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At least 307 records · Page 17Linked to original sources
PubMed1994

Radiation dosimetry measurements during U.S. Space Shuttle missions with the RME-III.

Time-resolved radiation dosimetry measurements inside the crew compartment have been made during recent Shuttle missions with the U.S. Air Force Radiation Monitoring Equipment-III (RME-III), a portable battery-powered four-channel tissue equivalent proportional counter. Results from the first six missions are presented and discussed. Half of the missions had orbital inclinations of 28.5 degrees with the remainder at inclinations of 57 degrees or greater; altitudes ranged from 300 to 600 km. The determined dose equivalent rates ranged from 70 to 5300 microSv/day. The RME-III measurements are in good agreement with other dosimetry measurements made aboard the vehicles. Measurements indicate that medium- and high-LET particles contribute less than 2% of the particle fluence for all missions, but up to 50% of the dose equivalent, depending on the spacecraft's altitude and orbital inclination. Isocontours of fluence, dose and dose equivalent rate have been developed from measurements made during the STS-28 mission. The drift rate of the South Atlantic Anomaly is estimated to be 0.49 degrees W/yr and 0.12 degrees N/yr. The calculated trapped proton and GCR dose for the STS-28 mission was significantly lower than the measured values.

Atlantic Ocean↗
PubMed1992

Biological monitoring of three 60Co radiation incident victims.

Radiation-induced structural chromosomal aberrations were the only adverse effects found in three workers overexposed to 60Co gamma-radiation. Chromosomal analyses were performed on the 5th and 75th days after exposure. Hematologic follow-up was carried out on the 5th, 12th, 16th, and 75th days after exposure. Hematologic findings did not differ over time in any of the three exposed workers. In two workers, we found dicentric chromosomes, which are conventional indicators for exposure to ionizing radiation.

Accidents, Occupational↗
PubMed2006

Long-term measurements of H*(10) at aviation altitudes in the northern hemisphere.

Monitoring the radiation field at aviation altitudes is achieved by the dosemeter system piDOS installed in a passenger aircraft. The basic detector is a 2 in. tissue-equivalent proportional counter (TEPC) mounted in a cabin-baggage-sized aluminium suitcase. The entire system was characterised in neutron and photon reference fields from which two calibration factors were determined according to the splitting of the measured dose deposition spectrum yd(y) into low-LET and high-LET regions. A total of 255 flights in the northern hemisphere was analysed. The dependencies of the ambient dose equivalent rates on altitude, latitude and solar activity have been determined. These new data extend the data base used in Germany for the validation of program codes to calculate the radiation exposure of air crew members.

Altitude↗
PubMed1998

Radiation use in the orthopaedic theatre: a prospective audit.

BACKGROUND: There is concern about the exposure of orthopaedic surgeons to radiation. The aim of this study was to monitor radiation use in theatre to improve practice and to attempt to quantify the radiation dose the orthopaedic surgeon may have received. METHODS: A 6-month prospective audit of all procedures performed in the orthopaedic theatre that used fluoroscopy or radiographs was undertaken An anthropomorphic phantom was used to measure scatter and direct-skin doses. Screening times were recorded in a subsequent 6-month post at a tertiary trauma centre. RESULTS: Fluoroscopy or radiographs were used in 378 procedures. Fluoroscopy was used in 260 procedures with a screening time of 124 min at an average of 0.48 min per procedure. Lead aprons were worn in 99% of cases and thyroid guards in 32%. All dosimeter badges were negative. The surgeon's hand was caught in the fluoroscopy beam in 15% of procedures. The phantom recordings ranged from 13 to 210 microGy for skin dose and 0.17-0.87 microGy for scatter dose. The calculated hand exposure was less than 5% of recommended levels. In the trauma post 210 min of screening was used potentially increasing the hand exposure to one-third of recommended limits. If a printer was used to record the image, 58% of intra-operative radiographs would have been avoided. CONCLUSIONS: Hand exposure to radiation is the limiting factor in orthopaedics. The extremity limit will only be exceeded if the hands are regularly caught in the beam. Dose-reduction gloves should be considered for high-risk procedures. A printer can reduce the need for intraoperative plain radiographs.

Body Burden↗
PubMed1990

Comparison of cytogenetic tests for monitoring overexposures from ionizing radiation.

The frequencies of chromosome aberrations induced by ionizing radiations were studied for use in assessment of doses in radiation accidents. The dose-effect relationships of formations of dicentric and acentric aberrations are compared with that of micronuclei detected in cultured human lymphocytes. The data suggest the applicability of micronucleus test as "biological dosimeter" with a similar sensitivity like the widely used dicentric analysis.

Adolescent↗
PubMed1995

Radiation protection design philosophy for a door interlock system for shared room remote afterloading brachytherapy.

A single remote afterloading system can sometimes be used for the radiation treatment of two or more patients in separate rooms simultaneously. This configuration poses certain radiation protection problems, especially in a busy clinic where some of the treatment rooms have to be used for other non-radiation related patients even though not all radiation treatments have been completed. In this report we describe a door interlock system that has been designed to allow for radiation protection purposes during radiation treatment but is disabled when the radiation treatment is completed--with enough safeguard built in to prevent accidental bypass of the interlock. In addition, the quality control procedures of the radiation monitor devices for these treatment rooms are described. These radiation protection procedures could be generalized to other remote afterloading systems.

Brachytherapy↗
PubMed2004

Measurements of environmental background radiation at location of coal-fired power plants.

Environmental radiation monitoring in the vicinity of coal-fired power plants which are used primarily to determine the variability in measured background exposures are presented in this article; this is in order to estimate the contribution due to the plants' operation. Measurements have been done using a multi-element, high sensitive dosemeter system composed of three solid, properly filtered, sintered CaSO4:Dy thermoluminescent detectors, and one low-atomic number, MgB4O7:Dy,Na thermoluminiscencent detector produced at the Vinca Institute. The dosemeters were deployed quarterly 1 m above ground level at locations within 20 km of the power plants. Twenty urban and suburban measured stations were established. Measurements were carried out over one year period, from the beginning of the summer of 1995 to the end of the spring of 1996. The registered annual absorbed dose in air, from all of the 20 stations, vary from 0.91 to 1.46 mGy a(-1). One of the highest values of the annual absorbed dose was measured at the station near to the plant, i.e. at the place the most exposed to the lighter fly ash from the plant stack, as it was expected. The annual absorbed dose registered at the measuring stations that were selected as a control because they were situated practically away from possible influence of the plants were from 0.91 to 0.98 mGy a(-1). The above values of absorbed doses become very important, by concurrence of the circumstances, because they represent the zero background radiation level before the incidence of depleted uranium over former Yougoslav territory in the Kosovo region in the spring of 1999. These measured absorbed dose exposures have to be compared with corresponding absorbed dose rates from the natural sources, such as soil having an exposure of 18-93 nGy h(-1) (average 35 nGy h(-1)) according to the UNSCEAR 2000 Report. This investigation has been primarily done in order to check the impact of coal-fired power plants on the background radiation level in its vicinity. According to the experimental results, influence was confirmed both qualitatively and quantitatively.

Air Pollution, Radioactive↗