Diagnostic needle biopsies for tissue biomarker profiling are performed through fine needle aspiration (FNA) or core needle biopsy (CNB). CNB provides larger tissue samples than FNA and is desirable for extracting the increased material volume necessary for biomarker profiling. CNB is generally performed by radiologists using ultrasound imaging or computed tomography to determine when the needle reaches the targeted tumor mass. Even with these guidance methods, the effectiveness of tumor detection is still unacceptably low. Some biopsy procedures have reported failure rates between 25-75% in acquiring diagnostically relevant tumor samples. In this SBIR Phase I program, Actuated Medical, Inc. will develop the PSITE ? Photoacoustic System Identifying Tumor Edges - to maximize viable tumor sample volume during CNB. The PSITE is a disposable optical fiber-biopsy needle system used to differentiate healthy and tumor tissues. PSITE will use multispectral photoacoustic signals in a ?line-imaging? biopsy needle system to differentiate healthy and tumor cells in situ, up to 2cm along the trajectory path in front of the needle. This additional information will allow the radiologist to evaluate tumor content along the entire CNB throw distance and reposition the capture needle before it is triggered to optimize the amount of tumor captured.