Suppose two people are exposed to equal doses of radiation (equal number of rads) inside their bodies. Suppose that the first person is exposed to alpha radiation, while the second person is exposed to protons. How many times worse is the biological risk for the first person than the second as a result of radiation weighting?
Biology · High School · Thu Feb 04 2021
Answered on
To determine how many times worse the biological risk is for the first person who is exposed to alpha radiation compared to the second person who is exposed to protons, we must consider the concept of radiation weighting factors, also known as radiation quality factors.
Radiation weighting factors are a way to account for the different levels of biological damage caused by different types of ionizing radiation. These factors are assigned by the International Commission on Radiological Protection (ICRP) and take into account the linear energy transfer (LET) of the particles, which essentially measures how much energy they deposit into biological tissue per unit length.
The radiation weighting factor for alpha particles is typically set at 20. This is because alpha particles are heavy, charged particles that have high LET, and therefore they can cause significant damage to cells and DNA by depositing a lot of energy over a short distance.
In contrast, protons are also charged particles but are much lighter than alpha particles. The radiation weighting factor for protons is generally lower, often around 2, because they have less mass and cause less concentrated damage along their path.
To find out how many times worse the biological risk is for alpha radiation compared to proton radiation, you can simply take the ratio of the weighting factors:
Biological risk ratio = (weighting factor for alpha radiation) / (weighting factor for protons) Biological risk ratio = 20 / 2 Biological risk ratio = 10
This means that if both the first person and the second person receive the same number of rads, the biological risk from alpha radiation is 10 times worse than that from proton radiation, based on the radiation weighting factors.