Which of the following is not used as a Radioisotope:

Ans. (d) Iodine-135Ref: Essentials of radiological Science 2nd ed. 115* Iodine-131 is used to treat the thyroid for cancers and other abnormal conditions such as hyperthyroidism* Iridium-192 can be implanted into cancers of the tongue.* Iodine-135 is an isotope of iodine which is an important isotope from the viewpoint of nuclear reactor physics. It is produced in relatively large amounts as a fission product, and decays to xenon-135, which is a nuclear poison.* Caesium-137 is another example of an implantable radioactive isotope used in the treatment of uterine or vaginal cancers.* Radium-223: This is a new radioisotope used in treatment for secondary cancer in the bones.* Strontium-89 and samarium-153: used for treatment of secondary bone CA.