Inclusion Criteria:  Males (n=4) or females (n=4) age 18 years or older Stated willingness to comply with all study procedures and availability for the duration of the study. Ability to give study-specific written informed consent.  Exclusion Criteria:  Pregnant or lactating females (positive pregnancy test) Metal implants (e.g. pacemakers, osteosynthesis material) Body weight > 100 kg Severe claustrophobia Abnormal kidney or liver function tests Unable to comply with study requirements