Computed Tomography for the Non-Destructive Imaging of Cultural Heritage: X-Ray, Gamma and Neutron Sources

Abstract

X-ray and neutron computed tomography (CT) have been used successfully for the non-destructive imaging of artifact in art conservation. These applications range from object investigations to the use of micro-focus CT for experimental studies. While there is precedent for the use of CT in art conservation, the method is still limited in application partially due to restricted access to facilities and the high cost of producing publishable results. The purpose of this study was to identify alternative CT methods including the use of different radiation sources and industrial imaging system. Both investigations of the use of low-flux neutron CT at the Royal Military College in Kingston compared to high-flux neutron CT at the Advanced Neutron Tomography And Radiography Experimental System (ANTARES) at FRM-II in Garching, Munich and the use of megavoltage gamma ray computed tomography at Kingston General Hospital in Kingston successfully imaged the corroded metal artifacts. The artifacts investigated were from the Diniacopoulos Collection at Queen’s University and were underwater concretions of L’Anse aux Bouleaux provided by Parks Canada. This study also evaluated the Xradia XCT-400 for comparison to similar systems used in conservation. This evaluation also provided successful images of corroded metal coins from the Diniacopoulos Collection for use in identification. To address the issue of cost prohibitive image analysis programs, a workflow using the open-source software programs ImageVis3D, 3DSlicer and ImageJ was developed. This workflow would enable researchers and conservators to produce publishable images and analyze the information in the CT data sets. Additionally, this workflow addresses some common research questions that might arise during investigations that would guide conservators in optimizing their imaging parameters and image analysis. The combination of the alternative radiation sources and the open-source workflow allows for greater accessibility of CT for conservators and researchers. While the preliminary success of the study is promising, more research is needed to optimize the scanning parameters and image analysis through the use of phantoms and comparisons to traditional investigative methods in conservation.