Effective dose equivalent calculation

The fraction of unattached daughters (fp), the equilibrium factor (F) and the activity median diameter (AMD) are plotted in Figure 6 for all the measurements. The AMD is derived from the aerosol measurements. These three parameters are important in the dosimetric models. At the top of Figure 6 the effective dose equivalent is plotted, computed with two models called the J-E (Jacobi-Eisfeld) and J-B (James-Birchall) models in the NEA-report (1983, table 2.9, linear interpolation between AMD=0.1 and 0.2 ym). The figure also shows the effective dose equivalent calculated from the equilibrium equivalent radon concentrations with the NEA dose conversion factor (NEA,1983, table 2.11). 

Table D-4. Weighting Factors for Calculating Effective Dose Equivalent for Selected Tissues...

Then the unattached fraction was calculated in each measurement and was found to be between. 05 and. 15 without aerosol sources in the room and below. 05 in the presence of aerosol sources. The effective dose equivalent was computed with the Jacobi-Eisfeld model and with the James-Birchall model and was more related to the radon concentration than to the equilibrium equivalent radon concentration. On the basis of our analysis a constant conversion factor per unit radon concentration of 5.6 (nSv/h)/(Bq/m ) or 50 (ySv/y)/(Bq/m3) was estimated. 

Figure 7. Effective dose equivalent per hour and per unit radon concentration (AJ-B, 7 J-E) as a function of the equilibrium factor. The full lines are calculated with the mean values of the 72 measurements (Xa -. 37/h, XVent . 41/h, P -. 53, A.M.D. —. 15 lJm) and changing attachment rates.

Figure 9. Effective dose equivalent per hour and per unit radon concentration (A J-B, V J-E), equilibrium factor ( ) and unattached fraction (o, right ordinate) versus the attachment rate. The curves are calculated as in Figure 7.

The calculation of effective dose equivalent is sometimes used even when reporting values for natural radioactivity. The concept of effective dose equivalent was developed for occupational exposures so that different types of exposure to various organs could be unified in terms of cancer risk. It is highly unlikely that the general population would require summation of risks from several sources of radiation exposure. 

It is now usual to calculate the effective dose equivalent (Appendix 1.2). The dose equivalent measured in Sieverts (Sv), takes into account the relative biological efficiency of different radiations. For gamma and beta radiation, the conversion factor is unity, but for alpha radiation it is 20. The effective dose equivalent allows also for the relative importance of irradiation of various organs to the risk of cancer. To convert thyroid dose from beta particles, measured in Gy, to effective dose equivalent, a factor 0.03 is applied. Thus the maximum thyroid doses estimated by Loutit et al. correspond to effective dose equivalents of 4.8 mSv (child) and 1.2 mSv (adult). Adding the external whole body gamma radiation, for which the conversion factor is unity, gives 5.4 mSv (child) and 1.8 mSv (adult). 

Tissue weighting factors are used with the tissue dose equivalent Hr to calculate the effective dose equivalent HE ... 

The liver, spleen, and red marrow are the most exposed organs. Calculations of the absorbed radiation dose resulting from liver and spleen scintigraphy are based on technetium-labeled colloids (International Commission on Radiological Protection 1987). The effective dose equivalent is 0.014 mSv/MBq. The effective whole-body dose in adults (70 kg) resulting from an intravenous injection of 185 MBq of Tc-tin colloid is... 

The effective dose equivalent per ICRP 62 has been replaced by the quantity effective dose. Values per unit administered activity were published in Addendum 1 (International Commission on Radiological Protection 1991). Values calculated accordingly are slightly lower than the effective whole body doses presented here. 

Based on a model for the subcutaneous injection of Tc-(Sb)-sulfide colloid into the umbihcal region, Bergquist et al. (1982) have calculated the radiation dose at the injection site assuming a tissue volume of 10 ml. Injection of 37 MBq (1 mGi) results in an average radiation dose of approximately 300 mGy at the injection site. The effective dose equivalent was determined as 0.005 mSv/MBq (Bergqvist et al. 1982). 

By considering all possible transfer routes, one can estimate what amount of a radionuclide released to the environment may end up in plants, animals, or man. When these figures are combined with the dose conversion factors ("committed effective dose equivalent per unit intake", according to ICRP) in Table 18.12, it is possible to calculate the dose received by man from intake of a radionuclide in the environment. The dose conversion factors dep d on the mode of intake (usually only inhalation or ingestion). Thus... 

TABLE 18.A4 Calculated effective dose equivalent and organ doses compared to the applicable FDA limits. 

The effective dose equivalent in man in millirem (mrem) is calculated using the following equation ... 

Activities, exposure rates in air, and dose rates (effective dose equivalent (EDE), anterior/posterior) were calculated for the unshielded case for the °°Mo product extraction samples in the SGB as weli as 20 A7100 ml Dilution samples in the Hood. The results (shown below) were used to assess unmitigated consequences. 

For calculating the effective dose equivalent, the values of the weighting factor (wT) are ... 

In the BSS [2] and in the 1990 Recommendations of the ICRP [6], the approach to calculating the committed effective dose is based on that used for the calculation of committed effective dose equivalent, although as a result of improved information on the late effects of radiation on the tissues of the body some changes have been made to the values of tissue weighting factors and a greater munber of tissues now have specified weighting factors (see Table A-in). 

For the sensitivity analyses, total effective dose equivalent (TEDE) was calculated for individual radionuclides at 50 000 yr for a receptor group 20 km down-gradient from the proposed repository. A total of 250 realizations were used to represent the range in TEDE resulting from parameter uncertainty. 

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