A 3-dimensional (3D) ultrasound system and a method for operating a 3D ultrasound system are provided. A 3D ultrasound system includes an extractor, a processor, and a controller. The extractor scans an image of an object in a human body, and extracts a region of interest (ROI) image in an inputted ROI with respect to a selected image. The processor detects edges from a plurality of side images of the object with respect to the ROI image. The controller measures the thickness of the image using the detected edges.
