Dosimetry of 188Re and 186Re sources based on Monte Carlo calculations for endovascular brachytherapy after balloon angioplasty

R ecent pre-clinical and clinical studies indicate that irradiation within the dose range of 15 to 30 Gy can reduce the rate of restenosis in patients who have undergone an angioplasty (Nath 1999, King 1998). Several delivery systems of intravascular brachytherapy have been developed to deliver doses within this rang with minimal normal tissue toxicity. One of the possible intravascular irradiation techniques, introduced by Amols and colleagues, is the use of filled balloon with radioactive solution (Amols et al.1996). This method has the advantage of accurate source position and a uniform dose to the vessel wall. However it has a potential of radiological toxicity from the radioactive liquid due to the risk of balloon rupture about 0.1% , (Amols et al.1996), since most commonly available beta emitters e.g. 90Y,32P,166Ho are bone seeking compounds , (Amols et al.1996) . 188Re (E β-max =2.12 MeV , half-life=16.9h ) and 186Re (E β-max =1.07 MeV , half-life=90.6 h ) as Perrhenate or DTPA form rapidly excreted ABSTRACT