Abstract: A goniometer for needle placement in connection with a computer tomograph to direct a needle at a proper angle to reach an area for biopsy or other surgical procedures in the human body. One embodiment of the device includes a double ring, the outer ring having arcuate graduations and a level mounted thereon, and the inner ring being rotatable in the outer ring to various angle positions and including a needle carrier for receiving a needle holder.The outer ring has serrations on a continuous arcuate surface and the inner ring has resilient detents to contact and rid on the serrations. A lever operated needle holder has a cam to lock a detent into a serration when the needle holder is moved to a position to retain a needle.