Radiation inhibition of arterial restenosis. A new frontier

Our conclusion, is that there is clear evidence of a therapeutic window confirming the effectiveness of irradiation. Using endovascular brachytherapy, the therapeutic window is narrow because large single doses are used, but they are well tolerated because of the small volumes and the rapid decrease in dose with tissue depth. Using external irradiation, fractionation should widen the therapeutic window over single doses, but if conformal therapy is not available, then larger volumes could compromise the results. With radioactive stents, extremely low dose rates lead to protracted irradiation, but with only very small volumes of vessel being exposed. However, there are the additional factors of varying dose rates and the peaks and troughs in spatial dose distribution to be considred. (orig.)