P. Finocchiaro INFN Laboratori Nazionali del Sud, Catania, Italy

1. Photosensor applications Medical imaging: scintillation detectors for TOF-PET P. Finocchiaro INFN Laboratori Nazionali del Sud, Catania, Italy

2. Medical Imaging: X-rays radiography Computed Tomography analog picture is impressed on the film digital data acquired, slices are computed (and printed on the film)

3. Medical Imaging: Magnetic Resonance MRI sensitive to the magnetic moment of protons digital data acquired slices of H distribution are computed

4. Medical Imaging: g-rays SPECT digital data acquired, slices are computed and printed on the film g-camera a g radioactive tracer is injected collimator photodetector g collimator scintillator

5. Medical Imaging: g-rays PET residual nucleus b+decay e+ 511 keV 511 keV a b+ radioactive tracer is injected

6. Medical Imaging: g-rays PET digital data acquired • data selected by: • 2-pixel coincidence • energy ≈ 511 keV data stored as sinograms or list mode Energy [a.u.] Energy [a.u.] • sinogram: a special 2D histogram • list mode: data recorded event by event slices are computed can be combined with CT or MRI

7. Medical Imaging: g-rays PET data stored as sinograms data stored in list mode slices are computed can be combined with CT or MRI • sinogram: a special 2D histogram • list mode: data recorded event by event

8. Medical Imaging: summary

9. Medical Imaging: g-rays TOF-PET ∆t ∆x ∆t Line Of Response (LOR) -6 0 3 -3 6 X position along LOR

10. Medical Imaging: g-rays TOF-PET digital data acquired data stored as list mode: position, energy, time • data selected by: • 2-pixel coincidence • energy ≈ 511 keV slices are computed with probability weight can be combined with CT or MRI improved resolution reduced background

11. Medical Imaging: g-rays TOF-PET further issue: Depth Of Interaction DOI Unknown DOI Known DOI several methods available to handle DOI blurred images

12. Medical Imaging: g-rays TOF-PET the TOPEM project TOPEM: A TOF-PET endorectal probe for diagnosis and follow up of the prostate cancer size ≈ 25 x 15 x 50 mm3 outer PET detector Lines of coincidence backplane contacts endorectal PET probe probe should also be compatible with MRI array of SiPM ≈ 450 LYSO scintillators connector array of SiPM backplane contacts

13. Medical Imaging: g-rays TOF-PET the TOPEM project outer PET detector SiPM 3x3x15 mm3 LYSO scintillator SiPM endorectal PET probe single scintillator prototype need to measure position (LOR, time), energy, DOI

14. Medical Imaging: g-rays TOF-PET the TOPEM project need to measure position (LOR, time), energy, DOI LOR known from geometry detector i detector j time measured by the two scintillators position along LOR X position along LOR

15. Medical Imaging: g-rays TOF-PET the TOPEM project need to measure position (LOR, time), energy, DOI

16. Light propagation and attenuation attenuation length latt • latt is a constant depending on • material type • shape • surface finish • wrapping

17. Medical Imaging: g-rays TOF-PET the TOPEM project need to measure position (LOR, time), energy, DOI detector i detector j energy measured by the two scintillators 511 keV 511 keV measured energy independent of the hit position • scintillator surface and wrapping chosen to obtain a convenient latt ≈ 15 mm

18. Medical Imaging: g-rays TOF-PET the TOPEM project need to measure position (LOR, time), energy, DOI

19. Medical Imaging: g-rays TOF-PET the TOPEM project need to measure position (LOR, time), energy, DOI

20. Medical Imaging: g-rays TOF-PET the TOPEM project need to measure position (LOR, time), energy, DOI DOI measured by the two SiPM DOI

21. Medical Imaging: g-rays TOF-PET the TOPEM project need to measure position (LOR, time), energy, DOI DOI calibration

22. Conclusion need to use detectors with: good time resolution (≈ 200 ps) reasonable energy resolution (< 15% @ 511 keV) reasonable DOI resolution: double readout surface finish & wrapping such that latt ≈ L

23. Thanks for your patience...