Medical imaging
Because CT and MRI are sensitive to different tissue properties, the appearances of the images obtained with the two techniques differ markedly. In CT, X-rays must be blocked by some form of dense tissue to create an image, so the image quality when looking at soft tissues will be poor. In MRI, while any nucleus with a net nuclear spin can be used, the proton of the hydrogen atom remains the most widely used, especially in the clinical setting, because it is so ubiquitous and returns a large signal. This nucleus, present in water molecules, allows the excellent soft-tissue contrast achievable with MRI.
Positron emission tomography–magnetic resonance imaging
Presently, the main clinical fields of PET-MRI are oncology, cardiology and neurology. Research studies are actively conducted at the moment to understand benefits of the new PET-MRI diagnostic method. The technology combines the exquisite structural and functional characterization of tissue provided by MRI with the extreme sensitivity of PET imaging of metabolism and tracking of uniquely labeled cell types or cell receptors.
There is discussion and investigation into utilizing PET-MR with Ion Therapy for the purpose of cancer treatment. with MRI's ability to accurately depict the proton density of tissue is a good match for the benefits and technical challenges of treatment planning utilizing Ion Therapy systems.