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

2. 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) M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete

3. WP 2 Objectives 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). Hybrid imaging system for small animal XCTFMT XCT module should: Enhanced contrast XCT strategies: Dual-energy XCT Use of X-ray contrast agents NoNameM.M. 2CEA-LETI (lead)51.7 7CT-Imaging6 5FIHGM18 6UZH1 1HMGU1 M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete

4. 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 M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete D2.1 M M D2.4D2.5 D2.2,2.3 D2.6,2.7 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. 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 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 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 M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete

6. WP2 Corrective actions and revised planning M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete Final prototype available @ CT-Imaging Mo.25 (04/2010) D 2.5 D 2.4 v2 Final prototype @ HMGU D 2.6 D 2.7 v2 M5 Scattering measurements Adjust DE protocol Mo.27 (06/2010) TBD Mo 24 (Now) on test bencheson final prototype at CTIon final prototype at HMGU Comparison of contrast enhancement strategies 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 → 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) Single energy CT Dual energy CT Contrast agent CT

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

8. WP2 (2.7) / WP5 (5.3) / Milestone 8 XCT final design, gantry development and shielding M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete XCT1) 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 FMT4) 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 1 2 3 4 5 6 7 8

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

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

11. Results: LE: Generator: 40kV-6mA Filter: 60um Sn 2.4 mAs HE: Generator: 70kV-2mA Filter: 100um Pb 0.8 mAs Dual-energy protocol for FMT-XCT Energy couple determination 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 M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete

12. 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 M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete

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

14. 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 M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete → Very limited beam hardening influence

15. Absorbed dose Low energyHigh energy Dose rate [mGy/min] Single radiography (300ms exposure) [mGy] Full tomographic scan (3’20’’ duration) [mGy] Dose rate [mGy/min] Single radiography (300ms exposure) [mGy] Full tomographic scan (3’20’’ duration) [mGy] Abdomen 93.930.47 312.8 14.780.07 49.0 Chest 65.400.33 217.8 10.250.05 34.1 Mean 77.560.39 258.3 12.160.06 40.5 M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete

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

17. Parameter optimization for final prototype 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 Optimal configuration Low energy: 35kV 2mA 50um tin filter High energy: 70kV 1.25mA 50um lead filter M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete 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 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 Conclusions 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. 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 Single energy CT Dual energy CT Contrast agent CT M.Brambilla - FMT-XCT year 2 Meeting – 26.03.2010, Crete