miniature swines were randomly divided into irradiation group ( n =7) and control group ( n =8). Immediately after balloon overstretch injury to LAD, radioactive liquid perfused balloon irradiation was performed at the target segment; radioactive dose was 24Gy. 35 days after the operation, the target segments were harvested to perform histologic and morphologic study (HE, MS, VVG) and immunohistochemical study (PCNA, ? smooth muscle actin). Results showed that the lumen area was significantly larger, the neointima area and vascular stenosis level were smaller, and less PCNA positive cells were present in the vascular wall in the irradiation group than in the control group ( P all