ABSTRACT
BACKGROUND: Fluorescence lifetime imaging (FLIM) is a novel imaging technique that generates image contrast between different states of tissue due to differences in fluorescence decay rates. OBJECTIVES: To establish whether FLIM of skin autofluorescence can provide useful contrast between basal cell carcinomas (BCCs) and surrounding uninvolved skin. METHODS: Unstained excision biopsies of 25 BCCs were imaged en face with FLIM following excitation of autofluorescence with a 355 nm pulsed ultraviolet laser. RESULTS: Using FLIM we were able to distinguish areas of BCC from surrounding skin in an ex vivo study. Significant reductions in mean fluorescence lifetimes between areas of BCC and areas of surrounding uninvolved skin were demonstrated (P < 0.0001). These differences were apparent irrespective of the decay model used to calculate the fluorescence lifetimes (single vs. stretched exponential) or the long-pass filter through which the emitted autofluorescence was collected (375 vs. 455 nm). Conversely, there was no significant difference between the BCC and uninvolved areas of each sample when mean autofluorescence intensities were examined. Moreover, wide-field false-colour images of fluorescence lifetimes clearly discriminated areas of BCC from the surrounding uninvolved skin. CONCLUSIONS: We therefore believe that FLIM has a potential future clinical role in imaging BCCs for rapid and noninvasive tumour delineation and as an aid to determine adequate excision margins with best preservation of normal tissue.
Subject(s)
Carcinoma, Basal Cell/diagnosis , Diagnostic Imaging/methods , Skin Neoplasms/diagnosis , Adult , Aged , Aged, 80 and over , Contrast Media , Female , Fluorescence , Humans , Male , Middle Aged , Neoplasm Staging/methods , Sensitivity and SpecificityABSTRACT
High-speed (video-rate) fluorescence lifetime imaging (FLIM) through a flexible endoscope is reported based on gated optical image intensifier technology. The optimization and potential application of FLIM to tissue autofluorescence for clinical applications are discussed.
Subject(s)
Endoscopes , Fiber Optic Technology/instrumentation , Image Enhancement/instrumentation , Microscopy, Fluorescence/instrumentation , Microscopy, Video/instrumentation , Animals , Computer Systems , Equipment Design , Equipment Failure Analysis , Image Enhancement/methods , Image Interpretation, Computer-Assisted/instrumentation , Image Interpretation, Computer-Assisted/methods , Mice , Microscopy, Fluorescence/methods , Microscopy, Video/methods , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
We demonstrate an optically sectioned fluorescence lifetime imaging microscope with a wide-field detector, using a convenient, continuously tunable (435-1150 nm) ultrafast source for fluorescence imaging applications that is derived from a visible supercontinuum generated in a microstructured fiber.
ABSTRACT
We report the development of a high-speed wide-field fluorescence-lifetime imaging (FLIM) system that provides fluorescence-lifetime images at rates of as many as 29 frames/s. A FLIM multiwell plate reader and a potentially portable FLIM endoscopic system operating at 355-nm excitation have been demonstrated.
