In minimally invasive surgery, doctors operate through punctures in a patient’s skin. A long-handled camera called an endoscope snaked into the body lets surgeons see what they’re doing.

Looking to add the sense of touch to these peephole procedures, MIT bioengineering student Jonathan Thierman invented an endoscope that can “feel” anatomical structures. A water-filled rubber membrane on the tip of a probe deforms when pressed against tissue. Changes to a pattern of dots painted on the membrane’s flip-side are captured by a small camera; electronic processing yields a 3-D representation of the tissue surface on a computer. Thierman says the probe can distinguish between tissue densities, allowing detection of a rigid tumor beneath a layer of fat. Doctors will be able to feel as well as see tumors once Thierman maps the image to a force-feed-back device-a project now under way.