![]() Hence data processing is usually the main limiting factor in CT-based research, as opposed to scanning. This process greatly exceeds the time required for collecting the original CT volume, which varies from 15-120 minutes (depending on the system). However, creating, manipulating and preparing a good quality virtual fossil on a computer can be very time-consuming, and difficult specimens can take 40 hours to process. This ability allows access to the morphological information contained inside fragile, rare, valuable or small specimens, including both extinct fossils and extant comparative material. The resulting 3D volumes can be used to create 'virtual' computerised images of specimens that can be manipulated, sectioned, prepared, dissected and measured as though in the hand, but – unlike handheld specimends - with internal as well as external morphology. All CT scanners reconstruct digital cross sections (slices) of an object, which can be stacked to create 3D volumes rather like traditional serial sectioning techniques (Sollas, 1904 Croft, 1950) hence 'tomography,' from the Greek tomos (slice) and graphein (to write). During the last 40 years, CT scanners have undergone several redesigns - often referred to as generations - but the basic concept has remained the same. The first system was developed by Godfrey Hounsfield (Hounsfield, 1973) and Allan McCormack (McCormack, 1963) and went online in 1972 at the Atkinson Morley's Hospital (London, UK). content/issue-2-2012-technical-articles/233-micro-ct-workflow INTRODUCTION: WHAT IS COMPUTED TOMOGRAPHY?Ĭomputed tomography (CT) is a non-destructive radiographic imaging technique for producing 3D computerised models of an object. A palaeobiologist’s guide to ‘virtual’ micro-CT preparation. Keywords: Computed tomography micro-CT scan X-ray microtomography fossil shark tooth segmentation and virtual preparationįinal citation: Abel, Richard Leslie, Laurini, Carolina Rettondini, and Richter, Martha 2012. Martha Richter, Department of Palaeontology, Natural History Museum, Cromwell Road, SW7 5BD London, United Kingdom. Bandeirantes, 3900 - CEP 14040-901, Bairro Monte Alegre, Ribeirão Preto, SP, Brazil. Richard Leslie Abel, MSK Laboratory, Department of Surgery and Cancer, Charring Cross Hospital, Imperial College, W6 8RF London, United Kingdom and Image and Analysis Centre, Mineralogy Department, Natural History Museum, Cromwell Road, SW7 5BD London, United Kingdom.Ĭarolina Rettondini Laurini, Laboratório de Paleontologia Departamento de Biologia FFCLRP - USP, Av. Hence there is the potential to usher in a new era of global scientific collaboration and public communication using specimens in museum collections. Micro CT and other 3D imaging techniques are increasingly utilized to facilitate data sharing among scientists and on education and outreach projects. Fragile, rare specimens and type materials in university and museum collections can therefore be virtually processed for a variety of purposes, including virtual loans, website illustrations, publications and digital collections. The original NHMUK copyrighted CT slice stack can be downloaded for practice of the described techniques, which include segmentation, rendering, movie animation, stereo-anaglyphy, data storage and dissemination. This paper presents a suggested workflow explaining the steps required, using as example a fossil tooth of Sphenacanthus hybodoides (Egerton), a shark from the Late Carboniferous of England. This technique can be applied to specimens or part of specimens embedded in the rock matrix that until now have been otherwise impossible to visualise. The latter comprises the techniques required to convert a 3D CT volume (stack of digital slices) into a virtual image of the fossil that can be prepared (separated) from the matrix and 'dissected' into its anatomical parts. Consequently the main limiting factor in CT-based analyses is no longer scanning, but the hurdles of data processing (see disclaimer). The technique has now reached a stage where systems can facilitate large-scale, non-destructive comparative studies of extinct fossils and their living relatives. In the last decade, CT technology has greatly improved, allowing bigger and denser objects to be scanned increasingly rapidly. Computed tomography (CT) is a 3D imaging modality for producing 'virtual' models of an object on a computer. ![]() This paper provides a brief but comprehensive guide to creating, preparing and dissecting a 'virtual' fossil, using a worked example to demonstrate some standard data processing techniques. Plain-language and multi-lingual abstracts Richard Leslie Abel, Carolina Rettondini Laurini, and Martha RichterĬopyright Palaeontological Association, May 2012 A palaeobiologist's guide to 'virtual' micro-CT preparation ![]()
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