the most radiosensitive tissues in the body are hematopoeitic(most commonly myeloid)/GI/germ cells n rapidily dividing tumor cells/lymphocytes.
i would go for myeloid and germ cells(primary spermatocytes).
pls correct me if i am wrong.
myeloid lukemias are the most important complication of radiation exposure other than giinflammations n ulcer/skin changes/ARDS/BONE MARROW DEPRESSION(FAILURE IN SEVERE RADIATION).