This book contains twenty-one selected papers based on communications presented at the "Third International Meeting on Fully Three-Dimensional Image Reconstruction in Radiology and Nuclear Medicine", held July 4-6, 1995 at Domaine d'Aix- Marlioz, Aix-les-Bains, France. 3D tomographic imaging systems based on ionising radiations tend to use 2D detectors in order to improve the radiation detection efficiency. Then, fully 3D image reconstruction algorithms are required to recover the 3D image of the region of interest. These systems include 3D radiology, 3D X-ray computerised tomography, single photon emission computerised tomography (SPECT), and positron emission tomography (PET). The material is this text divided into four parts covering the following topics: cone-beam and new geometries reconstruction, SPECT quantitation, patient motion and gated SPECT, and PET quantitation and reconstruction.Aud ience:This work will be of interest to scientists, physicists and physicians seeking new information and insight in the on-going research work in this expanding field.