Personal monitors individuals

Personal monitoring devices (sometimes referred to as "dosimeters") are carried or worn by individuals and are used to measure that individual s exposure to particular chemical(s). Devices that include a pump are called "active" monitors devices that do not include a pump are called "passive" monitors. Such devices are currently used for research purposes. It is possible that sometime in the future they may also be helpful in lAQ investigations in public and commercial buildings. 

Section 1 of the Report presents the quantities Hz and E and the relationship of each quantity to its corresponding radiation protection system. Section 2 describes the use of personal monitors for workers in the United States, including their calibration and how they are worn on individuals in various occupational settings. Section 3 discusses practical ways to use one or two personal monitors to obtain estimates of Hz and E. Section 4 provides the NCRP s... 

The response of a personal monitor varies when worn on individuals of different sizes and shapes and when worn at different locations on the body (Jahr et al., 1989 Wagner, 1989). Personal monitors showing good agreement when irradiated on a specific backscatter medium under calibration conditions might disagree when irradiated on another type of backscatter medium or on the body of an individual (Alberts et al., 1989). 

Current federal regulations limit the deep dose equivalent based on that part of the body likely to receive the highest exposure. If personal monitor results are not available or the personal monitor was not located at the position of highest exposure, the regulations allow the substitution of surveys and other radiation measurements (NRC, 1991). These requirements strongly influence the current practices in the United States for the number and location of personal monitors on individuals. 

In addition, multiple personal monitors are often used for situations in which a worker is exposed to a nonuniform radiation field, in an attempt to assess the region of the body receiving the highest deep dose equivalent. Approaches to the use of multiple personal monitors vary widely, and the number used and their locations depend on the particular work activity. For example, during work inside a steam generator, where the radiation fields are potentially isotropic, a total of 12 to 14 personal monitors may be placed at specific locations on both the front and the back of the body, and on top of the head. In other work situations, when the radiation field may be relatively directional but variable (e.g., during control-rod drive maintenance in a boiling-water reactor) the individual may wear all of the personal monitors at locations on the front of the body. 

Universities and research institutions also vary in their practices for wearing personal monitors. In typical situations, each individued is issued a single personal monitor and instructed orally to wear it at a location between the shoulders and the waist. These instructions are usually given in the initial employee training and are not found in laboratory procedures. 

For many situations where protective aprons are worn, the exposure is primarily to the front of the individual. Under these circumstances, a personal monitor located under the apron on the trunk of the individual indicates the dose equivalent to the shielded trunk of the body, and unshielded parts of the body may receive higher exposure. A monitor located outside and above the apron indicates the dose equivalent to the unshielded parts of the body. 

For some situations, such as certain nursing procedures, individuals may work part of the time with their backs to the patient while wearing an apron that covers both the front and the back. For irradiation to the back, a personal monitor located on the back under such an apron indicates irradiation of the shielded trunk of the body some unshielded parts of the body may receive higher exposures. A monitor that is located on the front under such an apron is shielded... 

In scenarios for which the irradiation geometry in practice is difficult to determine, investigators have recommended the use ofii/pdO) values determined from multiple personal monitors to obtain improved estimates ofi/g (Lakshmanan et al., 1991 Xu, 1994). These investigators have demonstrated that i p(10) values from personal monitors placed on the front (i.e., center of the chest) and back (t.e., center of the back) of individuals can be combined in specific algorithms that yield closer estimates of than the values of 10)... 

If an individual performs both radiographic procedures (i.e., procedures without use of a protective apron) and fluoroscopic procedures i.e., procedures with the use of a protective apron) during a given monitoring period, there may be no practical way to determine precisely the relative contribution each type of procedure made to the total /fp(lO) value recorded by a personal monitor. However, occupational exposure during radiographic procedures should be very low, since the worker is at a relatively large distance from the x-ray source and most often i.e., except for use of mobile x-ray systems) in a protective cubicle. 

If an individual s workload consists predominantly of fluoroscopic procedures, the recommendations given above with the protective apron are appropriate, when either a personal monitor is worn only at the neck outside and above the apron, or when personal monitors are worn both at the neck outside and above the apron and at the waist or chest under the apron. When the Hp(10) values recorded by the personal monitor worn at the waist or chest under the apron are consistently below the minimum detectable values, use of the recommendation for a personal monitor worn only at the neck outside and above the apron would be the more conservatively safe approach. 

If an individual s workload consists predominantly of radiographic procedures, where protective aprons are not worn, the recommendation given in Section 4.1 for use of Hp(lO) from one personal monitor as a surrogate for would be appropriate. For radiographic procedures, the irradiation conditions are adequately characterized by an anterior to posterior irradiation at effective energies of greater than 30 keV, with a personal monitor located on the front of the individual. 

This Report is one of the series developed under the auspices of Scientific Committee 46, a scientific program area committee of the National Council on Radiation Protection and Measurements (NCRP) concerned with operational radiation safety. The Report provides practical recommendations on the use of personal monitors to estimate effective dose equivalent (Hg) and effective dose (E) for occupationally-exposed individuals. The Report is limited to external exposures to low-LET radiation. Recent additions to the radiation protection literature have made the recommendations possible. In order to avoid delay in utilizing the recommendations in the United States, the quantity as well as E, has been included until such time as the federal radiation protection guidance and associated implementing regulations are revised to express dose limits in E as recommended by the NCRP. 

About the size of a package of cigarettes, individual sensors are available for H2S, phosgene, N02, HCN, and CO. In the near future, the series will be expanded to include CI2 and hydrazine. When used with the Chronotox microprocessor, the Monitox serves as a personal monitor as well as a gas detection alarm system. 

The personal monitoring of community air pollutants is required for four basic reasons these reasons are associated with a need for a more accurate description of an individual s contact with a pollutant that can affect health. 

As we have shown, personalized medicine at its fullest takes consideration of individual s hereditary, environmental, and lifestyle variances, and hence is not very far removed from the notion of holistic medicine. In clinical practice, holistic medicine has rapidly become the dominant theme in oncology where the therapeutic index of the drugs is perhaps the narrowest. A further development of such personalized medicine may be medical diagnostic devices in the home. A medical diagnostic device in each home could personalize monitoring, since families differ in their genomics and lifestyles and the risk factors implied by both of hereditary traits and phenotypic variances. 

Personal Monitoring Devices— Devices worn or carried by an individual to measure chemical exposure and/or radiation doses received. 

In mostresearch laboratory situations, it would be unusual to find an airborne radioactivity area on otherthan a short-term basis. If there is any possibility ofan approach to the limits while working on an open bench, the use of radioactive materials should be restricted to a hood, or in a glove box or hot cell. In a facility with a broad license, it is recommended that at least some ofthe more active individuals using radioisotopes should be included in a bioassay program for the same reason that others weara personal monitoring device, to ensure and document that no one is receiving an internal dose over the limits. 

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