1. Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL X-ray Fluorescence and X-ray Transmission Microtomography Imaging System G. R. Pereira(1)*, H.S. Rocha(1), M. J. Anjos (2), P. Faria(3), C. A. Pérez (4) and R. T. Lopes (1). (1) Nuclear Instrumentation Laboratory – COPPE / UFRJ, Brazil P.O. Box 68509, 21945-970, Fax: +55 (021) 25628444, gabriela@lin.ufrj.br (2) Physics Institute - UERJ, Brazil (3) Brazilian National Cancer Institute – LNLS, Brazil (4) Brazilian Synchrotron Light Source, Brazil

2. OBJECTIVE The main of this work is to determine the elemental and absorption distribution map in tissue samples. Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL

3. INTRODUCTION Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL New techniques have been developed using excellent properties of synchrotron radiation such as high photon flux, the broad energy spectrum and the natural collimation. In many studies, it is necessary to analyze biological tissues with small details that have close attenuation coefficients where transmission tomography is not adjusted. Some properties also depend on the individual distribution of elements inside of the sample.

4. Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL INTRODUCTION In order to get the distribution of an element in particular, fluorescence properties and the tomographic techniques can simultaneously be used. A technique for fluorescence tomography was attempted for the first time in 1989 by Cesareo and Mascarenhas. Since then, several papers have been presented in this area.

5. INTRODUCTION Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL One complication of fluorescence tomography is the reconstruction calculations that are more complex than transmission tomography’s algorithm. Hogan et al (1990) proposed adapting one of the algorithms used in X-ray transmission tomography. The simplest algorithm is based on the classical back projection algorithm used in transmission tomography. A algorithm more accurate applies corrections for absorption before and after the fluorescence point.

6. INTRODUCTION Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL The choice for breast tissue samples was accomplished with the world tendency to find diagnostic techniques for cancer and other diseases. The fluorescence mapping of iron, copper and zinc is very important in diagnostics. The biochemistry of these elements suggests that these metals may play an important role in carcinogenesis. However, the evidence linking iron, copper and zinc to cancer is far from conclusive. Using X-ray fluorescence tomography it can be obtained the elemental map of this metals without sample preparation.

7. For a particular element i and an atomic level, the fluorescence radiation hitting the energy dispersive detector can be obtained through integration over y’ Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL Translation Beam x y’y x’  X-Ray Beam Fluorescence Detector DD x’ = x cos  + y sin  y ’ = - x sin  + y cos  Rotation Transmission Detector THEORY

8. Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL If the solid angle defined by the detector surface is almost constant and the attenuation is small (μ B ≈ μ F ≈ 0) then In this case, the concentration of the element is proportional to the experimental projections and the usual algorithms of transmission tomography can be used for fluorescence tomography.

9. Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL EXPERIMENT

10. Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL RECONSTRUCTION

11. Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL EXPERIMENT XRF Operation Nominal Energy: 1.37GeV Injection Energy: 500MeV Electron Beam Current (maximum): 250 mA Beam Life Time: 15 h

12. EXPERIMENT Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL White beam (4-23) keV Multilayer Monochromator Ionization Chamber Two Sets of Slits (200μm x 200μm) and Transmission Detector Fluorescence Detector Sample Transmission Detector Fluorescence Detector

13. Tomography images of paper filter (right: x-ray fluorescence and left: Transmission) RESULTS Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL

14. Tomographic images of polyethylene samples filled with a standard solutions of Cu (200 ppm) (right: x-ray fluorescence and left: Transmission). RESULTS Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL

15. Tomography images of lung sample (top: transmission and bottom: fluorescence) (a)Fe (b) Cu, (c)Zn. RESULTS Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL (a) (b) (c)

16. X-Ray Fluorescence Tomography images of lung sample. RESULTS Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL

17. Tomography images of coronary vein sample (top: transmission and bottom: fluorescence) (a)Fe (b) Cu (c) Zn. Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL RESULTS (a) (b) (c)

18. Tomography images of heart sample (top: transmission and bottom: fluorescence) (a)Fe, (b) Cu, (c) Zn. RESULTS Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL (a) (b) (c)

19. Normal lobular breast parenchyma Cyst Adipose tissue RESULTS Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL

20. Micro cyst Sample of breast cancer RESULTS Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL

21. Sample of breast cancer after chemotherapy reduction. RESULTS Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL

22. RESULTS Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL Tomography images of healthy breast tissue sample (top: transmission and bottom: fluorescence) (a)Fe, (b) Cu, (c) Zn. (a) (b) (c)

23. RESULTS Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL Tomography images of malignant breast tumor sample (top: transmission and bottom: fluorescence) (a)Fe (b) Cu, (c) Zn. (a) (b) (c)

24. RESULTS Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL Tomography images of benign breast tumor sample (top: transmission and bottom: fluorescence) (a)Fe (b) Cu, (c) Zn. (a) (b) (c)

25. RESULTS Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL Normalized Fe fluorescence counting in 30º and 31º projection

26. RESULTS Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL Normalized Cu fluorescence counting in 30º and 31º projection

27. RESULTS Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL Normalized Zn fluorescence counting in 30º and 31º projection

28. CONCLUSION Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL We have shown that was possible to visualize the distribution of high atomic number elements on both, artificial and tissues samples. It was possible to compare the quantity of Zn, Cu and Fe for the breast tissue sample and was verified that these elements have a higher concentration on malignant tumor than normal tissue.

29. CONCLUSION Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL It will be necessary to measure more samples and quantify the difference in concentration in one sample and between normal and abnormal tissues to use the X- ray fluorescence microtomography as an analytic tool to analyze biological tissues.

30. CONCLUSION Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL The better definition of the interfaces in X-ray fluorescence images was striking and the spatial resolution of the system can be optimized as a function of the application. The experimental set up at XRF-LNLS has shown to be very promising and this effort at implementing X-ray fluorescence microtomography was justified by the high quality of the images obtained.

31. ACKNOWLEDGEMENTS This work was partially supported by the National Center for Science and Technology Development (CNPq), Rio de Janeiro State Research Foundation (FAPERJ) and Brazilian Synchrotron Light Laboratory (LNLS). Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL