Speaker
Dr
anabela da silva
(CEA-LETI)
Description
A small animal multimodality tomographer dedicated to co-registration of
fluorescence optical signal and X-rays measurements is under development in our
laboratory. The purpose of such a system is to offer the possibility to get in vivo
anatomical and functional information at once. Moreover, anatomical measurements
will be used as a regularization factor in order to get the reconstructions of the
biodistribution of fluorochromes more accurate and to speed up the treatment.
The best configuration for X-rays imaging is obtained when the animal is illuminated
perpendicularly and around its vertical axis. Furthermore, analytical solutions of
the optical problem can be derived for simple geometries. The cylindrical geometry
has been naturally chosen as a compromise: i) this geometry is suitable with X-rays
cone beam CT of the whole animal body; ii) by immersing the animal in an index
matching fluid, an analytical solution to the optical forward problem can be derived
and introduced in a reconstruction scheme.
An exact analytical solution to the Diffusion Approximation to the Radiative
Transport equation used for modeling the optical forward problem has been
established. For this geometry, we proceeded by analogy with the classical solutions
to the equations of heat conduction in solids.
The optical system is basically composed with a laser beam for excitation of the
fluorochromes, and a CCD camera coupled with a chromatic filter for the fluorescence
detection.
Experimental measurements on cylindrical phantoms with different fluorescent
inclusions geometries have been performed as a validation. The cylindrical
analytical approach has been compared to a Finite Element Method approach:
analytical approach brings a significant gain of computing time.
Author
Dr
anabela da silva
(CEA-LETI)
Co-authors
Dr
jean-marc dinten
(CEA-LETI)
Mr
mehdi leabad
(CEA-LETI)
Dr
philippe peltié
(CEA-LETI)
Dr
philippe rizo
(CEA-LETI)
Mr
thomas bordy
(CEA-LETI)