1. PET Activities at UiO NFR Review 16.04.2009 E. Bolle*

2. Outline PET intro AxialPET Beyond AxialPET Concept Implementation
Results
Beyond AxialPET
Continuation
Financing
Partners

3. Positron Emission Tomography
Medical technique for imaging functional processes in the body
Show areas with high metabolic activity (cancer)
Inject biologically active molecules tagged with radioactive tracers -> F-18, C-11, O-15…..
Detects pair of 511keV gammas (LOR)
Reconstruct 2D/3D images

4. Axial PET A Novel PET Detector Concept with Full 3D Reconstruction
AX-PET* collaboration
* INFN Bari, Ohio State University, CERN, University of Michigan, University of Oslo, INFN Roma, University of Valencia, PSI Villigen, ETH Zurich

5. Challenge Measure DOI (Depth Of Interaction)
No depth of interaction information → Parallax error!
Solution: Measure interaction point in 3 dimensions
Parallax error:
Increase with distance from center of FOV

6. Axial PET Geometry

7. Axial PET Concept LYSO gives x-y + energy
WLS derive axial (z) position
Readout on one end of WLS and LYSO. Reflector on opposite end
Light below angle of total reflection escapes LYSO → absorbed at one side by WLS
Light transport relies on internal reflection → Polished and crack-free surface
Resolution along the three dimensions can be tuned varying LYSO/WLS dimensions

8. Main Components
LYSO
1.19x3.22mm2 MPPC
3x3mm2 MPPC
WLS

9. Demonstrator 2 LYSO matrices of 8x6 crystals 312 WLS
3×3mm2 MPPC for LYSO
1.19×3.22mm2 MPPC for WLS
Mechanics for support and cooling (water)
Readout electronics on bottom
WLS
LYSO
3x3mm2 MPPC
1.19x3.22mm2 MPPC

10. Simulation & Image Reconstruction
Simulation studies are done to optimize demonstrator and improve understanding
Geant4 and Gate simulation software
Dedicated image reconstruction software is under development to optimize image quality with the new geometry

11. Results 2 layers assembled Acquired with a 22-Na source
Data from 2 layers of LYSO
Dato from one layer of WLS

12. Status
All components tested show satisfying performance for an AxialPET
Parts for 2 modules
Demonstrator with two detector being assembled:
Electronics is developed
Mechanics is produced
All components procured
First results in 2009
One almost assembled

13. Beyond AxialPET……

14. Funding Partners Approved a 4 year PET research program through FRITEK
FRITEK is a NFR-program
Financing for equipment, travel and 2 positions for the project period
1 Ph.D. (3 years)
1 Researcher (3 years)
Equipment should cover what’s needed to build a complete animal PET scanner
Funding until end 2012
Radiumhospitalet
MRI machine available and one of the few human PET scanners in Norway
Small Animal Unit
Part of Faculty of Medicine
Already have an animal PET scanner
AxialPET
INFN Bari, Ohio State University, CERN, University of Michigan, University of Oslo, INFN Roma, University of Valencia, PSI Villigen, ETH Zurich

15. Schedule 2009 2010 2011 2012 Simulation Image Reconstruction
Prototype Studies
Fix Geometry
Image Reconstruction
Scanner Implementation
Phantom Studies
Scanner Implementation
Phantom Studies
Pre-clinical Tests
Pre-clinical Studies

16. + Goals Build a small animal PET system with 3D event reconstruction
World class system performance
MRI compatibility +

17. Ultimate Goal
(a) Dynamically acquired PET images from a C57BL/6 mouse injected with [11C]-d-threo-methylphenidate show a specific dopamine transporter binding in the striatum (S) and nonspecific uptake in the Harderian glands (H). (b) Brain morphology is revealed from the magnetic resonance images simultaneously acquired using a 3D TSE sequence. (c) The fused images show enhanced tracer uptake, matching the morphology of the striatum in the magnetic resonance data. (d) Time-activity curves (TACs), derived from the PET data simultaneously acquired during MRI, allow further analysis such as kinetic modeling to determine the dopamine transporter binding potential. The clear separation of the striatum and cerebellum (Cb) curve indicates more specific tracer binding in the striatum than in the cerebellum. Both TACs include unbound tracer. Scale bars, 1 cm.

18. People and Publications
Involved: S.Stapnes, E.Bolle, O.Rohne, O.Dorholt, P.Nordahl and J.I.Buskenes
Publications 2008:
IEEE MIC 2008: proceedings of the IEEE NSS MIC conference, Dresden (Germany)
IPRD 2008: proceedings of the IPRD08 conference, Siena (Italy)
NDIP 2008: proceedings of the NDIP08 conference, Aix-les-Bains
SORMA (WEST) 2008: proceedings of the 2008 SORMA WEST conference