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HEAPHY 1 & 2 DIAGNOSTIC Delia DEPHOFF

ABSTRACT

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HEAPHY 1 & 2 DIAGNOSTIC Delia DEPHOFF

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  1. ABSTRACT Earlier this year Lakes Radiology was approached by Scion in Rotorua about using MRI and CT as part of a research project to assess the amount of water in wood. This paper reviews the process of setting up scan protocols, problems encountered and how they were solved, the significance of using MRI and CT, how the information obtained from the scans has assisted the researchers and what has been learned from this experience. Fri 30th Aug 2013 Session 2 / Talk 3 11:22 – 11:33 HEAPHY 1 & 2 DIAGNOSTIC Delia DEPHOFF

  2. Delia Dephoff NZIMRT Conference 2013 Hamilton Using MRI and CT for scientific research – one MRT’s experience As wet as four short planks

  3. Background – who, what and why Trials scans – setting things up Research series – modifications along the way Review – was it of value, and what I learned Introduction

  4. Scion - Crown Research Institute dedicated to improving the international competitiveness of the New Zealand forest industry and building a stronger biobased economy. Lakes Radiology - TRG Group – private medical imaging facility Background - Who

  5. Who Slobodan the researcher Delia the MRT

  6. Research on different wood drying processes Why CT and MRI? Non-destructive measurement of the moisture content of wood What was different about this research? 1st time MR &CT used in same research Background - discussion

  7. Kiln dried wood (KD) – dries from the outside –resulting in cracking and warping Dewatered wood (DW) – basically replaces water in wood with alcohol which is then extracted – wood dried quickly from the inside – minimise cracking and warping Background - Wood drying processes

  8. Trial Scans

  9. To scan the wood to set scan parameters To assess the data obtained and determine if the information would be useful for the research. Trial Scans - Aim

  10. PinusRadiata 100x50x600mm (2 foot 4x2) The Wood

  11. Matching their expectations to the capability of the scanners Trial Scans

  12. Trial Scans – Positioning

  13. Trial Scans - Technical factors?

  14. Based on extremity scan Dropped to 80 kVp , eff 50mAs (32mAs) Kernals – soft tissue (B41s) and Bone (B70s) 2mm slices and 0.75mm slices Pitch 1.5 16x0.6m Rotation time 1.5 Scan time 44.75s CTD I Vol 1.43 mGy CT protocol

  15. Trial Scans - CT

  16. Images - Streaking artefact ?partial volume averaging beam hardening (Seeram, 2001) Trial scans - CT - issues

  17. Trial Scans - CT Scans - Solutions

  18. Length of wood vs FOV Coils – spine coil and body matrix x 2 T1, PD, T2 Scanned a small block 5mm slices Trial Scans - MRI - Issues

  19. Trial Scans - MRI - coils

  20. HUGE amount of data esp CT Raw data – 2.5GB Siemens technical help Transferred data onto external hard drive Trial Scans - Data

  21. ResearchSeries

  22. 1st series – comparing kiln dried wood to de-watered wood 2nd series – de-watered wood, Green, 3xDW, 5xDW, 10xDW 3rd series – unexpected results therefore re-scan after 2xDW and 10xDW Research Series

  23. 1st Series – CT KD pre & post

  24. 1st Series – CT DW pre & post

  25. Wanted whole length of wood scanned Change parameters slightly Scan in two blocks, with overlap Slice 7mm Scan time approx 5mins each - 6 scans – 30mins to scan each set of wood 1st Series - MRI - Issues

  26. 1st Series – MRI KD – pre only T1 PD T2

  27. 1st Series – MRI DW pre & post T1 T2 PD 1st 2nd

  28. 2nd Series – MRI pre & post T2 T1 PD

  29. Talked and asked questions – resulted in some minor adjustments to the research • Wood processing • Basics of CT and MRI • Hounsfield Units • Kernals – AKA Convolution filters • B41s high frequency filter • B70s low frequency filter (Bushong2000) • B90s What do you do while scans are running?

  30. Results from 2nd series not quite as expected Water content was down after 3 DW, but increased after 5 DW, down again after 10DW 2x DW to 10 x DW Use alcohol as a reference 3rd Series

  31. 3rd Series with tube of alcohol - CT

  32. 3rd Series - CT

  33. 3rd Series MRI

  34. 3rd Series - MRI T1 PD T2 Green 2DW 10DW

  35. Review

  36. Yes and no PD most useful MR scan Amount of data, especially CT – time to analyse Unexpected results Was the scan data of helpful for their research?

  37. To get everything set on the trial scans, minimise errors, variables – check all parameters match If there are options (e.g. kernals) give all for analysis Revise CT and MR physics What have I learned?

  38. Water content of wood, free water and bound water Wood drying processes – kiln, dewatering and oven drying You cannot measure the water content of a wet piece of wood, but you can measure how much water it used to contain once it has been dried. What have I learned?

  39. Would I do it again? YES!

  40. Scion Research Lakes Radiology – TRG Group Slobodan Bradic Thanks to

  41. Bushong, S.C. (2000) Computed tomography. McGraw-Hill: New York Seeram, E. (2001) Computed tomography. Physical principles, clinical applications, and quality control (2nded). Saunders: Philadelphia References

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