What tissue is the most sensitive to radiation therapy?

Bone marrow is the most sensitive tissue to radiation therapy due to its high rate of cell division and proliferation. This sensitivity stems from the fact that bone marrow contains hematopoietic stem cells, which are responsible for the production of blood cells. When radiation is applied, these rapidly dividing cells can be more easily damaged than those in other types of tissues. This can lead to a reduction in blood cell counts, resulting in conditions like anemia, leukopenia, and thrombocytopenia.

In contrast, other tissues such as muscle, soft tissue, and cartilage generally have slower cell division rates and are therefore less sensitive to the effects of radiation. While all tissues have some degree of sensitivity to radiation, bone marrow's critical role in hematopoiesis makes it particularly vulnerable.