A comprehensive method for optical-emission computed tomography.
Optical-computed tomography (CT) and optical-emission computed tomography (ECT) are recent techniques with potential for high-resolution multi-faceted 3D imaging of the structure and function in unsectioned tissue samples up to 1-4 cc. Quantitative imaging of 3D fluorophore distribution (e.g. GFP) using optical-ECT is challenging due to attenuation present within the sample. Uncorrected reconstructed images appear hotter near the edges than at the center. A similar effect is seen in SPECT/PET imaging, although an important difference is attenuation occurs for both emission and excitation photons. This work presents a way to implement not only the emission attenuation correction utilized in SPECT, but also excitation attenuation correction and source strength modeling which are unique to optical-ECT. The performance of the correction methods was investigated by the use of a cylindrical gelatin phantom whose central region was filled with a known distribution of attenuation and fluorophores. Uncorrected and corrected reconstructions were compared to a sectioned slice of the phantom imaged using a fluorescent dissecting microscope. Significant attenuation artifacts were observed in uncorrected images and appeared up to 80% less intense in the central regions due to attenuation and an assumed uniform light source. The corrected reconstruction showed agreement throughout the verification image with only slight variations ( approximately 5%). Final experiments demonstrate the correction in tissue as applied to a tumor with constitutive RFP.
Thomas
Andrew
A
Duke University, Durham, NC, USA. ast5@duke.edu
Bowsher
James
J
Roper
Justin
J
Oliver
Tim
T
Dewhirst
Mark
M
Oldham
Mark
M
D000465:Algorithms; D000818:Animals; D016477:Artifacts; D001943:Breast Neoplasms / Q000473:pathology; D045744:Cell Line, Tumor; D005260:Female; D005780:Gelatin; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008027:Light; D051379:Mice; D008819:Mice, Nude; D008856:Microscopy, Fluorescence; D009374:Neoplasms, Experimental / Q000473:pathology; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D041622:Tomography, Optical / Q000295:instrumentation / Q000379:methods*; D014966:Xanthenes
D014966:Xanthenes; C034657:Texas red; D005780:Gelatin