Tiny endoscopes bring medical costs down

Viewing actual images of patients’ internal organs is more and more common in medical procedures. However, in many cases the treatment can be painful or uncomfortable, and high sterilisation costs can limit the procedure’s use. IVP’s prototypes aim to overcome such challenges.

With the IST project IVP finishing in September 2005, the project partners have developed two key prototypes; a new, smaller wired endoscope (called IVP1), and a tiny wireless-imaging probe taken in the form of a pill (IVP2). Both prototypes are equipped with illumination optics as well as mechanical components for swivelling the inbuilt image sensor. Project coordinator Christine Harendt of the Stuttgart Institute for Microelectronics explains further.

“We now have IVP1 ready – a wired prototype which we believe is currently the world’s smallest endoscope. The head is 3.5 millimetres in diameter, about the size of a match head. The image sensor itself is a typical CMOS chip measuring 2.7 by 2.3 millimetres. The great advantage of our prototype is the fact that the image sensor is incorporated into the head of the endoscope, which provides much better images for the surgeon.”

Harendt explains that existing endoscope heads, with the image sensor integrated into the head, are usually about twice this size. Other types with the image sensor set back from the head of the probe tend to suffer image resolution losses due to the additional fibre-optic link to the head that is needed.

The project team are now finalising the pill-sized wireless IVP2 probe. While the travel of the pill cannot be controlled, a tiny motor in the head enables the image sensor to swivel for views in different directions. The team has chosen to go for an external power source, where the probe draws power by induction from a vest worn by the patient. The vest also picks up the images transmitted by the probe, as well as transmitting them wirelessly to a nearby PC.

Both prototypes transmit colour images. However, Harendt says, the challenge for IVP2 is the bandwidth required. “The images have a high pixel content, which means high data transmission needs, so we are looking at how to compress the data to reduce the bandwidth required.”

Another of the key objectives for the IVP team, she stresses, was to make the technology cheap enough to allow the scopes to be disposable. “Obviously the IVP2 pill is disposable, but if we can also produce the wired IVP1 scope cheaply enough, full disposability brings great advantages for hospitals in reduced sterilisation costs.”

The two prototypes are now being readied for the required medical evaluation tests. One of the project partners, an endoscope manufacturer, is already examining the possibility of turning the IVP1 prototype into a commercial product suitable for use in abdominal surgery, gynaecology, urology and gastro-enterology.