The radioactive isotope used in the treatment of cancer is:

(a) plutonium-239

(b) arsenic-74

(c) cobalt - 60

(d) iodine-131

Blood cancers affect the production of blood cells. They are of many types and Leukaemia is one of them. It is treated with the isotope Iodine-131.

There are two types of isotope; Iodine-131-M195 and Iodine-131-HuM195. Both are considered safe for blood cancer treatment as a part of anti-leukemic therapy before other advanced treatments like the transplant of bone marrow, etc. is considered.