What is often the first sign of radiation exposure in affected tissues?

The first sign of radiation exposure in affected tissues is often inflammation. When tissues are exposed to radiation, they undergo a response characterized by the activation of immune cells and the release of various cytokines and signaling molecules. This inflammatory response is the body's way of attempting to heal any injury caused by the radiation.

Inflammation serves as an initial protective mechanism, signaling the presence of damage, and helps to mobilize the body's resources to repair the affected areas. This process can lead to symptoms such as redness, heat, swelling, and pain in the impacted region.

Over time, if the radiation exposure is significant, other effects such as fibrosis or cell death may occur, but these generally manifest later than the initial inflammatory response. Therefore, understanding that inflammation is often the first response provides a critical insight into how tissues react to radiation exposure.