Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL X-ray Fluorescence...

Nuclear Instrumentation Laboratory

Federal University of Rio de Janeiro -BRAZIL

X-ray Fluorescence and X-ray Transmission X-ray Fluorescence and X-ray Transmission Microtomography Imaging SystemMicrotomography 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, BrazilP.O. Box 68509, 21945-970, Fax: +55 (021) 25628444, [email protected]

(2) Physics Institute - UERJ, Brazil(3) Brazilian National Cancer Institute – LNLS, Brazil

(4) Brazilian Synchrotron Light Source, Brazil

OBJECTIVE

The main of this work is to determine the elemental and absorption distribution map in tissue samples.



INTRODUCTION



•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.



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.

INTRODUCTION



• 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.

INTRODUCTION



• 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.

For a particular element i and an atomic level , the fluorescence radiation hitting the energy dispersive detector can be obtained through integration over y’

f x y eB

y

x y dy

( , ' , ' ) ;( ', ') '

'

g x y d e

F

x y

Det

D

l dl

( , ' , ' ) ;( )

( ', ')

14

'.')','( dyNdyyxp elem



)',',()','()',',(')',( 0 yxgyxpyxfdyIxI i

Translation

Beam

x

y’ y

x’

X-Ray

Beam

Fluorescen

ce

Detecto

r

D

x’ = x cos + y sin

y ’ = - x sin + y cos

Rotation

Transmission Detector

THEORY

THEORY



If the solid angle defined by the detector surface is almost constant

and the attenuation is small (μB ≈ μF ≈ 0) then

cte)',',(,1)',',( gyxgyxf

-

elem

-

(x',y')dy'N'p(x',y')dyg,x')I(

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.



EXPERIMENT



RECONSTRUCTION



EXPERIMENT

XRF

• Operation Nominal Energy: 1.37GeV• Injection Energy: 500MeV• Electron Beam Current (maximum):

250 mA• Beam Life Time: 15 h

EXPERIMENT



White beam (4-23) keV

Multilayer Monochromator

Ionization Chamber

Two Sets of Slits (200μm x 200μm) and Transmission Detector

Fluorescence Detector

SampleTransmission

Detector

Fluorescence Detector

Tomography images of paper filter (right: x-ray fluorescence and left: Transmission)

RESULTS



Tomographic images of polyethylene samples filled with a standard solutions of Cu (200 ppm) (right: x-ray fluorescence and left: Transmission).

RESULTS



Tomography images of lung sample (top: transmission and bottom: fluorescence) (a)Fe (b) Cu, (c)Zn.

RESULTS



(a) (b) (c)

X-Ray Fluorescence Tomography images of lung sample.

RESULTS



Tomography images of coronary vein sample (top: transmission and bottom: fluorescence) (a)Fe (b) Cu (c) Zn.



RESULTS

(a) (b) (c)

Tomography images of heart sample (top: transmission and bottom: fluorescence) (a)Fe, (b) Cu, (c) Zn.

RESULTS



(a) (b) (c)

Normal lobular breast parenchymaCystAdipose tissue

RESULTS



Micro cystSample of breast cancer

RESULTS



Sample of breast cancer after chemotherapy reduction.

RESULTS



RESULTS



Tomography images of healthy breast tissue sample (top: transmission and bottom: fluorescence) (a)Fe, (b) Cu, (c) Zn.

(a) (b) (c)

RESULTS



Tomography images of malignant breast tumor sample (top: transmission and bottom: fluorescence) (a)Fe (b) Cu, (c) Zn.

(a) (b) (c)

RESULTS



Tomography images of benign breast tumor sample (top: transmission and bottom: fluorescence) (a)Fe (b) Cu, (c) Zn.

(a) (b) (c)

RESULTS



Normalized Fe fluorescence counting in 30º and 31º projection

1020 1035 1050 1065 10800.000

0.001

0.002

0.003

0.004

0.005

0.006

0.007

Sum Ray of the 30O and 31O projection

NO

RM

AL

IZE

D F

e F

LU

OR

ES

CE

NC

E benign tumor malignant tumor normal tissue

Iron

RESULTS



Normalized Cu fluorescence counting in 30º and 31º projection

1020 1035 1050 1065 1080

0.0000

0.0001

0.0002

0.0003

0.0004

0.0005

Sum ray of the 30Oand 31o projection

NO

RM

AL

IZE

D C

u F

LU

OR

ES

CE

NC

E benign tumor tmalignant tumornormal tissue

Copper

RESULTS



Normalized Zn fluorescence counting in 30º and 31º projection

1020 1035 1050 1065 1080-0.0002

0.0000

0.0002

0.0004

0.0006

0.0008

0.0010

0.0012

0.0014N

OR

MA

LIZ

ED

Zn

FL

UO

RE

SC

EN

CE

Sum ray of the 30Oand 31Oprojection

benign tumormalignant tumornormal tissue

Zinc

CONCLUSION



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.

CONCLUSION



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.

CONCLUSION



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 wasjustified by the high quality of the images obtained.

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).



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Nuclear Instrumentation Laboratory Federal University of Rio de Janeiro -BRAZIL X-ray Fluorescence...

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