LAUSR

Abstract. The judicious use of Compton scattered radiation continues to be a relevant challenge for the future of tomographic imaging. In this context, a new modality of Compton scattering tomography has been recently proposed. This new system has the advantage of being fixed, with a source and detectors placed on a ring passing through the source. The objective of this paper is to explore new possibilities for this new modality: scanning both small and large objects via a double scanning configuration. In fact, when an object under study is small and can be placed inside the detector ring, its scanning will be performed by the interior configuration. Otherwise, a large object placed outside the system will be scanned by the exterior configuration. The modeling of data acquisition of these two scanning modes leads to a new Radon transform on circular arcs (CirArcRT), established for the first time. Image reconstruction requires the inversion of CirArcRT, which is obtained via geometric inversion (GI). In fact, GI allows converting the circular arcs into corresponding half-lines, and consequently, the CirArcRT into a new Radon transform on half-lines, whose inversion is established. Numerical simulations are carried out to demonstrate the feasibility of the new modality. The ability for the same system to scan both small and large objects enlarges the fields of applications for tomography from biomedical imaging to nondestructive testing in industry as well as cultural heritage objects imaging.