一种调强放射治疗计划系统的研究

调强放疗（IMRT）是一种先进的适形放射治疗方法。它能提高放射治疗的治疗增益比,促进肿瘤的局部控制,本文介绍了一种调强放射治疗计划系统,它采用科学的精确的计算方法进行笔射束的剂量计算,采用反计划实现治疗计划的制定。     

议瓦里安23EX多叶光栅供电

美国瓦里安直线加速器是目前国际上先进的放射治疗专用设备,具有满足临床需要的光子线和电子线多档能量组合.系统不仅可开展常规放射治疗技术,还具有目前国际先进精确的图像引导放射治疗技术（IGRT）,调强放射治疗技术（IMRT）、快速旋转容积调强技术（Rapid Arc）及动态自适应放疗技术（DART）等.通过高精度和高稳定的剂量率为肿瘤患者提供全身各部位精确有效的治疗.其中MLC对于试型、调强治疗尤为重要.     

CT模拟定位系统

随着三维适形放疗（3DimensionalConformalRa－diationTherapy，3DCRT）技术的兴起和发展，特别是放射治疗技术主流的调强放疗（IntensityModulationRadiationTheraph，IMRT）的发展，集放射诊断、放疗计划、模拟定位和模拟治疗于一体的CT模拟定位系统（CTSimulationLocalizationSystem）在放射治疗中的作用与地位越来越重要，它将大大地改善和提高放射治疗的设计与照射质量。三维适形放疗使得高剂量区分布的形状在三维方向上与肿瘤靶区的形状一致，这要求有复杂而精确的放疗计划，而精确的放疗计划必须要求精确的三维图像进行空…     

螺旋断层放疗系统原理及其应用

目的：研究螺旋断层放疗系统的结构及治疗工作原理，初步探讨该设备在临床中的应用价值。方法：对国内第一台螺旋断层放疗设备系统展开研究，初步探讨螺旋断层与传统放疗技术相比在临床应用中的技术优势。结果：螺旋断层放疗系统是目前一种具有全新治疗技术的设备，其在CT的基础上融合直线加速器技术而得到了独一无二的新型组合，同时具备2种机器的功能特性。该系统已被证明了既能实现优异的调强放射治疗．又能做出卓越的图像引导放射治疗，甚至剂量引导下的放射治疗技术，开创了调强放射治疗（IMRT）计划、治疗实施和验证为一体。结论：图像引导下放射治疗（IGRT）和调强放射治疗技术，开辟了肿瘤放射治疗的新领域，它们在更好地控制肿瘤的情况下改善了患者的生存质量。Tomotherapy作为从一开始就被设计用来进行IGRT和IMRT治疗的设备．一直站在了技术发展的最前沿．而且将IGRT和IMRT技术发展得更为简单而高效。     

宫颈癌三维适形调强放射治疗摆位和照射技术

目的探讨宫颈癌三维适形调强放射治疗（IMRT）的治疗摆位、照射技术及放疗质量保证。方法采用体膜（或真空膜）固定体位，通过CT（或MRI）确定等中心点。调强治疗计划和实施由NOMOS公司Peacock系统完成，利用Varian600C直线加速器6MV—X线，采用1cm或2cm步进式断层技术（Peacock MiMiC）进行治疗摆位和照射。结果IMRT与传统的放射治疗技术相比，显著降低了正常组织和器官（如小肠、膀胧和直肠）的受照剂量，同时增加了肿瘤靶区剂量，肿瘤消退率100％。结论宫颈癌三维适形调强放射治疗（IMRT），剂量分布理想，局部控制较好，疗效确切，更好的保护正常组织，减少消化道、泌尿系和骨髓的毒性反应。     

肿瘤放疗新技术——容积弧形调强放射治疗技术

放射治疗是治疗恶性肿瘤的主要手段。目前,以医用直线加速器为代表的放疗设备及其应用技术呈现出前所未有的快速发展,各种精确放疗已成为放射治疗的主流。容积弧形调强放射治疗技术（VMAT）是在调强适形放射治疗（IMRT）基础上的放疗最新技术,本文介绍了VMAT技术的特点和优势。     

局部进展期胰腺癌综合治疗现状

胰腺癌是恶性程度高且预后极差的消化系统肿瘤。对无法切除的局部进展期肿瘤,主要采用局部外放射治疗联合全身化疗的多学科综合治疗。与放射治疗同步应用的化疗药物目前主要包括5-FU、卡培他滨与吉西他滨等。放疗技术目前推荐三维适形放射治疗或调强放疗（IMRT）。IMRT不仅可减低周围正常组织的照射剂量,还可提高肿瘤靶区的照射剂量,实现剂量递增。     

遗传算法用于IMRT逆向计划优化

调强放疗(IMRT)是一种先进的适形放射治疗方法,能提高放射治疗的治疗增益比,促进肿瘤的局部控制。介绍了遗传算法应用于IMRT逆向计划优化的算法模型和模拟结果     

碳纤维腹板俯卧位固定技术在直肠癌调强放疗中的应用

1目的调强放射治疗技术(intensity-modulated radi-ation therapy,IMRT)是近些年发展起来的一种先进的精确的放射治疗技术,整个靶区体积内剂量分布更均匀,较大幅度增加了肿瘤的剂量,提高了肿瘤控制率,使周边正常组织免受过量损伤。在实际工作中,直肠癌调强放疗可显著降低肿瘤局部复发     

专题论坛一-数字影像技术和精确放射治疗：调强放射治疗的临床应用

适形调强放射治疗(Intensity Modulated Radiation Therapy，IMRT)是近十年在三维适形放射治疗的基础上发展起来的一种崭新的放射技术，IMRT的设计主要致力于受常规放疗的限制部分、同时又要对肿瘤组织的照射不能限制，理论上讲、如果肿瘤能作放射治疗、那么IMRT将对许多肿瘤的治疗都会产生深远的影响，它可以根据肿瘤的形状给予致死剂量的照射，而对肿瘤邻近的正常组织器官接受较低的剂量照射。     

Relationship of epithelial ovarian cancer to other malignancies within families

The relationship of family history of cancer of the breast, colon/rectum, cervix, endometrium, lung, and thyroid to the risk of epithelial ovarian cancer was investigated in a large population-based case-control study. The data consisted of family histories from 493 epithelial ovarian cancer cases and 2,465 controls aged 20-54 years. After controlling for potential confounders, risk for epithelial ovarian cancer was found to be significantly elevated among women reporting breast cancer and colo/rectal cancer in a first-degree relative. Adjusted odds ratios were 1.5 (95% CI = 1.1-2.1) and 1.9 (95% CI = 1.1-3.3), respectively. None of the remaining four types of cancer was found to be statistically associated with the risk of epithelial ovarian cancer. However, when histologic subtypes of epithelial ovarian cancer were considered, a family history of breast cancer was found to be associated with an elevated risk of endometrioid ovarian cancer (odds ratio = 2.3; 95% CI = 1.1-4.7), as was a family history of endometrial cancer (odds ratio = 2.7; 95% CI = 1.0-6.9). The results are considered in the context of other studies of familial patterns of cancer and are compared with published findings concerning the occurrence of multiple primary cancers in the same individual. The findings indicate that further study is warranted regarding possible genetic relationships between epithelial ovarian cancer and cancers arising in other organs.     

甲醛接触工人肿瘤死亡流行病学

采用回顾性队列死亡率研究方法,凡1977年12月31日前在5家脲醛和/或酚醛树脂生产工厂工作满一年以上的工人进入队列,失访率低于5%。观察至1987年12月31日止接触组(1316人男性813人,人年19400)。男性接触组全肿瘤,肺癌、肝癌、胃癌、膀胱癌队列。具统计学意义的超额死亡,男性接触者为全肿瘤,脑瘤、肺癌、胃癌和膀胱癌,女性为全肿瘤,肺癌和肝癌。超额死亡危险随接触工龄延长而增加,三例鼻癌均发生于接触组,工龄在10以上。纠正了吸烟因素后,接触组死亡率高于对照组。     

扬中市上消化道癌地区聚集性研究

目的：探讨恶性肿瘤高发区江苏省扬中市内部是否存在上消化道癌地区聚集性并分析可能的原因，方法：利用扬中市肿瘤发病登记报告系统提供的资料分析各镇胃癌，食管癌，肝癌发病情况，观察地区间差异，并与各镇土壤微量元素硒含量进行相关性分析。结果：Poisson分布配合适度X^2检验；X^2胃癌＝190．4986，X^2食管癌＝103．3659，X^2肝癌＝59．1429，P＜0．001），提示扬中市各镇胃癌，食管癌，肝癌等发病率实际分布与理论分布不一致，其中以三跃镇最高发，三茅镇最低发。胃癌，肝癌发病率与土壤微量元素Se浓度呈负相关，相关系数分别为－0．7312和－0．7091。结论：扬中市上消化道癌分布存在地区聚集性，地质环境的影响可能是其中一个重要因素。     

Formaldehyde and cancer: a critical review

Formaldehyde is a naturally occurring chemical found in every human cell. It has been in widespread use for over a century as a disinfectant and preservative agent, and more recently in a number of industrial products. Animal studies indicate that formaldehyde is a rat carcinogen at high levels (>_ 10 ppm) of exposure. Results for lower levels of exposure show less clear-cut carcinogenic effects, and some species, such as mice and hamsters, appear much less sensitive to any carcinogenic potential of formaldehyde. Epidemiologic studies of the effects of formaldehyde exposure among humans provide inconsistent results. In general, these nonexperimental studies suffer from a number of biases and flaws. The epidemiologic studies fall into three categories: formaldehyde industry workers, case-control studies, and studies of professionals who use formaldehyde. Studies of industry workers with known exposure to formaldehyde report little evidence of an excess cancer risk. Nasopharyngeal cancer, the one cancer considered most strongly linked to formaldehyde among humans, appears after close examination to be likely a result of multiple subgroup analyses and misclassification. The case-control studies usually lack any direct measure of formaldehyde exposure and rely instead on hypothetical exposure based on occupational exposure matrices. Most of these studies, after adjustment for confounding factors, fail to find a significant association with putative formaldehyde exposure. The studies that do report a significant association suffer from methodologic problems limiting their interpretation. The investigations of professionals who use formaldehyde in their work, such as embalmers, pathologists, and anatomists, have the advantage over case-control studies of a much higher likelihood of actual formaldehyde exposure. The findings among these individuals, however, are at odds with those of the other two groups, with excesses of deaths from cancer of the brain and leukemia. The inconsistency between professionals and formaldehyde industry workers in cancer risk patterns suggest that formaldehyde is not the etiologic agent. When the epidemiologic data on formaldehyde and human cancer are examined in light of the widely accepted causal criteria of strength of the association, consistency and specificity of results, dose-response effects, and biologic coherence and plausibility, the studies published so far fail to provide credible causal evidence.     

A mixed methods,community‐based investigation on women's cancer awareness in Haiti

Despite a high number of cases, the awareness of breast and cervical cancer in Haiti and other low and middle‐income countries (LMICs) remains relatively unknown. The objective of the research was to understand perceptions and attitudes towards breast and cervical cancer in Haiti through community‐engaged research. We report Haitians perceptions of breast and cervical cancer symptoms, diagnosis, complications, treatment, community support and access to medical services. Five non‐governmental Haitian organisations performed a large survey across the country of Haiti in 2015. The survey and focus groups addressed demographics, reported knowledge of women's cancer, infrastructural issues and barriers to care, communication and media channels. The mixed quantitative and qualitative surveys with open‐ and closed‐ended questions were administered to 414 participants aged 13–65 (75% of whom were women). A separate, smaller survey on community support and gender‐based violence was conducted in 50 breast cancer patients and survivors as well. The quantitative data indicate low levels of knowledge about cancer across all geographic regions of the country amongst men and women. After coding participants' qualitative responses as “accurate” or “not accurate”, we determined the percentage of accurate responses related to knowledge. Data are reported broken down by geographic region, education, economic status and sex. Approximately one in five respondents reported knowing how a woman contracts breast or cervical cancer. Only 30% reported to know complications of breast cancer and 22% the complications of cervical cancer. When asked if they knew where to get a test for breast cancer, 20% said yes and 33% said they knew where to get a test for cervical cancer. The wealthiest and best educated generally had the most knowledge, but the poorest consistently had the second best. Forty percent of cancer patients reported to be victims of on‐going gender‐based violence. Further investigation should be undertaken examining the role of gender‐based violence and to address the knowledge of the working poor.     

Cancer incidence among laboratory workers in biomedical research and routine laboratories in Israel: Part I-the cohort study

BACKGROUND: Laboratory work is associated with exposure to a mixture of carcinogens. METHODS: The cohort is comprised of 4,300 laboratory workers. Cancer incidence was followed from 1960 to 1997. RESULTS: A total of 230 cases were included in the cohort. The overall cancer standardized incidence ratio (SIR) was 1.04 (0.91-1.18). When a 20-year latency was introduced, SIR was increased significantly: 1.35 (1.13-1.61). Among routine workers and researchers, SIR was elevated significantly for the total population and for women, when a 20-year latency was introduced. SIR was also elevated significantly in research, routine, bacteriology and virology, and isotope laboratories. With respect to specific sites, significantly increased SIR was observed in breast, ovary, and thyroid cancer among women; and prostate cancer, leukemia, and melanoma among men. CONCLUSIONS: We suggest that work in research and biomedical laboratories might involve an increased risk of certain types of cancer. Am. J. Ind. Med. 44:600-610, 2003.     

Cancer incidence among laboratory workers in biomedical research and routine laboratories in Israel: Part II-nested case-control study

BACKGROUND: A case-control study nested within a cohort study of biomedical laboratory workers was conducted to examine whether the excess cancer morbidity that we found can be explained by exposure to a particular group of substances, taking into consideration potential confounders. METHODS: The study population included 163 cases and two matched control groups: laboratory workers (311) and general population (448) workers. RESULTS: Multiple conditional regression analysis showed that working in research laboratories involved an increased risk of cancer generally among women [risk ratio 2.2 (1.2-4.3)], and of breast cancer particularly [risk ratio 2.3 (1.1-4.7). Seventy-six percent (76%) of breast, 87% of thyroid, 60% of ovary and prostate, 94% of melanoma, and 50% of leukemia cases were ever exposed to at least one known human carcinogen. CONCLUSION: Our results exclude the possibility that the excess cancer morbidity was related to personal risk factors but they may be explained by exposure factors. Am. J. Ind. Med. 44:611-626, 2003.