Breast phantom for ion chamber dosimetry

For studies of breast treatment techniques, a water phantom has been developed which allows high accuracy dose measurements using an ion chamber. The phantom is made from the torso of a female mannequin, which is supported so that it can be positioned either supine or prone. The back of the mannequin has been cut away to allow the phantom to be filled with water when positioned prone. The phantom can be simulated, planned, and treated in the manner of a patient. During “treatment” (prone rather than supine), ion chamber measurements can be made at any desired point within (or outside) the treatment volume. The ion chamber support system accurately assigns an (x, y, z) coordinate to each detector position within the phantom.