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RPC2001 VI Workshop on Resistive Plate Chamber

RPC2001 VI Workshop on Resistive Plate Chamber. Perspectives in Positron Emission Tomography (PET) with RPCs. A. Blanco (1,5), P.Fonte (1,4), I.Lopes (1), R.Marques (1,2), V.Peskov (3), A.Policarpo (1,2), V.Tchepel (1)

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RPC2001 VI Workshop on Resistive Plate Chamber

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  1. RPC2001VI Workshop on Resistive Plate Chamber Perspectives in Positron Emission Tomography (PET) with RPCs A.Blanco(1,5), P.Fonte (1,4), I.Lopes (1), R.Marques (1,2), V.Peskov (3), A.Policarpo (1,2), V.Tchepel (1) (1) LIP, laboratorio de Instrumentacao e Fisica Experimental de Particulas(2) Departamento de Física da Universidade de Coimbra(3) KTH, Stockholm(4) ISEC, Coimbra, Portugal.(5) GENP, Dept. Fisica de Particulas, Univ. Santiago de Compostela, Spain.

  2. Electronic Coincidence RPC2001VI Workshop on Resistive Plate Chamber What is and How PET works Positron Emission Tomography (PET) is a radiotracer imaging technique, in which tracer compounds labelled with positron emitting radionuclides are injected into the subject of the study. These tracers compounds can then be used to track biomedical and physiological process. Coincidence events can be stored in arrays corresponding to projections through the object and reconstructed using standard tomographic techniques. Two anti-parallel 511 keV photons produced Unstable parent nucleus Positron combines with electron and annihilates Proton decays to neutron in nucleus positron and neutrino emitted Resulting image shows the tracer distribution throughout the object of the study. Perspectives in Positron Emission Tomography (PET) with RPC´s Alberto Blanco

  3. a) b) X = 80 cmTOF = 2.6 ns a) Reconstructed image without TOF. b) Reconstructed image using TOF information [NIM A 471(2001) 200-204] RPC2001VI Workshop on Resistive Plate Chamber TOF-PET Perspectives in Positron Emission Tomography (PET) with RPC´s Alberto Blanco

  4. RPC2001VI Workshop on Resistive Plate Chamber The basic idea Stacked plates Quantum Efficiency? Compton or photoelectric interaction  e- .... Incident photon Geant simulations High quantum efficiency material Gas gap A previous work “The Rutherford Appleton Laboratory´s Mark I Multiwire Proportional Counter Position Camera”J.E. Bateman et al. NIM 225 (1984) 209-231 Perspectives in Positron Emission Tomography (PET) with RPC´s Alberto Blanco

  5. Can we trust Geant 4? Experimental data Geant 4 RPC2001VI Workshop on Resistive Plate Chamber Efficiency of a MWPC with 21 lead plates (250 um) [from J.E. Bateman NIM 221 (1984 131-141] Geant seems accurate Perspectives in Positron Emission Tomography (PET) with RPC´s Alberto Blanco

  6. Can we trust Geant 4? Experimental data Geant 4 0 10 ) 2 2 Range (g/cm -2 10 -4 10 -2 -1 0 1 10 10 10 10 Energy (MeV) Ranges of electrons in Aluminium From NIST (National Institute of Standards and Technology). RPC2001VI Workshop on Resistive Plate Chamber Perspectives in Positron Emission Tomography (PET) with RPC´s Alberto Blanco

  7. Can we trust Geant 4? Experimental data Geant 4 Absorption curves of monoenergetic electrons of various energies in aluminium. [From J. Marshall and A. G. Ward, Can. J. Research A15, 39 (1937)] RPC2001VI Workshop on Resistive Plate Chamber Perspectives in Positron Emission Tomography (PET) with RPC´s Alberto Blanco

  8. Can we trust Geant 4? Experimental data Geant 4 RPC2001VI Workshop on Resistive Plate Chamber 82Sr Projected PSF due to range only 11C 68Ga 18F mm water equivalent From “Mathematical removal of positron range blurring in high resolution tomography” Derenzo et all. IEEE NS, vol 33 No1” Perspectives in Positron Emission Tomography (PET) with RPC´s Alberto Blanco

  9. RPC2001VI Workshop on Resistive Plate Chamber The basic idea Geant 4 simulation Stacked plates Mechanically more convenient  .... Data from the simulation on Geant 4 showing quantum efficiency vs. plate thickness for tree different materials and 30 stacked plates. Perspectives in Positron Emission Tomography (PET) with RPC´s Alberto Blanco

  10. RPC2001VI Workshop on Resistive Plate Chamber The basic idea Geant 4 simulation Stacked plates 22 % Mechanically more convenient  .... Data from the simulation on Geant 4 showing quantum efficiency vs. plate thickness for tree different materials and 100 stacked plates. Perspectives in Positron Emission Tomography (PET) with RPC´s Alberto Blanco

  11. Time Z-Codification Y-Codification X-Codification RPC2001VI Workshop on Resistive Plate Chamber The detector blocks • n - stacked counters built with a high quantum efficiency material • Tridimensional localisation of the photon interaction point. • Time measurement independent of position measurement yielding a 50 ps resolution. Perspectives in Positron Emission Tomography (PET) with RPC´s Alberto Blanco

  12. RC passive network RC passive network X-strips (deposited on glass) RPC2001VI Workshop on Resistive Plate Chamber The detector blocks Time signal HV TESTED X right X left out left 10 strips for each coordinate at 4 mm pitch Y-strips (on PCB) out right Other position readout methods also possible Perspectives in Positron Emission Tomography (PET) with RPC´s Alberto Blanco

  13. 1) RPC PET (100 m counter resolution) 180 m FWHM 2) RPC PET (500 m counter resolution) 490 mFWHM Reconstructed point spread function [PSF] of the source. No parallax effect RPC2001VI Workshop on Resistive Plate Chamber Expected spatial resolution 1 cm Geant 4 simulation of 3 point-like positron source (max energy 640 keV) surrounded by a water sphere and seen by a RPC-PET with spatial resolution of 100m. Perspectives in Positron Emission Tomography (PET) with RPC´s Alberto Blanco

  14. RPC2001VI Workshop on Resistive Plate Chamber The two possible applications Human PET Small animal PET +Tridimensionallocalisation of the interaction point of photons, reducing the parallax effect, with high spatial resolution providing a good image quality. + The low cost. + The excellent timingallows to improve the background rejection. - TOF capability is of no value due to the small dimension of the object. + An higher radiation dose may be acceptable, with animals. + The lack of energy resolution play a minor role. The compton interactions in the object are almost negligible. +TOF capability compensates the low efficiency. - The lack of energy resolution increase the compton background. Perspectives in Positron Emission Tomography (PET) with RPC´s Alberto Blanco

  15. Object 4x3x1 cm3 The detector in Geant. RPC2001VI Workshop on Resistive Plate Chamber The first prototype a small animal PET • 2 head rotatory system • 16 stacked glass-metal counters  2%  • 32 1mm wide X pickup strip • Time measurement not yet included Glass Copper strips Copper Perspectives in Positron Emission Tomography (PET) with RPC´s Alberto Blanco

  16. RPC2001VI Workshop on Resistive Plate Chamber Conclusions Simulations suggest that RPC´s could be used for TOF-PET Low cost large field of view  increased sensitivity High spatial resolution provides high definition images Perspectives in Positron Emission Tomography (PET) with RPC´s Alberto Blanco

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