Department of Radiology
Imaging Division
University Hopital Zürich

Within the last years, hybrid PET/MRI systems have been introduced as a new imaging modalitiy combining a Positrone-Emission-Tomograph (PET) with a highfield Magnetic-Resonance Imaging (MRI) scanner. This technique has become feasible by the replacement of the conventional photomultiplier tubes with semiconductor avalanche photodiodes (APDs) in the PET detector ring, thereby allowing the construction of a MR-compatible PET system. These systems provide the combined advantages of both imaging technologies: the high intrinisic soft-tissue contrast of MRI with the biochemical and metabolic information from PET.

Though the first PET/MRI systems allowing for simultaneous image acquisition with both scanner types are now commercially available, many different aspects of this new technique remain to be further improved, e.g. in conventional PET/CT installations the implemented CT scanner provides information for attenuation correction of the PET data sets. The conversion of CT data to PET attenuation maps is easy to perform, whereas the calculation of attenuation maps from MRI data is technically challenging and still not completely solved. Moreover, oncological whole-body imaging with PET/MRI is hamepered by the lacking of a suitable MRI technique for lung assessment.

Our group established close collaborations to the Department of Nuclear Medicine of the USZ as well as to the University of Tübingen (Germany) to develop, improve and evaluate PET/MRI techniques for clinical applications.

The figure to the left displays an overlay image of simultaneously acquired PET and MRI data sets in a patient with an intracranial mass. The 13C-methionine PET shows increased amino acid metabolism, whereas the fractional anisotropy map of diffusion tensor MRI visulaizes fiber tracts.

Selected contributions
Stegger L, Martirosian P, Schwenzer N, Bisdas S, Kolb A, Pfannenberg C, Claussen CD, Pichler B, Schick F, Boss A. Simultaneous PET/MR imaging of the brain – Feasibility of cerebral blood flow measurements with FAIR-TrueFISP arterial spin labeling MRI. Acta Radiologica (in Press)

Stolzmann P, Veit-Haibach P, Chuck N, Rossi C, Frauenfelder T, Alkadhi H, von Schulthess GK, Boss A. Detection Rate, Location, and Size of Pulmonary Nodules in Three-modality PET/CT-MR: Comparison of low-dose CT and Dixon-based MR Imaging. Investigative Radiology (in press)

Schwenzer NF, Stegger L, Bisdas S, Schraml C, Kolb A, Boss A, Müller M, Reimold M, Ernemann U, Claussen CD, Pfannenberg C, Schmidt H. Simultaneous PET/MR imaging in a human brain PET/MR system in 50 patients-Current state of image quality. Eur J Radiol. 2012 Jan 17. [Epub ahead of print]

Boss A, Stegger L, Bisdas S, Kolb A, Schwenzer N, Pfister M, Claussen CD, Pichler BJ, Pfannenberg C. Feasibility of simultaneous PET/MR imaging in the Head and Upper Neck Area Eur Radiol, 10.2.2011, Epub ahead of Print

Thorwart D, Henke G, Müller AC, Reimold M, Beyer T, Boss A, Kolb A, Pichler BJ, Pfannenberg C. Simultaneous [68Ga]DOTATOC PET/MR for IMRT treatment planning of meningioma: First experience. Int J Radiat Oncol Biol Phys. 81(1):277-83 (2011)

Boss A, Bisdas S, Kolb A, Hofmann M, Ernemann U, Claussen CD, Pfannenberg C, Pichler BJ, Reimold M, Stegger L. Hybrid PET/MRI of intracranial masses: initial experiences and comparison to PET/CT. J Nucl Med. 51(8):1198-205. (2010)

Boss A, Kolb A, Hofmann M, Bisdas S, Nägele T, Ernemann U, Stegger L, Rossi C, Schlemmer HP, Pfannenberg C, Reimold M, Claussen CD, Pichler BJ, Klose U. Diffusion tensor imaging in a human PET/MR hybrid system. Invest Radiol. 45(5):270-4. (2010)

Bisdas S, Nägele T, Schlemmer HP, Boss A, Claussen CD, Pichler B, Ernemann U. Switching on the lights for real-time multimodality tumor neuroimaging: The integrated positron-emission tomography/MR imaging system. AJNR Am J Neuroradiol. 2010 Apr;31(4):610-4.

Research Topics
Contact Information
Andreas Boss
Department of Radiology
Imaging Division
University Hospital of Zürich
Rämistr. 100
8006 Zürich
Tel.: +41-44-2553677
FAX: +41-44-2554344