Risks and Safety Aspects of MR-PET

The introduction of MR-PET systems into medical practice not only may lead to a gain in clinical diagnosis as compared to PET-CT imaging due to the superior soft tissue contrast of the MR technology but can also substantially reduce exposure of patients to ionizing radiation. On the other hand, there are also risks and health effects associated with the use of diagnostic MR devices that have to be considered carefully. In this chapter, the biophysical and biological aspects relevant for the assessment of health effects related to the use of ionizing radiation in PET and (electro)magnetic fields in MR are summarized. On this basis, the current safety standards will be presented – which, however, do not address the possibility of synergistic effects of ionizing radiation and (electro)magnetic fields. In the light of the developing MR-PET technology, it is of utmost importance to investigate this aspect in more detail for exposure levels that will occur at MR-PET systems. Finally, some considerations concerning the justification and optimization of MR-PET examination will be made.