An X-ray imaging inspection system for inspecting items comprises an X-ray source 10 extending around an imaging volume 16, and defining a plurality of source points 14 from which X-rays can be directed through the imaging volume. An X-ray detector array 12 also extends around the imaging volume 16 and is arranged to detect X-rays from the source points which have passed through the imaging volume, and to produce output signals dependent on the detected X-rays. A conveyor 20 is arranged to convey the items through the imaging volume 16.