Noninvasively focusing acoustical energy on a mass such as a tumor within tissue to reduce or eliminate the mass. The presence of the mass in the tissue is detected by applying acoustic energy to the substance. The mass is localized to determine its position. Temporal signatures are developed to drive the acoustical energy on the mass. Dynamic focusing of the acoustical energy on the mass to reduce or eliminate it is accomplished utilizing the temporal signatures.
 The United States Government has rights in this invention pursuant to Contract No. W-7405-ENG-48 between the United States Department of Energy and the University of California for the operation of Lawrence Livermore National Laboratory.