Abstract: There is an "edge effect" or "candy wrapper" problem at the stent edges for β-particle emitting stent im-plantation. The mechanism for "candy wrapper" may conclude low activity level of radiation, aggressive injury to vessel at the margins of the stent and neointimal proliferation due to low-dose radiation stimulation. The methods to solve the "candy wraper" could be proposed:(1) the square-shouldered balloon, (2) the cold-end stent, (3) the hot-end stent, (4) a self-expanding radioactive stent, (5) theγ-stent and so on.