Development of a simultaneous PET/MRI scanner

A combined magnetic resonance imaging (MRI) and positron emission tomography (PET) scanner would be a great benefit to nuclear medicine. The anatomical detail given by MRI and spectroscopy available with magnetic resonance spectroscopy (MRS) complement the quantitative physiological imaging obtained with PET. Such a device has not become a reality because of the incompatibilities of photomultiplier tubes (PMTs) and their associated electronics with MRI´s high magnetic fields, as well as significant constraints on PET camera size due to the limited patient port of MR scanners. Recent advances in solid-state electronics have opened the possibility of replacing photomultiplier tubes with avalanche photodiodes (APDs) that are compact and do not share the vulnerabilities of PMTs to magnetic fields. Currently, we are planning to build a miniature PET tomograph using only solid-state electronics to give a combination MRI/PET scanner for small animals. This technology, once developed, can be extended to human scanner designs.