ASTM_F_3259_-_17.pdf

Designation:F325917Standard Guide forMicro-computed Tomography of Tissue EngineeredScaffolds1This standard is issued under the fixed designation F3259;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide is a resource for conducting micro-computedtomography(microCT)imaging and analysis of porous scaf-folds for tissue engineering applications.Considerations areprovided for sample preparation,image acquisition parameterselection,post-processing,and data interpretation.1.2 The information in this guide is intended to be appli-cable to products that include a porous scaffold component andare designed for tissue engineering repair strategies.Thescaffolds may be fabricated from synthetic polymers(e.g.,absorbable polyesters)or natural materials(e.g.,calciumphosphates),mammalian or human derived materials(e.g.,demineralized bone)or combinations of these.While someconsiderations are provided for imaging of materials that are ofmoderate to high radiodensity,specific guidelines are notprovided for imaging metallic scaffolds.1.3 Applicability of the guidelines herein will depend onscaffold material type and the users application(e.g.,experi-mental design,as manufactured characterization)as appropri-ate.1.4 The guidelines for microCT discussed herein are mostsuitable for specimen scanning in vitro.Specific guidelinesrelevant to direct in vivo imaging of scaffolds are not includedbecause the imaging parameters will be dependent on theimplantation site,animal size,breathing etc.In addition,consensus recommendations for in vivo imaging are providedin Bouxsein et al 2010(1).2While the specific imagingparameters and processing recommendations discussed inBouxsein et al are specific to bone imaging,many of theconsiderations and precautions are also applicable for in vivoscaffold imaging.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:3F2450 Guide for Assessing Microstructure of PolymericScaffolds for Use in Tissue-Engineered Medical ProductsF2603 Guide for Interpreting Images of Polymeric TissueScaffolds3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 microarchitecture,nthe set of structural features ofan object defined at the microscale.3.1.2 volume of interest(VOI),na 3D sub-volume insidean image that contains the features to be analyzed.4.Significance and Use4.1 X-ray microcomputed tomography(microCT)is a non-destructive three-dimensional imaging method that can be usedto reconstruct the microarchitecture of a tissue engineeredmedical product(TEMP)scaffold that may or may not containingrown tissue.MicroCT was first developed to study ceramicsfor the auto-industry and adapted for bone morphology at themicroscale(Feldkamp et al 1989)(2).More recently,theimaging method has been adapted for in vivo applications andstudies of multiple natural and synthetic materials.1This guide is under the jurisdiction of ASTM Committee F04 on Medical andSurgical Materials and Devices and is the direct responsibility of SubcommitteeF04.42 on Biomaterials and Biomolecules for TEMPs.Current edition approved May 1,2017.Published September 2017.DOI:10.1520/F3259-17.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 4.2 Alternate characterization methods for assessing scaf-fold microarchitecture and tissue ingrowth are limited by theirtwo dimensional nature(e.g.,microscopy)and