Scatter modelling and correction strategies in fully 3-D PET

PET offers the possibility of quantitative measurements of tracer concentra tion in vivo. However, there are several issues that must be considered in order to fully realise this potential. Whilst, a correction for a number of background and physical phenomena need to be performed, the two most signi ficant effects are the photon attenuation in the patient and the contributi on in the images of events arising from photons scattered in the patient an d the gantry. The non-homogeneous distribution of attenuation within the th oracic cavity complicates the interpretation of PET images and precludes th e application of simple scatter correction methods developed for homogeneou s media. The development of more sophisticated techniques for quantificatio n of PET images are still required. Recent progress in 3D PET instrumentati on and image reconstructions has created a need for a concise review of the relevance and accuracy of scatter correction strategies. Improved quantifi cation of PET images, remains an area of considerable research interest and several research groups are concentrating their efforts towards the develo pment of more accurate scatter modelling and correction algorithms. ((C) 20 01 Lippincott Williams & Wilkins).