title: The use of chloroaluminium phthalocyanine tetrasulfonate (AlPcTS) for time-delayed fluorescence imaging.
abstract: Phthalocyanine derivatives are currently under investigation for use in photodynamic therapy, which is a promising cancer treatment. 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 excitation scatter and background autofluorescence can be eliminated by using time-resolved imaging techniques without the need for filters. A tissue phantom was assembled to test a constructed time-gated imaging system by drilling 36 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 chloroaluminium phthalocyanine tetrasulfonate (AlPcTS) at differing concentrations in neat aqueous solvent and cell suspensions within the wells. A mixture of Intralipid (to mimic tissue scatter) and Evan's blue (to mimic tissue absorption) of depths ranging from 1 mm to 10 mm was placed on top of the PMMA block. The ensuing images were analysed using signal-to-noise ratios and contrast-detail curves. The results indicate that the time-gated imaging system can prevent background excitation scatter from distorting the fluorescence signal from a longer-lived photosensitizer without the need for filters.
authors.affiliation: Department of Information Technology, National University of Ireland, Galway, Republic of Ireland.
authors.forename: Sarah
authors.initials: S
authors.lastname: Gundy
authors.forename: Wil
authors.initials: W
authors.lastname: Van der Putten
authors.forename: Andy
authors.initials: A
authors.lastname: Shearer
authors.forename: Daniel
authors.initials: D
authors.lastname: Buckton
authors.forename: Alan G
authors.initials: AG
authors.lastname: Ryder
authors.forename: Michael
authors.initials: M
authors.lastname: Ball
mesh_terms: D019544:Equipment Failure Analysis; D005456:Fluorescent Dyes; D007211:Indoles / Q000032:analysis* / Q000737:chemistry* / Q000627:therapeutic use; D008856:Microscopy, Fluorescence / Q000295:instrumentation* / Q000379:methods*; D009942:Organometallic Compounds / Q000032:analysis* / Q000737:chemistry* / Q000627:therapeutic use; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D005456:Fluorescent Dyes; D007211:Indoles; D009942:Organometallic Compounds; C052736:chloroaluminum tetrasulfophthalocyanine