Effective dose

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The effective dose, or earlier also the effective equivalent dose, is a measure of human radiation exposure . In addition to the dose equivalent , which already take into account the different effectiveness of the various types of radiation (e.g. alpha , beta , gamma , X-ray or neutron radiation ), the effective dose also takes into account the different sensitivity of the organs to ionizing radiation.

Effective dose in relation to other “dose” terms. See dose equivalent for details .

calculation

To calculate the effective dose , the organ doses H T are multiplied by the tissue weighting factors w T (see below) of the organ T. The sum of the organ doses weighted in this way gives the effective dose:

.

The unit of the effective dose, like that of the organ dose, is the Sievert , abbreviation Sv.

The determination of an effective dose evaluates the different risk of the occurrence of stochastic harmful effects when individual organs and tissues or the whole body are exposed. The human skin is z. B. far less sensitive to radiation exposure than various internal organs .

Tissue weighting factors are proposed for worldwide use by the International Commission on Radiological Protection (ICRP). The tissue weighting factors were introduced in 1977 and last updated in March 2007. The estimated factors are age and gender averaged . Compared to the recommendations of 1990 (ICRP 60), the estimated value of the tissue weighting factor for the gonads has been significantly reduced and a modified estimate of the genetic risk has been taken into account. The ICRP 103 figures form the basis of the radiation protection ordinance applicable in Germany .

Tissue weighting factors

The following table shows proposals made by the ICRP in 1990 and 2007:

Organs and tissues ICRP 60 (1990) ICRP 103 (2007)
Bone marrow (red) 0.12 0.12
Large intestine 0.12 0.12
lung 0.12 0.12
stomach 0.12 0.12
chest 0.05 0.12
Gonads 0.20 0.08
bladder 0.05 0.04
esophagus 0.05 0.04
liver 0.05 0.04
thyroid 0.05 0.04
skin 0.01 0.01
Bone surface 0.01 0.01
brain not defined 0.01
Salivary glands not defined 0.01
other organs and tissues 0.05 0.12
total 1.00 1.00

Other tissues are adrenal glands, upper respiratory tract, gall bladder, heart, kidneys, lymph nodes, muscle tissue, oral mucosa, pancreas, prostate (men), small intestine, spleen, thymus, uterus / cervix (women).

Individual evidence

  1. ↑ Hanno Krieger: Fundamentals of radiation physics and radiation protection . Vieweg + Teubner Verlag, 2007, ISBN 978-3-8351-0199-9 . P. 323
  2. ^ ICRP publication 103, p. 37
  3. ↑ ICRP Publication 103, p. 41
  4. ^ ICRP publication 103, p. 53
  5. ^ ICRP (Ed.): Annals of the ICRP: ICRP Publication 60 - 1990 Recommendations of the International Commission on Radiological Protection . Pergamon Press, Oxford 1991, ISBN 0-08-042275-6 .
  6. ^ ICRP (Ed.): Annals of the ICRP: ICRP Publication 103 - The 2007 Recommendations of the International Commission on Radiological Protection . Elsevier, Amsterdam 2007, ISBN 978-0-7020-3048-2 .
    The recommendations of the International Commission on Radiological Protection (ICRP) from 2007. (PDF; 1.1 MB) ICRP publication 103. Adopted in March 2007. Publications of the International Commission on Radiological Protection. German edition published by the Federal Office for Radiation Protection. P. 61