X-ray computed Tmography in situ? Yes, it is possible!

X-ray computed tomography (CT) is widely used in medicine as a diagnostic tool for human health. However, it is also becoming a diagnostic technique useful in the cultural heritage field, because it enables a detailed, non-destructive investigation of a wide range of artworks, revealing their internal structure, execution technique and, as necessary, conservation issues, using either virtual sections or full 3-D visualizations of objects. In some cases, conservators request a CT scan before granting the loan of a precious masterpiece, in order to establish its state of conservation and evaluate the possible risks involved in its transport. However, CT loses its real preventive purpose if the objects must be moved to a diagnostic laboratory to undergo the test, thus exposing them to possible damage during transfer. To overcome this limitation, the X-ray Imaging Group of the Physics and Astronomy Department of Bologna University has developed a transportable system for in-situ x-ray CT analysis of objects of considerable size. This paper describes this equipment and the main results of three in-situ analyses of works of art characterized by different factors that made it unadvisable to transfer them to a diagnostic laboratory.