THE HAZARDS OF LOW VOLTAGE RADIATION.
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Biophysical Phenomena↗
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Results for “RADIATION MONITORING”
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SURVEY OF RADIUM SOURCES IN OFFICES OF PRIVATE PHYSICIANS.
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Data Collection↗
[The efficiency of film dosimeters in the national film dosimetric monitoring of radiation workers in x-ray diagnosis].
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Film Dosimetry↗
The use of prostate-specific antigen (PSA) for the monitoring of radiation therapy in prostate cancer.
BACKGROUND: The classic methods for surveilling the efficacy of radiotherapy in prostate cancer are not accurate enough. The objective of this analysis was to determine whether prostate-specific antigen could perform this task. MATERIALS AND METHODS: From 1/95 to 10/95, 16 patients were treated at our clinic. 7 of these underwent primary irradiation, 4 treatment for local recurrence, and 5 had adjuvant radiotherapy. Radiotherapy was carried out with a total dose of 60 Gy in 30 fractions, 10 fractions per week, to the prostate bed plus 2 cm safety margin. RESULTS: PSA levels usually start to decline between the 3rd and the 4th week of radiotherapy with a half-life of 2.5 months. Five patients had equal or rising PSA levels, including all three patients with recurrent tumor. DISCUSSION: In most cases, PSA declined continuously from the 3rd week of therapy. Our median half-life was similar to other reported results. Persisting or rising PSA levels are an indicator for local or distant recurrence; all our patients who developed a recurrence showed a corresponding PSA increase.
Humans↗
Implications of dose distribution on monitoring requirements in U mines and mills.
In U mines and mills, mean doses from gamma radiation and 222Rn daughters, respectively, range from 10-30% of the individual limits recommended by the International Commission on Radiological Protection (ICRP), while the mean exposure to long-lived dust can be as low as a few percent or as high as 30% of the ICRP recommended limit. In certain mines, 220Rn daughters are present and should also be measured and accounted for. When the doses (or dose equivalents) from all the components of the radiation sources are taken into account, according to the ICRP notions of effective dose equivalent and committed effective dose equivalent, the mean of the combined doses can reach 30-50% of the combined permissible limit of dose. It is generally observed that individual doses and exposure to radiation are log-normally distributed. Since individual exposures to each specific hazard are generally not correlated, there is a probability that a number of individuals belong to the upper part of each exposure distribution. Therefore, it can happen that non-negligible fractions of the populations are liable to be close to the combined dose limit or to be overexposed. Consequently, in view of the observed nature of the distributions and the need to account for all sources of radiation, it is essential that appropriate radiation monitoring techniques be used to measure and record all significant doses and exposures. The analysis of the results of appropriate monitoring practices will lead to improved engineering controls of radiation hazards and optimum use of preventive resources.
Air Pollutants, Radioactive↗
Radiation factors in space and a system for their monitoring.
The radiation environment is of special concern when the spaceship flies in deep space. The annual fluence of the galactic cosmic rays is approximately 10(8) cm-2 and the absorbed dose of the solar cosmic rays can reach 10 Gy per event behind the shielding thickness of 3-5 g cm-2 Al. For the radiation environment monitoring it is planned to place a measuring complex on the space probes "Mars" and "Spectr" flying outside the magnetosphere. This complex is to measure: cosmic rays composition, particle flux, dose equivalent, energy and LET spectra, solar X-rays spectrum. On line data transmission by the space probes permits to obtain the radiation environment data in space.
Cosmic Radiation↗
Environmental monitoring in the vicinity of the Mayak atomic facility.
The goal of radiation monitoring in the zone influenced by the operation of the Mayak Production Association is to provide information for activities aimed at environmental preservation in that territory. The priority tasks of the radioecological monitoring system are measuring all parameters of radiation impact on the environment (which contribute up to 95% of the total population exposure dose), and estimating all parameters required to support effective decision-making. The basic methods for radioecological monitoring are: unification and standardization of field and laboratory techniques for radionuclide analysis; measurement of gamma-irradiation dose rate; measurement of 137Cs, 90Sr, and plutonium concentrations in soils; measurement of radionuclide concentration in surface and ground waters and the atmosphere; study of the pathways of horizontal and vertical migration of radionuclides in natural media; and establishment of data bases including ecological mapping. Based on the information obtained, assessment of contamination and forecasts of the future radiation situation are prepared using models.
Air Pollutants, Radioactive↗
Fallout dosage and monitoring.
At present there are a large number of people capable of conducting the task of surface and area radiation monitoring including external monitoring of personnel. Once the extent and the intensity of radioactivity in an area is determined, good use of personnel can be made without too much risk. This is fortunate for the medical profession whose personnel can devote their talents to casualty care during or following nuclear warfare. Most individuals who know how to detect and measure the extent of radioactive contamination are also capable of conducting personnel decontamination operations and would do so if necessary. Consequently the spread of contamination can be minimized by adequate decontamination and the medical personnel can treat casualties who are relatively free of external radioactive contamination. The appropriate use of trained manpower and radiation detection equipment which are available in California combined with sufficient rehearsals prior to a nuclear war will greatly reduce any casualty damage due to radioactive fallout.The chances of survival of individuals can be greatly improved with a little knowledge of protection from radioactive contamination and of salvage of food and water.
California↗
Revealing smuggled nuclear material covered by a legitimate radioisotope shipment using CdTe-based gamma-ray spectrometry.
Illicit trade of nuclear materials (NM) represents a serious challenge to radiation monitoring upon scenarios, when legitimate radioisotope shipments are used to obscure the weak radiation of NM. Planar and hemispherical Cd(Zn)Te detectors with a portable mini-multichannel analyzer were proven to be suitable, in measuring times of 10min order, for revealing the presence of low-enriched or natural U-bearing reactor fuel pellets in amounts of kg order, placed beside transport containers of lead or depleted uranium, which contain high activity 60Co (10GBq range) or 192Ir (TBq range) radioisotope sources. Such a hand-held or portable device may help authorities combating illicit trafficking of nuclear materials.
Equipment Design↗
Radiation safety system of the B-Factory at the Stanford Linear Accelerator Center.
The radiation safety system of the B-Factory accelerator facility at the Stanford Linear Accelerator Center is described. The radiation safety system, which is designed to protect people from prompt radiation exposure due to beam operation, consists of the access control system and the radiation containment system. The access control system prevents people from being exposed to the very high radiation levels inside a beamline shielding enclosure. The access control system consists of barriers, a standard entry module at every entrance, and beam stoppers. The radiation containment system prevents people from being exposed to the radiation outside a shielding enclosure due to either normal or abnormal operation. The radiation containment system consists of power limiting devices, shielding, dump and collimator, and an active radiation monitoring system. The inter-related elements for the access control system and radiation containment system, as well as the associated interlock network, are described. The policies and practices used in establishing the radiation safety system are also compared with the regulatory requirements.
California↗
Outpatient treatment with (131)I-anti-B1 antibody: radiation exposure to family members.
UNLABELLED: The Nuclear Regulatory Commission (NRC) regulations that govern release of patients administered radioactive material have been revised to include dose-based criteria in addition to the conventional activity-based criteria. A licensee may now release a patient if the total effective dose equivalent to another individual from exposure to the released patient is not likely to exceed 5 mSv (500 mrem). The result of this dose-based release limit is that now many patients given therapeutic amounts of radioactive material no longer require hospitalization. This article presents measured dose data for 26 family members exposed to 22 patients treated for non-Hodgkin's lymphoma with (131)I-anti-B1 antibody after their release according to the new NRC dose-based regulations. METHODS: The patients received administered activities ranging from 0.94 to 4.77 GBq (25--129 mCi). Family members were provided with radiation monitoring devices (film badges, thermoluminescent or optically stimulated luminescent dosimeters, or electronic digital dosimeters). Radiation safety personnel instructed the family members on the proper wearing and use of the devices. Instruction was also provided on actions recommended to maintain doses to potentially exposed individuals as low as is reasonably achievable. RESULTS: Family members wore the dosimeters for 2--17 d, with the range of measured dose values extending from 0.17 to 4.09 mSv (17--409 mrem). The average dose for infinite time based on dosimeter readings was 32% of the predicted doses projected to be received by the family members using the NRC method provided in regulatory guide 8.39. CONCLUSION: Therapy with (131)I-anti-B1 antibody can be conducted on an outpatient basis using the established recommended protocol. The patients can be released immediately with confidence that doses to other individuals will be below the 5-mSv (500 mrem) limit.
Ambulatory Care↗
[Planning and implementation of protective measures in emergencies during railway transportation of radioactive cargo].
Protective measures in emergencies during railway transportation of radioactive cargoes must be planned in advance, by obligatorily taking into account many factors that influence the scope, nature, specific features and consequences of radiation transport accidents. Of great importance are radiation monitoring, protective regimens, and requirements for decontamination of various objects in liquidating the consequences of a radiation transport accident.
Accidents↗
[A model of protectability of the ISS service module habitable compartments for radiation risk assessment].
A geometric model of the International space station (ISS) service module has been built up with account of basic structural components and spatial heterogeneity of matter distribution in SM equipment for the purpose of evaluating influence of a selected matter distribution function on the R-16 absorbed dose estimation. The uniform matter distribution function was shown to give the absorbed dose upper bound. Correspondingly, equipment representation as a homogeneous average density matter gives the absorbed dose lower bound. The best results were achieved using the normal law (Gauss law) for the matter distribution function. Shielding functions for DB-8 detectors (new radiation monitoring system elements) are presented.
Humans↗
A dose-per-pulse monitor for a dual-mode medical accelerator.
On a radiotherapy accelerator, the dose monitoring system is the last level of protection between the patient and the extremely high dose rate which all accelerators are capable of producing. The risk of losing this level of protection is substantially reduced if two or more dose monitoring systems are used which are mechanically and electrically independent in design. This paper describes the installation of an independent radiation monitor in a dual-mode, computer-controlled accelerator with a moveable monitor chamber. The added device is fixed in the beam path, is capable of monitoring each beam pulse, and is capable of terminating irradiation within the pulse repetition period if any measured pulse is unacceptably high.
Electrons↗
Feasibility study of a personal dosemeter based upon silicon diodes used in remote controlling.
The availability of low cost personal dosemeters is very important for routine worker monitoring. The aim of this work is to evaluate the performance of commercial silicon diodes, commonly used for infrared communication, as a personal radiation monitor. The instrument prototype was characterised both as an area monitor and a personal monitor. Instrument response was measured in the energy range form 37 keV to (60)Co energy. The angular response was also evaluated too.
Dose-Response Relationship, Radiation↗
Superheated drop neutron detectors used at the ESRF.
The ESRF operates a 6 GeV electron storage ring to produce X-rays. The experimental hall is classified as a free access area in terms of radiation protection. Interlocked radiation monitors guarantee the corresponding dose constraint. Measurements have shown that the radiation field outside the storage ring is dominated by neutrons. Apfel REMbrandt superheated drop detectors have been chosen. In total, 64 monitors are installed around the storage ring, interlocked to the accelerator personnel safety system. Since the radiation fields are highly pulsed, the response of the REMbrandt monitors to pulsed radiation was measured and compared with theoretical predictions. Dose recordings from the bubble detectors are shown, illustrating the good correlation between beam losses and dose rates, as well as showing the correspondence between neutron and photon dose values. Finally, around the beamline hutches, REMbrandt neutron monitors have been used to evaluate the ratio between neutron and photon dose rates.
Dose-Response Relationship, Radiation↗
Evolution of UV-B regulation and protection in plants.
Plants have evolved under the influence of UV-B radiation and have acquired systems for monitoring it and investing appropriate resources for protection against it, i.e., filters, quenchers of radicals and reactive oxygen species, and repair systems. An hypothesis for how plants monitor radiation has been presented.
Amino Acids↗
Cosmic-ray ionization in the lower atmosphere.
A high-pressure ion chamber filled with 2.5825 X 10(5) kg m-2 argon as used to measure the dose rates of several sites of interest in an attempt to evaluate the dose rates contributed by cosmic rays. Observation sites included two water reservoirs deeper than 110 m, Mount Ali which is higher than 2500 m, airliners flying at altitudes higher than 6700 m, and some sites at sea level. The results of this investigation were compared with those reported by the United Nations Scientific Committee on the Effects of Atomic Radiation and used for the determination of background radiation monitored with thermoluminescent dosimeters and sodium iodide detectors.
Calibration↗