Radiation biodosimetry

Source- This post on “Radiation biodosimetry” has been created based on the article “Radiationbiodosimetry: the ABCs of responding to a radiological event” published in “The Hindu” on 05th July 2024.

Why in the News?

Radiation biodosimetry is extremely important in responding to a large-scale radiological event, such as an Improvised Nuclear Device or reactor accident. It helps in the assessment of the level of radiation and the administration of drugs in accordance with the exposure levels.

What is biodosimetry?

Biodosimetry- Biodosimetry is the determination of the amount of radiation to which an individual was exposed to, based on changes in blood, urine, or hair. It is particularly useful in a radiological event, where the exposed individuals do not carry any personal radiation monitoring devices.

What are the different methods employed in biodosimetry?

1. Gold standard biodosimetry assay/Dicentric Chromosome Assay (DCA) – It involves the measurement of chromosome aberrations, in white blood cells.

Process- In this process when the DNA of a person who is exposed to radiation is irradiated, there is formation of Dicentric Chromosome (DC). These Dicentric Chromosome (DCs) are counted to assess the exposure levels. Higher the DCs, higher is the exposure level.

Advantage and Disadvantage
The Dicentric Chromosome Assay (DCA) has been successfully employed in many radiation accidents, where the number of exposed people is small.
However, when the number of persons exposed to radiation are large, this process is not very useful as it is too labour intensive and has very less output of approxiamtely 10 samples per day.

2. Cytokinesis Block Micronucleus Assay (CBMN)- In this process the white blood cells are made to divide, but arrested before division is complete. Following radiation exposure, some DNA is ejected during division forming a ‘micronucleus‘. This ‘micronucleus‘ helps in determining the exposure to radiation.

Advantage and Disadvantage- This assay is slightly simpler to perform and score. However,the overall time to confirm the exposure level is longer (~3 days), as it requires longer culturing of the cells.

As seen above, the present methods of biodosimetry (DCA and CBMN assays) suffers from the challenge of low scalability and low speed of radiation detection. Center for Radiological Research at Columbia University has established several commercial High Throughput Screening (HTS) platforms, which would significantly increase the radiation detection rates.

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