Measuring what happens inside the body during treatment
Medical imaging gives quantitative information about anatomy, physiology and tissue properties. Our research uses magnetic resonance imaging (MRI) not only to see the patient, but to measure what matters for treatment: temperature, tissue composition and the electrical properties that determine how electromagnetic fields behave in the body.
A central focus is the integration of imaging with electromagnetic modelling and therapy, so that treatments can be planned, monitored and adapted for each patient.
MR thermometry measures temperature changes non-invasively using the proton resonance frequency shift (PRFS) of water. During hyperthermia it can replace or complement invasive temperature probes and provide a full 3D temperature map. The technique is sensitive to motion, breathing, susceptibility changes and fat, which is why we develop acquisition and correction methods, such as multi-echo sequences and models that correct for air motion.
We evaluated MR thermometry in the pelvis, the head and neck and the extremities, including multi-institutional studies of MR-guided hyperthermia systems and clinical studies with LMU Munich. See Hyperthermia & MR-Guided Therapy.
Heating a patient inside an MRI scanner requires antennas and applicators that do not disturb the images, and MR coils that work despite the heating hardware. We designed MR-compatible antennas such as a printed Yagi-Uda antenna, the MRcollar applicator for deep heating in the head and neck, water boluses with tailored properties, and a dual-function approach in which the same hardware heats and images. Recent work includes RF coil design for ultra-high-field (7 T) MRI.
The conductivity and permittivity of tissue determine how electromagnetic fields are absorbed, but they differ between patients and are usually taken from literature tables. With TiCEPT (Tissue Composition based Electrical Properties Tomography) we estimate wideband electrical properties from tissue composition measured with quantitative multinuclear MRI of hydrogen, sodium and potassium. This links imaging directly to patient-specific modelling. See Model Inference & Calibration.
Patient-specific treatment planning starts with an accurate 3D model of the patient. We developed automatic segmentation of head and neck CT and MR images, multimodal and groupwise image registration, and methods that adapt models to MR images acquired in treatment position.
Dutch Cancer Society project on multi-coil MR-guided hyperthermia for precision treatment of advanced head and neck cancer.
Collaboration on MR-guided RF hyperthermia, including a visiting research period at GE Global Research in Niskayuna (2016).
European Marie Curie training network on biomedical imaging and informatics, with a work package on MR thermometry.
Erasmus MC and LMU Munich.
MR thermometry uses magnetic resonance imaging to measure temperature changes in the body without inserting probes, most often based on the proton resonance frequency shift of water. It provides 3D temperature maps during thermal therapies such as hyperthermia.
Electrical properties tomography estimates the conductivity and permittivity of tissue from MRI. TiCEPT, developed in the EM4Care+Cure lab, derives these properties over a wide frequency range from tissue composition measured with multinuclear MRI.
Hyperthermia & MR-Guided Therapy Model Inference & Calibration Computational Medicine