PHARMACOKINETICS AND RADIATION-DOSE OF O-15 LABELED BUTANOL IN RCBF STUDIES IN HUMANS

In this positron emission tomography (PET) study in humans we determin ed the pharmacokinetics and radiation dose of oxygen-15 labelled butan ol, a recently introduced tracer for regional cerebral blood flow (rCB F). This report includes a description of the automated preparation of O-15-butanol which allows repetitive activation studies, each 15 min apart. Dynamic rCBF studies were extended by prolonged measurements up to 15 min after injection over different organs such as brain, liver, kidneys and bladder. All measurements were done with a whole-body PET camera PC4096-15WB. Based on the pharmacokinetic data in 13 subjects the radiation doses to single organs were calculated according to MIRD pamphlet No. 11 and the effective dose defined by ICRP 60 as an indic ator of radiation dose to the total body. The liver received the highe st radiation dose of about 2.2 mGy per 1500 MBq of injected O-15-butan ol, which is the typical amount of administered tracer in one rCBF mea surement. The dose to the kidneys was 1.6 mGy, to the stomach 0.8 mGy, and to the brain 0.16 mGy. The effective dose was 0.54 mGy, which was similar to that of (H2O)-O-15, but lower than the effective dose from (CO2)-O-15 in amounts typically applied in human rCBF studies.