Phase Contrast Imaging with X-ray tube Institute for Roentgen Optics /IRO/, Moscow Vladimir Shovkun and Muradin Kumakhov Proc. SPIE v.5943, 2005 Institute for Roentgen Optics. Vladimir Ya. Shovkun. E-mail: chovkoun@mail.ru 1
Phase-contrast (PC) imaging δ~ 1.35 10-6 ρ λ 2, ρ -density [g cm -3 ], λ -wavelength [Å] Cph ~ ρ, ρ -density variations Λ~ λ Ro/S Spatial coherence length Λ 2.8 μm (R 0 =0.4m, S =0.01mm and λ =0.71Å) Institute for Roentgen Optics. Vladimir Ya. Shovkun. E-mail: chovkoun@mail.ru 2
Practical Application of PC-imaging Radiographic image of fish air bubbles X-ray tube /IRO-product/ Mo-target U=30kV I=0.9mA R 0 =20cm R 1 =39 cm X-ray film: AA-400 Exposure: 300sec Institute for Roentgen Optics. Vladimir Ya. Shovkun. E-mail: chovkoun@mail.ru 3
Practical Application of PC-imaging Radiographic image of a small fish (5 cm in length). Institute for Roentgen Optics. Vladimir Ya. Shovkun. E-mail: chovkoun@mail.ru 4
Practical Application of PC-imaging The fish ribs with 0.1 0.2 mm in thickness have the edge enhancement visibility. Ribs=Model of micro calcifications. X-ray tube /IRO/ Mo-target: U=30 kv i=0.3 ma R 0 =30 cm R 1 =90 cm X-ray film: SR-45 EXPOSE: 13minutes Institute for Roentgen Optics. Vladimir Ya. Shovkun. E-mail: chovkoun@mail.ru 5
Practical Application of PC-imaging Image of joint weld for AL-Li alloys. Cracks and Inclusions. SCALE 1 millimeter Boundaries of slag inclusions in Al-Li matrix (thick 6mm) are clearly seen in radiograph. X-ray tube /IRO product/ was operated at: U=37kV (Mo-anode) and I=0.6mA. Ro=30cm. R 1 =60cm. SR-45 X-ray film. Exposition=1hour. Institute for Roentgen Optics. Vladimir Ya. Shovkun. E-mail: chovkoun@mail.ru 6
Cellular metal: hollow sapphire spheres Intensity, ADU. 3,6k 3,2k 2,8k 2,4k 2,0k 0 75 150 225 300 Distance, Arb.Units. Three sapphire balls: Al 2 O 3. The CCD-camera. Edge-enhancement visibility of balls boundaries. Diameter of balls 0.1mm. U=38kV (Mo-anode), I=1.2mA, R 0 =17cm, R 1 =74 cm, exposition: 11sec. There is an enhancement of the X-ray flux in the center of the upper ball (i.e. X-ray lens). Institute for Roentgen Optics. Vladimir Ya. Shovkun. E-mail: chovkoun@mail.ru 7
Practical Applications /summary/: Histological investigation of thin specimen: thick 1cm and more. Core needle biopsy specimen radiography: thick 1mm and more. Detection of microcalcifications (ρ=3 [g cm -3 ]and ρ =2 [g cm -3 ] in breast tissue ) as a early stage of cancer. Control of cracks and inclusions in light materials (Be, Li, Al, Si and so on). Perspective of full field PC-mammography development : -field of view 18x24 cm -an average thick of breast 4.2cm -max. thick of breast 10 cm -exposition < 6 sec (to avoid motion artefact ) -entrance dose < 0.01 Gy (1R) Institute for Roentgen Optics. Vladimir Ya. Shovkun. E-mail: chovkoun@mail.ru 8
Phase contrast imaging (PCI) Monochromator Image plane, X-ray films 1991 Somenkov V.A. 1993 Ingal V.N. Disadvantage: Low efficiency of scheme ~10-3 10-4 X-Ray Tube Object Crystalanalyzer IN LINE HOLOGRAPHY : 1995 Snegirev A. 1996 Wilkins S.W. Mammography application: 1999 Kotre C.J. 2000 Ohara H. 2002 Wu X. 2002 Donnelly E.F. Disadvantages: 1. Impractically large distances R 0 and R 1 ; Low flux. 2. Low brilliance of X-ray tube used. Institute for Roentgen Optics. Vladimir Ya. Shovkun. E-mail: chovkoun@mail.ru 9
Characteristic features of PC-mammography experiments; cnv=conventional P, kw X-ray tube S, mm R, m Resolution micron Testobject C ph % 0.94mm Kotre C.J. cnv Mo. 28kV 0.7x 0.3 2.2 30-40 Perspex. +Phantom 6cm Donnelly E.F. 40kV 0.1 4.4 30-40 3mm Lucite. 10 W. 0.12mm Wu X. 10 30kV 0.02 0.57 100 Plastic. +BR12 2cm. Plastic Ohara H. cnv W. 0.1 2 90 Diam. 8mm 15 50kV Institute for Roentgen Optics. Vladimir Ya. Shovkun. E-mail: chovkoun@mail.ru 10
Measurements of the PC- signal Mammography: Experiment and Theory RADIOGRAPHIC IMAGE OF FIBERS WITH DIAMETERS: 0.14mm and 0.045mm Institute for Roentgen Optics. Vladimir Ya. Shovkun. E-mail: chovkoun@mail.ru 11
Systematic evaluation of PC-signal EXPERIMENT THEORY Optical density, OD. 0,60 C 0,58 ph 0,56 C abs Intensity, arb. unit. 1,08 1,05 1,02 0,99 energy= 12-30 kev source size=0.03 mm resolution=0.03 mm R 0 =30cm, R 1 =60cm 0,54 0,0 0,4 0,8 1,2 1,6 Image plane, mm. 0,96-0,4-0,2 0,0 0,2 0,4 Image plane, mm. Experimental Results for fiber 0.14 mm without phantom: Cph = 2.9 ± 0.4% Cabs = 2.2± 0.4% with phantom : Cph = 2.5 ± 1.2% Cabs = 1.6± 1.2% Theory: Cph = 4.4% Cabs = 0.9% Institute for Roentgen Optics. Vladimir Ya. Shovkun. E-mail: chovkoun@mail.ru 12
Theoretical estimation of the phase-contrast signal: C PH for different values of source size, detector resolution and incoming x-ray spectra. In calculations of PC- signal (C + ph ) we assumed: - X-ray tube with Mo-anode (U=30 kv); -the source-object distance R 0 = 6 cm; -the object-detector distance R 1 = 53 cm; - diameter of PMMA-fiber = 0.045mm. # Input data for calculations Results Energy range, kev Source size, microns Detector resolution, microns Phase-contrast signal, C + ph % 1. 18 0 Infinite 42 2. 12-30 0 Infinite 40 3. 12-30 0 30 10 4. 18 10 10 3,7 5. 12-30 10 10 3.1 6. 12-30 10 30 2.6 7. 12-30 20 30 1 Institute for Roentgen Optics. Vladimir Ya. Shovkun. E-mail: chovkoun@mail.ru 13
Development of X-ray tubes in IRO A) Presented work: Power=70W Focal spot size < 50micron Resolving Power [pairs line/mm] Breast phantom CIRS 11 Thickness= 4.5cm R 0 =20cm R 1 =16cm Exposition:~2 sec Exposure load: ~4 ma*sec B) Future work: Power=200W and focal spot size=30micron Institute for Roentgen Optics. Vladimir Ya. Shovkun. E-mail: chovkoun@mail.ru 14
Comparison of a conventional mammography unit with the developed phase-contrast radiographic apparatus. 1. Field of view 2. Power load 3. Detection of microcalcification Conventional mammography unit 24 x 18 cm 5 2kW 0.2-0.3mm practical threshold Phase contrast mammography Large field/small field 15 x 10cm/ø 3-5 cm 0.5kW? /0.1 kw 0.1mm? / 0.1-0.3mm design study/ under study 4. Contrast. Theory 5. Exposure load* ) 6. R o R 1 4% for 0.1mm microcalcification 25 ma sec 56cm 1cm 4% for 0.1mm microcalcification 4mA sec 20cm 16cm * ) Data for the breast phantom CIRS 11 with thick 4.5cm Institute for Roentgen Optics. Vladimir Ya. Shovkun. E-mail: chovkoun@mail.ru 15
The Apparatus The apparatus consists of a micro focus X-ray tube (left), the water phantom with fibers and the X-ay film detector. Institute for Roentgen Optics. Vladimir Ya. Shovkun. E-mail: chovkoun@mail.ru 16
Conclusions Theoretical approach was developed and experimentally proven. Phase contrast images of thin PMMA fibers can be obtained under short the sourceobject distance (6cm) and object-detector distance (30cm) in the presence of additional scattering (water phantom). It is shown that the detection threshold is 0.045mm for the density difference of 1g/cm 3. Further development of high brilliance X- ray tubes is important for phase contrast radiography and other applications. Institute for Roentgen Optics. Vladimir Ya. Shovkun. E-mail: chovkoun@mail.ru 17