The role of PET scanning in determining pharmacoselective doses in oncology drug development.

Molecular imaging is the most sensitive and specific method for measuring in vivo molecular pathways in man. Its use in oncology has developed significantly over the last 5-10 years. Molecules can be labelled with positron emitting isotopes and the emitted radiation is detected using sensitive positron emission tomography (PET) cameras. It is now possible to measure in vivo and normal tissue pharmacokinetics of anti-cancer drugs and investigate their mechanism of action. Radiolabelling of tracers can be used to measure specific pharmacodynamic endpoints and target identification. Increasing evidence shows how these technologies, when added to early drug development, can rapidly reduce the time for entry into man and early identification of mechanisms of action. With the move towards more segmented markets and identification of specific subgroups, PET's use for noninvasive biomarkers will become in- creasingly important. However, much international effort between academia and industry is required with prioritisation of development of this technology.