The EU MATHIAS project has developed a new clinical imaging method that could enable doctors to tackle one of the main killers of patients with a weakened immune system. The new test involves attaching radioactively labelled antibodies to the infecting structures formed by the fungus Aspergillus fumigatus that is the primary cause of invasive pulmonary aspergillosis. At present, a definitive diagnosis for the disease is only obtained at autopsy or relies heavily on an invasive biopsy, an extremely unpleasant procedure that involves the taking of tissue samples or fluid from a patient‘s lungs, which is not always applicable in suffering patients. By using radioactively labelled antibodies in the new imaging method, clinicians are able to clearly see the growing fungus. The project researchers used a combination of PET and MRI imaging, diagnostic tools that are available in most hospitals, to identify the disease and to rule out lung infections caused by other pathogens, such as bacteria or viruses.