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Foot camera for early detection of rheumatic diseases

Prototype of a camera imaging the changes in blood microcirculation in toes and feet ready for clinical trial

PTB-News 2.2020
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A foot camera makes the blood circulation within the forefoot visible and helps physicians diagnose rheumatic diseases earlier.

Left: Foot phantom imaged by means of the new scanner to check its efficiency. As soon as the device has been approved for clinical trials, images such as those generated by the hand imaging system (right) are expected: sections of two film recordings showing the different distribution of the contrast agent in the hands of a healthy patient (top) and of a patient affected by a rheumatic disease (bottom) approx. 45 seconds after starting the examination.

Rheumatism is considered to be a widespread disease that may affect anyone. To be more precise, rheumatism encompasses various diseases of the locomotor system. Some of the most widespread of them are rheumatoid arthritis and arthrosis. More than a million people are affected in Germany. A few years ago, a fluorescence imaging system to assess microcirculation in the hands was developed with the participation of PTB. Several clinical studies have already been undertaken with this system.

Together with Xiralite GmbH, PTB has now developed a new fluorescence imaging system within the scope of a project funded by the Federal Ministry for Economic Affairs and Energy (BMWi). By applying the contrast agent indocyanine green (ICG), this system visualizes the blood flow in the superficial vessels of the toe joints. Whereas in hand imaging, the examination is limited to the back of the hand, the foot camera is able to acquire data from the vessels both on the upper part and from the lower part of the foot, as it is equipped with several fluorescence cameras and a more complex spatial arrangement of the LEDs used to excite fluorescence. The examination only takes a few minutes. It is painless and free from side-effects. Another advantage of this method is that the foot camera may be used together with the hand imaging system. It is thus possible to examine the joints of both the hands and the toes while administering only one dose of contrast agent. The combined method should allow centers of rheumatism to be detected at an earlier stage than is possible with an X-ray device and at lower cost than with a magnetic resonance tomograph. The prototype has already proven its functional efficiency in exhaustive tests carried out on the model of a foot, and clinical trials are currently being prepared.

The new foot camera can be used not only to diagnose rheumatic diseases, but also as a diagnostic tool for diabetes mellitus and the so-called diabetic foot syndrome. Detecting disturbed microcirculation may help improve a patient᾽s state of health and possibly reduce the number of amputations.


Dirk Grosenick
Department 8.3
Biomedical Optics
Phone: +49 30 3481-7302
Opens window for sending emaildirk.grosenick(at)ptb.de