Dual-Modality Preclinical SPECT/MRI Instrumentation

Single photon emission tomography (SPET or SPECT) and magnetic resonance imaging (MRI) are in use routinely in hospitals worldwide. Each of these modalities is steadily growing in study volume and makes a major contribution to healthcare, with approximately 40 million SPECT and 60 million MRI patient exams completed every year. Also in the preclinical research field both SPECT and MRI are found to play important roles, with an installed base of about 200 microSPECT and 400 small animal MRI systems in use as of the beginning of 2009. The high magnetic field strengths of modern MRI machines, both clinical and preclinical, preclude the use of conventional photomultiplier-tube based SPECT equipment in the vicinity of the magnet. If a patient or a laboratory animal is to be imaged by both modalities, the two studies must be done in separate imaging sessions—always in different rooms and often in different departments and sometimes even in different buildings within a medical facility. Combined SPECT/MRI imaging is important since non-invasive probing of intact, living biological organisms—human or laboratory animal—bridges the gap between exponentially growing understanding of molecular and genetic mechanisms and the phenotypical embodiments of diseases and their response to treatments.