All organs are not equally damaged by same amount of radiation dosage. But, on which basis equivalency is measured? (i..e 1 gray in this organ equals 10 sievert) Is it arbitrarily qualitative or quantitative as well? Then what is the quantity? ( concentration of reactive oxygen species, DNA mutation frequency, Radiative cellular apoptosis..., percent Coagulation of biomolecules). But all humans are not equally affected by same amount of radiation energy applied on same organ. Then, does the equivalency chart vary from person-to-person, species-to-species, or year to year ?(i.e. refining of values with increasing precision) I f so, thaen how the equivalency are standardized?
For derivation of dose limits, radiation weighting factors, tissue weighting factors etc, you may be interested in
Article Classification of radiation effects for dose limitation purp...
Article History of radiation detriment and its calculation methodolo...
The effective dose weighting factors were developed by the ICRP committee and are not based on experimental evidence. See the similar question
Can any one explain the ICRP dose limits, radiation weighting factors and tissue weighting factors?
Gy (derived from Louis Harold Gray) is an absorbed dose, while Sv (derived from Rolf Maximilian Sievert) is either an equivalent dose (to an organ or a tissue) or an effective dose.
For Hal Gray, you may be interested in
Article The Life of Louis Harold Gray
For derivation of dose limits, radiation weighting factors, tissue weighting factors etc, you may be interested in
Article Classification of radiation effects for dose limitation purp...
Article History of radiation detriment and its calculation methodolo...
There is a problem generated by the ICRP. The Commission limits number of terms for dosimetric quantities in use. As a result:
· gray (Gy) is a unit of adsorbed dose, kerma and RBE weighted dose
· sievert (Sv) is a unit of equivalent dose, dose equivalent and effective dose.
All the quantities are strongly defined in the IAEA General Safety requirements Part 3 (GSR Part 3) available from https://www.iaea.org/publications/8930/radiation-protection-and-safety-of-radiation-sources-international-basic-safety-standards
Therefore, the right question is relationship between dosimetric quantities, but not between Gy and Sv. For more details, see my 2019 publication in IntechOpen uploaded in Research Gate:
Kutkov V. Dosimetry for Use in Preparedness and Response to Radiological and Nuclear Emergency. In: Ionizing and Non-ionizing Radiation/Editor A. Osibote, London: IntechOpen, 2019.
Absorbed dose (Grays) is a well-defined physical quantity.
Equivalent dose (Sieverts) is not a physical quantity, but a regulatory tool. It is supposed to express in a rough way the biological damage produced by radiation. It is fixed by ICRP on basis of a review of available experimental data. But it is inherently an arbitrary average of many non systematic data of various origins, which only includes few among the many factors that may cause variations of the biological effects for the same absorbed dose.
The definition of the sievert was changed several times during the last decades. A sievert in 2019 is not equal to a Sievert in 1980.
The aim of the equivalent dose is to allow a simple and manageable organisation of radiation protection, and it should not be used for other purposes.
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