Optical Imaging - Correction Techniques in Emission Tomography - page 255

FIGURE 12.8: (See color insert.) Tomographic imaging of fluorescent
proteins and corresponding X-ray CT from a nude mouse implanted with
GFP-expressing lung tumors, obtained 10 days post-image implantation. (a)
Epi-illumination image of the mouse at the excitation wavelength; (b) Epi-
illumination image at the emission wavelength showing high skin autofluores-
cence. (c) Tomographic slice (in color, after threshold was applied) obtained
from the tumor depth (7 mm from top surface) overlaid on the white light
image of the mouse. (d, e) CT coronal and axial slices, respectively; the tumor
position is marked by arrows. (f) Axially reconstructed slice corresponding to
the yellow dashed rectangle on (e). (From [31].)
ters to filter for the excitation or fluorescence wavelength. This type of hybrid
FMT-XCT scanners allows 360-degree projection viewing for both FMT and
XCT and the use of CCD cameras for photon detection leads to high spatial
sampling of photon fields propagating through tissues such as small animals.
Combination of the FMT and XCT modality into a single system eliminates
the need to transfer the imaging subject from one system to the other using
a specially designed case or markers for co-localization; the imaging subject
is optimally co-localized in time and space, while it is placed on a comfort-
able bed. Reconstruction algorithms that are being developed specifically for
datasets from this type of system use the X-ray data to improve FMT imag-
ing quality in several aspects: the anatomy is used for assignment of optical
FIGURE 12.9: (See color insert.) Multimodality imaging. The fluorescent
reconstructions of Figure 12.8 rendered simultaneously with X-ray CT images.
The tumor is indicated by an arrow. (From [31].)