Peer-Reviewed Journal Details
Mandatory Fields
Gundy, S;Van der Putten, W;Shearer, A;Buckton, D;Ryder, AG
2004
November
Journal Of Biomedical Optics
Determination of the modulation transfer function for a time-gated fluorescence imaging system
Published
WOS: 2 ()
Optional Fields
TUMOR-BEARING MICE PHOTODYNAMIC THERAPY PHTHALOCYANINE TETRASULFONATE DELAYED FLUORESCENCE MURINE MODEL DIAGNOSIS LOCALIZATION BRONCHOSCOPY CANCER
9
1206
1213
The use of fluorescence for cancer detection is currently under investigation. Presently, steady-state fluorescence detection methods are in use, but have limitations due to poor contrast between the fluorescence of the tumor and background autofluorescence. Improved contrast can be obtained with time-resolved techniques because of the differing lifetimes between autofluorescence and exogenous photosensitizers that selectively accumulate within tumor tissue. An imaging system is constructed using a fast-gated (200-ps) charge-coupled device (CCD) camera and a pulsed 635-nm laser diode. To characterize the ability of the system to transfer object contrast to an image, the modulation transfer function (MTF) of the system is acquired by employing an extended knife-edge technique. A knife-edge target is assembled by drilling a rectangular well into a block of polymethyl methacrylate (PMMA). The imaging system records images of the photosensitizer, chloroaluminum phthalocyanine tetrasulfonate (AlPcTS), with in the well. AlPcTS was chosen to test the system because of its strong absorption of 635-nm, high fluorescence yield, and relatively long fluorescence lifetime (similar to7.5 ns). The results show that the system is capable of resolving 10(-4) M AlPcTS fluorescence as small as 1 mm. The findings of this study contribute to the development of a time-gated imaging system using fluorescence lifetimes. (C) 2004 Society of Photo-Optical Instrumentation Engineers.
1083-3668
10.1117/1.1803550
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