“…Like other β-radiation sources, Y 90 β-electrons do not penetrate as deep as iodine-125 (I 125 ) or palladium-103 (Pd 103 ) photons. 5 , 6 Therefore, for an equivalent depth dose, Y 90 will deliver more radiation to the ocular surface, with less side scatter to normal ocular tissues. Another difference is that I 125 , Pd 103 , and Ru 106 plaques emit radiation at low dose rates, resulting in application times ranging from several days to 1 week.…”