Clinically useful radiation from cobalt 60 is: (A) Gamma radiation, (B) Beta radiation, (C) Alpha paicles, (D) Photons
Answer is A. Cobalt units produce stable, dichromatic gamma beams of 1.17 and 1.33 MeV, resulting in an average beam energy of 1.25 MeV. The cobalt-60 isotope has a half-life of 5.3 years Reference: Eric J Hall Textbook of Radiobiology for Radiologist; 5th edition