A radiation treatment garment includes, in some embodiments, a window having a visually-transparent material for viewing alignment tattoos on a wearer. In some other embodiments, the radiation treatment garment includes a support pouch for receiving and supporting a male wearer's external genitalia, wherein the support pouch is configured to support the external genitalia in a position that is anterior and superior to the natural gravity-induced position. In some further embodiments, the radiation treatment garment includes both the window and the support pouch.