Multispectral camera highlights cancer remnants for removal during
20 November 2013
Researchers at the Fraunhofer Project Group for Automation in
Medicine and Biotechnology (PAMB) have developed a multispectral
fluorescence camera system that can make hidden tumour cells visible
After removing the main piece of tumour tissue tiny clusters of
cancer cells can be left behind as they are difficult to recognize.
Tumour margins blend into healthy tissue and are difficult to
differentiate. Distributed domains of cancer and pre-malignancies
are also difficult to recognize. These pose great challenges even to
skilful and experienced surgeons.
Up to now, doctors have depended exclusively upon their trained
eyes when excising pieces of tumours. The new camera can help
visualize during surgery even the smallest, easy-to-overlook
malignant pieces of tumour and thereby support the surgeons during
Fluorescent molecules that selectively attach to tumour cells are
injected into the patients blood prior to the operation. If the
corresponding area is then illuminated with a specific wavelength of
light, fluorescence is emitted and the malignant tissue glows green,
blue, red, or any other colour, depending on the injected dye, while
the healthy tissue appears the same. In this way, the surgeon can
see clusters of tumours cells that cannot be recognized by the naked
The new camera can display several fluorescent dyes and the
reflectance image simultaneously in real time. This also allows
arteries and delicate nerves that must not be injured during an
operation to be coloured with a specific dye.
Fluorescence imaging showing tissue dyed in two
In the future the camera will be integrated into various medical
imaging systems such as surgical microscopes, endoscopes, etc.
“The visibility of the dye to the camera depends in large part on
the selection of the correct set of fluorescence filters. The filter
separates the incident excitation wavelengths from the fluorescing
wavelengths so that the diseased tissue is also set apart from its
surroundings, even at very low light intensities,” says Nikolas
Dimitriadis, a scientist at PAMB.
The system requires only one camera and one set of filters for
their imaging, which can present up to four dyes at the same time.
The team has also developed software that processes the images iand
presents it continuously on a monitor during surgery. The
information from the fluorescent image is superposed on the normal
“The operator receives significantly more accurate information.
Millimetre-sized tumour remnants or metastases that a surgeon would
otherwise possibly overlook are recognizable in detail on the
monitor. Patients operated under fluorescent light have improved
chances of survival,” says Dr Nikolas Dimitriadis, head of the
Biomedical Optics Group at PAMB.
The multispectral fluorescence camera system can be converted to
other combinations of dyes. One preparation that is already
available to make tumours visible is 5-amino levulinic acid (5-ALA),
which is used for glioblastomas, one of the most frequent malignant
brain tumours in adults. 5-ALA leads to an accumulation of a red dye
in the tumour and can likewise be detected with the camera.
The multispectral fluorescence imaging system should have passed
testing for use with humans as soon as next year. The first clinical
tests with patients suffering from glioblastomas are planned for
PAMB is exhibiting the prototype of the system at the Medica
Trade Fair in Düsseldorf in the joint Fraunhofer booth (Halle 10,
Booth F05) between 20-23 November 2013.