The disclosure describes a device for asymmetrical irradiation of a body cavity or site, such as after removal of tissue, e.g. biopsy or lumpectomy. The device includes an elongated tubular shaft having an inner lumen and a tubular wall with a plurality of lumens extending within the wall which are configured for receiving a radiation source. The distal portion of the tubular shaft is cut into a plurality of longitudinally separated wall segments with a lumen extending within at least one of the wall segments. A support member is positioned within the separated wall segments to support and position the wall segments in a desired configuration for brachytherapy. An expandable member such as an inflatable balloon is mounted on the distal shaft portion about the separated wall segments wall which when inflated secures the distal shaft portion within a desired intracorporeal site for brachytherapy treatment.