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PROSPET: First tests and results

PROSPET: First tests and results. Gabriel Cañizares Ledo Consejo Superior de Investigaciones Científicas - Instituto de Instrumentación para Imagen Molecular (i3M). Disclosure. Nothing to disclosure. Index. Motivation Position Emission Tomography (PET) Two Panels Prototype

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PROSPET: First tests and results

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  1. PROSPET:Firsttests and results Gabriel Cañizares Ledo Consejo Superior de Investigaciones Científicas - Instituto de Instrumentación para Imagen Molecular (i3M)

  2. Disclosure Nothing to disclosure

  3. Index • Motivation • Position EmissionTomography (PET) • TwoPanelsPrototype • PROSPET SystemConfiguration • SpatialResolution. Sensitivity • PhantomsStudies. PatientReconstruction • Summary and Conclusions

  4. Motivation Prostate: Glandular organ. Seminal expulsion CaP: Mostfrequenttumour in men. No symptoms in earlystadiums Randomtissueextractionforstudy: BlindBiopsy. High probabilityfor false negative test. What are weproposing? A dedicated PET systemforCaP

  5. PositronEmissionTomography (PET) • Radiotracer: Molecule + Radioactiveelement. 18F-FDG, 68Ga-PSMA, etc… • 511 keV gamma raysdetectors. Scintillator cristal + Photodetectors • Twocoincidence gamma rays: Line of Response (LOR) • Time of Flight (TOF). Weneed a verygood time resolution (200 ps) • Wepropose a specific PET systemforCaP • Ourgoals: • > 3 mm SpatialResolution • > 15% EnergyResolution • DOI capabilities

  6. Two panel prototype LYSO scintillator block 50x50x15 mm3 12x12 SiPMphotosensor, pitch 4.2 mm Median SpatialResolution: 1.9 ± 0.2 mm Median EnergyResolution: 13 ± 1 % DoIResolution: 3.7 mm Time resolution > 2 ns (required 0.2 ns) Wehavesimulatedthisdevice and wehaveobservedartifacts 3 patientsweremeasured. Resultnotsatisfactory Patient 50 mm 50 mm Simulation 15 mm

  7. PROSPET SystemConfiguration 24 Module Detectors in a ring configuration 410 mm systemaperture (300 mm FOV) Axial FOV: 80 mm (twosteps) 1 to 13 coincidencesallowed, againsthalf ring MaximumLikelihoodEstimationMethod (MLEM). Iterativemethod Couldallow molecular-imagingguidedbiopsy

  8. SpatialResolution. NEMA Protocol NEMA protocolsource positions: 1 cm and 10 cm radial and CFOVaxial and 3/8FOVaxial (17 mm) DOI informationimprovessystem performance at FOVedge Spatialresolution < 3 mm forthewhole FOV

  9. Sensitivity Following NEMA protocol, activitySource: 825 kBq. 0.25 mm SourceDiameter22Na CTR: 3 ns. TW: 5 ns. 1.7 % (50% EW) vs 2.3 % (Gate v7.2)

  10. Phantoms Studies We can resolve 6 mm rodswith 5:1 activity ratio 11x11 Array22Na 4.6 mm pitch

  11. Patientresults Patient > 70 yearswithclearhot-spots CaP (possiblemetastasis) 7.48 mCi F-Choline, acquisition 2 hourslater. 7 minutes foreach axial FOV Normalization and attenuation (waterelipsoid) correctionshavebeenimplemented 3 iterations, 2 subsets, voxelsize 1x1x1 mm, virtual pixel 1x1 mm. No Normalization No Attenuation PROSPET Final Image Philips GEMINI TF

  12. Summary and Conclusions • CaPisthemostfrequentcancer in men> 50 years • Eventhough, biopsies are maderandomly and thereis a chance for a false positive • We are proposing a specific PET system in order to help in the diagnosis and in vivo biopsy • Detector modules achievelessthan 2 mm in spatialresolution and > 15% energyresolution • With no time information, twopanelsconfigurationpresents no reliableresults • Forreconstructionprocesswe are using a MLEM algorithmwith 3 iteration • Spatialresolution and sensitivity are theexpected • Patientimagepresents a goodsimilaritywiththe PET systemreference • Nextsteps: CT attenuationcorrection + more phantoms (NECR)

  13. Thanks! I3M Detectorsfor Molecular ImagingLaboratory (DMIL): Prof. J.M. Benlloch PhD F. Sanchez PhD A.J. Gonzalez PhD Andrea González-Montoro, PhD L. Moliner, PhD J.Barrio, PhD M. Freire E. Lamprou N.Cucarella K. Vidal V. Ilisie L. Hernández S. Aguilar Hospital La Fe (Valencia). UrologyDepartment CD Vera-Donoso MD, F. Boronat Tormo MD, Laura Lorenzo MD Hospital La Fe (Valencia). Nuclear Medicine Irene Torres PhD, Pablo Sopena MD, Pilar Bello MD

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