Physics of Molecular Imaging Systems

The group has developed a new detector concept for simultaneous Positron Emission Tomography (PET) and Magnetic Resonance (MR) Imaging and has applied it in a pre-clinical PET/MR scanner. The new MR-compatible detector stack uses analog and digital Silicon PhotoMultiplier (SiPM) technology which will further advance the performance (sub-nanosecond coincidence resolution time) of future semiconductor-based PET systems. The team has developed a new data acquisition and control environment that enables purely software-based data processing. With this, the application of new iterative algorithms becomes possible, such as self-normalization and -calibration, or maximum likelihood crystal identification to improve the image resolution and sensitivity. A special gamma-transparent radio frequency coil supporting simultaneous PET/MR has been developed for imaging of animals with a size up to rabbits.

    Selected publications

    Research Papers
    1. Schulz V, Torres-Espallardo I, Renisch S, Hu Z, Ojha N, Börnert P, Perkuhn M, Niendorf T, Schäfer WM, Brockmann H, Krohn T, Buhl A, Günther RW, Mottaghy FM, and Krombach GA. Automatic, three-segment, MR-based attenuation correction for whole-body PET/MR data. Eur J Nucl Med Mol Imaging. 2011;38(1):138‑52.
    1. Salomon A, Goedicke A, Schweizer B, Aach T, and Schulz V. Simultaneous reconstruction of activity and attenuation for PET/MR. IEEE Trans Med Imaging. 2011;30(3):804‑13.
    1. Truhn D, Kiessling F, and Schulz V. Optimized RF shielding techniques for simultaneous PET/MR. Med Phys. 2011;38(7):3995‑4000.
    1. Berker Y, Franke J, Salomon A, Palmowski M, Donker HCW, Temur Y, Mottaghy FM, Kuhl C, Izquierdo-Garcia D, Fayad ZA, Kiessling F, and Schulz V. MRI-based attenuation correction for hybrid PET/MRI systems: a 4-class tissue segmentation technique using a combined ultrashort-echo-time/Dixon MRI sequence. J Nucl Med. 2012;53(5):796‑804. Erratum in: J Nucl Med. 2012 Sep;53(9):1496.
    1. Salomon A, Goldschmidt B, Botnar R, Kiessling F, and Schulz V. A self-normalization reconstruction technique for PET scans using the positron emission data. IEEE Trans Med Imaging. 2012;31(12):2234‑40.
    Reviews / Perspectives
    1. Keereman V, Mollet P, Berker Y, Schulz V, and Vandenberghe S. Challenges and current methods for attenuation correction in PET/MR. MAGMA. 2013;26(1):81‑98.

     

    Upcoming conferences

    • Mar 2014: International Workshop on Magnetic Particle Imaging 2014 (IWMPI)
    • May 2014: Joint Annual Meeting ISMRM-ESMRMB 2014 (ISMRM)
    • May 2014: 3rd Conference on PET/MR and SPECT/MR (PSMR)
    • Jun 2014: 9th European Molecular Imaging Meeting (EMIM)
    • Jun 2014: SNMMI 2014 Annual Meeting (SNMMI)
    • Sep 2014: Sventh Annual World Molecular Imaging Congress (WMIC)
    • Oct 2014: 27th Annual Congress of the European Association of Nuclear Medicine (EANM)
    • Nov 2014: Nuclear Science Symposium and Medical Imaging Conference 2014 (NSS/MIC)

     

    Open topics for Master’s theses

    Group members

    Yannick (Dipl.-Ing. in Electrical Engineering, RWTH Aachen University, 2010; Diplôme d’Ingénieur, Ecole Centrale Paris; BSc/MSc in Physics, Université Paris-Sud) explores new methods for PET attenuation correction in PET/MR. His main areas of research are MR pulse sequence development and image post-processing, as well as PET image reconstruction and novel contrast mechanisms.

    Pierre (Dipl.-Ing. in Electrical Engineering, Technische Universität Darmstadt) focuses his research on concepts and designs of FPGA-based scalable and modular PET data acquisition architectures suitable for simultaneous PET/MR imaging with support for analogue as well as digital Silicon Photomultiplier (SiPM) detectors. Such a platform will be the enabler for real time FPGA-based PET data processing for novel crystal positioning algorithms, which is a further research domain Pierre is focusing on in his Ph.D. work.

    Benjamin holds a Diploma in Computer Engineering from RWTH Aachen University. He develops novel processing algorithms for hybrid PET/MR scanners with fully digital readout. Here, he focuses on real-time singles and coincidence processing of digital PET detector raw-data and the development of highly scalable PET computing architectures.

    André (Dr.-Ing. in Electrical Engineering, RWTH Aachen University, 2011) explores and develops novel reconstruction and simulation software algorithms for emission tomography in clinical whole-body and small-animal 3D PET and SPECT imaging.

    David (MSc in Physics, RWTH Aachen University, 2011) works on PET detector technologies for digital PET/MR. He evaluates the capabilities of the digital SiPM chip and develops novel signal processing algorithms. Further research topics are monolithic and complex crystal architectures.

    Marcel (BSc/MSc in Physics, RWTH Aachen University, 2012) works on Magnetic Particle Imaging (MPI) detector technology. The focus of his work is the exploration of enhanced magnetic field configurations and the development of reconstruction algorithms.

    Daniel (MD Student RWTH Aachen University, Dipl.-Phys. RWTH Aachen 2007, MSc Imperial College London 2006) works on shielding enclosures for PET detectors in PET/MR. His main focus lies on eddy current calculations and optimisation of shielding setups in the high frequency range. In addition, he explores methods and MR sequences to quantify the effect of non-magnetic metallic conductors (e.g. copper) on image quality in an MR device.

    Jakob (BSc/MSc in Physics, RWTH Aachen University, 2011) works on the electromagnetic integration of the PET/MR project. The target of his work is to explore the possibilities of highly integrated PET/MR devices and to study interference phenomena between these two imaging modalities. In addition, he supports the 19F-MRI project by investigating quantitatively the suitability of different fluorine samples.