Requirements to MRI and MRS data to be applicable for radiation treatment

Magnetic Resonance Imaging (MRI) use for Radiotherapy planning began in the 1980 and is still developing today. MRI is now an important morphological and functional imaging able to open new diagnostic and planning scenario. As new technologies become more complex, their best clinical application often becomes very difficult. The intent of this paper is to highlight methods and requirements necessary to apply MRI in radiation treatments. The concept of image is still in progress, following the evolution of human body knowledge. Many different methods to get diagnostic information of a tumour will be acquired; MRI images will be more and more important in the next future. The combination of information from complementary imaging modalities is expected to have a great benefit in cancer treatment. This fact is particularly relevant for target definition, which remains, one of the most important sources of error in Radiotherapy. Anatomical imaging with CT and MRI produces different gross tumour volumes. Functional imaging with modalities such as MRI and PET will generally reveal an even different volume. Thus a decision has to be taken about how to combine such information in clinical applications. The solutions of these new problems are 'in progress' and a lot of researches in clinical applications are in discussion