MicroCT for bone and biomaterials characterization. Lea Vaiana PARALAB SL

Transcription

1 MicroCT for bone and biomaterials characterization Lea Vaiana PARALAB SL

2 Distribución de equipamiento Científico para laboratorio y proceso Oficinas en Barcelona, Madrid y Bilbao. Asesoramiento pre-venta Apoyo post-venta: asesoramiento técnico y servicio técnico Profundo conocimiento de las técnicas/equipamientos/aplicaciones Servicio Técnico Laboratorio de aplicaciones Equipo multidisciplinar Químicos (PhD), Biólogos (PhD), Ingenieros Electrónicos

3 Investigate the 3D structure... Investigate the 3D structure...

4 ...non-destructively Use microct for Everything that has to be Analyzed withouth being destroyed Analyzed repeatidly over time Characterized at micron resolution level Characterized quantitatively Output Morphometry Structure thickness Pore size/spacing Connectivity Density Structure Model Index (SMI) Material phase volume and surface quantification Geometry Circumference, Moment of Inertia, Center of Gravity etc.

5 History of microct 1972 : The first CT scanner was invented by Hounsfield. First patient brain-scan 1979: Nobel prize to Hounsfield and Cormack 1980s: The first X-ray microtomography system First microct publication (reconstructed slices of a small tropical snail, voxel size 50 µm) 1994: µct 20 first commercial microct worldwide by SCANCO Medical

6 CT-Basics Based on measurement of attenuation of X-rays (Beer-Lambert):

7 Measurement of one projection Io t I t

8 CT-Basics In-vivo Specimen ex-vivo

9 Reconstruction Typically Projections Filtered back projection algorithm for reconstruction of slices 2D projections Scan 3D volume of attenuation reconstructed from slices source sample detector

10 Applications

11 Endless Applications Bone morphometry and Biomechanics Biomaterials Paleontology Geology And more... Clinical Food Dental Material Analysis

12 Bone biomechanics Bone is a complex material, with a multiphasic, heterogeneous and anisotropic microstructure.

13 Bone Quality Bone Quality = Geometry of bone 3D-Microarchitecture Local material properties Bone turnover To asses bone quality we need to investigate the 3D structure of bone non-destructively.

14 Why we chose CT Imaging of mineralized structure Quantitative 3D method Non-destructive High resolution ~1 µm ex-vivo ~10 µm in-vivo small animals ~100 µm in-vivo humans

15 From scanning to results 3D Resulting Image Identification of regions of interest and analysis Binary Image Original Image

16 Bone morphometry: Standard Indices Density (mg HA/ccm) Morphometry Calibrated with HA Phantom Apparent Density (Bone + Marrow Space) Material Density (Bone) Tb.N, Tb.Sp, Tb.Th Anisotropy Connectivity Density Structure Model Index (SMI) BV, TV, BS and derived parameters Geometry Circumference, Moment of Inertia, Center of Gravity etc.

17 Thickness and Separation Object (or marrow space) is filled with spheres. Their diameter then is the local thickness (separation) Thickness color-coded Separation color-coded

18 Right settings for the right application Ex-vivo ~1 µm In-vivo small animals In-vivo humans ~10 µm Resolution ~100 µm X-ray dose hours 10 min Scan time 2 min ~50 GB ~15 GB Data size 1 GB

19 Ex-vivo high resolution Mouse trabecular structure, 1 µm

20 Cortical Bone with μct 50

21 In-vivo small animals Follow up of same animal during treatement Baseline Week 2 Week 4

22 % Morphometry longitudinal studies 3D BV/TV (Trabecular Bone Volume) Sham OP Sham hpth(1-34) 25 µg/kg s.c OVX OVX Zoledronate 5 µg/kg s.c. OVX a-ethinylestradiol 0.3 mg/kg p.o weeks

23 Morphometry longitudinal studies 3DTb.N (Trabecular Number) 3DTb.Th (Trabecular Thickness) mm Tb.Sp (Trabecular Separation) Sham OP 0.25 Sham hpth(1-34) 25 µg/kg s.c OVX weeks weeks mm 1/mm weeks OVX Zoledronate 5 µg/kg s.c. OVX a-ethinylestradiol 0.3 mg/kg p.o

24 Clinical HRpQCT Charité Berlin

25 Cortical Porosity Burghardt et al. JCEM 2010

26 Finite Element Analysis software Features: Can solve models with millions of elements on workstation computers Built-in library of pre-defined tests (compression, tension, torsion, etc.) for easy generation of boundary conditions Can assign density-dependent element material properties

27 Articular Cartilage diseased healthy Images: Dr. K Stok, ETHZ

28 Biomaterials Courtesy of S. Hofmann, Silk fibroin scaffold Porosity in ceramic scaffold

29 Morphometry same as for bone Density (mg HA/ccm) Morphometry Calibrated with HA Phantom Strut.N, Strut.Sp, Strut.Th Anisotropy Connectivity Density Structure Model Index (SMI) OV, TV, OS and derived parameters Geometry Circumference, Moment of Inertia, Center of Gravity etc.

30 Pore size analysis Color coded wall thickness of the sample and color coded pore diameter of the sample. Local pore size distribution

31 Permeability simulation a b c Accessible volume is shown in yellow Accessible volume versus local pore diameter Left: a. accessible volume with sphere diameter of 16 µm. Middle: b. 24 µm. Right: c. 48 µm. Virtual spheres with increasing diameter

32 Biomaterials Bone graft substitute Scaffold mineralization

33 Contact Surface Analysis Is the implant attached to bone? expressed in % of the (local) implant diameter % 90.00% 80.00% 70.00% 60.00% 50.00% 40.00% 30.00% 20.00% 10.00% Slice No % 103 Attachment in [%]

34 Scanners Overview Specimen scanners Desktop scanners µct 35, 40 Cabinet type µct 50, 100 In vivo scanners Small animal scanners vivact 40 vivact 80 Clinical scanner XtremeCT II

35 Accessories Automatic sample holder changer Animal and sample holders Compression/tension stage Animal monitoring and gating Cooling/heating stage Quality control HA phantom

36 Thank you Send us a sample for a free of charge test scan lea.vaiana@paralab.es