Absorbed radiation doses to major human organs after intravenous bolus administration of 2-[(18)F]fluoro-2-deoxy-d-glucose (FDG) were reviewed. Absorbed doses were calculated using the medical internal radiation dose (MIRD) formalism from experimental activity-time curves. Thirty patients (22 with macroscopic lung tumour and 8 without observable disease) were investigated using a state-of-the-art combined positron emission tomography/computer tomography system (Siemens Biograph 64). Each patient underwent a series of 10 consecutive whole-body PET scans during the first 60-min post-FDG administration. Differences were observed between organ radiation doses in this work and those reported in International Commission for Radiation Protection 106 (21 % in effective dose). The presence of tumour did not affect the FDG biodistribution. Large inter-individual variations in organ-absorbed doses were observed. This in combination with the lack of a model for bladder voiding suitable for all patients suggests the need for a more precise estimate of normal-organ radiation doses. This will be beneficial in optimising FDG administration in clinical routine.