I am a new researcher in the X-fluorescence Computed Tomography field. I am doing the attenuation correction of the XFCT imaging system and I am confused with something.
As we know that while doing the attenuation correction for emission tomography, we need to convert the attenuation coefficient value for the energy of 511 KeV by using some Bi/Trilinear method! That means :
""Transmission CT energy ( attenuation coefficient value) ==> Emission CT energy ( attenuation coefficient value) "".
As it is known XFCT has two parts: Fluorescent Excitation ( Transmission) and Fluorescent Emission. I have Attenuation co-efficient values for 30KeV energy.
What will be the process for converting the attenuation co-efficient values for XFCT? Would I need to convert the attenuation co-efficient value two times ( for transmission and emission) ?
I am a bit confused about this problem!
Dear Amit Chakraborty ,
you are right.
There are two attenuation coefficients involved:
a) that of the excitation radiation, which has a photon energy a bit higher than the absorption edge energy of the excited atom, and
b) that of the fluorescence radiation, the photon energy of which is smaller than the edge energy (binding energy).
Binding energies (= absorption edge energies) as well as emission energies can be found for example in the 'X-ray Data Booklet'...
https://xdb.lbl.gov/
X-ray attenuation coefficients can be gathered for example from the NIST/XCOM data base as x-ray mass-attenuation coefficients( µ/rho)*):
https://physics.nist.gov/PhysRefData/Xcom/html/xcom1.html
*) just multiply by the density rho to get µ; but pay attention to the energy unit (MeV) and the application of decimal points, as well as the unit of (µ/rho) in [cm²/g] of the result.
Best regards
G.M.
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