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FMT-XCT – Workpackage 2 advancement

Summary of advancements and challenges in developing an integrated hybrid imaging system for small animal XCT and FMT. Includes objectives, deliverables, problems, corrective actions, and planning.

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FMT-XCT – Workpackage 2 advancement

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  1. FMT-XCT Year 2 meeting 26.03.2010 – Heraklion, Crete Markus MronzMarek Karolczak Marco Brambilla Véronique Rebuffel FMT-XCT – Workpackage 2 advancement

  2. M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete Outline • Work-package 2 advancement summary • X-ray CT system design • Dual-energy X-ray protocol • Scattered radiation estimation • Absorbed dose estimation • Conclusions • (XPCI proposal)

  3. M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete WP 2 Objectives Hybrid imaging system for small animal XCT FMT XCT module should: • provide adequate accommodation of the optical components, • eliminate X-ray interference with optical components, • offer improved contrast between organs as is important for optimal use of XCT information as priors in the FMT inversion procedure (WP4). Enhanced contrast XCT strategies: • Dual-energy XCT • Use of X-ray contrast agents

  4. D2.6,2.7 D2.2,2.3 D2.4 D2.5 D2.1 M M M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete WP 2 Deliverables: current state Deliverables: • D2.1 (mo.1): XCT design - completed Report “WP2: XCT design”, 11/2008, issued by CEA-LETI and CT-Imaging distributed to the Consortium. • D2.2 & 2.3 (mo.15): Dual energy prototype & software - completed Prototype and software demonstrated during Training session (06/2009). Report ready to be delivered. • D2.4 (mo.18): Preliminary technical specifications - completed Based on LETI lab bench. Report ready to be delivered • D2.5 (mo.21): Measurements of scattered energy - partially completed Based on LETI lab bench only. Draft report prepared. • D2.6 (mo.24): Optimal contrast-enhancing strategy - delayed • D2.7 (mo.24): Optimized system design - almost completed Update from D2.1 Milestone (n°5) : selection of an appropriate XCT technology for FMT-XCT system (by the executive committee) Month 18: preliminary recommendation / Month 24: official decision

  5. M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete WP 2 Problems CEA-LETI bench is different from final prototype • more intense x-rays source • different environment → Repeat optimization process for FMT-XCT system → Repeat measurements (dose, contrast) on FMT-XCT system CEA-LETI bench not convenient for extensive tests using living mice • vertical position, fixation by forelegs • successive CTs, (Dual energy + with contrast agent), very difficult on a living mouse → Tests planned for D2.6 require a more easily usable bench Final prototype available only end of May 2010 • Defect delivered gantry motor (still waiting !!!) • Problem with the PLC (re-design of the PCB of the PLC) • Time to construct the X-Ray shielding → Integrate gantry motor when delivered and finalize the prototype → Integration of the FMT chain (more than initially planned) has started at CT-Imaging

  6. Scattering measurements Adjust DE protocol Comparison of contrast enhancement strategies on test benches on final prototype at CTI on final prototype at HMGU • Single energy CT • Dual energy CT • Contrast agent CT Comparison of on specified living mice. Refine data analysis procedure and comparison protocol Possible experimental approaches: →DE experiments at CEA-LETI, contrast agent ones at FIHGM →All experiments at FIHGM →All experiments using the final prototype (required) M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete WP2 Corrective actions and revised planning Mo 24 (Now) Mo.25 (04/2010) Mo.27 (06/2010) TBD Final prototype available @ CT-Imaging D 2.5 D 2.4 v2 Final prototype @ HMGU D 2.6 D 2.7 v2 M5 D2.5 (mo.21): Measurements of scattered energy → Update current preliminary report D2.7 (mo.24): Optimized system design → Update current report integrating last changes D2.6 (mo.24): Optimal contrast-enhancing strategy →

  7. M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete WP2 (2.7) / WP5 (5.3) / Milestone 8 XCT final design, gantry development and shielding Back view Front view Dimensions: 145 cm x 140 cm x 103 cm

  8. M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete WP2 (2.7) / WP5 (5.3) / Milestone 8 XCT final design, gantry development and shielding 1 7 6 3 8 5 4 2 XCT 1) X-Ray tube: Oxford UltraBright 80W, 90kV, 13-20µm 2) Detector: Hamamatsu C7942, Csl scintil. + CMOS photo array, 2400 x 2400 pix, 9 f/s @ 4x4 binning 3) Beam modification: collimator, shutter, prefilter for dual energy mode FMT 4)CCD camera: Princeton Instr. Pixis 1024 5) Filter wheel: FRM 65 (Owis) 6) Scattered X-Ray protection: CCD shutter and shielding 7) Laser positioning: KDT 105 and optical collimator 8) Stray light shielding: PEAK tube with openings for optical path

  9. M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete WP2 (2.7) / WP5 (5.3) / Milestone 8 XCT final design, gantry development and shielding Network Block diagram of the main components XCT acquistion PC FMT acquistion PC FMT Laser stage control Detector CCD camera PLC Master PLC Slave Animal bed Illumination Gantry motor X-Ray shutter Gantry position X-Ray prefilter Interlock IO‘s CCD shutter X-Ray tube CDD filter wheel

  10. M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete Task 2.2: CT bench at CEA-LETI Versatile tool, in order to help Dual Energy development and validation.

  11. M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete Dual-energy protocol for FMT-XCT Energy couple determination • Results: • LE: • Generator: 40kV-6mA • Filter: 60um Sn • 2.4 mAs • HE: • Generator: 70kV-2mA • Filter: 100um Pb • 0.8 mAs • Multi-parametric problem • x-rays generator kV and mA • x-rays filters • duration of irradiation for LE and HE acquisitions • By means of a simulation software: • simulated all the dual energy chain trying different combinations of the parameters • find the combination with best figure of merit • Tried different FOMs and different levels of simulation accuracy • Validate results with phantom and animal study

  12. M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete DE protocol validation (1/2) Observations: • Little contrast between organs • Contrast between soft tissues/adipose tissue • High level of noise (mainly in HE) • Same type of contrast in LE/HE

  13. Easy: to distinguish bones from soft tissues Mouse 1 Feasible: to distinguish adipose from other soft tissues Mouse 2 Very difficult: to identify organs Mouse 3 M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete DE protocol validation (2/2) High energy does not add significant information (unless very high dose @ both energies)

  14. M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete Beam hardening estimation • Stronger attenuation of lower part of the spectrum • (in radiographs) attenuation not linear any more against object thickness • (in tomography) cupping artifacts Radiography: • good linearity at both LE and HE LE Tomography: • Negligible cupping → Very limited beam hardening influence

  15. M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete Absorbed dose

  16. M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete Scattered X-ray measure for CCD shielding Scattered field depends on the bench • Not possible to estimate shielding geometry • Possible to estimate shielding thickness

  17. M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete Parameter optimization for final prototype Optimal configuration Low energy: • 35kV • 2mA • 50um tin filter High energy: • 70kV • 1.25mA • 50um lead filter • Optimization by simulation using datasheet parameters • Simulation prarameters: • source: • Oxford Instr. UltraBright u-focus • 13um focal spot size • 20-90kV anodic voltage range • 2mA maximum anodic current • W anode • detector: • Hamamatsu C7942 (same as CEA-LETI bench) • geometry: • source-obj. dist.: 20cm • obj.-detector dist.: 20cm • Better contrast than CEA-LETI bench • To be verified experimentally on final prototype !

  18. M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete Conclusions and perspectives Conclusions • Prototype construction almost completed • Prototype testing planned • Dual energy protocol developed and tested (to be confirmed) • Most relevant information (and dose) in low energy data • Preliminary scattered radiation measurements performed • Optimal contrast enhancement strategy not yet defined Perspectives • Scarce information contribution from high energy data • Dual energy protocol not suggested • Low energy acquisition only • We propose at no additional man-months: • Different X-ray contrast enhancement technique investigation • X-rays phase contrast imaging

  19. M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete Thank you

  20. Single energy CT • Dual energy CT • Contrast agent CT M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete WP 2 Remaining and corrective actions • D2.5 (mo.21): Measurements of scattered energy - Month 27 • X-ray measurements on the final prototype (first experiments done by CT-Imaging) • Optimization of the CCD camera shielding • D2.7 (mo.24): Optimized system design - Month 27 - Update of the prepared report integrating last changes • D2.6 (mo.24): Optimal contrast-enhancing strategy - Month 30 to be discussed Comparison of on specified living mice. Possible experimental approaches: -> X-ray experiments at CEA-LETI, contrast agent ones at FIHGM -> All experiments at FIHGM -> All experiments using the final prototype (required) Refine data analysis procedure and comparison protocol

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