Quantification of the whole-body distribution of PET radiopharmaceuticals, applied to 3-N-([18F]fluoroethyl)spiperone.

Using a multi slice whole body PET scanner PC4096-15WB, diagnostic measurements of the cerebral distribution of the D2 receptor ligand 3-N-([18F]fluoroethyl)spiperone were extended to quantify the biodistribution of this PET radiopharmaceutical. As a rotating line source was used for measured attenuation correction, transmission scans could be combined with emission scans even after injection of the tracer. Only 1% of the total administered dose (TAD) was found in the whole brain at 180 min, but the striatum and pituitary were still excellently delineated. Urinary bladder, gall bladder, and liver were the organs with the highest TAD ranging from 6% to 25%. The gall bladder is the critical organ with an absorbed dose of about 200 muGy/MBq followed by the urinary bladder and liver with 83 and 66 muGy/MBq, respectively. In the rest of the body radioactivity was evenly distributed. The total body dose was found to be 11.9 muGy/MBq.