对比3DCRT和IGRT技术对肝癌放射治疗的作用与评价

目的 通过比较三维适形放疗(3DCRT)和影像引导放疗(IGRT)两种治疗技术,评价两种治疗技术对肝癌放疗患者生存质量的影响。方法 2009年3月—2010年7月22例肝区病灶放疗患者,其中3DCRT组12例,常规放射治疗;IGRT组10例,每日治疗前以CBCT+ABC技术采集患者CBCT图像,根据靶区及邻近器官进行治疗计划CT图像和CBCT容积图像的配准,记录X(TableShiftLat)、Y(TableShiftLong)、Z(TableShiftVert)三个方向的偏移数据,并校正摆位误差,记做CBCT_前,为包含摆位误差的放疗分次间的重复性;治疗结束后再次行CBCT扫描记做CBCT_后,表明在照射期间内靶区及脏器位置的重复性,即个体化放疗分次内肿瘤运动。利用SPSS软件计算IGRT+ABC技术在线治疗校正下的肝脏肿瘤放疗的平均误差及标准差。结果 应用ABC技术时,放疗分次间的重复性较差,而放疗分次内的重复性较好。计算得到的现有无影像引导的摆位规范下CTV-PTV外放为X为0.8 cm、Y为0.9 cm、Z为0.9 cm;现有影像引导(IGRT)的摆位规范下CTV-PTV外放为X为0.3 cm、Y为0.4 cm、Z为0.2 cm。1、2年生存率3DCRT组和IGRT 组分别为58.3%和16.7%、70% 和 20%,中位生存期分别为12、16个月。结论 肝脏作为软组织体,在器官运动过程中各点的位移幅度不同,治疗过程中,因软组织内部不同位置的形变差异无法估量,治疗误差将会有很大不确定性。3DCRT与IGRT两种治疗结果相比,从近期疗效看,IGRT组局部控制率有提高,放疗反应明显减轻。1,2年生存率IGRT组有提高,中位生存期延长。IGRT的应用使肝癌的放射治疗进入一个新的阶段,值得临床进一步研究。     

三维超声在前列腺癌图像引导放疗中的应用与评价研究

目的以锥形束CT校准为金标准, 评价前列腺癌图像引导放疗中三维超声校准的准确度, 并分析影响其准确度的危险因素。方法选择2018年12月至2021年12月河北北方学院附属第一医院放疗科51例前列腺癌患者为研究对象。患者均接受每周3次分次容积旋转调强放疗前基于骨骼的锥形束CT校准和基于软组织的三维超声校准。以锥形束CT校准数据为金标准, 采用Bland-Altman法分析三维超声校准数据与其一致性。准确度允许阈值设置为3 mm, 评价三维超声相对锥形束CT校准的准确度。采用logistic回归分析影响三维超声校准准确度的危险因素。结果共获取51例患者左右、头脚、腹背3个方向上765对锥形束CT和三维超声校准数据。左右方向上三维超声校准数据和锥形束CT校准数据分别为(1.39±0.11)和(1.13±0.07)mm, 头脚方向上分别为(1.98±0.20)和(1.61±0.12)mm, 腹背方向上分别为(2.68±0.48)和(1.78±0.27)mm, 差异均具有统计学意义(t=-6.42, P<0.001;t=-7.07, P<0.001;t=-7.34, P<0.0...     

超声成像在放疗中的临床应用

超声图像引导放疗（image guided radiation therapy,IGRT）是通过采集靶区二维超声断层图像或三维重建技术,辅助减小分次治疗的摆位误差、分次治疗间的靶区移位和变形以及同一分次中的靶区运动的技术。本文将系统回顾三维超声成像作为日常图像引导工具在放疗中的应用,并讨论这种成像技术在多种部位（如前列腺癌、妇科肿瘤和乳腺癌）中包括详细的扫描、采集技术及使用步骤的运用。最后,简要回顾放疗中用于靶区定位的其他成像技术,并比较这些成像技术之间的差异。     

CBCT配合6D治疗床对食管癌放疗摆位偏差的纠正

目的:探讨食管癌影像引导的放射治疗(Image Guided Radiation Therapy,IGRT)6个自由度(Six-degree,6D)摆位误差的纠正和再纠正.方法:2008年6月到2009年6月我院用ELEKTA公司的具有六维调节床的Synergy IGRT治疗机治疗胸部肿瘤患者14例.所有患者在每次的治疗前(IGRT纠正前)、IGRT六维床纠正后和治疗后用KV级的锥形束CT(Cone Beam CT,CBCT)扫描获取患者的3种容积CT图像.结果:IGRT纠正前、纠正后六维误差有4项的摆位偏差经纠正后差异有统计学意义.纠正前后摆位边界的减少幅度,平移为0.67 cm～1.27cm,旋转为1.6度～2.3度.患者在IGRT治疗后的体位变化对六维误差影响仅Z轴平移和Y轴旋转变化差异有统计学意义,但患者治疗中体位的平移均小于0.04cm,体位旋转均小于0.2度.IGRT纠正后的平移误差均小于1mm,旋转误差均小于0.5度.结论:IGRT对胸部肿瘤放疗的摆位误差纠正有明显的作用,且能较大幅度减少摆位边界,缩小计划靶区而减少正常组织的受量.胸部肿瘤IGRT治疗过程虽然体位有所变动,但六维变化范围均很小不影响治疗.当IGRT纠正前的六维偏差有渐大趋势时要注意热塑体模是否有变形的可能.为提高和保证胸部肿瘤放疗的精确性,当平移误差大于1mm,旋转误差大于0.5度时要重新配准纠正六维误差.     

膈肌与上腹部肿瘤靶区运动过程中位置变化相关性的临床应用

目的:通过图像引导放射治疗（IGRT）加速器机载锥形束CT(cone beam CT,CBCT)实时观察膈肌与上腹部器官及肿瘤运动过程中位置的变化,揭示二者运动的内在变化规律,提高肿瘤放疗质控的效率。方法:对10例上腹部肿瘤病例整个治疗过程的全程跟踪及相关临床数据收集、分析、总结,得到了肿瘤患者膈肌与上腹部器官及肿瘤运动过程中位置的变化范围。结果:在患者保持平静呼吸而且在定位、扫描及治疗过程中体位相同的状态下,患者靶区与膈肌的相对移动基本一致。结论:患者靶区与膈肌的相对移动的确定,能够进一步提高肿瘤实际治疗的过程中质控的效率,为上腹部肿瘤精确治疗质控提供新的方法。     

图像引导放射治疗的临床应用

图像引导放射治疗(IGRT)是继三维适形放疗(3DCRT)和调强适形放疗(IMRT)之后,又一新的放疗技术,是提高放射治疗精度、保证与控制放疗质量的重要手段.这一技术发展快,普及快,有很强的治疗优势.     

四维放射治疗的研究现状

如何更准确地确定靶区、了解个性化靶区运动规律,并借以制定放疗计划及实施放疗,即图像引导放射治疗(image-guided radiotherapy,IGRT),已成为国内外肿瘤放疗研究的热点和方向。近10余年来,IGRT研究主要围绕肉眼靶区(gross target volume,GTV)的确定、靶区运动的测定及限定、实施照射过程中靶区位置的验证等开展,均属于三维     

COMPASS验证系统在放射治疗中的应用研究

目的:测试COMPASS三维验证系统在临床应用中的可行性。方法:以三维水箱为基准,比较分析COMPASS系统在百分深度剂量(Percentage depth dose,PDD)、输出因子(Output factor,OUF)、离轴曲线(Profile)和绝对剂量等方面的测量数据与三维水箱所测量数据的相关性和一致性;在均匀模体和非均匀模体中验证7例患者的放疗计划,检测COMPASS系统软件的剂量计算精度和剂量重建精度;通过BallBearming模体测试COMPASS系统硬件对加速器等中心的影响。结果:COMPASS系统测量和重新计算的PDD、OUF、Profile与三维水箱测量的数据具有较好的一致性,其绝对剂量偏差均小于2.5%;COMPASS系统软件在均匀模体和非均匀模体中验证7例患者放疗计划的绝对剂量偏差均小于3%,γ通过率不低于93%,重建精度和剂量计算精度接近于计划系统(Teatmentplanning system,TPS);COMPASS系统的硬件不影响等中心的精度,在三个方向上的偏差都小于1mm。结论:COMPASS系统的独立计算功能和剂量重建功能具有类似TPS的精度,可以提供三维的剂量分布信息,为临床治疗提供安全、可靠的技术保障。     

锥形束CT成像技术及其在放疗中的应用

图像引导放疗(image-guided raduotherapy,IGRT)是继三维适形、调强放疗之后,又一新的放疗技术,它在分次治疗摆位时和(或)治疗中采集图像和(或)其他信号,利用这些图像和(或)信号,引导此次治疗和(或)后续分次治疗~([1]).     

图像引导放疗的实现方式

图像引导放疗（image-guided radiotherapy，IGRT）是继三维适形放疗（3DCRT）和调强放疗（IMRT）之后，又一新的放疗技术。如果从字面理解IGRT的定义，3DCRT、IMRT甚至传统的二维放疗（2DRT）都可称为IGRT，因为它们在定位阶段、计划阶段和（或）实施阶段都用到图像。3DCRT和IMRT在定位阶段和计划阶段，用到三维CT图像，或三维CT图像结合其他模式图像，在治疗阶段用到射野图像。     

HT系统MVCT图像不同采集间距及配准条件对鼻咽癌放疗精度影响

目的 探讨HT系统MVCT图像不同采集间距及配准条件对鼻咽癌放疗精度的影响,以期为鼻咽癌IGRT提供参考依据。方法 应用头颈部仿真模体在HT系统上模拟x、y、z轴向的摆位误差并行MVCT扫描,将所获得的图像与计划CT图像进行配准,图像采集间距分别选择粗糙、正常和精细3种模式,配准条件分别设置为骨配准、骨和软组织配准和全图像配准。比较配准所得误差值与实际误差,评估不同采集间距及配准条件下鼻咽癌放疗精度的差异。结果 图像采集间距分别为粗糙,正常和精细时,骨配准、骨和软组织配准、全图像配准的误差分别为(1.51±0.47)、(1.54±0.35)、(1.81±0.53) mm,(1.41±0.37)、(1.53±0.36)、(1.56±0.39) mm和(1.51±0.27)、(1.57±0.32)、(1.73±0.33) mm (P<0.05)。当配准条件设置为骨配准时,3种采集间距的精度相近(P>0.05)。当采集间距选择精细时,稳定性最高,但耗时最长。结论 鼻咽癌HT前的MVCT扫描应结合临床实际情况选择合适的采集间距及配准条件。     

Non image-guided core needle biopsies can be used safely to improve diagnostic efficiency for soft tissue tumors

IntroductionFront-line biopsy remains the rule in the management of soft tissue mass syndromes. Although open biopsy has long been considered the gold standard, it has recently been shown that a percutaneous biopsy is associated with a reduction in the rate of complications and cost, while maintaining high diagnostic accuracy. Though there is much literature regarding the diagnostic accuracy of image-guided and open biopsies for soft tissue tumors, the accuracy of percutaneous non image-guided biopsies has not been well documented. The objective of this study was to compare the failure rate of non image-guided biopsies, image-guided biopsies and open biopsies for the diagnosis of soft tissue tumors. We also attempted to identify the failure risk factors for non image-guided biopsies and we compared the diagnostic delay of the three types of biopsy.Materials and methodsThis was a continuous, single-center retrospective study. We reviewed the results from 337 patients managed with a biopsy (percutaneous or open) for a soft tissue tumor, all carried out in our center between January 2010 and December 2015. Biopsy technique was chosen by the treating orthopedic surgeon, according to the clinical and radiological characteristics of the mass. 141 patients (41.8%) had a non-image-guided biopsy as the first-line diagnostic procedure, 81 (24.0%) had an image-guided biopsy, and 115 (34.1%) an open biopsy. Diagnostic failure was defined either by a non-contributory biopsy, the need for repeat biopsy, or a major histological discordance obtained from the resected tumor piece. The risk factors studied were tumor characteristics, patient’ characteristics and sampling modalities. Diagnostic delay was defined as the period between the day of the first external consultation at the hospital and the day of the notification of the diagnosis by the physician.ResultsWe obtained a failure rate of 9.9% (14 patients) for non image-guided biopsies. Eleven were non-contributive and three were considered as errors of diagnosis. The failure rate for image-guided biopsies was 18.5% (15 patients), with no significant difference compared with non image-guided biopsies. The open biopsies were associated with a failure rate of 6.9% (eight patients). We found no failure risk factors for non image-guided biopsies. Diagnostic delay was significantly shorter for non image-guided biopsies (p = 0.001).ConclusionWhen performed in a referral center by the patient's surgeon, a non-image-guided core needle biopsy is a safe procedure which ensures equivalent diagnostic accuracy for soft tissue tumors, while reducing the diagnostic delay.     

瓦里安机载图像引导系统在鼻咽癌图像引导放疗中联合应用的探索

目的:比较瓦里安OBI引导系统的千伏级锥形束CT (KV-CBCT)、千伏级平面成像(KV-planar)、兆伏级电子射野影像装置(MV-EPID)3种图像系统的综合性能,探索3种系统在鼻咽癌每日图像引导放疗中联合应用的价值。方法:利用人体仿真头颈模体在左右/前后/头脚方向分别进行KV-CBCT、KV-planar、M...     

Radiologie interventionnelle et tumeurs des tissus mous : du diagnostic au traitement

Interventional radiology plays an increasing role in the management of soft tissue tumors. For initial diagnosis, precise and safe image-guided biopsies; soft tissue tumor biopsies must be performed in accordance with international guidelines. Then, in a therapeutic phase, interventional radiology, particularly with thermal ablation techniques (radiofrequency, cryoablation), can be proposed for specific indications like salvage treatment of recurrent tumor after surgery and radiotherapy, focal ablation for oligometastatic sarcomas, or treatment of benign locally aggressive tumors such as symptomatic hemangiomas or desmoid tumors. A multidisciplinary approach remains mandatory to achieve optimal patient selection for interventional radiology techniques.     

影像学技术在图像引导宫颈癌近距离放射治疗中的应用

图像引导放射治疗是一种很有前途的放射治疗技术,可以提高宫颈癌患者的局部控制率,降低并发症发生率。MRI软组织分辨率高,是图像引导宫颈癌近距离放射治疗公认的金标准。CT软组织分辨率虽不及MRI,但更易识别施源器、源和源路径,在宫颈癌的放疗计划中,CT的使用率远远高于MRI。新的成像技术,如PET和MRI,改善了放疗计划中靶区的勾画,特别是PET联合CT、MRI,在功能成像方面也显得越来越重要。在病人初始分期方面,超声已经被MRI取代,但在图像引导妇科插植和腔内近距离治疗中起重要作用。本综述的目的是评估各种影像技术在图像引导宫颈癌近距离放射治疗中的应用。     

Automatic target localization and verification for on-line image-guided stereotactic body radiotherapy of the spine

To facilitate image-guided stereotactic body radiotherapy (IG-SBRT) of spinal and paraspinal tumors, the authors have developed an on-line image registration system for automated target localization and patient position verification with high precision. When rotations are present in a patient's daily setup position, a setup error of a few millimeters can be introduced in localization of the isocenter by using surrounding bony structures. This setup error not only will deteriorate the dose coverage of the tumor, more importantly it will overdose the spinal cord. To resolve this issue, the image registration program developed by the authors detects translational shifts as well as rotational shifts using 3D CT image registration. Unacceptable rotations were corrected by either repositioning the patient or adjusting the treatment couch that was capable of rotational corrections when such a couch was available for clinical use. One pair of orthogonal digitally reconstructed radiographs (DRR) were generated from the daily pretreatment CT scan to compare with the corresponding DRRs generated from the planning CT scan to confirm the target shift correction. After the patient's position was corrected a pair of orthogonal portal images were taken for final verification. The accuracy of the image registration result was found to be within 0.1 mm on a head and neck phantom. Target shifts of a fraction of a millimeter were readily visible in our DRR comparison and portal image verification. The time needed to complete the image registration and DRR comparison was about 3 minutes. An integrated system that combines a high-speed CT scanner and a linear accelerator was used for imaging and treatment delivery. Application of the program in actual IG-SBRT cases demonstrated that it was accurate, fast, and reliable. It serves as a useful tool for image-guided radiotherapy where high precision of target localization is required.     

Evaluation of Ultra-low-dose Paediatric Cone-beam Computed Tomography for Image-guided Radiotherapy

AimsIn image-guided radiotherapy, daily cone-beam computed tomography (CBCT) is rarely applied to children due to concerns over imaging dose. Simulating low-dose CBCT can aid clinical protocol design by allowing visualisation of new scan protocols in patients without delivering additional dose. This work simulated ultra-low-dose CBCT and evaluated its use for paediatric image-guided radiotherapy by assessment of image registration accuracy and visual image quality.Materials and methodsUltra-low-dose CBCT was simulated by adding the appropriate amount of noise to projection images prior to reconstruction. This simulation was validated in phantoms before application to paediatric patient data. Scans from 20 patients acquired at our current clinical protocol (0.8 mGy) were simulated for a range of ultra-low doses (0.5, 0.4, 0.2 and 0.125 mGy) creating 100 scans in total. Automatic registration accuracy was assessed in all 100 scans. Inter-observer registration variation was next assessed for a subset of 40 scans (five scans at each simulated dose and 20 scans at the current clinical protocol). This subset was assessed for visual image quality by Likert scale grading of registration performance and visibility of target coverage, organs at risk, soft-tissue structures and bony anatomy.ResultsSimulated and acquired phantom scans were in excellent agreement. For patient scans, bony atomy registration discrepancies for ultra-low-dose scans fell within 2 mm (translation) and 1° (rotation) compared with the current clinical protocol, with excellent inter-observer agreement. Soft-tissue registration showed large discrepancies. Bone visualisation and registration performance reached over 75% acceptability (rated ‘well’ or ‘very well’) down to the lowest doses. Soft-tissue visualisation did not reach this threshold for any dose.ConclusionUltra-low-dose CBCT was accurately simulated and evaluated in patient data. Patient scans simulated down to 0.125 mGy were appropriate for bony anatomy set-up. The large dose reduction could allow for more frequent (e.g. daily) image guidance and, hence, more accurate set-up for paediatric radiotherapy.     

Bladder Cancer Radiotherapy Margins: A Comparison of Daily Alignment using Skin,Bone or Soft Tissue

AimsTo determine the clinical target volume (CTV) to planning target volume (PTV) margins required for bladder coverage when using skin or bony or soft tissue matching on a daily basis.Materials and methodsTwenty-seven patients with T2–T4 transitional cell carcinoma of the bladder were treated with daily online adaptive image-guided radiotherapy using cone beam computed tomography. All daily CTVs were contoured by a single observer. A retrospective comparison of coverage of the bladder CTV using skin, bone and soft tissue matching was conducted.ResultsWith the skin set-up, bladder CTV coverage with a margin of 0.5, 1.0, 1.5, 2.0 and 2.5 cm was 0, 19, 56, 93 and 96%, respectively. For the daily set-up based on bone, the respective coverage was 0, 41, 63, 89 and 96%. For soft tissue set-up based on the geometric centre of the bladder, coverage was 52, 89, 96, 100 and 100%, respectively.ConclusionsBased on coverage of the CTV, the required CTV to PTV margins are smaller for the daily online soft tissue set-up compared with skin or bone.     

Technical evaluation of radiation dose delivered in prostate cancer patients as measured by an implantable MOSFET dosimeter

PURPOSE: To perform a comparison of the daily measured dose at depth in tissue with the predicted dose values from treatment plans for 29 prostate cancer patients involved in a clinical trial. METHODS AND MATERIALS: Patients from three clinical sites were implanted with one or two dosimeters in or near the prostatic capsule. The implantable device, known as the DVS, is based on a metal-oxide-semiconductor field effect transistor (MOSFET) detector. A portable telemetric readout system couples to the dosimeter antenna (visible on kilovoltage, computed tomography, and ultrasonography) for data transfer. The predicted dose values were determined by the location of the MOSFET on the treatment planning computed tomography scan. Serial computed tomography images were taken every 2 weeks to evaluate any migration of the device. The clinical protocol did not permit alteration of the treatment parameters using the dosimeter readings. For some patients, one of several image-guided radiotherapy (RT) modalities was used for target localization. RESULTS: The evaluation of dose discrepancy showed that in many patients the standard deviation exceeded the previous values obtained for the dosimeter in a phantom. In some patients, the cumulative dose disagreed with the planned dose by > or =5%. The data presented suggest that an implantable dosimeter can help identify dose discrepancies (random or systematic) for patients treated with external beam RT and could be used as a daily treatment verification tool for image-guided RT and adaptive RT. CONCLUSION: The results of our study have shown that knowledge of the dose delivered per fraction can potentially prevent over- or under-dosage to the treatment area and increase the accuracy of RT. The implantable dosimeter could also be used as a localizer for image-guided RT.     

Innovations in image-guided radiotherapy

The limited ability to control for the location of a tumour compromises the accuracy with which radiation can be delivered to tumour-bearing tissue. The resultant requirement for larger treatment volumes to accommodate target uncertainty restricts the radiation dose because more surrounding normal tissue is exposed. With image-guided radiotherapy (IGRT) these volumes can be optimized and tumoricidal doses can be delivered, achieving maximal tumour control with minimal complications. Moreover, with the ability of high-precision dose delivery and real-time knowledge of the target volume location, IGRT has initiated the exploration of new indications for radiotherapy, some of which were previously considered infeasible.