Photogen Technologies has announced a joint venture with Elan Corporation to develop and commercialise nanoparticulate diagnostic imaging agents for the detection and treatment of cancer that has spread to patients' lymph nodes. The goal of the joint venture, according to Photogen, is to develop a treatment that would more than halve the number of lymph node surgeries by precisely locating the nodes where cancer has spread and at the same time, if necessary, treating the affected lymph nodes in one non-invasive procedure.