OVGU_Stimulate_Broschuere_EN

Another milestone is a novel intuitive instrument tracking method. After all, the instruments are to
be safely navigated through the human body and precisely positioned at their target point. “Our
idea is a tracking system with optical Moiré Phase markers”, says the scientist, who explains: "The
Moiré patterns can be compared with lenticular images. They change their appearance with minimal
rotation. The position and orientation of the markers can be measured by a camera inside the
MRI gantry and used to control the MRI image acquisition. When the needle is moved, for example,
through the patient's breathing, the imaging plane follows the movement."
The ablation probes, which are used for the novel local heat therapy of the liver tumor, are to
be guided in this manner. During heat therapy, microwaves heat the tumour from the inside. The
problem: the blood in the blood vessels transports the heat away from the tumour, so that it partially
cools down again.
“The ablation needle can only measure the temperature at its tip. In order to achieve complete
thermometry during the procedure, we would like to use the MRI device itself as a temperature
measuring device," says Dr. Urte Kägebein, naming another milestone. To take the liver as an
example: MRI technology offers a unique opportunity to measure physical parameters such as the
elasticity of liver tissue or temperature distribution. With the help of software developed in-house,
this information would merge with that of the ablation needle to form an image.
“In contrast to diagnostics, additional equipment is needed for the treatment inside the MRI gantry,
as well as medical staff working close to the patient. But the space in the gantry is and remains
limited," says Enrico Pannicke, drawing attention to the challenges posed by individual technical
developments: finding solutions that eliminate the additional power cables, that meet the sterility
demands of an operation, that improve access to the patient, that optimise patient positioning...
The engineers focus on the modular design of a patient table that meets the different scenarios of
an intervention. “It is important,” says Enrico Pannicke, "to ensure that the electronic components
operate in a strong magnetic field and do not interfere with the sensitive measuring system of the
MRI."