- ore 11: :45 F. Garibaldi - Introduzione e stato dell'arte dell'esperimento - ore 11: :30 A. Gabrielli - Presentazione della catena HPTDC-NINO su crate VME in laboratorio. - ore 12: :30 P. Musico - AOB Genova - ore 13: :30 Pausa Pranzo- - ore 14: :15 F. Loddo - AOB Bari Riunione TOPEM Bologna

Topem: Stato dell’arte F,Garibaldi – Bologna  L’esperimento: perche’ e come  Challenges/problems  A che punto siamo (qualche risultato preliminare(Roma,Bari/Ct,Lns)  Next steps  Interazione con referees  Richiesta fondi integrativi?

PSA SENSITIVITY 83% SPECIFICITY 17% CT Selective indication :  PSA > 10 ng/ml  cT3  Gleas on score > 7 diagnosis is made from tissue obtained on a blind biopsy Need to consider fundamental changes in the approach to diagnosing prostate cancer In the future, multimodality imaging approach tailored to each patient PSA  DRE  TRUS  biopsy Prostate cancer is the most common cancer and the second leading cause of cancer death

Limited space for the PET detector PET detector must not use magnetic materials  Could distort MR image PET detector must not emit in MR frequency  Could produce MR image artifacts MR-compatible PET shielding materials  Could distort MR image  MR gradient field-eddy currents  Could produce noise in detector  Could heat detector  MR RF transmit  Could produce false PET events  MR materials  Will produce more gamma attenuation PET/MR Design Challenges -CITRATE that is present in the normal prostate -CREATINA that may increase in the phlogosis and all the proliferative processes -COLINE more specific for a neoplastic transformation MRI & MRS

Requirements for radionuclide imaging - radiotracer (high specificity) - high sensitivity - practical consideration, cost Dedicated high resolution high sensitivity PET probe for prostate imaging Detector goals - 3D photon position capability - spatial resolution ~ 1mm - high coincidence photon efficiency - energy resolution ~ 12% or better - TOF ~ 300 ps or better drawback of the standard PET - detectors far away from prostate - poor spatial resolution (6 – 12 mm) - poor photon detection efficiency (<1%) - activity ouside the organ -> poor contrast resolution - relative high cost per study

Dedicated PET detector ring (Moses) Better than standard scannner but still limited. - Endorectal probe: PET coupled to a dedicated detector or to a standard PET scanner huge background from the bladder !! Could we reduce or eliminate it?

Signals from Different Voxels are Coupled  Statistical Noise Does Not Obey Counting Statistics Signals from Different Voxels are Coupled  Statistical Noise Does Not Obey Counting Statistics If there are N counts in the image, SNR = TOF provides a huge Performance Increase! n conv = D/d n TOF =Δx/d

Timing resolution depends on - scintillator (kind (n.of photons, decay time, geometry (light path)) - photodetector (time jitter, capacitance, PDE etc) - coupling (light collection efficiency) - electronics (in our case has to be very compact  ASIC) - front end - readout architecture

Surti, Karp et al. LaBr3 A big advantage of SiPMs in a fast timing is a low time jitter, below 100 ps. However, a fast timing is limited by rather low photon detection efficiency (PDE), not exceeding 10 – 20%, depending on the number of pixels. This is of particular importance in timing with slow scintillators, like LSO, with the decay time constant of about 40 ns. Thus the expected time resolution is a direct function of sqr(n.p.e.) (PDE of SiPM). Thus, the application of SiPMs to TOF PET detectors requires a number of optimizations related to the size of the device, its PDE, number of pixels and finally its capacitance. Mozsynski

[1(2) x 1 (2)] x [4 (5) x 4(5)] (5) cm3 Array SiPm Endorectal (SPECT and) PET [(2.5 x 5 (6) mm2] probe in multimodality with MRI DOI S. Majewski ≈1.5 mm

S. Majewski 7 T 0 T

LYSO (LSO) vs LaBr3(Ce) - Pixellated (not available for LaBr3(Ce)) vs continuous (dependence on layout) - Availabilty of LaBr3(Ce) - Balancing “isolation” of prostate from bladder vs SNR (NECR)

Low Density  Radial Elongation Resolution vs. PositionPenetration Blurs Image 3 Attenuation Lengths Some Degradation with LuI 3, More with Ce/LaBr 3

Low Photoelectric Fraction  Low Coincidence Efficiency PhotoelectricCompton Both Photons Deposit >350 keV 3 Atten. Lengths Some Degradation with LuI 3, More with Ce/LaBr 3

Coincidence Timing Resolution New Scintillators Capable of Time-of-Flight 500 ps Resolution  5x Reduction in Noise Variance New Scintillators Capable of Time-of-Flight 500 ps Resolution  5x Reduction in Noise Variance

suddivisione compiti - Roma - caratterizzazione SiPm (Meddi) - misure con minidetectors (Garibaldi) - simulazione (collaborazione con Cagliari (?) e Genova (?)) - PET/MRI: Maraviglia e coll. - Bari - Ranieri: ASIC - De Leo (coll. con CT (e Lecce)) - Bologna - scheda ibrida per timing (coll. con Genova) - Genova - scheda ibrida timing (coll con Bologna) - LNS - caratterizzazione SiPM (PDE etc) - timing con SiPM

Roma (Meddi). Caratterizzazione SiPM IRST

Roma. F. G. - simulazione: pending… (installato Geant4, (e Gate), codice Geant4 per prostata da Neal Clinthorne. Collaborazione possibile con Viviana Fanti (Cern/Cagliari), e Genova? - da fare: misure “di base” con mini-rivelatori - LYSO continuo e pixellato ( 1 x 1 mm2, 3 x 3 mm2) accoppiati a SiPM Hamamatsu 4 x 4 (3x3 mm2), Misure DOI con 10 mm e 5 mm di spessore (sandwitch). Readout disponibile, interfaccia per SiPM (Paolo). - scintillatori, prima meta’ Aprile, 1 array SiPm Hamamatsu gia’ disponibile - readout: interfaccia Paolo - primo minidetector in funzione  test in MRI (con e senza screening (rame). (verifca effetto PET su MRI)

Catania-Bari: misure di timing con pmt veloci

TOPEM: attività prevista del gruppo INFN-LNS Strumenti disponibili: Laser pulsato 40ps 408nm Laser pulsato 40ps 650nm Sorgenti radioattive Camera oscura Sfera integratrice Cella peltier & dito freddo Amplificatore di tensione Gain=200, 4GHz Oscilloscopio digitale 4GHz Sistema di DAQ multiparametrico ADC, QDC, TDC, Scaler Misure da effettuare su SiPM: Dark noise & cross-talk Gain Timing con laser Risoluzione energetica con laser? (se fattibile) PDE (2 punti, 408nm e 650nm) Timing con scintillatore (1 SiPM + laser) Timing in coincidenza con scint. (2 SiPM + 22 Na) Timing vs temperatura Time walk Risoluzione energetica con scintillatore ( 22 Na, 137 Cs) altro.....

1mm x 1mm testati 24 campioni LNS : Cosentino-Finocchiaro

1mm x 1mm testati 24 campioni

1mm x 1mm testati 4 campioni

1mm x 1mm testati 4 campioni

spettri in carica con luce laser, a tre diverse intensità

Bilancio 2010 > Riunione Assegnazioni > Gruppo V > Esperimento TOPEM > Verbale riunione Verbale del Referee L_esperimento intende realizzare un nuovo sistema di imaging della prostata, basato su un rivelatore PET in combinazione con una MRI di tipo endorettale. La tecnica proposta intende risolvere gli attuali problemi diagnostici del cancro della prostata attraverso un rivelatore PET in grado di migliorare efficienza e risoluzione spaziale dell_imaging prostatico dopo la somministrazione di Colina radiomarcata C11. L_immagine funzionale combinata con MRI ad alta risoluzione dovrebbe migliorare in modo consistente il valore prognostico. Il finanziamento proposto avvia un primo studio di fattibilit_ articolato in quattro punti: a) realizzazione di un rivelatore PET composto da due testate delle dimensioni di circa 2 x 2 cm2 con cristalli pixellati di LYSO/LSO e lettura della luce di scintillazione mediante array di SiPM; b) verifica della sua compatibilita_ con MRI mediante test degli effetti del campo magnetico sull_imaging PET e degli effetti dell_apparato PET sull_ imaging MRI; c) studio della coincidenza temporale con SiPM per valutare i vantaggi della tecnica ToF sull_imaging prostatico; d) progettazione di un front-end integrato per la lettura e l_analisi timing dei SiPM. La Commissione ritiene che i risultati dello studio di fattibilita_ siano vincolanti ai fini del prosieguo dell_esperimento. Data la necessit_ di integrare fra di loro parti complesse (SiPM, FE chip, readout) la Commissione chiede alla collaborazione di indicare un Technical Coordinator che presenti un documento descrittivo del sistema per maggio referees: Aloisio, Pani, Del Guerra, Greco, Ambrosi Commento del Resp. Nazionale

 Higher Sensitivity  Lower channel-to-channel crosstalk  better signal quality  Great flexibility in processing data  Enhanced data  Complexity  Speed  High Cost Electronics Individual Channel Electronics: IDE AS VA-TA chip based, multiplexed readout 1024 Ch. ~ 2 kHz Anger Logic: Resistive Chains Cristal and Phototubes, Planar view Resistive chain and output signals phototube crystal Gamma Emission posizion (X,Y) obtained with: 4096 ch at 10 KHz

Low Density  Radial Elongation Resolution vs. PositionPenetration Blurs Image 3 Attenuation Lengths Some Degradation with LuI 3, More with Ce/LaBr 3

Low Photoelectric Fraction  Low Coincidence Efficiency PhotoelectricCompton Both Photons Deposit >350 keV 3 Atten. Lengths Some Degradation with LuI 3, More with Ce/LaBr 3

Coincidence Timing Resolution New Scintillators Capable of Time-of-Flight 500 ps Resolution  5x Reduction in Noise Variance New Scintillators Capable of Time-of-Flight 500 ps Resolution  5x Reduction in Noise Variance

Conclusi ons For SPECT: CeBr 3 and LaBr 3 are compelling –Better light output & energy resolution than NaI:Tl –Shorter attenuation length than NaI:Tl –No other performance drawbacks! For PET: LuI 3 is very interesting, but has some tradeoffs –Energy resolution, light output, & timing excellent –Worse attenuation length & photoelectric fraction LaBr 3 and CeBr 3 have more severe tradeoffs –Atten. length & photoelectric fraction much worse Economic Growth is Absolutely Necessary