From these discussions we can conclude that Bone marrow is the most radiosensitive tissue of the body.

What tissue type is most radiosensitive?

Amongst the body cells, the most sensitive are spermatogonia and erythroblasts, epidermal stem cells, gastrointestinal stem cells. The least sensitive are nerve cells and muscle fibers.

Which of the following tissues or organs is the most sensitive to radiation?

For example, since the blood forming cells were one of the most sensitive cells due to their rapid regeneration rate, the blood forming organs are one of the most sensitive organs to radiation. Muscle and nerve cells were relatively insensitive to radiation, and therefore, so are the muscles and the brain.