In vivo imaging of light-emitting probes.
In vivo imaging of cells tagged with light-emitting probes, such as firefly luciferase or fluorescent proteins, is a powerful technology that enables a wide range of biological studies in small research animals. Reporters with emission in the red to infrared (>600 nm) are preferred due to the low absorption in tissue at these wavelengths. Modeling of photon diffusion through tissue indicates that bioluminescent cell counts as low as a few hundred can be detected subcutaneously, while approximately 10(6) cells are required to detect signals at approximately 2 cm depth in tissue. Signal-to-noise estimates show that cooled back-thinned integrating charge coupled devices (CCDs) are preferred to image-intensified CCDs for this application, mainly due to their high quantum efficiency (approximately 85%) at wavelengths >600 nm where tissue absorption is low. Instrumentation for in vivo imaging developed at Xenogen is described and several examples of images of mice with bioluminescent cells are presented.
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Xenogen Corporation, 860 Atlantic Avenue, Alameda, CA 94501, USA. brice@xenogen.com
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Nelson
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D000818:Animals; D003952:Diagnostic Imaging / Q000379:methods; D005456:Fluorescent Dyes; D049452:Green Fluorescent Proteins; D008156:Luciferases; D008163:Luminescent Measurements; D008164:Luminescent Proteins; D051379:Mice; D008807:Mice, Inbred BALB C; D009369:Neoplasms / Q000175:diagnosis; D011014:Pneumonia / Q000175:diagnosis; D000097573:Red Fluorescent Protein
D005456:Fluorescent Dyes; D049452:Green Fluorescent Proteins; D008156:Luciferases; D008164:Luminescent Proteins; D000097573:Red Fluorescent Protein