Patent ID: 8454488

Claim:
A method for selectively exposing portions of a tissue mass to radiation comprising: providing a plurality of partially attenuated catheters and at least one unattenuated catheter, each partially attenuated and unattenuated catheter comprising a hollow tubular element having a central axis and a distal end portion with an outer periphery, each partially attenuated catheter further including a radiation attenuator partially covering said outer periphery of said distal end portion, wherein said radiation attenuator defines an unattenuated window portion of said distal end; positioning each of said partially attenuated catheters into a tissue mass such that the unattenuated window portion faces a center of mass; positioning the at least one unattenuated catheter proximate the center of mass; inserting a radiation source through the hollow tubular element of one of said partially attenuated catheters such that the radiation source resides proximate the unattenuated window portion; withdrawing said radiation source from the partially attenuated catheter following a predetermined dwell period at the window portion; repeating the steps of inserting and withdrawing the radiation source for each remaining partially attenuated catheter positioned in the tissue mass; inserting the radiation source through the at least one unattenuated catheter; and withdrawing said radiation source from the at least one unattenuated catheter.