A dual modality endocavity imaging and treatment system for detection of cancer and targeted biopsy and treatment procedures, comprising: a housing a nuclear detector system housed within the housing and configured for detecting nuclear radiation imaging data an ultrasound detector system housed within the housing for detecting ultrasound imaging data a needle associated with the housing and adjustably positionable relative thereto and a data processing module configured to receive the nuclear radiation imaging data and the ultrasound imaging data and to generate and output an image showing the relative position of the needle and an endocavity object of interest. The needle may include a distinct radiation signature to facilitate imaging thereof.