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Radiation Injuries
Published in Thomas A. Carder, Handling of Radiation Accident Patients, 1993
Recall the term whole-body exposure which means exposure to the trunk of the body, the head, the lens of the eye, the arms above the elbows, and the legs above the knees. Also recall that extremity exposure means exposure to the arms at the elbow and below and to the legs at the knee and below. The new regulation redefines the whole-body and extremity to include the elbow and knee as part of the whole-body. So, if you hear that a patient from a nuclear plant (after January 1, 1994) has received a whole-body exposure you will know what parts are included in the whole-body. You will also know that if you are told the patient has an extremity exposure to the leg, he/she has received the exposure below the knee. The new regulation relates whole-body exposure to determining external exposure to gamma radiation with Deep Dose Equivalent (DDE) as measured by dosimeters.
Radiation Protection and Safety in Radiotherapy
Published in Kwan Hoong Ng, Ngie Min Ung, Robin Hill, Problems and Solutions in Medical Physics, 2023
Kwan Hoong Ng, Ngie Min Ung, Robin Hill
Solution:Absorbed dose DT is a measure of the energy deposited in a medium by ionising radiation. It is equal to the energy deposited per unit mass of a medium, and so has the unit joules (J) per kilogram (kg), with the adopted name of Gray (Gy) where 1 Gy = 1 J·kg−1.Equivalent dose HT is a measure of the radiation dose to tissue where an attempt has been made to allow for the different relative biological effects of different types of ionising radiation. The equivalent dose in tissue T is given by the expression: where DT, R is the absorbed dose averaged over the tissue or organ T, due to radiation R. Equivalent dose is measured using the sievert (Sv).Effective dose HE is the sum of the weighted equivalent doses in all the tissues and organs of the body. It is given by the expression: where HT is the equivalent dose in tissue or organ T, and WT is the weighting factor for tissue T. Effective dose is measured using the sievert (Sv).Deep dose equivalent Hp (10) is the dose equivalent at a tissue depth of 1 cm (1000 mg.cm−2) due to external whole body exposure to ionising radiation. Deep dose equivalent is measured using the sievert (Sv).Shallow dose equivalent Hp (0.07) is the external exposure dose equivalent to the skin or an extremity at a tissue depth of 0.07 mm (7 mg·cm−2) averaged over an area of 1 cm2. Shallow dose equivalent is measured using the sievert (Sv).
Cohort profile: four early uranium processing facilities in the US and Canada
Published in International Journal of Radiation Biology, 2021
Ashley P. Golden, Cato M. Milder, Elizabeth D. Ellis, Jeri L. Anderson, John D. Boice, Stephen J. Bertke, Lydia B. Zablotska
Exposure to external ionizing radiation at all facilities was estimated using film badge (Mallinckrodt, Middlesex, and Port Hope) and pocket chamber data (Middlesex). For Fernald, external dose data were obtained from the facility exposure database. These data were assumed to represent the deep dose equivalent (Hp(10)) due to gamma radiation exposure. For Fernald, Mallinckrodt, and Middlesex, additional external dose data were obtained from the DOE Radiation Exposure Monitoring System (REMS) for facilities other than workers’ respective primary sites. Likewise, three additional sources of film badge data were included for the Mallinckrodt cohort, as previously described (Golden et al. 2019). Neutron dose measurements were not available as there was little potential for exposure to neutrons at these sites. The Mallinckrodt cohort also had data available for occupational medical chest X-rays, primarily conventional chest radiography. Thus, these contributions to the external dose estimate for Mallinckrodt study subjects were separated out so that sensitivity analyses could be run with and without that component. The Middlesex cohort is currently missing film badge doses between the years 1949 and 1952; these annualized doses were singly imputed from the mean of each individual’s previous and later annual doses, weighted by the number of days worked in each year. For individuals who only worked during 1949–1952 and therefore had no prior or later film badge records, doses were singly imputed from means of all other workers’ exposures during that year if they had any evidence of exposure (from bioassay records, etc.).