FMT-XCT Workpackage 2 Project advancement Marco Brambilla Véronique Rebuffel Holger Bruenner Marek Karolczak

FMT-XCT 1 st year meeting – 24 April M.Brambilla 2 Outline Work-package 2 objectives and tasks X-ray CT system design (task 2.1) Dual-energy XCT system development (task 2.2)  XCT prototype development  On-bench CT at LETI  Dual energy protocol definition and optimization Work-package advancement Revised planning

FMT-XCT 1 st year meeting – 24 April M.Brambilla 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: PARTNERS: CEA-LETI (No.2, lead) CEA-LIME (No.2) VAMP (No.7) FIHGM (No.5) + UZH (No.6) + HMGU (No.1) Enhanced contrast XCT strategies: Dual-energy XCT Use of X-ray contrast agents

FMT-XCT 1 st year meeting – 24 April M.Brambilla 4 WP 2 tasks, deliverables & milestones Significant 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 Year 1Year 2 MM M D DD DD 7 Deliverables: -D2.1 / due month 1: XCT design -D2.2 / due month 15: Dual energy prototype -D2.3 / due month 15: Dual energy processing software -…D2.4 to 2.7: due month 18, 21, 24

FMT-XCT 1 st year meeting – 24 April M.Brambilla 5 Task 2.1: XCT system design (1/2) Report “WP2: XCT design”, november 2008, issued by CEA-LETI and VAMP, approved by HMGU, distributed to the Consortium. Remark: this report fulfils most of the objectives of the task 2.7 « optimal XCT design », this was decided because of the (long) delivery time of the system key components. Geometrical configuration Appropriate X-ray tube and detector Mechanics Safety and normative requirements Electrical design

FMT-XCT 1 st year meeting – 24 April M.Brambilla 6 Task 2.1: XCT system design (2/2) Oxford instruments UltraBright 80 Watts power, 20-90kV, down to 13µm focal spot size Detector: Hamamatsu C7943 (CsI scintil. + CMOS photo. array), 100μm pixel size, 1248x1248 pixels, 7 frames per second 400 mm Non-continuous rotation mode acquisitions in 4mn per energy scan. Expected resolution 0.1 mm

FMT-XCT 1 st year meeting – 24 April M.Brambilla 7 Task 2.2: XCT prototype development Under development at VAMP. First parts have been constructed and others ordered (parts in stock can be used). Status of detector: up to now, VAMP have not yet received positive feedback from Hamamatsu approving our specifications to the chosen detector

FMT-XCT 1 st year meeting – 24 April M.Brambilla 8 Task 2.2: On-bench CT at LETI Vertical tomographic axis Versatile tool, in order to help Dual Energy development and validation.

FMT-XCT 1 st year meeting – 24 April M.Brambilla 9 Radiography Measure of x-rays attenuation μ = μ(E, material) Contrast depends on: object composition incident beam spectrum transversed length of each material Tomography volume reconstruction by means of filtered backprojection algorithm GL → μ(E, material) Contrast depends only on object materials i0i0 i source detector object X-Rays imaging principle Dual-energy imaging / Theory (1/4) Ideal Model (linear detector, no scatter…) μ l →

FMT-XCT 1 st year meeting – 24 April M.Brambilla 10 E1E1 E2E2 μ = μ(E, material) Image the same object with x-rays of different energies (2 or >) Obtain quantitative information on chemical composition of the object Contrast enhancement Dual-energy imaging / Theory (2/4) X-Rays dual energy principle

FMT-XCT 1 st year meeting – 24 April M.Brambilla 11 Project (a 1,..., a n ) measurement into ( l 1, l 2 ) representation Single material images or combined “closer” basis: contrast enhancement noise amplification Many applications in NDT, security and medicine ( l 1, l 2 ) basis functions: in principle: any in pratice, often: attenuation spectra of two base materials projected values: base materials equivalent lengths X-Rays dual energy principle Dual-energy imaging / Theory (3/4)

FMT-XCT 1 st year meeting – 24 April M.Brambilla 12 bone Soft tissue LE (75kV) An example: bone/soft tissue separation Dual-energy imaging / Theory (4/4)

FMT-XCT 1 st year meeting – 24 April M.Brambilla 13 Biological tissues analysis The absorption curves are all enclosed between those of cortical bone and adipose tissue. Plexiglass is almost superimposed to adipose tissue. All the other soft tissues are indeed indistinguishable from water Breast tissue is the only one which differs from water (probably due to high adipose tissue content) May adipose tissue act as a contrast agent ? ICRU-44 data of human tissue (hopefully not too different from mouse’s ones) Possible base materials: water and plexiglas. Dual-energy protocol for FMT-XCT (1/5)

FMT-XCT 1 st year meeting – 24 April M.Brambilla 14 Multiparametric problem x-rays generator kV and mA x-rays filters: material and thickness 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 Find a figure of merit to optimize equivalent length contrast Tried different FOMs and different levels of simulation accuracy →Only very realistic simulations give affordable results Validate results with phantom and animal study Dual-energy protocol for FMT-XCT (2/5) Energy couple determination

FMT-XCT 1 st year meeting – 24 April M.Brambilla 15 RESULTS Best contrast configuration: LE: Generator: 40kV-6mA Filter: 60um Sn 2.4 mAs HE: Generator: 70kV-2mA Filter: 100um Pb 0.8 mAs Angles: θ 1,θ 2 ~ 1.5° θ 3 ~ 3.1° θ1θ1 θ3θ3 θ2θ2 Dual-energy protocol for FMT-XCT (3/5) Energy couple determination

FMT-XCT 1 st year meeting – 24 April M.Brambilla 16 Phantom measurements 35mm cylindrical container filled with: 1 quail's leg 1 Plexiglas cylinder 1 piece of lamb liver water Mouse measurements 1 euthanized mouse Measurement parameters from optimization LE: 40kV, 6mA, 50um Tin filter HE: 70kV, 2mA, 100um Lead filter “low” resolution: 360 1° step; binned images Dual-energy protocol for FMT-XCT (4/5) Energy couple validation

FMT-XCT 1 st year meeting – 24 April M.Brambilla 17 Reconstructed volume 200um/voxel Dual-energy protocol for FMT-XCT (5/5) Energy couple validation

FMT-XCT 1 st year meeting – 24 April M.Brambilla 18 Dual-energy data processing decomposition in data domain or reconstructed volume? enhanced contrast reconstruction Dual-energy acquisition protocol Validate chosen acquisition sequence: Dual-energy calibration protocol CEA-LETI bench is different from final prototype more intense x-rays source detector with higher resolution but less sensitivity → Repeat optimization process for FMT-XCT system Evaluate scattering effects from a first estimation: 15-20% in projections assess contrast reduction in reconstructed volumes (both LE & HE) consider the possibility of using anti-scattering grids Task 2.2: Remaining sub-tasks

FMT-XCT 1 st year meeting – 24 April M.Brambilla 19 WP 2: Revised planning To be approved by the Consortium….

FMT-XCT 1 st year meeting – 24 April M.Brambilla 20 Optimization of the delivered dose (Task 2.3) to the animal flat panel detector → minor problem (no need for scans) diffused adequate external shielding already reckoned main problem: the optical chain → design suitable protections WP 2: Other tasks Minimization of X-ray interference (task 2.4) Dual-energy contrast (task 2.5) Use of X-ray contrast agents (task 2.6) To provide an optimal XCT design (task 2.7) Month 18 Month 24 CEA-LETI, VAMP, HMGU CEA-LETI, VAMP CEA-LETI, CEA-LIME, HMGU CEA-LETI, FIHGM, UZH, HMGU

FMT-XCT 1 st year meeting – 24 April M.Brambilla 21 WP 2: Training session Organized by CEA-LETI in Grenoble Open to all FMT-XCT partners Date: ~ second part of june (to be confirmed) Program to be discussed: X-ray imaging (theory, experimental demonstration) Prototype demonstration Simulation software tool presentation Tour of facilities (X-ray and optical) Duration: 1.5, 2, 2.5 days ?

FMT-XCT 1 st year meeting – 24 April M.Brambilla 22 Thanks for you attention