The efficacy of beta and gamma emitters in reducing clinical and angiographic restenosis in patients with in-stent restenosis has been confirmed by a number of studies. This review is intended to give an overview of the individual trials, summarize pertinent lessons that have been learned and give insight into the future of intracoronary radiation. The encouraging results from the clinical trials have established vascular brachytherapy as a standard of care for patients with in-stent restenosis.