Dosimetric quality and evolution of edema after low-dose-rate brachytherapy for small prostates: Implications for the use of newer isotopes

Although smaller prostates have greater Day 1 swelling, good Day 30 dosimetry can be achieved, making them excellent candidates for 125I seeds (half-life [t½] = 60 days). Smaller prostates may be suboptimal for shorter t½ sources such as 131Cs (t½ = 9.7 days), in which the majority of the dose may be delivered to an edematous gland, unless the planning is adjusted to anticipate the edema.