RadioGelTM is a hydrogel liquid containing tiny Yttrium-90 phosphate particles to be injected into a tumor. This hydrogel is a liquid at temperatures below body temperature but begins to gel, harden, upon injection as the temperature increases to normal body temperature, thereby locking the particles in place. The particles emit a very high concentrated and contained beta irradiation to kill the tumor. The beta radiation has a short penetration distance so there is minimal collateral damage to healthy tissues outside of the injected area.