PIXSCAN CT scanner for Small Animal Imaging Based on hybrid pixel detectors

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1 PIXSCAN CT scanner for Small Animal Imaging Based on hybrid pixel detectors Centre de Physique des Particules de M arseille (CPPM -IN2P3), France S. B a s o lo, A. B o n is s e n t, P. B re u g n o n, J.C. C le m e n s, P. D e lp ie rre, B. D in k e s p ile r, R. K h o u ri, I. K o u d o b in e, C. M e e s s e n, M. M e n o u n i, C. M o re l, P. P a n g a u d, E. V ig e o la s CNRS Grenoble & D2am CRG beam -line, France J.F. B e ra r, N. B o u d e t, B. C a illo t, C. M o u g e t, CREATIS, UM R-CNRS-5515, INSERM -U630, Lyon, France F. P e yrin, D. S a p p e y- M a rin ie r, S. V a lto n, Institut de Biologie du Développement de M arseille (IBDM ), France F.D e b a rd ie u x, F.M a n n, G. R ou gon 1

2 Summary Interest of hybrids pixels for X rays Large surface X ray detector Validation with crystallography Scanner CT prototype Ongoing work for the final version Prospective: PET CT 2

3 Interest of HPS for X ray imaging what we do not have with CCD s or CMOS pixels (APS) Photon counting noise suppression electronic et physic Energy selection large dynamic range, flux et luminosity contrast improvement Very fast data acquisition (< 2 ms) Choice of the sensor substrate (Si, CdTE, AsGa) Maximum efficiency =>Dose reduction 3

4 Building Hybrid Pixel Detectors Sensor Si or CdTe Thickness: 0,3 mm Readout chip 1 complete electronic chain for each pixel Photon counting ATLAS/LHC CERN 70 Millions de pixels Crystallograph y ( ESRF, SOLEIL) Small Animal Imaging 4

Readout of pixel counter overflows during exposure 3.

5 Si sensor X ray detector Thickness XPAD2 500µm Pixels 330 x 330 µm 2 15 bit Counter linear until 10 6 ph/sec/pixel 65 x 8 mm 2 PCB (rooting and support) 1. Readout of pixel counter overflows during exposure 3. Addition in an external 16 bit counter => Dynamic range: Storage in memory chips 6 7 july 2005 =>IWORID, 423 images) XPAD2 s ALTERA prog. device ETHERNET interface Monitoring by PC 5

6 Large surface X Ray PixelDetector 8 modules tiled 6,8 x 6,5 cm 2 HPS Detector Pixels size: 330 x 330 µm images, 2 ms gap 6

$CRYSTALLOGRAPHY Diffraction / Zéolithe XPAD <=> Slit + PM Good image$ XPAD air water distance from the center Comparison XPAD <=> CCD (+P)

7 CRYSTALLOGRAPHY Diffraction / Zéolithe XPAD <=> Slit + PM Good image quality Factor of 20 less in time Small Angle (SAXS) Polyurethane CCD XPAD air water distance from the center Comparison XPAD <=> CCD (+P) Much better resolution water / air (direct X conversion=> no fluorescence,...) 7

8 Small Animal CT scanner HPS Detector X ray source Mouse (Rotating) 8

9 PIXSCAN Prototype 9

10 PIXSCAN Prototype Mouse 10

11 TOMOGRAPHIQUE IMAGES Cone beam tomographic reconstruction by FDK algorithms (collaboration with CREATIS, Lyon, France) 360 projections (1 per degree) Phantom => geometry One slice 11

12 Ongoing work for the next CT scanner Aims resolution: 60 µm => pixel size = 120 µm Energy selection => double threshold Dynamic range ~ infinite Continuous readout during exposure noise suppression Time gap between images < 1 msec => very fast image transfer Dose reduction efficiency > 95% at 50 kev (CdTe and gap < 1 msec) Gamma (511 kev) absorption < 2% => 300 µm CdTe 12

13 XPAD3 New chip, the XPAD3, technology : IBM 0,25 µm Pixels de 125 µm Double threshold Radiation hard 13 bit counter/pixel Test chips analog and digital Complete XPAD3 : Design under work 1 x 1,5 cm 2 first version to be submitted in sept

Collaboration with LETI (Grenoble, France) CdTe / XPAD1 Co 57 (122 KeV )

14 Sensor => CdTe CdTe CdTe 300µm or CdZnTe Strong absorption / thin thickness => 95% efficiency at 50 kev Radiation hard Bump bonding => Collaboration with LETI (Grenoble, France) CdTe / XPAD1 Co 57 (122 KeV ) CdTe sensor on XPAD2 Linear over 4 décades of incident flux (see talk from F. Glasser 14

15 Medical Imaging complementarities Anatomy Physiology Metabolism Molecular PET IRM X Ultrasound s Optical 15

16 PET CT PET + CT scan simultaneous imaging several CT images during the PET Anatomic image + functional image (tumors) PET data correction for absorption and for movements during PET exposure Without positioning problems 16

17 CLEARPET CLEARPET de Lausanne (C. Morel) To be installed at Marseille (CPPM) 17

18 PIXSCAN in the ClearPET X ray Source The full detector CLEARPET (C. Morel) (and the X ray source) rotate several times to take CT images during the PET) CdTe Hybrid Pixel Detector (HPS) 18

19 Conclusion A large surface X Ray Hybid Pixel Detector has been built It is in use for : Crystallography: saving a factor of 20 / slit + PM scan Resolution improvement / CCD CT scan (PIXSCAN): 400 images separated by 2 ms Starting tomographic images New chip in submicronic technology under design for a pixel size of 125 µm and CdTe sensor Plans: First version PIXSCAN (silicium) June 2006 Finale PIXSCAN (CdZnTe) End 2006 Simultaneous PET CT July

PIXSCAN CT-scanner for Small Animal Imaging Based on hybrid pixel detectors

PIXSCAN CT-scanner for Small Animal Imaging Based on hybrid pixel detectors Centre de Physique des Particules de Marseille (CPPM-IN2P3), France S. Basolo, A. Bonissent, P. Breugnon, J.C. Clemens, P. Delpierre,