No disturbance of myelination in the central nervous system by selective3Hβ-irradiation

Summary The effect of a selective irradiation of myelin by³H -particles was studied by light and electron microscopic methods in guinea pig spinal cord. The animals were injected with [³H]leucine shortly after birth when the rate of myelin biosynthesis is high and sacrificed 130 days later. In spinal cord the radioactivity was mainly preserved in myelin because the half life of myelin proteins is much higher than that of most other CNS protein. As a consequence the irradiation dose in the white matter was much higher than in the gray matter. In myelin internally irradiated by³H -particles within 130 days at a dose of 10 Gy no alterations could be detected either by morphological or by morphometric methods.Supported by the Deutsche Forschungsgemeinschaft     

探究4种临床CT扫描方式对受检者辐射剂量的影响及胸部扫描辐射场的空间分布

目的 探究4种临床CT扫描方式对受检者常见组织吸收剂量的影响及胸部扫描的辐射场空间分布,以期为受检者与机房内空间辐射防护提供依据。方法 利用热释光探测器（TLD）测量仿真体模的眼晶体、甲状腺、性腺、胸部和腹部皮肤在4种CT扫描方式下的吸收剂量。利用TLD监测胸部螺旋扫描时距离CT诊断床不同位置处的空气比释动能。结果 仿真体模的眼晶体、甲状腺、性腺、胸部和腹部皮肤在4种CT扫描方式下的吸收剂量分别为0.040～64.818 mGy、0.154～10.155 mGy、0.028～0.154 mGy、0.443～17.141 mGy和0.093～14.346 mGy。胸部扫描时空间辐射场的空气比释动能最大值为0.049 mGy,且与CT球管距离越大数值越小。结论 4种CT扫描方式对受检者常见组织的吸收剂量一般不会超过阈剂量。单次CT胸部扫描时陪检者所受剂量较小。为减少辐射危害,在CT扫描中可采取屏蔽措施来减少受检者组织吸收剂量,同时陪检者应适当增加与球管和诊断床的距离。     

131I的电离辐射对甲状腺功能早期影响的研究

目的探讨131I的电离辐射与甲状腺组织功能早期改变的关系,如血清TNF、IL-1β、IL-6、IL-8等细胞因子水平变化以及甲状腺组织本身的病理改变等.方法选用兔作动物实验(15只),分别在0、6、24、48、72h及1周时抽血做IL-1β、IL-8测定,并每次随机处死1～2只兔以做病理切片观察,1周时同时做甲功测定(TT3、TT4、FT3、FT4)并与0h比较.17例病情中及重度甲亢患者用治疗剂量的131I治疗(每人次用量146.2～469.9MBq,平均267.5MBq),治疗前和治疗后4～7天抽血做TNF、IL-1β、IL-6和IL-8测定.结果①使用131I6h后即可见兔血清IL-1β增高(P<0.05),IL-8于48h达高峰(P<0.01),两种细胞因子于1周时皆降低到0h水平(P>0.05).1周内兔血清甲状腺激素水平无明显变化(P>0.05).②甲亢患者131I治疗前后血清细胞因子的变化与兔有所不同,TNF无明显变化(P>0.05),IL-6和IL-8升高(P<0.05),而IL-1β反而降低,且差异显著(P<0.05).③摄取131I后兔甲状腺组织在不同时间内呈现不同的病理改变.结论①甲状腺组织摄取一定剂量的131I在不同时间内呈现不同的病理改变,但短期内甲状腺激素水平无明显变化.②某些细胞因子IL-1β、IL-6、IL-8等似可用作观察甲状腺组织对131I辐射效应反应的指标,但其临床价值有待于进一步探讨.     

不同照射剂量及照后培养不同时间小鼠骨髓基质细胞损伤的变化

目的 :研究γ射线照射剂量及照射后培养时间对体外培养的骨髓基质细胞 (BMSC)损伤的影响。方法 :体外培养的BMSC随机分为正常组和不同剂量照射组 ,利用流式细胞仪 (FCM)、HE染色等技术观察处理后BMSC凋亡率和坏死率的变化。结果 :照射剂量从 0增至 5 0Gy时 ,凋亡率和坏死率随照后培养时间的延长其增加的幅度较小 ,当照射剂量从 5 0Gy增至 70Gy时 ,其增加幅度较大 ;当剂量大于 70Gy时 ,BMSC的损伤主要表现为坏死率的相对增高。结论 :BMSC的凋亡和坏死与照射剂量和照后培养时间有关 ,且表现出一定的规律性     

真空紫外辐照对加成型硅橡胶光学性能的影响

考察了加成型硅橡胶在真空环境中经1000ESH紫外辐照后的性能变化。结果表明,辐照后材料均出现发黄的现象,光学透过率大幅度 下降,同时加入硅酸钾包覆后制备的热控涂层反射率下降。经原位测试与离位测试,发现加成型硅橡胶在两种不同条件下测得的结果差异较小,而在有机硅橡胶中加入ZnO后原位与离位测试结果则差异明显,表现出明显的漂白作用。     

肉苁蓉总苷对~(60)Coγ射线损伤小鼠免疫功能的防护作用

目的　研究肉苁蓉总苷 (GCs)对 6 0 Co损伤小鼠免疫功能及 30 d存活率的影响。方法　小鼠在不同剂量6 0 Coγ射线照射前后 ,均服以 GCs,观察辐射及 GCs对其免疫功能的改变。结果　 6 0 Co照射剂量为 2 ,4及 7Gy时 ,可造成小鼠体液免疫、细胞免疫功能和非特异性免疫功能及 30 d存活率下降 (P<0 .0 5或 P<0 .0 1) ;GCs(31.2 5 ,6 2 .5 ,12 5 m g/ kg)组可促进上述各指标的恢复 ,对 6 0 Co损伤小鼠的抗体产生、外周血 T淋巴细胞数目、迟发型超敏反应、腹腔巨噬细胞的吞噬功能均有明显保护作用 (P<0 .0 1或 P<0 .0 5 ) ;且能提高受照小鼠的脾指数、胸腺指数及 30 d存活率 (P<0 .0 1或 P<0 .0 5 )。结论　 GCs对辐射损伤小鼠的免疫功能具有较强防护作用     

电磁辐射对小鼠神经系统超微结构影向的分析

目的探讨移动电话的电磁辐射对生物体的影响.方法用大众常用移动电话作为辐射源,工作频率为900MHz,功率密度为1190μW/cm2,在一定范围对小鼠辐射2h/d,30d后把小鼠断颈处死,取出大脑皮层、海马和小脑进行电镜观察分析.结果电镜所见,处理组与对照组小鼠的神经系统的细胞超微结构未见明显异常.结论一定时间内,移动电话的电磁辐射,对小鼠神经系统的细胞超微结构并没有明显影响.     

Principles of cancer treatment by radiotherapy

Radiotherapy (or radiation therapy) uses ionizing radiation to selectively kill cancer cells, especially for solid tumours. Like surgery, it is meant to be a ‘local’ treatment, although its beneficial systemic effects are being discovered. It is most commonly used in addition to surgery (adjuvant, e.g. breast), but its role in the neoadjuvant setting in combination with chemotherapy for some cancers (e.g. rectum) is also established. In early stages of cancer, it can be the definitive treatment, avoiding surgery and enabling organ preservation (e.g. larynx), while in late stages, it can provide excellent palliation (e.g. bone metastasis). Radiotherapy can be delivered at various energy levels (kiloVolts, megaVolts), with various subatomic particles (e.g. electrons, protons, and high-energy electromagnetic radiation). The traditional bulky equipment (e.g. linear accelerator) needs to be housed in an underground bunker and uses complex imaging to improve precision and avoid radiation to normal tissues. Fractionated regimens spanning several days reduce individual doses. Modern techniques using mobile devices (e.g. TARGIT-IORT) can deliver radiotherapy during surgery with the highest precision and immediacy.     

Cost-effectiveness of postmastectomy hypofractionated radiation therapy vs conventional fractionated radiation therapy for high-risk breast cancer

BackgroundThe phase 3 NCT00793962 trial demonstrated that postmastectomy hypofractionated radiation therapy (HFRT) was noninferior to conventional fractionated radiation therapy (CFRT) in patients with high-risk breast cancer. This study assessed the cost-effectiveness of postmastectomy HFRT vs CFRT based on the NCT00793962 trial.MethodsA Markov model was adopted to synthesize the medical costs and health benefits of patients with high-risk breast cancer based on data from the NCT00793962 trial. Main outcomes were discounted lifetime costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER). We employed a time-dependent horizon from Chinese, French and USA payer perspectives. Model robustness was evaluated with one-way and probabilistic sensitivity analyses.ResultsPatients receiving CFRT versus HFRT gained an incremental 0.0163 QALYs, 0.0118 QALYs and 0.0028 QALYs; meanwhile an incremental cost of $2351.92, $4978.34 and $8812.70 from Chinese, French and USA payer perspectives, respectively. Thus CFRT versus HFRT yielded an ICER of $144,281.47, $420,636.10 and $3,187,955.76 per QALY from Chinese, French and USA payer perspectives, respectively. HFRT could maintain a trend of >50% probabilities of cost-effectiveness below a willingness-to-pay (WTP) of $178,882.00 in China, while HFRT was dominant relative to CFRT, regardless of the WTP values in France and the USA. Sensitivity analyses indicated that the ICERs were most sensitive to the parameters of overall survival after radiotherapy.ConclusionsPostmastectomy HFRT could be used as a cost-effective substitute for CFRT in patients with high-risk breast cancer and should be considered in appropriately selected patients.