Needle insertion in CT scanner with image overlay -cadaver studies

An image overlay system is presented to assist needle placement in conventional CT scanners. The device consists of a flat LCD display and a half mirror and is mounted on the gantry. Looking at the patient through the mirror, the CT image appears to be floating inside the patient with correct size and position, thereby providing the physician with two-dimensional "X-ray vision" to guide needle placement procedures. The physician inserts the needle following the optimal path identified in the CT image that is rendered on the LCD and thereby reflected in the mirror. The system promises to increase needle placement accuracy and also to reduce X-ray dose, patient discomfort, and procedure time by eliminating faulty insertion attempts. We report cadaver experiments in several clinical applications with a clinically applicable device.