FP7 FMTXCT ProjectUMCE-HGUGM second year activity report

Partner FIHGM

Laboratorio de Imagen Médica. Medicina ExperimentalHospital 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

Fenestra Iopamiro

Use of X-ray contrast agents

Use of X-ray contrast agents

Increase in CT number shown by the different contrast agents, Fenestra (A) and Iopamiro (B). Both scans were performed with the same settings, 50 kV peak voltage, 200 µA anode current and 125 µm pixel size.

Detector Dynamic Range Expansion

Dual-Exposure technique

Dual exposure

CNR (PTFE/Air) = 22.11

Single exposure

CNR (PTFE/Air) = 13.91

Detector Dynamic Range Expansion

Dual-Exposure technique

Detector Dynamic Range Expansion

Dual-Exposure technique

Workpackage 2: XCT development

Use of X-ray contrast agents

Double exposure techniques

Dual energy X-ray source

Multi-Energy data acquisition/processingNew Tube Features

Voltage setting range 40 to 110 kV

Current setting range 10 to 800 μA

Output window Beryllium (thickness 500 μm)

Focal spot size 15 μm (6 W) – 80 μm (50 W)

Emission angle 62 deg (max)

Power 50 W

July 10th

July 10th

September 2009

Work plan for the first semester of 2010

Deploy FIBHGM FDK code in CEA-LETI

Start the dual-energy experiment in FIBHGM using the new CT

Exchange visits with CEA-LETI to carry out live-animal experiments with contrast and dual-energy techniques

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 materials Scatterers Absorbers

+ +

Phantom design

Heterogeneities

4 mm

Fluorescent spheres, 2 mm

(Should their size vary?)

Material autofluorescence?

PET quantification

PET quantification

NEMA NU-4 2008

Metrics for comparisonResolution given by FWHM of a point spread

function (PSF) [1,2]. Noise of the image background [3],

noise=STD/ mean.

Characterization of FMT: metrics

[1] Culver et al. Three-dimensional diffuse optical tomography in the parallel plane transmission geometry. Med Phys 30 (2), 2003.

[2] Patwardhan et al. Time-dependent whole-body fluorescence tomography of probe bio-distributions in mice. Optics Express 13 (7), 2005.

[3] Ros et al. The influence of a relaxation parameter on SPECT iterative reconstruction algorithms. PMB1994

Relaxation parameter: 0.001, 0.005, 0.01, 0.05, 0.1, 0.2, 0.5, 0.7, 1, 1.5

Number of iterations: 0-100

Metrics: noise and resolution.

Metrics depend on (reconstructing with ART) Relaxation parameter.Number of iterations.Depth.

Methods: ART.Compute metrics for range of parameters.

Characterization of FMT: influence of parameters

5 iterations. 20 iterations. 40 iterations.

Higher number of iterations, higher resolution.

x

Resolution versus relaxation parameter and iteration number

YX

Z

z

X(mm)

Norm

alized counts

X(mm)

Norm

alized counts

X(mm)

Norm

alized counts

Optimum relaxation parameter and iteration number

Noi

se•Optimum: 20 iterations y α = 0.05-0.1 (low noise & no so low resolution).Relaxation parameter: 0.001, 0.005, 0.01, 0.05, 0.1, 0.2, 0.5, 0.7, 1, 1.5

Number of iterations: 0-100

Metrics: noise and resolution.

α=0.001

α=1.5

α=0.05

Iteration number

α=0.05

α=0.1

α=0.2

α=0.5

α=0.7

α=1

α=1.5

Iteration number

Discussion

Metric dependence on parameters and depth complicates comparison.

Select/decide for optimum parameters.

Characterization of FMT: linearity

R2 = 0.986

Can not detect concentrations below 103~104 nM. Any suggestions?