锥形束CT图像分析鼻咽癌临床靶区外放的研究

目的:利用在线采集的千伏级锥形束CT(cone beam computed tomo-graphy,CBCT)图像,分析鼻咽癌放疗过程中摆位误差的大小,从而获得临床靶区(clinical target volume,CTV)的合理外放边界.方法:16例鼻咽癌患者均采用三维适形放疗或调强放疗.放疗过程中以传统的热塑面膜固定头颈部,激光灯摆位.分次放疗前患者在治疗床上进行CBCT扫描,并将CBCT图像与计划CT图像进行在线配准,根据配准得到的平移矢量调整治疗床的位置,从而修正摆位误差,并分别记录各个方向上平移矢量.结果:16例患者共计160组配准数据.为满足至少95%放疗分次的CTV接受处方剂量,计划靶区各方向上的外放间距均为4 mm.结论:鼻咽癌三维适形调强放疗时具有一定的摆住误差.基于千伏级CBCT图像分析的在线校正方法能减小该摆位误差,并有助于确定合适的CTV外放.     

头颈部肿瘤螺旋断层放疗中的CTV-PTV边界大小分析

目的 探讨螺旋断层放射治疗头颈部肿瘤在六维方向上的摆位误差,并以此误差分析计划靶区(planning target volume,PTV)到临床靶区(clinical target volume,CTV)的预留边界大小.方法 应用兆伏(MV) CT于放疗实施前对24例头颈部肿瘤患者进行扫描,通过自适应软件对重建的容积图像与计划CT扫描图像进行自动匹配和手动调节,记录六维方向上的摆位误差值并调整床位后给予放疗.对记录数据进行统计学分析,计算临床靶体积到计划靶体积的外放边界.结果 24例患者共行327次MVCT扫描,其中摆位偏差在左右、头足和前后方向上的平均平移误差分别是(-0.88 ±2.37)mm、(-1.18±2.82)mm和(1.41±1.82) mm;在倾斜、旋转和偏离三个旋转方向上平均误差分别是(0.15±0.54)°、(0.27±0.96)°和(0.01 ±0.52)°.PTV-CTV外扩边界分别是X轴方向为3.42 mm、Y轴方向为4.33 mm、Z轴方向为4.09 mm.结论 MVCT图像引导下自适应功能在头颈部肿瘤放射治疗中可以有效修正患者的摆位误差,在保证CTV-PTV边界3～5 mm绝对安全的前提下,也保证了单次大剂量放疗肿瘤区域的剂量准确性和对正常组织的充分保护.     

前列腺癌TomoTherapy治疗过程中分次间及分次内误差研究

为了探讨MVCT在线图像引导技术分析前列腺癌螺旋断层放疗过程中分次间误差及分次内误差,并计算CTV-PTV的外扩边界,对10例早期前列腺癌患者行螺旋断层调强放疗.靶区为前列腺及精囊,剂量76 Gy/34次.所有患者每次治疗前及治疗后均行MVCT扫描,10例患者共行MVCT扫描680次.分次间误差在左右方向最小,≤5 m...     

探讨鼻咽癌调强计划剂量分布和验证通过率受摆位误差的影响

目的 在鼻咽癌放疗中,通过锥形束计算机体层摄影术(CBCT)扫描得出摆位误差,探讨摆位误差对鼻咽癌调强计划剂量分布以及验证计划r通过率的影响.方法 选取25例鼻咽癌患者,每例患者在治疗期间进行10次CBCT扫描,共扫描250次.把扫描图像与计划CT图像进行融合配准得出X、Y、Z等3个方向的摆位误差,然后把摆位误差数据分别模拟回计划系统中的调强计划和验证计划中.重新计算调强计划分析肿瘤靶区和危及器官剂量的变化、重新计算验证计划并传回Delta4三维剂量验证软件中,分析验证计划r通过率的变化.结果 在X、Y、Z方向上的摆位误差为(-0.05±1.23)mm、(-0.48±1.66)mm、(0.59±1.23)mm.计划靶区的最大剂量(Dmax)比原计划高(P<0.05)、靶区98%的体积剂量和平均剂量比原计划低(P<0.05).脊髓、脑干、视神经、视交叉、晶体再计划的最大剂量和腮腺50%的体积剂量都比原计划高(P<0.05).验证计划各射野和总剂量的再r通过率比原r通过率低(P<0.05).结论 摆位误差使鼻咽癌在放疗中靶区剂量的减少和危及器官剂量的增加,造成治疗增益比的下降.而使验证计划r通过率的降低也反映出其对实际治疗的影响.因此放疗前的摆位误差校正是非常有必要的.     

头颈部肿瘤自适应放疗的研究进展

调强放射治疗(intensity-modulated radiation therapy,IMRT)是头颈部恶性肿瘤的重要治疗方法之一。但在IMRT过程中,摆位误差、解剖结构的移位及变形、肿瘤退缩或进展及形状改变等,可导致靶区和危及器官的照射剂量和体积出现“偏差”,影响IMRT的精确性。图像引导的放射治疗(image-guidedradiotherapy,IGRT)可部分纠正摆位误差,从而提高放疗精度,但不能解决非刚性误差以及解剖结构变化带来的剂量差异。自适应放射治疗(adaptive radiation therapy,ART)是在IMRT和IGRT基础上出现的新型放疗技术,能修正IMRT和IGRT靶区和危及器官的偏差。通过患者图像、剂量等反馈信息对原治疗计划重新优化和调整,这是一种基于反馈控制理论的治疗策略。其目的是使放射治疗更加精确化、个体化。     

Tomotherapy摆位误差修正的精度及其对PTV外放边界的影响

目的探讨Tomotherapy兆伏级CT(megavoltage CT,MVCT)摆位误差修正的精度及其对计划靶区(planning target volume,PTV)外放边界的影响。方法选取头颈部、胸部和腹部肿瘤患者各20例。每例患者治疗期间各随机选6次治疗,每次治疗前行MVCT扫描、配准,得到摆位修正前误差数据,摆位修正后再进行1次MVCT扫描、配准,得到修正后的误差数据,分析修正前和修正后误差分布情况,并计算MVCT摆位修正前、后因摆位误差引起的PTV外放边界大小。结果摆位修正后的摆位误差比修正前下降,所有部位修正后摆位误差的平均值均≤0.5 mm。在每次治疗前进行误差修正的情况下,所有部位因摆位误差引起的PTV外放边界均<2 mm。结论MVCT摆位误差修正可减小PTV外放边界大小,修正后精度非常高,可保证Tomotherapy治疗摆位的精度。     

分次间位置不确定性对宫颈癌调强放疗靶区结构累积剂量影响

目的 采用锥形束CT(CBCT)获取分次间宫颈癌调强摆位误差,分析摆位误差对靶区累积剂量偏差的变化。方法 对48例宫颈癌调强患者,全程696次CBCT获取摆位误差。将误差值输入治疗计划系统中,由摆位误差剂量叠加得到累积摆位误差剂量,通过偏差公式与标准计划剂量计算偏差百分比。结果 摆位误差造成等中心距离偏移0.58(0.36,0.80) cm。累积摆位误差剂量与标准计划剂量经WilCoxon检验存在不同的统计学差异。靶区剂量偏差均呈降低,在微分剂量体积直方图(DVH)呈负偏态,峰值降低。DVH图呈反S型向左偏移,斜率增大。靶区HI偏差由小到大为CTV1、CTV2、GTV/CTV、CTV3、CTVn、CTVall、GTVnd;靶区HI偏差均增大。结论 宫颈癌调强摆位误差对靶区累积剂量影响存在统计学差异,靶区累积剂量均降低,靶区剂量均匀性变劣。分次间位置不确定性导致靶区分次剂量增高或降低,对肿瘤细胞的生物效应和肿瘤复发有待进一步探讨。宫颈癌调强放疗,每次治疗前需进行CBCT位置校准以保证靶区各结构剂量准确性。     

适形和调强放疗摆位误差的个体化分析

0引言随着医学影像和放射物理的飞速发展,目前基于三维计划系统的精确放疗已成为目前临床放疗的成熟技术,患者体位的控制,其分次摆位的准确性是其中关键的环节。本文利用电子射野影像系统(electronic portal imaging device,EPID)技术寻找适形调强患者摆位误差的规律,探讨开展放疗患者摆位误差个体化测量的可行性,并进一步个体化外放靶区(PTV)。     

螺旋断层放疗系统调强放疗验证

目的 通过螺旋断层放疗系统一系列调强放疗验证方法的研究,探讨其调强放疗的质量保证验证方法是否可行.方法 采用断层放疗计划系统进行调强放疗计划设计.为实现其剂量验证,笔者采用圆柱形固体水模体、0.056cm3 AISL电离室及EDR2胶片来实现对计划进行绝对剂量及相对剂量验证.将剂最胶片和电离室分别置于模体中,调用患者治疗计划束流数据对模体进行模拟照射;由此得出轴向截面上的等剂量分布和点绝对剂量,与计划模体的等剂量曲线及计算剂量结果进行比对.束流照射前,利用调强放疗兆伏特CT对摆位模体实行图像引导,与计划系统中模体千伏特CT图像进行配准比较,实现验证模体摆位准确性.结果 轴向测得注量分布与断层放疗计划系统计算结果相一致,测量点绝对剂量测量的结果与计划系统的计算误差均在±3%以内.测量模体的摆位误差基本可保持在1mm以内,但由于床从摆位虚拟中心到束流中心之间存在垂直下降2mm的系统误差,需要在模体或患者摆位中予以考虑.结论 3个月临床实践证明断层放疗的调强放疗所采用上述质量保证措施是切实可行的,建立了其质最保证体系.     

利用锥形束CT图像分析非小细胞肺癌临床靶区外放的研究

目的 探讨非小细胞肺癌三维适形放射治疗临床靶区的外放范围。方法 8例非小细胞肺癌患者均采用三维适形放疗或调强放疗。分次放疗前、后患者在治疗床上进行锥形束CT扫描,并将锥形束CT图像与计划CT图像进行在线配准,根据配准得到的平移矢量调整治疗床的位置,从而修正摆位误差,并分别记录各个方向上平移矢量。结果 8例患者共计160组配准数据。如果放射治疗过程中未进行在线图像引导校正,在实际应用中临床靶区外放10.9 mm;如果每次放射治疗均进行在线图像引导校正,在实际应用中临床靶区外放2.2 mm。结论 非小细胞肺癌三维适形调强放疗时具有一定的摆位误差。基于锥形束CT图像分析的在线校正方法能减小该摆位误差,并有助于确定合适的临床靶区外放。     

Schwannomas of Head and Neck and Review of Literature

Benign nerve cell tumours have been given various names like schwannoma, neurilemmoma, neurinoma, neurofibroma, spindle cell tumours etc. Extra cranial head and neck schwannomas usually present as solitary and well-demarcated lesions. The lesion can cause secondary symptoms, such as nasal obstruction, dysphasia, and hoarseness, depending upon the location of the lesion. Fine needle aspiration cytology, CT scans, and MRI may be of limited help in the diagnosis of schwannomas. The treatment is complete surgical excision of the benign tumour and postoperative histopathological examination establishes the final diagnosis.     

A comparative study of knowledge and awareness of colorectal and breast cancerA comparative study of knowledge and awareness of colorectal and breast cancer

Aims: To assess and compare knowledge and awareness of colorectal cancer and breast cancer in a sample of the general population. Methods: Eleven hundred visitors to six different outpatient clinics, in a University Hospital, were given a study-specific questionnaire, based on educational material from the British Association of Cancer United Patients (CancerBACUP). The questionnaire consisted of 12 statements on the incidence, presentation, detection, treatment and prognosis of colorectal and breast cancer. Results: One thousand and sixty-eight individuals returned the questionnaire. One thousand and four completed questionnaires were analysed. The mean age (SD) of respondents was 50.1 (17.2) years, and the male to female ratio was 2:3. Respondents had read more about breast than about colorectal cancer (60.3%vs 32.4%,P <0.0001, McNemar's test). The proportion of correct answers for each statement on breast cancer was higher than for answers to corresponding items on colorectal cancer. Mean overall scores (95% CI) for breast and colorectal cancer were 88.1 (86.9, 89.2) and 64.4 (62.5, 66.3) respectively, the mean difference (95% CI) being 23.7 (22.0, 25.5). Scores were higher for breast cancer irrespective of age or gender. Conclusion: There is a low level of understanding of colorectal cancer in the general population when compared to breast cancer. This highlights the importance of public education in this common cancer.     

Quality of life and care in leukemia,myeloma and non-malignant disease. Opinions of patients and relatives,and effects of geography and time

In a questionnaire study 140 subjects answered 4200 questions in 1980 and 1986. They consisted of patients with myeloma, acute leukemia, lung carcinoma, and non-malignant disease and their relatives. In 22 additional cases the questionnaire was not answered. The results show that myeloma patients are less content with the general care than leukemia patients (P < 0.05). Similarly, relatives of deceased myeloma patients are less satisfied with the information given to them than relatives of deceased leukemia patients (P < 0.001). The information has improved with time, however, since the patients were more satisfied in 1986 than in 1980 (P < 0.001) and relatives of myeloma patients still alive were more satisfied than relatives of patients who had died earlier (P < 0.001).     

miRNA与肿瘤侵袭转移

目前,microRNA (miRNA)已成为肿瘤研究中最基本的参与者,主要通过与靶标基因3 'UTR(非翻译区)的完全或不完全配对,降解靶标基因mRNA或抑制其翻译,从而参与调控个体发育、细胞凋亡、增殖及分化等生命活动.miRNA作为调控基因表达的重要分子在肿瘤侵袭转移中的作用越来越受到重视,表明miRNA在肿瘤侵袭和转移中的作用机制具有重要的理论意义,同时也可为肿瘤的诊断和治疗提供新方法.本文就miRNA通过调控上皮间质转化及肿瘤干细胞导致肿瘤侵袭转移的最新研究进展作一综述.     

芦荟大黄素及芦荟提取物的诱变性和抗诱变性

目的:用L5178Y小鼠淋巴瘤细胞体外微核试验评价芦荟大黄素和芦荟提取物的诱变和抗诱变作用,为其安全性评价提供依据。方法:设溶剂对照、阳性对照和抗诱变对照,芦荟大黄素和芦荟提取物诱变和抗诱变试验各设4个剂量组,处理L5178Y细胞12 h后按常规方法进行体外微核试验分析。结果:较高浓度(6.67μg/ml)的芦荟大黄素可致微核细胞率增加,与对照组比较,差异有统计学意义(P0.05);而芦荟提取物未见此效应。在一定剂量范围内,芦荟大黄素(0.22～6μg/ml)和芦荟提取物(20～180μg/ml)对甲磺酸甲酯(MMS)所致微核细胞率均有一定程度的拮抗作用,与对照组比较,差异有统计学意义(P0.01)。结论:芦荟大黄素具有一定的诱变作用,而在本实验剂量范围内的芦荟提取物未见遗传毒性。两种受试物在一定范围内均能较好地拮抗MMS所致的染色体损伤。     

甲状腺手术的技巧及副损伤的预防和处置

鉴于甲状腺手术是普外科的常见手术，为求其日渐完美，以有益于病人，现根据作者的体会，并结合阅读相关文献，就其手术操作、喉返神经处理、甲状旁腺处理进行扼要阐述。     

甲胎蛋白与自噬在肝癌发生发展中的作用及其相互关系

甲胎蛋白（AFP）作为临床诊断肝癌最常用的肿瘤标志物,有抑制免疫、促进细胞生长、抑制癌细胞凋亡的作用。自噬是一种维持细胞生存的重要途径之一,其与肝癌的发生发展及治疗有着密切联系,对肝癌既有抑制又有促进作用。PI3K/AKT作为两者共有的信号通路,它们是否有着相互关系来促进肝癌的发展尚需进一步研究。     

Erythrocyte levels of cadmium and lead and risk of B-cell non-Hodgkin lymphoma and multiple myeloma

Cadmium and lead are persistent environmental toxins that are known or probable carcinogens, based on evidence for causality for nonhematologic cancers. Associations of these metals with risk of non-Hodgkin lymphoma (NHL) and multiple myeloma (MM) are unknown but biologically plausible. To examine the associations of circulating levels of lead and cadmium exposure with risk of B-cell NHL (B-NHL) and multiple myeloma, we conducted a nested case-control study among 299 incident B-cell NHLs and 76 MM cases within the Cancer Prevention Study-II Nutrition Cohort (CPS-II NC). Each case was incidence-density matched to two eligible controls on age, race, sex and blood draw date. Conditional logistic regression was used to estimate relative risks (RR) and 95% confidence intervals (CI) for lymphoid malignancies overall and stratified by subtype. We observed a significant positive association between high erythrocyte lead concentration and risk of lymphoid malignancies overall (RR = 1.16, 95% CI: 1.02-1.33 per 17.6 μg/L (1 standard deviation [SD])) and follicular lymphoma in particular (RR = 1.80, 95% CI: 1.15-2.80 per SD). In contrast, there was no association between erythrocyte cadmium and risk of B-NHL (RR = 0.89, 95% CI: 0.75-1.06 per 0.37 μg/L [1 SD]), or any B-NHL subtypes; but a strong inverse association with MM risk (RR = 0.59, 95% CI: 0.38-0.89, per SD). Results from our study suggest a positive association between erythrocyte lead level and risk of lymphoid malignancies and a possible inverse association between cadmium and myeloma. Additional research is needed to confirm and further explore these findings.     

Comparison of the Efficacy and Safety of Ceftibuten and Cefaclor in the Treatment of Pneumonia and Bronchiectasis

Summary

In a multicentre, international study of 187 adult patients with bacterial pneumonia or bronchiectasis, the safety and efficacy of a regimen of 200 mg ceftibuten administered twice-daily was compared with cefaclor given in a dosage of 500 mg three times a day. Of the 94 evaluable patients, 66 received ceftibuten and 28 received cefaclor. The overall bacteriological response was similar in the two treatment groups with elimination of the original pathogen in 91% and 89% of the patients receiving ceftibuten and cefaclor, respectively. The overall clinical response mirrored the bacteriological results with a successful clinical outcome in 92% of ceftibuten-treated patients compared with 93% in patients receiving cefaclor. Adverse experiences were, in general, few and mild, being reported in 8% and 17% of patients receiving ceftibuten and cefaclor, respectively.