säteilyosuus

Säteilyosuus refers to the portion of a dose of ionizing radiation that is specifically absorbed by a particular tissue or organ. It is a crucial concept in radiation protection and dosimetry, as different tissues have varying sensitivities to radiation damage. Understanding the säteilyosuus helps in assessing the biological risk associated with radiation exposure.

When ionizing radiation interacts with matter, it deposits energy. This deposited energy per unit mass is known as absorbed dose, measured in grays (Gy). However, absorbed dose alone does not fully account for the biological impact. The säteilyosuus considers factors like the type of radiation and the radiosensitivity of the exposed tissue. For instance, a gray of alpha radiation is biologically more damaging than a gray of gamma radiation, meaning it has a higher radiation-weighted dose. Similarly, organs like the gonads and bone marrow are considered more radiosensitive than, for example, skin or bone.

In practical radiation protection, the concept is used to calculate effective dose, which represents the overall risk to the whole body from non-uniform radiation exposure. This involves multiplying the absorbed dose in each organ by a tissue weighting factor, which reflects its relative sensitivity, and then summing these values. Therefore, säteilyosuus is a fundamental component in quantifying the potential health effects of radiation exposure and in establishing dose limits for workers and the public.