Abstract: The invention relates to an apparatus for selective destruction of cells including soft tissues and bones inside a living subject's body.This apparatus is characterized in that it comproses:means for generating gas bubbles in situ within the cells to be selectively destroyed, andimplosion means capable of provoking the implosion in situ of the gas bubbles, thereby destroying the cells to be destroyed which are adjacent the imploded gas bubbles.The invention makes it possible to destroy cells inside a living subject's body by a non-invasive and extracorporeal and also extremely simple and efficient way, further permitting the treatment of metastases.