatment outcomes.     

类器官在肿瘤放射治疗相关研究中的应用进展

类器官是一种体外培养的三维微型结构,源自健康个体或患者的人多能干细胞或成体干细胞。相对于传统的细胞系或动物模型,类器官被视为更有前途的高保真模型,在疾病建模、药物开发、建立活体生物库和探索个性化治疗方面具有独特的优势。近年来,类器官技术的飞速发展为革新肿瘤临床前实验模型和推动临床个性化诊疗带来了新希望。本综述旨在介绍类器官在肿瘤放射治疗领域的发展现状和最新进展,讨论癌症类器官模型的优势和局限,并对其在放射治疗领域的应用前景进行展望。     

脊髓转移瘤的影像学诊断与治疗研究进展

脊髓转移瘤（ISCM）是肿瘤晚期患者癌灶转移至脊髓,压迫脊髓或神经根引起躯体疼痛、感觉减退或麻木的一种危险的转移性疾病,严重者可导致机体瘫痪,患者的生活质量显著降低。随着肿瘤发病率的上升以及新型影像诊断技术在临床中的应用,ISCM的检出率明显提高。但遗憾的是,针对ISCM的治疗目前尚无统一的共识。虽然在以往的ISCM治疗中放疗的作用较为局限,但随着放疗技术的发展与提高,对于存在手术禁忌证或化疗效果较差的患者,放疗已成为其主要的治疗方式。笔者就近年来ISCM的影像学诊断与治疗研究进展做一综述。     

Biodegradable materials for bone defect repair

Compared with non-degradable materials,biodegradable biomaterials play an increasingly important role in the repairing of severe bone defects,and have attracted extensive attention from researchers.In the treatment of bone defects,scaffolds made of biodegradable materials can provide a crawling bridge for new bone tissue in the gap and a platform for cells and growth factors to play a physiological role,which will eventually be degraded and absorbed in the body and be replaced by the new bone tissue.Traditional biodegradable materials include polymers,ceramics and metals,which have been used in bone defect repairing for many years.Although these materials have more or fewer shortcomings,they are still the cornerstone of our development of a new generation of degradable materials.With the rapid development of modern science and technology,in the 21st century,more and more kinds of new biodegradable materials emerge in endlessly,such as new intelligent micro-nano materials and cell-based products.At the same time,there are many new fabrication technologies of improving biodegradable materials,such as modular fabrication,3D and 4D printing,interface reinforcement and nanotechnology.This review will introduce various kinds of biodegradable materials commonly used in bone defect repairing,especially the newly emerging materials and their fabrication technology in recent years,and look forward to the future research direction,hoping to provide researchers in the field with some inspiration and reference.     

Multi-fractionated stereotactic radiotherapy

Precision and accuracy of a patient's treatment are key advantages of single-fraction stereotactic radiosurgery (SRS) for arteriovenous malformations (AVMS) and some small brain metastases. These advantages are equally valuable in fractionated treatment of the pituitary, brain metastases and brain boost fields. The need to implement the preciseness from stereotactic radiosurgery to fractionated treatments was recognized. Using our experience with single-fraction stereotactic radiosurgery as a model, we developed a multi-fractionated stereotactic radiotherapy technique that allows us to immobilize a patient daily and implement important existing devices such as the Brown-Roberts-Wells (BRW) angiographic localizer, CT scan localizer, and non-coplanar shaped field treatment planning. Development of this technique also allows us to achieve reproducible patient positioning based on immobilization techniques using polyurethane foam immobilization and heat moldable plastic technology without the necessity of the invasive technique of skull fixation. The development, implementation and dosimetry of this technique will be discussed in this paper.     

Dynamic targeting image-guided radiotherapy.

Volumetric imaging and planning for 3-dimensional (3D) conformal radiotherapy and intensity-modulated radiotherapy (IMRT) have highlighted the need to the oncology community to better understand the geometric uncertainties inherent in the radiotherapy delivery process, including setup error (interfraction) as well as organ motion during treatment (intrafraction). This has ushered in the development of emerging technologies and clinical processes, collectively referred to as image-guided radiotherapy (IGRT). The goal of IGRT is to provide the tools needed to manage both inter- and intrafraction motion to improve the accuracy of treatment delivery. Like IMRT, IGRT is a process involving all steps in the radiotherapy treatment process, including patient immobilization, computed tomography (CT) simulation, treatment planning, plan verification, patient setup verification and correction, delivery, and quality assurance. The technology and capability of the Dynamic Targeting IGRT system developed by Varian Medical Systems is presented. The core of this system is a Clinac or Trilogy accelerator equipped with a gantry-mounted imaging system known as the On-Board Imager (OBI). This includes a kilovoltage (kV) x-ray source, an amorphous silicon kV digital image detector, and 2 robotic arms that independently position the kV source and imager orthogonal to the treatment beam. A similar robotic arm positions the PortalVision megavoltage (MV) portal digital image detector, allowing both to be used in concert. The system is designed to support a variety of imaging modalities. The following applications and how they fit in the overall clinical process are described: kV and MV planar radiographic imaging for patient repositioning, kV volumetric cone beam CT imaging for patient repositioning, and kV planar fluoroscopic imaging for gating verification. Achieving image-guided motion management throughout the radiation oncology process requires not just a single product, but a suite of integrated products to manipulate all patient data, including images, efficiently and effectively.     

Second place Alpha Cradle Award winner. Medulloblastoma immobilization and treatment considerations

Medulloblastoma is the most common type of primary intracranial tumor in children. It is a highly malignant and radiosensitive tumor. National treatment protocols outline a very specific simulation procedure with detailed dosimetry to guarantee dose homogeneity. Actual treatment geometry is directly dependent on the reproducibility of patient position. The SMP Alpha Cradle system affords just the precise immobilization needed for daily treatment field reproducibility. A step by step outline of the Alpha Cradle fabrication process is included here; accompanied with diagrams and photographs of our suggested modifications for immobilization of the medulloblastoma patient in the reverse cradle application position.     

原发性肝细胞肝癌手术联合放疗的进展

肝癌是一种严重危害人类健康的常见恶性肿瘤,手术切除是早中期肝细胞肝癌（hepatocellular carcinoma,HCC）的主要根治手段,而术后复发率高是影响其疗效的主要因素。然而,目前尚无普遍接受的可降低HCC术后较高复发率的辅助治疗方式。精准放疗技术的应用,使肿瘤局部可准确地获得更高的放疗剂量,也越来越多地应用于HCC的治疗。鉴于精准放疗在中晚期肝癌的治疗地位越来越明确,而是否能作为HCC的辅助治疗尚有争议,本文将综述放疗作为手术的辅助治疗在HCC的研究进展,以期为HCC的临床辅助治疗的应用提供参考依据。     

The use of general anaesthesia in paediatric radiotherapy

Radiotherapy plays a key role in the management of paediatric cancers. Over the past few years there has been a steady decline in the use of radiation as concerns over long-term side effects have become apparent and the use of chemotherapy has expanded. That said, radiotherapy still plays a major part in the management of brain tumours, haematological malignancies, soft tissue tumours and in the palliation of symptoms.As the technology behind radiotherapy has advanced, this has enabled an increase in the conformity of radiation and therefore higher dose delivery to the tumour and reduction in the radiation received by normal tissues and organs at risk. A consequence of increased beam conformity is a greater need to ensure accuracy of patient position and limit movement during treatment. Achieving this can be particularly challenging with children due to their age, understanding of the situation, and ultimately their ability to comply with a treatment process that is quite daunting.The use of general anaesthesia within radiotherapy is not a new concept and it is widely acknowledged as being a safe and effective method of immobilising children. This paper presents a systematically undertaken review of the literature related to radiotherapy, general anaesthesia and play preparation within paediatric radiotherapywith specific emphasis on the role of general anaesthesia in achieving immobilization of patient position.