Time-gated fluorescence imaging of chloroaluminum phthalocyanine tetrasulfonate in a tissue phantom

Autor: Daniel Buckton, Alan G. Ryder, Andrew Shearer, Wilhelm J.M. van der Putten, Michael Ball, Sarah L. Gundy
Rok vydání: 2003
Předmět:
Zdroj: SPIE Proceedings.
ISSN: 0277-786X
DOI: 10.1117/12.462794
Popis: Phthalocyanine derivatives are currently under investigation for use in Photodynamic Therapy, which is a promising treatment for cancer. These materials, which display preferential uptake in cancerous cells, also exhibit high fluorescence yields, and can be used for tumour detection. Problems with steady-state fluorescence techniques such as background autofluorescence can be eliminated by the use of time-resolved techniques. Improved contrast can be obtained with time-resolved techniques because of the differing lifetimes between endogenous and exogenous photosensitisers. An imaging system was constructed using a fast (200 psec) gated CCD camera and a pulsed 635 nm laser diode. A tissue phantom was assembled to test the system by drilling thirty-six wells of varying diameter and depth (10 mm to 1 mm) into a block of polymethyl methacrylate (PMMA). The system was used to record images of chloroaluminum phthalocyanine tetrasulfonate within the wells at differing concentrations in phosphate buffer. A mixture of 1) Intralipid to mimic tissue scatter, 2) Evans blue to mimic tissue absorption, and 3) zinc phthalocyanine tetrasulfonate to mimic healthy tissue autofluorescence of varying depth was placed on top of the PMMA block. These results contribute to the precision of a time-gated imaging system to image living organisms using fluorescence lifetimes.
Databáze: OpenAIRE