Abstract: The present invention relates to diffuse ultrasound along with chemical agents to treat tissue, called sonodynamic therapy (SDT), and a system for treatment using SDT that comprises a whole body ensonification apparatus and control system. The whole body ensonification may reduce the chances of missing desired tissue that may not be easily detectable or may be found throughout the body. The apparatus has a plurality of diffuse ultrasound transducers for ensonifying at least part of a chamber filled with fluid and designed to accommodate a body for treatment. The person may be treated with sono-sensitive chemical agents, which may be activated when ensonified by the apparatus.