New radiological approach for analysis and identification of foreign objects in ancient and historic mummies P. Gostner a , M. Bonelli b, * , P. Pernter a , A. Graefen c , A. Zink c a Department of Radiodiagnostics, Central Hospital, Via L. Böhler 5, 39100 Bolzano, Italy b Department of Medical Radiation Physics, Central Hospital, Via L. Böhler 5, 39100 Bolzano, Italy c EURAC Institute for Mummies and the Iceman, EURAC Research, Viale Druso 1, 39100 Bolzano, Italy article info Article history: Received 10 April 2012 Received in revised form 6 October 2012 Accepted 10 October 2012 Keywords: Mummies Computed tomography Foreign objects Material analysis abstract Traditional x-ray images of mummies may reveal foreign objects lodged within the body or its wrap- pings, but can only give a vague idea of the material of which these objects consist. More precise information may be obtained by means of computed tomography which delivers not only a three- dimensional reconstruction of the object’s shape, but also a measurement of radiodensity and a repre- sentation of the radiological structure. While the density values and structures of body tissues and substances are well documented in radiological publications, little data exist of material not usually found in the human body. The aim of this study is to analyse the radiological density and structure of a series of test objects, so that these may serve as a reference for comparison with potential foreign objects found in mummified remains. Value and limitations of this method are discussed and the practical application is demonstrated through four examples. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction As a result of the technical advances in the field of radio- diagnostics, radiological examinations are being used to study ancient and historic mummified remains more and more frequently. Apart from the high information gain offered by this form of study, such analyses have the additional advantage of being non-invasive, therefore avoiding any damage to valuable archaeo- logical finds, museum exhibits or other testaments of ancient cultures. Conventional x-ray imaging (Harris and Wente, 1980; Ikram and Dodson, 1998) and computed tomography (CT) (Lynnerup, 2007 , 2010; Alt and Rühli, 2010; Rühli et al., 2004) are the most commonly applied techniques. Most studies focus on issues such as potential disease, trauma, kinship, age at death, cause of death and embalming technique (Jackowski et al., 2008; Hawass et al., 2009, 2010; Pernter et al., 2007; Tchapla et al., 2004; Wade et al., 2011; zur Nedden et al., 1994). Such examinations occasionally reveal foreign objects, located either within the wrapping material or in the body interior and are thus not visible from the outside (Harris and Wente, 1980; Ikram and Dodson, 1998). Apart from the general detection of such objects, it is also important to determine their form and composi- tion. In some cases, the question arises whether these objects may be linked to the cause of death or whether they have a religious or cult significance and were placed on/in the body in the course of funerary preparations. A 3-dimensional reconstruction of the CT data, constituting a figural representation, may yield decisive answers. For a more precise historical placement, however, the material type must also be determined. This is not only the case for adornments or cult objects, but also for weapon fragments such as arrow- or lance-heads (Gostner and Egarter Vigl, 2002). Computed tomography offers a means of determining the material composition, firstly by depicting the form and structure, secondly by measuring the radiological density. This physical quantity is measured in Hounsfield units (HU). Whilst the typical density and structures of body tissues and substances are well documented in current literature (Kalender, 2011), no such compilation exists for material types not found in the human body. The aim of this study, therefore, is to determine the HU-values and the radiological structure of a large variety of materials and to evaluate the applicability of the results. Additionally, four case * Corresponding author. Department of Medical Physics, Central Hospital Bol- zano, Via L. Böhler 5, 39100 Bolzano, Italy. Tel.: þ39 0471 907519. E-mail address: marco.bonelli@asbz.it (M. Bonelli). Contents lists available at SciVerse ScienceDirect Journal of Archaeological Science journal homepage: http://www.elsevier.com/locate/jas 0305-4403/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jas.2012.10.011 Journal of Archaeological Science 40 (2013) 1003e1011