高纯硅低能粒子辐照E′色心形成动力学研究

考虑固有点缺陷形成E′色心的情况，建立了E′色心形成的动力学模型，得到了高纯硅低能粒子辐照E′色心浓度与辐照剂量的关系式.结果表明，在低辐照剂量下，E′色心浓度随剂量的变化呈线性增长；随着辐照剂量的增加，E′色心浓度随剂量的变化呈饱和趋势.如果进一步考虑E′色心和其他物质反应形成新的稳定结构，E′色心浓度随剂量的变化呈双指数关系，E′色心浓度随剂量的变化不再趋于饱和状态，而是偏离饱和状态.理论结果和实验结果很好地符合，说明建立的模型是有效的.     

部分耗尽SOI MOSFET总剂量效应与偏置状态的关系

实验表明SOI MOSFET掩埋氧化层中的总剂量辐射效应与辐射过程中的偏置状态有关. 对诱发背沟道泄漏电流的陷阱电荷进行了研究. 建立一个数值模型来模拟不同偏置下陷进电荷的建立, 它包括辐射产生的载流子复合和俘获的过程. 模拟结果与实验结果相符, 解释了总剂量辐射效应受偏置状态影响的机理.     

Radiation dose measurements for staff members involved in holmium-166 preclinical trial

AimNeutron-activated holmium-166 (¹⁶⁶Ho) is an excellent radionuclide for internal radiation therapy (Eβmax = 1.84 MeV) with an appropriate half-life (26.8 h), which emits photons (81 keV, 6.2%) suitable to be detected by gamma cameras. Preparing and injecting radiopharmaceuticals containing beta/gamma emitting holmium-166 implies a risk of exceeding the upper limit for skin and hand radiation equivalent doses (500 mSv/an). This study was aimed to estimate the whole body and finger exposure for staff responsible for dose preparation, dose dispensing, and dose injection of holmium-166 therapy.MethodsTo measure the finger dose from external exposure, all staff members wore TLD dosimeters. Personal dose equivalents Hp(10) were measured using electronic personal dosimeters (EPD MK2, Thermo Fischer Scientific) placed on the left side of the chest. During our study, staff members administered more than 40 ¹⁶⁶Ho-based therapies for preclinical trial. Appropriate radiation safety procedures and shielding were applied at each stage.ResultsIn this study, the whole body doses were 2.80 ± 1.56 nSv MBq⁻¹ for one ¹⁶⁶Ho-therapy preparation/formulation, and 2.68 ± 1.70 nSv MBq⁻¹ for one intravenous injection. Maximum finger doses were 2.9 ± 0.2 μSv MBq⁻¹ and 2.5 ± 0.3 μSv MBq⁻¹ for preparation and injection, respectively (activities injected: 72 ± 3 MBq).ConclusionExtrapolated annual doses from 300 ¹⁶⁶Ho radionuclide therapies were lower than the annual limit doses for skin and the whole body, 500 mSv and 20 mSv, respectively, reported in the European Directive EURATOM 96/29 when applying appropriate radiation protection standards. However, these doses have to be added to other diagnostic or therapeutic protocols, performed in preclinical facilities.     

月季辐射生物学效应研究初报

~(60)Co—r射线处理月季休眠枝条,研究不同剂量、不同花色品种的损伤和诱变效应。结果表明,辐射损伤随照射剂量的增大而加重,恢复也较慢,产生纯花色变异及花器变异的比例增大。相关分析表明,照射剂量对变异频率有重要作用,辐射损伤对变异频率的作用甚微;Gr系和HT系的粉红色品种其花器具有较高的变异频率。铅砖屏蔽枝条基部可提高其耐辐射能力。反复修剪有利于变异性状的显现。     

大剂量补充微量元素治疗“胃溃疡型腺癌伴广泛转移”一例

阐述了一例胃底溃疡型腺癌伴周边器官淋巴组织广泛转移患者，行“贲门MT术”姑息治疗后，经九个月大剂量多种微量元素制剂补充达到很好的临床效果。     

MCNP Dose Calculations in a CT Phantom for Therapeutic External Photon Beam

In this paper, we have addressed the problem of the radiation transport with the Monte Carlo N particle(MCNP) code. This is a general purpose Monte Carlo tool designed to transport neutron, photon and electron in three dimensional geometries. To examine the performance of MCNP5 code in the field of external radiotherapy, we performed the modeling of an Electron Density phantom (EDP) irradiated by photons from 60Co source. The model was used to calculate the Percent Depth Dose (PDD) at different depths in an EDP. One field size for PDD has been examined. A 60Co photons source placed at 80 cm source to surface distance (SSD). The results of calculations were compared to TPS data obtained at National Institute of Oncology of Rabat.     

TLD measurements and Monte Carlo simulations for glandular dose and scatter fraction assessment in mammography: A comparative study

The main purpose of this study was to validate and compare Mean Glandular Dose (MGD) values obtained using Monte Carlo simulations with experimental values obtained from Entrance Surface Dose (ESD) and depth dose measurements performed in a Hospital mammography unit. ESD and depth dose were measured using ThermoLuminescent Dosimeters (TLDs), and a tissue equivalent mammography phantom recommended by the American College of Radiology (ACR). Measurements and Monte Carlo simulations were also compared with the MGD calculated using the Automatic Exposure Control (AEC) system of the mammographic unit. In the simulations the Doppler energy broadening effect was also taken into account. The simulated ESD are about 5%–10% higher than the measured ESD values. The deviation between the measured and simulated MGD values in the phantom is of about 15%. The MGD evaluated using the AEC system is smaller both with respect to the Monte Carlo simulation and experimental result by a factor of about 15% and 25% respectively. Moreover the BackScatter Factor (BSF) estimated by Monte Carlo simulations was used for the MGD calculation according to the Wu’s method. Finally the inclusion of the energy broadening effect on MGD calculation produces negligible variations on the simulated results.     

UV dosimeter based on polyamide woven fabric and nitro blue tetrazolium chloride as an active compound

This paper reports on the preparation and features of a UV light dosimeter composed of nitro blue tetrazolium chloride (NBT) and polyamide woven fabric. This textile dosimeter is based on the conversion reaction of NBT into formazan, which was initially examined in aerated aqueous solutions through steady state UV irradiation. Irradiated solutions change their colour as a consequence of the formation of polydisperse NBT formazan particles. This was analysed in relation to the absorbed dose of UV light through UV–VIS spectrophotometry and dynamic laser light scattering measurements. When NBT substrate molecules are embedded in polyamide textile, UV irradiation leads to similar effects as in solution. However, the tinge intensity changes at much lower absorbed doses. The dependence of the tinge intensity on the absorbed dose was followed by measurements of the remission of light from the NBT-polyamide samples. Consequently, the calibration parameters were calculated such as the dose sensitivity, dose range, and quasi-linear dose range. An improvement of the NBT-polyamide samples by application of a colour levelling agent and improvement of their resistance to humidity is presented. Finally, the samples were used for estimation of absorbed UV energy distribution showing their capability as new dosimeters for in-plane high resolution radiation dose measurements.     

Study on induced radioactivity of China Spallation Neutron Source

China Spallation Neutron Source (CSNS) is the first High Energy Intense Proton Accelerator planned to be constructed in China during the State Eleventh Five-Year Plan period, whose induced radioactivity is very important for occupational disease hazard assessment and environmental impact assessment. Adopting the FLUKA code, the authors have constructed a cylinder-tunnel geometric model and a line-source sampling physical model, deduced proper formulas to calculate air activation, and analyzed various issues with regard to the activation of different tunnel parts. The results show that the environmental impact resulting from induced activation is negligible, whereas the residual radiation in the tunnels has a great influence on maintenance personnel, so strict measures should be adopted.     

Study of radiation background at the north crossing point of the BEPCⅡ in collision mode

Understanding the radiation background at the north crossing point (NCP) in the tunnel of BEPCII is crucial for the performance safety of the High Purity Germanium (HPGe) detector, and in turn of great significance for long-term stable running of the energy measurement system. Therefore, as the first step, a NaI(Tl) detector is constructed to continuously measure the radiation level of photons as background for future experiments. Furthermore, gamma and neutron dosimeters are utilized to explore the radiation distribution in the vicinity of the NCP where the HPGe detector will be located. Synthesizing all obtained information, the shielding for neutron irradiation is studied based on model-dependent theoretical analysis.