نتایج جستجو برای: absolute dose
تعداد نتایج: 394859 فیلتر نتایج به سال:
This review is concerned with exposure risk and the environmental pathways models used for predictive assessment of radiation dose. Exposure factors, the adequacy of available data, and the model subcomponents are critically reviewed from the standpoint of absolute error propagation. Although the models are inherently capable of better absolute accuracy, a calculated dose is usually overestimat...
A molecular biological rationale for the linear nonthreshold dose-response pattern for carcinogenesis is presented based on the mutagenic activation of oncogens as the basis of initiation. The approach assumes that the linear nonthreshold dose pattern at very low doses applies only to tissues that are promoted by intrinsic and extrinsic agents other than the one being modeled, and that risk is ...
BACKGROUND Many women develop breast cancer after treatment for Hodgkin lymphoma (HL) at a young age. We estimated this future risk, taking into account age and calendar year of HL diagnosis, HL treatment information, population breast cancer incidence rates, and competing causes of death. METHODS Relative risks of breast cancer for categories defined by radiation dose to the chest (0, 20- < ...
Sixteen cases of either a pityriasiform or discoid eczematous rash occurring in patients with rheumatoid arthritis receiving treatment with gold (sodium aurothiomalate and auranofin) were studied. The results suggest that this is a dose related, not allergic, reaction to gold. The development of this rash is not an absolute indication to stop treatment with gold. Control can often be effected w...
introduction: esophageal cancer is one of the most frequently occurring cancers in iran and having a high incidence rate among other countries. radiotherapy is one of the three methods (surgery, radiotherapy and chemotherapy) for radical or palliative treatment of esophageal cancer. in this method of treatment, the organs such as heart and spinal cord are regarded as organs at r...
introduction radiation exposures from diagnostic medical examinations are generally low and are almost always justified by the benefits of accurate diagnosis of possible disease conditions. therefore, entrance skin dose (esd), body organ dose (bod), and effective dose (ed) from adult patients undergoing routine thorax posterior-anterior (pa) and thorax right lateral (rlat) were estimated in uni...
background: changes in body composition may be used for monitoring progression/ regression of a disease. prompt γ-rays in vivo neutron activation analysis (ivnaa) has been widely used for the measurement of body composition in recent years. objective: in this paper, we tried to improve the safety of ivnaa operator. methods: the most important factor for reducing the operator receiving dose is t...
The purpose is to devise a patient-specific quality assurance procedure for RapidArc radiotherapy using the MapCHECK detector array. We use our existing MapCHECK system and a Solid Water phantom with an embedded ion chamber to develop a quality assurance procedure for RapidArc treatment after commissioning. The ion chamber used to measure the absolute dose is surrounded by 6 cm layers of solid ...
Since 2003, we use the GSI heavy-ion microprobe to irradiate living cells with ions from the UNILAC [1]. Two specific properties of the microbeam method make it stand out among other, more conventional irradiation procedures: First, we precisely control the dose by counting and switching individual particles that are to be delivered to the target, down to the low-dose limit of a single ion per ...
A mathematical model is described which determines the impact of a schedule of vaccination on the time course of a certain class of diseases. The data are the demographic variables and parameters and age-dependent non-fatal and fatal case rates. Given the age- and time-dependent rates of vaccination including coverage and corresponding efficacies, various schedules may be distinguished by eithe...
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