Radioactive Cobalt60 in Plastic Tubing for Interstitial Radiation Therapy1

Whenever a suitable new source of ionizing radiation becomes available, the radiotherapist is challenged or exercise his ingenuity to adapt old technics or invent new ones to exploit fully any physical advantages of the new source over the conventional ones already in use. During the past three years studies have been under way to develop methods by which radioactive cobalt60 may be used interstitially to supplant radium in this form of therapy (1) 2, 3). Some advantages of cobalt60 over radium for this purpose are as follows: (1) The beta radiation is much softer, 0.31 mev (max.) and is easily filtered out. (2) The gamma radiation is homogeneous, 1.16 and 1.31 mev. (3) There is no leakage—no gaseous radioactive daughters. (4) The dangers of breakage are eliminated. (5) Suitable alloys of cobalt are chemically inert. (6) It will not localize in bone; cobalt ions are quickly eliminated. (7) It is magnetic, which makes handling easier and safer. (8) The strength is calculable before irradiation in the pile....