三维适形放射治疗在纵隔转移肿瘤中的临床应用

目的：探讨三维适形加量放射治疗在纵隔转移肿瘤中的应用。方法：66例纵隔转移肿瘤患者随机分为两组，普放组和普放 三维适形组。每组33例。结果：近期疗效两组分别为：完全缓解(CR)率11％、23％，部分缓解(PR)率60％、71％，无进展(NK)率29％、6％。两组1 2级急性放射性肺炎发生率37％、19％、1 2级急性放射性食管炎发生率52％、35％。两组间1 2级急性放射性肺炎和急性放射性食管炎有显著性差异。结论：三雏适形加量放射治疗在纵隔转移肿瘤中有良好的应用，近期疗效好于普放治疗，远期疗效有待进一步观察。     

模拟先天性髋脱位截骨术的研究

目的:建立个性化先天性髋脱位(CDH)的计算机三维交互模型和三维骨刀模型,模拟截骨。方法:利用螺旋体积CT获得CDH患儿髋关节扫描数据,采用图象滤波技术简化大容量CT数据。用B+树组织按Marching Cubes方法完成CDH三维表面模型、骨刀模型的重构。通过对B+树的不完全遍历和回溯,定位表面模型间的交点并分割髋关节模型。结果:邻域平均滤波器化简原始数据效果满意。按改进的Marching Cubes方法完成的CDH三维模型、骨刀模型重构,保证了生成三维重构的三角面片间、曲面间相互连通,可快速定位表面模型间的交点;利用层次包围盒和三维相关信息实现快速切割;通过对参数的修改,可有效的描述平面骨刀和球面骨刀模型的位置变换。结论:本研究建立的CDH计算机三维交互模型和三维骨刀模型,结构精确、真实、可靠,建模效率高及切割速度快。可满足实时交互的需要。初步实现了对未知体三维交互模型任意位置的平面切割、球面切割、拾取和拼合。为进一步实现模拟手术的研究奠定了基础。     

基于仿真切割的陶瓷晶粒三维形貌特征评价系统

本文通过仿真切割的方法建立晶粒三雏空间形貌特征与其随机截面形貌参数之间的关系。在实际应用时，利用上述方法建立的关系，通过测量材料切面上的晶粒截面参数来查询其三雏形貌特征。晶粒三雏形貌特征的几何模型是基于特定晶体的生长习性而建立的，并考虑到因生长环境的不同而可能引起形状的变化，因而更接近特定的实际晶粒。晶粒截面各种参数均可通过界定晶粒截面边界来获得。     

基于计算机视觉和粒子系统的三维云模拟

云是很常见的一种自然现象，真实感云的模拟是计算机图形学领域具有挑战性的研究课题。文章提出了一种基于计算机视觉和粒子系统的三维云建模方法。首先利用计算机视觉技术从现有的二维云图像中提取云的三维信息，然后利用粒子系统填充该三维空间，最后通过纹理映射和Billboard技术实现三维云的绘制。与以往云建模方法相比，该方法简单、实用，适用于模拟不同种类的云，如层云、积云、卷云等。     

基于工业CT断层图像的三维可视化

工业CT图像三维可视化能够对工业构件提供真实、直观的反映。体绘制技术可以显示工业CT三维数据的整体特征和内部细节信息。根据光线投射算法的特点，采用对原始数据场进行最大熵原则的预处理的方法，加快了绘制速度，在一定程度上改进了光线投射算法，取得了较好的显示效果。     

肺癌三维适形放疗计划设计的剂量学分析

 目的 比较肺癌常规二维放疗和三维适形放疗计划的剂量学特征。方法 采用美国RAHD三维放疗计划系统对20例肺癌术后患者分别进行常规二维及三维适形放疗计划设计，根据剂量-体积直方图等参数对两者剂量学特征进行评估分析。结果 与常规二维计划相比较，三维适形放疗计划的靶区适形度好，剂量分布均匀；全肺受照体积V20及脊髓最大剂量均明显低于二维计划。结论 肺癌患者采用三维适形放疗技术，可提高靶区剂量，进而有助于提高肿瘤局部控制率，同时能有效地保护靶区周围正常组织和器官。     

鼻咽癌的三维适形放射治疗

介绍了鼻咽癌三维适形放射治疗的一般概念，以及鼻咽癌二维放射治疗的缺陷和三维适形放射治疗的可能优势；几种靶区的划定方法，并阐述了几种设计和实施鼻咽癌三维适形放射治疗的方法和步骤。通过剂量学和临床治疗结果的比较，展示出三维适形放射治疗在提高鼻咽癌局部区域控制率和保护正常组织器官方面比传统二维放射治疗有着明显的优势，同时也提出进行三维适形放射治疗时存在的一些问题。     

食管癌三维适形放射治疗

三维适形放射治疗是目前我国临床运用广泛的精确放射治疗方式之一，尤其近10年来，三维适形放射治疗在提高局控率和生存率方面取得了长足进步。本文对近5年来国内多家医院食管癌三维适形放射治疗方法进行综述，介绍目前食管癌三维适形放射治疗在剂量以及分割方式、适应症选择以及并发症控制、单一的三维适形放射治疗以及多种治疗手段的综合运用上存在不同的见解。     

三维适形放疗联合三苯氧胺治疗恶性脑胶质瘤术后患者的疗效观察

目的观察三维适形放疗联合三苯氧胺治疗恶性脑胶质瘤术后患者的疗效及不良反应。方法 50例恶性脑胶质瘤术后患者随机分为三维适形放疗联合三苯氧胺组(治疗组)和单纯三维适形放疗组(对照组),每组25例。三维适形放疗采用6MV X线,2Gy/次,1次/d,每周5次,DT56⁶0Gy。治疗组同步口服三苯氧胺,从放射治疗第1天开始,连服2个月。结果治疗组和对照组的1、2年生存率分别为64.0%、32.0%和36.0%、8.0%(P<0.05)。三苯氧胺主要不良反应为血栓栓塞,发生率为5.0%。结论三维适形放疗联合三苯氧胺能提高恶性脑胶质瘤术后患者的生存率,且未增加毒性反应。     

三维适形放疗治疗食管癌食管气管沟淋巴结转移的疗效分析

目的回顾性分析食管癌食管气管沟淋巴结转移的三维适形放疗疗效。方法对42例食管癌食管气管沟淋巴结转移病例行三维适形放疗,其中常规分割24例,2．0Gy／次,1次／天,5次／周,共32～34次;大分割18例,2．5～3．0Gy／次,1杉天,5黜周,共20-25次。结果42例患者均顺利完成治疗,近期疗效为完全缓解（CR）12例,部分缓解（PR）21例,无变化（NC）9例,总有效率（CR＋PR）78．6％。1、3、5年生存率分别为66．7％、26．2％、9．5％。急性放射性食管炎、气管炎1、2级反应发生率为47．6％,3、4级反应发生率为40．5％。结论三雏适形放疗是治疗食管癌食管气管沟淋巴结转移的较为有效的手段。     

3-D portal image analysis in clinical practice: an evaluation of 2-D and 3-D analysis techniques as applied to 30 prostate cancer patients

Purpose: To investigate the clinical importance and feasibility of a 3-D portal image analysis method in comparison with a standard 2-D portal image analysis method for pelvic irradiation techniques.

Methods and Materials: In this study, images of 30 patients who were treated for prostate cancer were used. A total of 837 imaged fields were analyzed by a single technologist, using automatic 2-D and 3-D techniques independently. Standard deviations (SDs) of the random, systematic, and overall variations, and the overall mean were calculated for the resulting data sets (2-D and 3-D), in the three principal directions (left–right [L-R], cranial–caudal [C-C], anterior–posterior [A-P]). The 3-D analysis included rotations as well. For the translational differences between the three data sets, the overall SD and overall mean were computed. The influence of out-of-plane rotations on the 2-D registration accuracy was determined by analyzing the difference between the 2-D and 3-D translation data as function of rotations. To assess the reliability of the 2-D and 3-D methods, the number of times the automatic match was manually adjusted was counted. Finally, an estimate of the workload was made.

Results: The SDs of the random and systematic components of the rotations around the three orthogonal axes were 1.1 (L-R), 0.6 (C-C), 0.5 (A-P) and 0.9 (L-R), 0.6 (C-C), 0.8 (A-P) degrees, respectively. The overall mean rotation around the L-R axis was 0.7°, which deviated significantly from zero. Translational setup errors were comparable for 2-D and 3-D analysis (ranging from 1.4 to 2.2 mm SD and from 1.5 to 2.5 mm SD, respectively). The variation of the difference between the 2-D and 3-D translation data increased from 1.1 mm (SD) for zero rotations to 2.7 mm (SD) for out-of-plane rotations of 3°, due to a reduced 2-D registration accuracy for large rotations. The number of times the analysis was not considered acceptable and was manually adjusted was 44% for the 2-D analysis, and 6% for the 3-D analysis.

Conclusion: True 3-D analysis of setup errors for a group of 30 patients with prostate cancer demonstrated that setup rotations are rather small. The deformation of the projected anatomy in portal images caused by out-of-plane rotations leads to a reduced 2-D registration accuracy. For rotations larger than 3° this effect can be quite pronounced, making 3-D registration the preferred method. Furthermore, the automatic 3-D registration has a higher success rate, most likely because this technique uses more information compared to the 2-D method.     

Pathological assessment of intraductal spread of carcinoma in relation to surgical margin state in breast-conserving surgery

BACKGROUND: Spreading of carcinoma has been considered to be a prognostic factor for local failure after breast-conserving therapy. The extensive intraductal component (EIC) was defined as when the component of intraductal carcinoma constitutes more than 25% of the primary tumor with intraductal foci. However, the definition of EIC was based on the predominance of intraductal component surrounding the invasive lesions and not on the segmental anatomy. We designated carcinoma extension as the intraductal spread of carcinoma (ISC) along with the duct-lobular system by three-dimensional (3-D) reconstruction analysis. This study was initiated to simplify the method of two-dimensional (2-D) pathological examination based on 3-D mapping. METHODS: Thirty-four specimens from breast cancer patients were subjected to 3-D reconstruction. We investigated the correlation between actual extension of intraductal carcinoma and EIC defined by 2-D examination or ISC grading defined by 3-D reconstruction. Furthermore, using another 62 histological mappings, we investigated how correctly the simplified 2-D method using several paraffin blocks reflected the actual carcinoma spread and margin state. RESULTS: Carcinoma extension over 2 cm was observed in 64% specimens that were EIC positive and 26% specimens that were EIC negative. In contrast, according to the ISC grading defined by 3-D reconstruction, none of the specimens with a low grade of ISC demonstrated carcinoma extension over 2 cm. Carcinoma extension over 2 cm was observed in 71% of specimens with a high grade of ISC, thus demonstrating a correlation between carcinoma extension and ISC grading. In addition, the simplified 2-D method using only several blocks reflected both the 3-D ISC grading and surgical margin state. CONCLUSIONS: We conclude that ISC grading correlates with carcinoma extension and surgical margin state. From a clinical point of view, the simplified 2-D examination using paraffin blocks may contribute to routine surgical pathology in evaluating the degree of carcinoma extension in breast-conserving therapy.     

Stereoscopic presentation of computed tomography and magnetic resonance images

This technical note describes a direct and simple method of stereoscopically presenting three-dimensional (3-D) CT and MRI volumetric models. This method has negligible cost both in monetary terms and in extra processing time, is extremely accessible, easy to learn and apply and can be effectively used in the absence of any sophisticated equipment. It has the potential to greatly boost the communications value of many complex studies where 3-D models are already normally generated.     

一种视频编码中去低照度噪声方法

提出了一种消除低照度、中慢速运动视频序列中噪声的方法。在编码的不同阶段采取不同的滤波方法：在预测编码阶段，对于帧内块利用空域相关信息采取高斯去噪方法，对于帧间块利用时域相关信息采取运动补偿去噪策略；在变换编码阶段，采取8×8整数DCT变换的方法。在量化中去除高频噪声。实验结果表明了方法的有效性，降低了码流。     

Histogram reduction method for calculating complication probabilities for three-dimensional treatment planning evaluations

New tools are needed to help in evaluating 3-D treatment plans because of the large volume of data. One technique which may prove useful is the application of complication probability calculations. A method of calculating complication probabilities for inhomogeneously irradiated normal tissues is presented in this paper. The method uses clinical estimates of tolerance doses for a few discreet conditions of uniform partial organ irradiation, an empirical fit of a continuous function to these data, and a technique (the effective volume method) for transforming nonuniform dose-volume histograms into equivalent uniform histograms. The behavior of the effective volume histogram reduction method for various boundary conditions is reviewed. The use of complication probabilities in evaluating treatment plans is presented, using examples from an NCI 3-D treatment planning contract.     

The microRNA expression associated with morphogenesis of breast cancer cells in three-dimensional organotypic culture

Three-dimensional organotypic culture using reconstituted basement membrane matrix Matrigel (rBM 3-D) is an indispensable tool to characterize morphogenesis of mammary epithelial cells and to elucidate the tumor-modulating actions of extracellular matrix (ECM). microRNAs (miRNAs) are a novel class of oncogenes and tumor suppressors. The majority of our current knowledge of miRNA expression and function in cancer cells is derived from monolayer 2-D culture on plastic substratum, which lacks consideration of the influence of ECM-mediated morphogenesis on miRNAs. In the present study, we compared the expression of miRNAs in rBM 3-D and 2-D cultures of the non-invasive MCF-7 and the invasive MDA-MB231 cells. Our findings revealed a profound difference in miRNA profiles between 2-D and rBM 3-D cultures within each cell type. Moreover, rBM 3-D culture exhibited greater discrimination in miRNA profiles between MCF-7 and MDA-MB231 cells than 2-D culture. The disparate miRNA profiles correlated with distinct mass morphogenesis of MCF-7 and invasive stellate morphogenesis of MDA-MB231 cells in rBM 3-D culture. Supplementation of the tumor promoting type I collagen in rBM 3-D culture substantially altered the miRNA signature of mass morphologenesis of MCF-7 cells in rBM 3-D culture. Overexpression of the differentially expressed miR-200 family member miR429 in MDA-MB231 cells attenuated their invasive stellate morphogenesis in rBM 3-D culture. In summary, we provide the first miRNA signatures of morphogenesis of human breast cancer cells in rBM 3-D culture and warrant further utilization of rBM 3-D culture in investigation of miRNAs in breast cancer.     

1,25-Dihydroxycholecalciferol (1,25-D3) inhibits the growth of squamous cell carcinoma and down-modulates p21(Waf1/Cip1) in vitro and in vivo.

1,25-Dihydroxycholecalciferol (1,25-D3) has significant antitumor effects in the murine squamous cell carcinoma (SCC) tumor model in vitro and in vivo. We investigated the basis for this antiproliferative activity and found that, in vitro, 1,25-D3 administration is associated with altered expression of cell cycle regulatory proteins, treatment results in retinoblastoma dephosphorylation, decreased expression of p21(Waf1/Cip1) (p21) mRNA and protein, and increased expression of p27Kip1 (p27) mRNA and protein. Dexamethasone, which acts synergistically with 1,25-D3 to inhibit SCC proliferation, enhanced 1,25-D3-induced down-modulation of p21 without affecting the ability of 1,25-D3 to increase p27 expression. 1,25-D3 did not induce cleavage of poly(ADP-ribose) polymerase. These in vitro data suggest that 1,25-D3 exerts antitumor activity in SCC by perturbing cell cycle progression rather than by inducing apoptosis. In vivo, a 1,25-D3 treatment regimen that results in a decrease in SCC tumor volume is associated with a statistically significant decrease in intratumoral p21 expression. p21 expression is not changed in tumors isolated from control animals or animals treated with a nontherapeutic dose of 1,25-D3. Intratumoral p27 levels were not modulated by 1,25-D3 treatment. Thus, both in vitro and in vivo, 1,25-D3-mediated growth inhibition is associated with p21 down-modulation.     

Evaluation of synergism by a novel three-dimensional model for the combined action of cisplatin and etoposide on the growth of a human small-cell lung-cancer cell line,SBC-3

Although the combination of cisplatin and etoposide has been used as standard therapy for small-cell lung cancer, it is difficult to demonstrate combination effects between cisplatin and etoposide in vitro. We therefore adopted a 3-dimensional (3-D) model to analyze the combination effects of anticancer drugs, and compared the results of analysis by the new 3-D model with those obtained from traditional 2-D models for the cisplatin-etoposide combination. In this study, using a human small-cell lung-cancer cell line (SBC-3), 3-D model analysis clearly identified a relationship depending on the concentrations of both drugs, and demonstrated that peak synergy occurred at the higher concentrations of cisplatin and etoposide. Antagonistic interactions were noted with a nadir at low concentrations of etoposide and cisplatin. In contrast, 2-D models such as combination index and isobologam analysis fail to characterize the complex interactions between cisplatin and etoposide, since their joint effects are concentration-dependent. Combination index (CI) plots show that synergy is evident only for molar ratios of cisplatin:etoposide of 2:1 to 1:5. On isobologram analysis, synergy could be detected when great inhibitory effects on cell growth were present (high endpoint), but not with small inhibitory effects (lower endpoints). Thus, either synergy or antagonism may occur, but depend on the selection of variables, such as the molar ratios or the endpoints chosen for the experiments. This could explain the inconsistency in the in vitro combination effects reported to date. The 3-D model, which compensates for the above deficiencies of 2-D models, can facilitate rigorous analysis of drug interactions over the entire clinical dose range, using microcomputers and sophisticated graphics programs. This direct and pragmatic method offers investigators a practical new tool with which to analyze drug combinations for cancer chemotherapy. Int. J. Cancer 71:311-319, 1997. © 1997 Wiley-Liss Inc.     

New diagnostic imaging of gastointestinal tumors: a preliminary study of three-dimensional tumor structure and volumetry

BACKGROUND: The aim of the present report was to present preliminary results of the pre-operative evaluation of three-dimensional tumor structure and volumetry using three-dimensional computed tomography (3-D CT) and three-dimensional endoscopic ultrasonography (3-D EUS). MATERIALS AND METHODS: Diagnostic imaging was performed for 2 patients (one with gastric cancer, one with a rectal tumor) using virtual endoscopy, 3-D CT for the patient with gastric cancer and 3-D EUS for the patient with the rectal tumor, for the pre-operative evaluation of tumor structure and volumetry. Computer-generated image analysis of resected tumors was also performed. RESULTS: The gastric tumor was successfully visualized using 3-D CT and the rectal tumor was successfully visualized using 3-D EUS. The values obtained for volume of the stomach tumor, calculated using 3-D CT and resected materials, were 15.1 cm3 and 11.4 cm3, respectively. The values obtained for volume of the rectal tumor, calculated using 3-D EUS and resected materials, were 2.3 cm3 and 3.9 cm3, respectively. CONCLUSION: The present findings demonstrate that clinically useful results can be obtained by using 3-D CT and 3-D EUS for the pre-operative evaluation of 3-D tumor structure and volumetry of gastrointestinal tumors. We expect that further studies of these methods will lead to the establishment of new diagnostic criteria for gastrointestinal tumors based on tumor volume in the near future.