Cancer particle implantation has a certain amount of radiation, and with active protection, the radiation hazard will be greatly reduced. Cancer particle implantation generally uses iodine-125 particles, which are low-energy gamma rays with an average energy of 28kev and a half-life of 59.4 days. the common activity of the particles is 0.3-0.8mCi and the effective radiation diameter is 1.7cm. the energy is very low and the penetration distance is short. 2-4mm away from the radiation source, the radiation dose will be reduced by 80%-93%. Lead has a good absorption of iodine-125 with 0.1mm lead. Patient iodine-125 particle implantation, after wearing lead suit can reduce the radioactivity to 1%, which can greatly reduce the radiation dose to the staff. No special protection is needed after cancer particle implantation.