Jaane Rauschenberg1, Andr De Oliveira2, Florian Maier1, Wolfhard Semmler1, Michael Bock1
1Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany; 2Siemens AG, Erlangen, Germany
Passive markers such as contrast-agent filled spheres provide a cost-effective and reliable method to localize devices in an MR system. In this work two real time methods are evaluated that track the position of a robotic assistance system with passive markers. A fully automatic localization algorithm with sub-pixel precision, a combination of a phase-only cross correlation with a center-of-mass algorithm, is compared to a direct coordinate exchange between robot and MR. Slice positions and orientations are evaluated in a phantom experiment yielding a similar angular precision of about 1.3 for the needle axis.