Brachytherapy after angioplasty is an effective technique to avoid this adverse effect. It utilizes radioactive isotopes placed in vessels subjected for radiation. Several experimental and clinical studies showed the efficacy of brachytherapy and established the dose of radiation. However no study was reported so far checking the effects of different dose rates. Therefore the aim of this experiment is to check the effect of different dose rates on neointima proliferation utilizing P32 after PTCA, establish its role on vessel remodelling as well as to examine its safety (thrombosis and vessel injury). A total of 117 porcine arteries were subjected to toxicity, balloon in jury or stenting followed by 20-235 cGy/s of intracoronary radiation (ICR) from a centred P32 source wire to 1 mm beyond lumen surface or a sham ICR procedure. After 4 weeks angiography and IVUS was performed, animals were euthanized and vessels were harvested for histomorphometry. Brachytherapy is an effective method to decrease restenosis after PTCA; No edge effect was observed; Thrombus formation was more frequent after ICR; Thrombosis did not exceed 50% of the vessel lumen and was related to wall injury; Thrombosis did not correlate with dose rate; In the toxicity group and after balloon injury dose rate had a big impact on vessels positive remodelling; Inhibition of neointima proliferation was the main ; effect of brachytherapy in stented vessels; Dose rate up to 235 cGy/s is safe and effective to reduce restenosis after PTCA.