Needle insertion in CT Scanner with Image Overlay - Phantom and Cadaver Studies -

We present an image overlay system that assists in surgical needle insertions inside conventional CT scanners. The device is mounted on the gantry of the CT scanner and consists of a flat LCD display and a semi-transparent mirror. In the preoperative calibration process the overlay system and the imaging plane of the scanner are registered. As a result, looking at the patient through the mirror, the CT image appears to be floating inside the patient with correct size and position 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 phantom studies and cadaver experiments in several clinical applications.