FP7 FMTXCT Project UMCE-HGUGM first year activity report Partner FIHGM Laboratorio de Imagen Médica. Medicina Experimental Hospital Universitario Gregorio Marañón, Madrid

Workpackage 2: XCT development Workpackage 8: FMT-XCT imaging accuracy versus PET-XCT

Workpackage 2: XCT development Use of X-ray contrast agents Double exposure techniques Dual energy X-ray source

CT System Outline Mechanical Design

Multi-Energy data acquisition/processing New Tube Features Voltage setting range40 to 110 kV Current setting range10 to 800 μA Output windowBeryllium (thickness 500 μm) Focal spot size15 μm (6 W) – 80 μm (50 W) Emission angle62 deg (max) Power50 W

CT System Outline Linear stage to change magnification factor and FOV Filter wheel to change X-ray beam properties X-ray shutter Continuous and step and shoot acquistion protocols Acquisition SW with online raw data processing GPU implementation to increase processing speed allowing the use of faster detectors

Detector Dynamic Range Expansion Dual-Exposure technique Main features Two datasets acquired First Low SNR for dense materials Detector not saturated for soft materials Second High SNR for dense materials Detector saturated for soft materials Same X-ray beam spectral properties Different photon flux

Detector Dynamic Range Expansion Dual-Exposure technique Dataset #1Dataset #2

Detector Dynamic Range Expansion Dual-Exposure technique (work in progress) Dual exposure CNR (PTFE/Air) = Single exposure CNR (PTFE/Air) = 13.91

Mean Energy = 55.6 kVMean Energy = 66.1 kV Multi-Energy data acquisition/processing Simulated Spectra for the new tube Changing filter setting Spectral simulations carried out using SPEKTR software libraries Siewerdsen, et.al., “Spektr: A computational tool for x-ray spectral analysis and imaging system optimization”, Med. Phys.31(9), 2004

Mean Energy = 34.9 kVMean Energy = 66.1 kV Multi-Energy data acquisition/processing Simulated Spectra for the new tube Changing X-ray tube setting

Fenestra Iopamiro Use of X-ray contrast agents

Mouse 200 µA, voltage 50 kV 200 µm Fenestra LC Mouse 200 µA, voltage 50 kV 200 µm Iopamiro

Mouse 200 µA, voltage 50 kV 200 µm Iopamiro Dynamic study

Workpackage 8: FMT-XCT imaging accuracy versus PET-XCT

Materials selection for the optical phantom construction Water Gelatin Silicon Ti02 Pro Jet Polyester resin India ink Lipid emulsions (Intralipid) Polymer microspheres Bulk materialsScatterersAbsorbers ++

Things to have in mind when designing a FMT phantom. Resolution is depth dependent Diffusion approximation: One photon mean free path ≈ 1mm Source Detector Source

Things to have in mind when designing a FMT phantom. Heterogeneities, surface

Phantom design Heterogeneities 4 mm Fluorescent spheres, 2 mm (Should their size vary?)

FMT-XCT

How to insert the fluorophore in the phantom? Resin vs Silicon - Mix the fluorophore with the bulk material* - Capillaries (diffusive-non diffusive interfaces) - Pellets * John Baeten et al “Development of fluorescent materials for Diffuse Fluorescence Tomography standars and phantoms” Optics express vol

What to measure Resolution. FWHM of point-like source? Quantification accuracy Sensitivity: In-vivo specific application PET phantom remarks

Will the imaging performance hold in the “many body imaging situation”?

PET phantom

Detector Dynamic Range Expansion Dual-Exposure technique Main features X-ray tube current calculation for the second scan Based on Histogran processing Shift the histogram to place 75% of the total value into the High-Gain region Dataset combination Detector Model Image combination based on a Maximum-Likelihood calculation assuming Independent Gaussian distribution. - i : Acquisition number - j : Pixel number - A: Current value - N: Noise value

FMT system

Resultados preliminares, maniquíes: Agar based, TiO2 (scatter), Blank ink (absorption) coronal Z=0.25 cm Planar imaging