scansione PET in uno scanner ibrido dedicato). 2

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1 G. Mettivier, P. Russo Dipartimento di Scienze Fisiche, Università degli Studi di Napoli Federico II INFN, Sezione di Napoli Dott. Giovanni Mettivier, PhD Nell imaging del seno per la diagnosi tumorale l esame mammografico rappresenta attualmente il gold standard. Nella relazione verrà illustrato il passaggio, attualmente in atto, verso l'introduzione in ambito clinico di tecniche di imaging tridimensionale dei tessuti mammari, rispetto all'imaging bidimensionale fornito dalla tecnica convenzionale mammografica. Tali tecniche di imaging a raggi X includono: - la Tomosintesi Digitale - la Tomografia Computerizzata con fascio a cono e rivelatori digitali flat panel (eventualmente accoppiata a utilizzo di mezzo di contrasto o a scansione PET in uno scanner ibrido dedicato). 2 1

2 Jemal A, et al., Cancer Statistics MLO view CC view 4 2

3 The earlier the tumor is detected the higher are the chances of complete cure and a longer relapse-free survival time. Diagnostic performance: sensitivity of 60% 90% and specificity of 80% 95%. E. Castelli et al., Radiology, Volume 259: Number 3 June 2011 Problems: false-negatives, false-positives, overdiagnosis, overtreatment, radiation exposure! 5 Mammography renders a two dimensional image of the breast with superimposed tissue that is sometimes difficult to interpret, leads to unnecessary recalls and does not enable a visualization of malignancies in an early stadium. J. Baker & J. Lo, Duke University in Durham, NC, USA A. Hebecker, T. Mertelmeier & J. Orman, Siemens Medical 6 Solutions, Erlangen, Germany 6 3

4 Digital Breast Tomosynthesis (DBT) is expected to overcome this limitation by providing slice images of the breast. J. Baker & J. Lo, Duke University in Durham, NC, USA A. Hebecker, T. Mertelmeier & J. Orman, Siemens Medical Solutions, Erlangen, Germany 7 A. Smith, 8 4

5 A method of imaging the breast in three dimensions A. Smith, 9 3D Breast Tomosynthesis White Paper

6 Tomosynthesis prototype based on a Siemens MAMMOMAT Novation DR system (2006). Hologic SELENIA Dimensions 3D (2011). 11 Hologic Selenia Dimensions 3D DBT FDA Document ucm226757, Sep. 24, 2010: Executive Summary 12 6

7 A. Smith, 13 A. Smith,

8 3D Breast Tomosynthesis D Breast Tomosynthesis

9 Dose di radiazione anche al torace! ( CT/M della GE a fine anni 70) Acquisizione di centinaia di proiezioni Ricostruzione 3D dell immagine Dose assorbita per ogni seno comparabile a quella delle due viste mammografiche (limite eur. ~ 5 mgy mammella standard) 18 J. Boone U.C. Davis Medical Center 25 9

10 Courtesy of Prof. J. Boone, Univ. California Davis 19 Courtesy of Prof. J. Boone, Univ. California Davis 20 10

11 J. Boone, Computed tomography for imaging the breast, J. Mammary Glad. Biol. Neoplasia, (2006) 11: Courtesy of Prof. J. Boone, Univ. California Davis 22 11

12 16.6 Second Acquisition Time 500 views (30 FPS) 80 kvp 3-8 ma( mas) Courtesy of Prof. J. Boone, Univ. California Davis 23 Courtesy of Prof. J. Boone, Univ. California Davis 24 12

13 Courtesy of Prof. J. Boone, Univ. California Davis 25 Courtesy of Prof. J. Boone, Univ. California Davis 26 13

14 Courtesy of Prof. J. Boone, Univ. California Davis 27 Courtesy of Prof. J. Boone, Univ. California Davis 28 14

15 Courtesy of Prof. J. Boone, Univ. California Davis 29 Courtesy of Prof. J. Boone, Univ. California Davis 30 15

16 Courtesy of Prof. J. Boone, Univ. California Davis 31 M. Yaffe et al., The myth of the breast, Med. Phys. 36, 5437 (2009) 32 16

17 Courtesy of Prof. J. Boone, Univ. California Davis 33 the exponent is a critical factor for determining detection thresholds for lesions 34 K. G. Metheany et al., Characterizing anatomical variability in breast CT images Med. Phys. 35, 4685 (2008) 17

18 Courtesy of Prof. J. Boone, Univ. California Davis 35 Courtesy of Prof. J. Boone, Univ. California Davis 36 18

19 Koning corporation, University of Rochester Medical Center (Prof. R. Ning) 37 A. O Connell, D. O Connor, J. Clin. Imaging Sci. 2, 7 (2012) 38 19

20 A. O Connell, D. O Connor, J. Clin. Imaging Sci. 2, 7 (2012)

21 W. Kalender et al., High-resolution spiral CT of the breast at very low dose: concept and featibility considerations, Eur. Radiol. (2012) 22:

22 CdTe Medipix2 detector 5 mm hot detail 15:1 activity ratio 99m Tc First European prototype (5 in USA) for Cone-Beam Breast CT/SPECT for laboratory investigations. X-ray tube (1), flat panel detector (2), rotating gantry (3), pinhole compact gamma camera (4) and PMMA breast phantom (5)

23 45 Boone et al., «Dedicated Breast CT: Radiation Dose and Image Quality Evaluation», Radiology, pp 658 December

24 Past experience in using Monte Carlo for simulating BCT devices for evaluating the dose distribution in a breast phantom 3D dose distribution of the PMMA breast phantom irradiated with a 80 kvp beam. Data are normalized to the minimum value registered

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26 Past experience in using Monte Carlo for simulating BCT devices for evaluating the scattered pattern and correcting for cupping artifacts Simulated 2D scatter distributions in 8-14 cm diameter PMMA cylinders as a function of X-ray tube voltage and added Cu filtration. Rows refer to varying tube voltages and columns refer to varying phantom diameters 52 26

27 R 1 = 576 mm R 2 = 614 mm 1. Microfocus X-ray tube; 2. High resolution Flat panel detector; 3. Rotating gantry. R1+R2 ~ 1.2 m

28 55 Decremento dell indice di rifrazione Indice di assorbimento Nf Densità elettronica 2 Nf Mappa di fase, 2 Sfasamento,, Mappa di attenuazione, 4,, Coefficiente di attenuazione lineare 57 28

29 58 s 59 29

30 Sorgenti coerenti -> Radiazione di sincrotrone Sorgenti parzialmente coerenti -> Sorgenti cliniche (Tubo a raggi X) Wilkins et al., Phase-contrast imaging using polychromatic hard X-rays, Nature 384, 1996 Lateral coherence length Wu and Liu, Med. Phys. 34, 2007 Phase-contrast visibility Figure of merit Phase-space shearing length L <<1 59 Anodo Mo, kvp Spot 0.1 mm R1= 65 cm, R2 = 0-50cm, M 2 Contrasto in attenuazione Contrasto di fase Konika Minolta Regius Pureview Type M 60 30

31 61 PMMA step wedge phantom kvp R 1 = 576 mm R 2 = 614 mm 62 31

32 Normalized signal 1.0 Large Focus 50 µm kvp 50 kvp 60 kvp 70 kvp 80 kvp 90 kvp 100 kvp C = 57% 25% 21% 14% 8% 7% Position (mm) C = image contrast Edge enhancement effect best 40 kvp Normalized signal Large Focus 50 µm 3 Step (14 mm/ 8 mm PMMA) Position (mm) 40 kvp 50 kvp 60 kvp 70 kvp 80 kvp 90 kvp 100 kvp 63 Normalized signal kvp 90 kvp 80 kvp 70 kvp 60 kvp 50 kvp 40 kvp Small Focus 7 µm 3 Step (14 mm/ 8 mm PMMA) Position (mm) Normalized signal 1.0 Small Focus 7 µm kvp 90 kvp 80 kvp 70 kvp 60 kvp 50 kvp 40 kvp Position (mm) 64 32

33 Phase image C = 93% 33% 38% 42% 35% 56% C = image contrast Anka phase software T. Weitkamp, et al., ANKAphase: software for single-distance phaseretrieval from inline X-ray phase contrast radiographs, Journal of Synchrotron Radiation, 2011 δ β Φ =(2π/λ) δ s PMMA Thickness (mm) 25 Large Focus Position (mm) 25 Small Focus PMMA Thickness (mm) kvp (9.52 mgy AK) 50 kvp (7.27 mgy) 60 kvp (6.25 mgy) 70 kvp (5.63 mgy) 80 kvp (5.26 mgy) 90 kvp (5.03 mgy) 100 kvp (4.87 mgy) 40 kvp 50 kvp 60 kvp 70 kvp 80 kvp 90 kvp 100 kvp Position (mm) 65 -Ln I/Io kvp 60 kvp 80 kvp 100 kvp Small Focus PMMA Thickness [mm] Reconstructed PMMA Thickness (mm) kvp 60 kvp 80 kvp 100 kvp Actual PMMA Thickness (mm) Absorption imaging Phase-retrieval imaging 66 33

34 Phase-contrast tomography Phase-retrieval tomography 67 Mammography BR3D Phantom (CIRS inc., USA) Specks mm mm mm mm mm mm 68 34

35 80 kvp, R 1 = 576 mm, R 2 = 614 mm, M = 1.9, 7 µm focal spot Air Kerma ~ 2.5 mgy mm mm mm mm mm Speck size mm mm mm mm Air Kerma ~ 5.3 mgy Slice thickness = 75 µm 80 kvp, HVL =6.11 mm Al, E eff = 40 kv R 1 = 576 mm, R 2 = 614 mm 7 µm focal spot 70 35

36 Prionas et al., Kilovoltage Rotational External Beam Radiotherapy on a Breast Computed Tomography Platform: A Feasibility Study, International Journal of Radiation Oncology*Biology*Physics, Volume 84, Issue 2, 1 October 2012, Pages Prionas et al., Kilovoltage Rotational External Beam Radiotherapy on a Breast Computed Tomography Platform: A Feasibility Study, International Journal of Radiation Oncology*Biology*Physics, Volume 84, Issue 2, 1 October 2012, Pages

37 Prionas et al., Kilovoltage Rotational External Beam Radiotherapy on a Breast Computed Tomography Platform: A Feasibility Study, International Journal of Radiation Oncology*Biology*Physics, Volume 84, Issue 2, 1 October 2012, Pages Grazie per l attenzione Dott. Giovanni Mettivier, PhD mettivier@na.infn.it 74 37