Molecular Imaging:the role of radionuclides techniques

Transcription

1 High resolution and high efficiency multimodal detector for Molecular Breast Imaging F. Garibaldi NDIP 2014 Tours July Molecular Imaging:the role of radionuclides techniques Breast cancer diagnosis Detector performance A novel dual detector Multimodality (scintigraphy + tomosinthesys) Conclusions and outlook

2 Molecular Imaging Modalities CT Ultrasound A F Optical (Bioluminescence, fluorescence) A Tissue Density, Z µm Structure 0.1 mm Doppler A M Topography µm to mm ~10 3 cells quantitative MRI F M PET/SPECT A F M H Concentration 0.1 mm BOLD, DCE -galactocidase 0.1 µmole H / µmole 31 P Radiotracer ~1-2 mm <10-12 mole = quantitative

3 Techniques (scintigraphy) Single Photon Emission Mammography Single Photon Emission Computed Tomography Positron Emission Tomography parallel hole pinhole multi-pinhole coded aperturea Compton Camera

4 damaged area CT PET PET/CT

5 - Breast cancer -Not everything can be done with these devices - Dedicated detectors are needed - Focusing on small object and imaging at the same time the whole organ (or body)

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7 Important parameters for detectability/visibility they are correlated CsI(Na) SNR S BKG S IC Max BKG Max energy resolution plays only a secondary additional role when small volumes are involved CsI(Tl) efficiency (collimation) time (and modality) uptake (radiopharmacy) scintillator detector intrinsic properties electronics, DAQ Uniformity of p.h.response (affecs the overall en res. and the energy window selection) pixel dim/n.of pixels X N channel i 1 N channel i 1 c i X i c i spatial resolution Bialkali PMT Bialkali PMT X X i N p.e. R i FWHM X FWHM X i N p.e.

8 MCP (Burle) 1.5x1.5 mm2 LaBr 3

9 Importance of pixel identification good pixel identification is fundamental for correct digitization affecting spatial resolution and contrast C8 strips M16 (4 x 4) mm 2 Individual readout means better pixel identification better image M64 (2 x 2) mm 2 resitive network Individual channel readout Individual channel readout

10 Anger Logic: Resistive Chains Electronics Individual Channel Electronics: MAROC3 chip based, multiplexed readout 4096 Ch khz phototube crystal Cristal and Phototubes, Planar view Resistive chain and output signals Higher Sensitivity Lower channel-to-channel crosstalk better signal quality Great flexibility in processing data Enhanced data Complexity Speed High Cost Gamma Emission posizion (X,Y) obtained with: X Z = = X + - X - Y + - Y - ; Y = Z Z X + X + Y + Y X = c = i i (X i N th,y ) = i i å channel i = 1 N å i = 1 c X i channel c i ;Y = channel signal th i N å channel i = 1 N å channel i = 1 cy c channel position i i i

11 Something you cannot do well with standard systems Breast cancer and for invasive lobular carcionoma

12 Importantce of detection of small lesions Multifocality Average sensitivity of MBI as a function of tumor size (M. O Connor et al. Expert Rev. Anticancer, 2009)

13 Courtesy R. Pani

14 Geant4 simulations 1 detector - par.hole coll. - NaI(Tl) 1.5 mm pitch(the smallest pixel in this applications (~13000 pixel in 150 x 200 mm2) - H8500 (6 x 6) mm2 anode pixel -Individual channles electronics Sensitivity dominates the visibility, so we should try to get closer to the lesion and modify collimation and modality most cancers are in the upper part of the breast 2 detectors

15 tum: (5, 6, 7, 8,9,10,12) uptake 1:10; breast 6 cm NaI(Tl) 1.5 pitch; H8500(6x6 mm2) 6 mm 7 mm NaI(Tl) 1.2 pitch H9500 (3x3 mm2) NaI(Tl) 1.3 pitch; H8500(6x6 mm2) tum 8 mm

16 We can do even much better (spot ompression) (just getting closer to the source and using pinhole collimation) "Italian/European Patent No. RM2008A000541

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18 Comparative Sensitivity of Scintimammography, single-head MBI and dual-head MBI (M. Oconnor et al. Mayo clinic) Sensitivity 100 MBI dual head MBI single head Scintimammography >20 Tumor diameter (mm)

19 Paziente A MLO - 10 trials, University of Roma2 (TOV) in comparison with standard dedicated detectors (Gammamedica and Dilon) - 2 big tumors - 1 small tumor (< 10 mm) - 7 negative, suspicious to mammography, negative (or positive in some case) ultrasound and MRI

20 Multimodality Project funded by FILAS Regione Lazio: collaboratin between Italian National Institute of Health (ISS), Italian National Institute of Nuclear Physicis (INFN) and Metaltronica s.r.l. Tomosinthesys + scintigraphy

21 Hamamatsu SiPM photodetector 3 mm pitch array 16 x x 200 mm2

22 Compact electronic readout Total thickness ~ 5 cm 16x16 MPPC module Electronic Readout Readout electronics characteristics: - single channel approach (~3000 channels) - settable trigger for each channel - 5 kevent / second throughput - supply voltage temperature feedback on each MPPC module Frontend Board 3D model

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24 Labr3(Ce) DE/E might be important for lesion close to the chest (high background)

25 Screening for women at risk (dense breast)? The dose has to be much lower ~ the same as for mammography (~ 1/5 (740 MBq))

26 Summary and conclusions - Molecular imaging is a powerfull tool for diagnosis and follow up of diseases - Radioncuclide techniques have a key role - Dedicated devices are frequently needed - Focusing on small object and imaging at the same time the whole organ -Multimodality is mandatory in most cases (practical problems, cost etc)

27 outlook -improving reconstruction algorithms to fully profit of multichannel electronics - optimizing modality and protocol (comparison with MRI) - new radiotracer? (Tc99m av 3 pepetide) - Multimodality (tomosinthesys + scintigraphy) - multicenter trial (international (Italy, USA)) starting early clinics ~ 10 trials/day ~ 5000 in 2 years

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29 0.6 mm pitch H mm pitch Burle

30 Labr3 Continuoum different performances for different window treatment, diffusing (a), absorbing (b) a b

31 Molecular Imaging the in vivo characterization and measurement of biologic processes at the cellular and molecular level. probe the molecular abnormalities that are the basis of disease rather than to image the end effects of these molecular alterations. imaging of specific molecular targets enables: earlier detection and characterization of disease; earlier and direct molecular assessment of treatment effects;

32 "Italian Patent Pending No. RM2008A000541".

33 Freon/CsI RICH detector (like ALICE) Spectroscopy analysis of 12 B : Aerogel vs. RICH K-selection similar is not Hermes areogel RICH always the 12 C(e,e K) 12 B Signal 2.5 Bckgnd Aerogel Kaon selection same! Signal 7 Bckgnd RICH Kaon selection

34 Important parameters for detectability/visibility they are correlated CsI(Na) SNR S BKG S IC Max BKG Max energy resolution plays only a secondary additional role when small volumes are involved CsI(Tl) efficiency (collimation) time (and modality) uptake (radiopharmacy) scintillator detector intrinsic properties electronics, DAQ Uniformity of p.h.response (affecs the overall en res. and the energy window selection) pixel dim/n.of pixels X N channel i 1 N channel i 1 c i X i c i spatial resolution Bialkali PMT Bialkali PMT X X i N p.e. R i FWHM X FWHM X i N p.e.

35 P.Judy, S. Majewski

36 T1 T2 STIR

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38 Geant4 simulations 1 detector - par.hole coll. - NaI(Tl) 1.5 mm pitch(the smallest pixel in this applications (~13000 pixel in 150 x 200 mm2) - H8500 (6 x 6) mm2 anode pixel -Individual channles electronics Sensitivity dominates the visibility, so we should try to get closer to the lesion and modify collimation and modality most cancers are in the upper part of the breast 2 detectors