Brachytherapy applicators incorporate various forms of selective shielding devices for controlling the direction and intensity of radiation directed at a patient's tissue. In some forms the applicators include a retractable sheath, in some a series of retractable fingers. In other forms the applicator, having an inflatable balloon, has a shield which is retractable from a position adjacent to the balloon or retracted from the balloon, or a shield can itself be inflatable, separately or together with the balloon.