1. Filipe Castro Departamento de Física & i3n Universidade de Aveiro C S I(N A ) W AVELENGTH - SHIFTING FIBER GAMMA CAMERA USING S I PM S LIP Lisboa Apr. 2012 IDPASC School on Digital Counting Photosensors for Extreme Low Light Levels

2. 2 Improve sensitivity of scintigraphy exams Typical radionuclide: 99m Tc (140 keV, T 1/2 = 6.02 h ) Motivation Exp. setup Results Ongoing and future work CsI(Na)-WSF gamma camera Bénard and Turcotte, Breast Cancer Research (2005) Mammoscintigraphy images with 99m Tc-MIBI: Better spatial resolution Better positioning with compact portable app.-specific camera Earlier detection of smaller tumours Reduce rate of negative biopsies MOTIVATION

3. 3 Design Motivation Exp. setup Results Ongoing and future work CsI(Na)-WSF gamma camera 1x1 mm 2 Hamamatsu SiPM MPPC S10362-11-100U λ -shifting fibers to read out γ -rays’ position of interaction in the crystal SiPMs to detect light from optical fibers (also Ma-PMTs) E-PMT to provide energy signal and trigger for acquisition 64 anode Hamamatsu Ma-PMT C S I(N A ) WAVELENGTH-SHIFTING FIBER GAMMA CAMERA Patent number WO2010080046-A2

4. Photon detection components and characteristics Motivation Exp. setup Results Ongoing and future work CsI(Na)-WSF gamma camera C S I(N A ) WAVELENGTH-SHIFTING FIBER GAMMA CAMERA Crystal with embedded fibers: Photodetector efficiency: 4 420 nm to 494 nm trapping efficiency > 5.6%

5. 5 Assembling and testing small prototype with 10x10 SiPMs (1cm 2 ) Motivation Exp. setup Results Ongoing and future work CsI(Na)-WSF gamma camera EXPERIMENTAL SETUP SiPMs E-PMT TRIGGER SiPMs SiPM E-PMT TRIGGER

6. 6 Readout electronics Motivation Exp. setup Results Ongoing and future work CsI(Na)-WSF gamma camera EXPERIMENTAL SETUP With larger initial RC and final CR–RC shaping With lower initial RC and no last stage

7. 7 Readout electronics Motivation Exp. setup Results Ongoing and future work CsI(Na)-WSF gamma camera EXPERIMENTAL SETUP With larger initial RC and final CR–RC shaping With lower initial RC and no last stage

8. 8 Temperature influence Intro Exp. setup Results Ongoing and future work CsI(Na)-WSF gamma camera RESULTS T = 25˚C Constant gain T = 20 ºCT = 25 ºC

9. 9 Imaging with 57 Co (122 keV) Motivation Exp. setup Results Ongoing and future work CsI(Na)-WSF gamma camera RESULTS – 10 X 10 S I PM PROOF - OF - CONCEPT PROTOTYPE Two positioning algorithms, based on maximum values: 1 mm hole Pb collimator manual positioning over (x,y) positions, i = SiPM with max. signal, for the n neighboring SiPMs which signal sum is maximum (1,1)(2,2)(3,3)(4,4)(5,5)(6,6)(7,7)(8,8)(9,9) (10, 10) E res ~ 23% FWHM V bias common to each 10 SiPM, T = 20ºC

10. 10 Imaging with 57 Co (122 keV) : 4-hole Pb collimator Motivation Exp. setup Results Ongoing and future work CsI(Na)-WSF gamma camera RESULTS – 10 X 10 S I PM PROOF - OF - CONCEPT PROTOTYPE

11. 11 Imaging with 99m Tc (140 keV) Motivation Exp. setup Results Ongoing and future work CsI(Na)-WSF gamma camera Parallel-hole collimator from large FOV gamma camera L=40 mm, d= 2 mm, t ≈ 200 µm RESULTS – 10 X 10 S I PM PROOF - OF - CONCEPT PROTOTYPE Syringe needle with 99m Tc

12. 12 Imaging with 99m Tc (140 keV) Motivation Exp. setup Results Ongoing and future work CsI(Na)-WSF gamma camera RESULTS – 10 X 10 S I PM PROOF - OF - CONCEPT PROTOTYPE A ~ 100 uCi E res ~ 20% FWHM V bias common to each 10 SiPM, T = 20ºC

13. larger crystal assembled with fibers glued to SiPM-coupling pieces 4 E-PMTs to read out crystal biasing SiPMs in groups of 8 Larger prototype (10x10 cm 2  100x100 SiPMs): Motivation Exp. setup Results Ongoing and future work CsI(Na)-WSF gamma camera 13 ONGOING AND FUTURE WORK 16 channel SiPM power supply PCB developed by ISA S.A. (Coimbra), 8 bit DAC to adjust ~ 69-73 V

14. biasing R6236 E-PMTs with individual compact PCB HV supplies readout with VA32HDR14.2 chips  DAQ with X3-10M (also V bias control) SiPM cooling Small animal or phantom studies, prototype characterization Larger prototype (10x10 cm 2  100x100 SiPMs): Motivation Exp. setup Results Ongoing and future work CsI(Na)-WSF gamma camera 14 ONGOING AND FUTURE WORK Hamamatsu C11152-51 drawn to scale

15. Questions? Doubts? Ideas? Remarks? 15 Coffee? THANKS FOR THE ATTENTION! Acknowledgments: DRIM team @ UA (João Veloso, Carlos Azevedo, Ana Luísa, Lara, Moutinho, …) A.J.D. Soares (project mentor) Jorge Isidoro (Nuclear Medicine @ HUC) ISA S.A. (Rodrigo Ferreira, Miguel Ferreira)

16. 16 Conventional gamma camera Main componentsFunction Collimator (Pb) accept only γ -rays alligned with holes Scintillation crystal, e.g. NaI(Tl) convert γ -rays into visible light Photodetectors, e.g. PMT convert light into electric signals Electronics and softwaresignal processing and image formation