Dosimetry methods

The use of the patch method, although yielding some good data about exposure over the years, started to fade quickly when whole-body dosimeter methodology was introduced. The whole-body dosimetry method gave more precise whole-body exposure values from one worker to another since the whole garment was extracted and analyzed, and one did not have to extrapolate exposure to large areas of the body. ° ... 

Ginsberg GL, Foos BP, Firestone MP (2005) Review and analysis of inhalation dosimetry methods for application to children s risk assessment. J Toxicol Environ Health A, 68(8) 573-615. 

Performing an accurate dosimetry is a prerequisite of any radiolysis study. However, all standard chemical dosimetry methods cannot be used in nanoporous media, as they all rely on known radiolytic yields that are expected to be modified by confinement. An alternative would be to use Monte Carlo particle transport code (i.e. MNCP, EGS4, Geant, Penelope) that allows a calculation of the deposited dose. PENELOPE (Penetration and Energy Loss of Positrons and Electrons) has especially proven to be efficient in microdosimetric calculations.This code can treat electron propagation down to 100 eV, for any material. Therefore, these simulations cannot handle sub-nanometric pore and do not take into account the fact that for certain materials pore diameter is smaller than spurs and/or track size. For nanometric to micrometric pores, the approximation usually proposed is to correct the dose by the mean density of the system... 

Each application will require different transducer properties to get the expected effect. For example, ultrasonic cleaning requires a broad uniform sound field, drills and welders require high amplitude motions, ultrasonic flowmeters utilize narrow uniform sound beams with stable amplitudes, and so on. Thus it is unlikely that one dosimetry method can be used for all types of transducers and sonic devices, a feature previously highlighted by Welkowitz [22]. 

The slope of the linear part and the incubation time are very dependent on hardness, grain structure, purity, mechanical fatigue strength, surface finish, and conditions of the eroded material. All these parameters should be carefully monitored in order to obtain reproducible results which was also necessary in dosimetry methods described above which used cleaning effects. It is, of course, inevitable that the foil used as a solid test probe will interfere with the cavitation field to some extent. Erosion rates have, however, been linearly correlated to the total noise of cavitation [125]. 

A dosimetry method based on the detection of the H radical involves its reaction with DPPH to generate DPPH2 which can easily be monitored by UV spectrometry. With this method, Verrall et al. reported a linear correlation between percent degradation of DPPH and free energy of cavitation [185]. 

Fortunately accurate and absolute measurements of the transmitted power are not always required to assess the effectiveness of a given ultrasonic treatment. In many instances, the important thing is to produce a dosimetry method which is reproducible and easy to handle and will achieve relative measurements. Furthermore the convenient method of choice can be calibrated with a more accurate, but probably more tedious one, and from that point on it can be used with more confidence. 

Studies of people occupationally exposed to di- -butyl phthalate are needed to assess the effects of di- -butyl phthalate on human health. Since one of the most significant effects in animals is testicular atrophy, epidemiology studies of reproductive parameters in humans exposed to di- -butyl phthalate would be particularly relevant. Such studies would be most valuable if dosimetry methods could be developed to provide reliable exposure data to accompany health effects data. This would assist in establishing cause/effect relationships and developing methods to monitor individuals living near hazardous waste sites. 

Using epidemiological methods, the relationship between aflatoxln exposure and human liver cancer has been hindered by inadequate data on aflatoxln consumption, excretion, metabolism, and the general poor quality of world-wide cancer morbidity and mortality statistics. Molecular dosimetry methods are needed to help accurately assess an individual s exposure to aflatoxins. This is especially important because of the recent reclassification by the... 

Development of sensitive EPR dosimetry methods , Linkoping University medical dissertations. No. 1044 (2008)] with permission from Dr. H. Gustafsson... 

AR459 1.190 Calculational and dosimetry methods for determining pressure vessel neutron fluence... 

In the following text, a few dosimeter systems will be mentioned that are commonly used in radiation chemistry. For a more detailed treatment of chemical and physical dosimetry, see O Chap. 49 in Vol. 5 on Dosimetry Methods. However, more attention will be paid to pulse dosimetry that is used in pulse radiolysis investigations. 

During irradiation of alkali halide crystals, different F centers form and the transparent crystals become colored (Robinson and Chandratillake 1987 Kroh 1991). During annealing these crystals, and also annealing irradiated aluminum oxide, fluorescence photons are emitted. This phenomenon is utilized in thermoluminescence dosimetry (TLD). (See Sect. 49.3.2.2 in Chap. 49, Vol. 5, on Dosimetry Methods. ) The thermoluminescence of irradiated quartz crystals is used for dating archeological objects. 

Abstract Chemical and physical radiation dosimetry methods, used for the measurement of absorbed dose mainly during the practical use of ionizing radiation, are discussed with respect to their characteristics and fields of application. 

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