Dr. Khadija B. Tahir Profile

Dr. Khadija B. Tahir

at Imperial College London

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Publications (7)

Proceedings Article | 26 February 2010 Paper

Tomographic imaging of flourescence resonance energy transfer in highly light scattering media

Vadim Soloviev, James McGinty, Khadija Tahir, Romain Laine, Daniel Stuckey, P. Surya Mohan, Joseph Hajnal, Alessandro Sardini, Paul M. French, Simon Arridge

Proceedings Volume 7573, 75730G (2010) https://doi.org/10.1117/12.840522

KEYWORDS: Fluorescence resonance energy transfer, Light scattering, Tomography, Luminescence, Resonance energy transfer, Quantum efficiency, Proteins, Fluorescence lifetime imaging, Scattering, Calcium

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Proceedings Article | 24 February 2010 Paper

tomoFLIM: fluorescence lifetime projection tomography

James McGinty, Daniel Stuckey, Khadija Tahir, Romain Laine, Joseph Hajnal, Alessandro Sardini, Paul French

Proceedings Volume 7570, 75700G (2010) https://doi.org/10.1117/12.841753

KEYWORDS: Luminescence, Fluorescence resonance energy transfer, Calcium, Tomography, Reconstruction algorithms, Fluorescence lifetime imaging, Head, 3D modeling, 3D image processing, Fluorescent proteins

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Optical Projection Tomography (OPT) is a wide-field technique for measuring the threedimensional distribution of absorbing/fluorescing species in non-scattering (optically cleared) samples up to ~1cm in size, and as such is the optical analogue of X-ray computed tomography. We have extended the intensity-based OPT technique to measure the three-dimensional fluorescence lifetime distribution (tomoFLIM) in transparent samples. Due to its inherent ratiometric nature, fluorescence lifetime measurements are robust against intensity-based artifacts as well as producing a quantitative measure of the fluorescence signal, making it particularly suited to Förster Resonance Energy Transfer (FRET) measurements. We implement tomoFLIM via OPT by acquiring a series of wide-field time-gated images at different relative time delays with respect to a train of excitation pulses for a range of projection angles. For each time delay, the three-dimensional time-gated intensity distribution is reconstructed using a filtered back projection algorithm and the fluorescence lifetime is subsequently determined for each reconstructed horizontal plane by iterative fitting of an appropriate decay model. We present a tomographic reconstruction of a fluorescence lifetime resolved FRET calcium contruct, TN-L15 cytosol suspension, in a silicone phantom. This genetically encoded sensor, TN-L15, comprises the calcium-binding domain of Troponin C, flanked by the fluorophores cyan fluorescent protein and citrine. In the presence of calcium ions TN-L15 changes conformation bringing the two fluorophores into close proximity, resulting in FRET. We also present autofluorescence and fluorescently labelled tomoFLIM reconstructions of chick embryos, including a genetically encoded fluorophore TagRFP-T. The fluorophore was electroporated in ovo into the neural tube of the embryos, which were subsequently dissected two days post-electroporation, fixed in ethanol and optically cleared for OPT/tomoFLIM acquisition. The reconstructed 3-D fluorescence lifetime image provides contrast between the genetically labelled TagRFP-T and the emitted autofluorescence.

Proceedings Article | 12 July 2007 Paper

Fluorescence lifetime imaging through turbid media reconstructed in the Fourier domain using time-gated imaging data

Vadim Soloviev, Khadija Tahir, James McGinty, Dan Elson, Mark Neil, Alessandro Sardini, Joseph Hajnal, Simon Arridge, Paul French

Proceedings Volume 6629, 66291V (2007) https://doi.org/10.1117/12.728481

KEYWORDS: Luminescence, Scattering, Quantum efficiency, Fluorescence lifetime imaging, CCD cameras, Picosecond phenomena, Fourier transforms, Tomography, Cameras, Epoxies

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Proceedings Article | 1 January 1998 Paper

Higher-order transport approximations for optical tomography applications

Cassiano de Oliveria, Khadija Tahir

Proceedings Volume 3194, (1998) https://doi.org/10.1117/12.301059

KEYWORDS: Optical tomography, Inverse scattering problem

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Proceedings Article | 25 September 1995 Paper

Saturated electron lens design using a second-order finite element method

John Hodkinson, Khadija Tahir

Proceedings Volume 2522, (1995) https://doi.org/10.1117/12.221587

KEYWORDS: Finite element methods, Chemical elements, Magnetism, Lens design, Optical design, Spherical lenses, Chromatic aberrations, Monochromatic aberrations, Modeling, Electron microscopes

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Proceedings Article | 3 September 1993 Paper

Computer-aided design of photomultiplier tubes using a 3D program

Khadija Tahir, John Rouse, Eric Munro

Proceedings Volume 2014, (1993) https://doi.org/10.1117/12.155694

KEYWORDS: Photomultipliers, Computer aided design, Electrodes, 3D modeling, Ray tracing, Spherical lenses, Numerical modeling, Computer simulations, Sensors, Electron beams

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Proceedings Article | 1 April 1993 Paper

Computational aspects of photomultiplier design

Khadija Tahir, John Rouse, Xieqing Zhu, Eric Munro

Proceedings Volume 1982, (1993) https://doi.org/10.1117/12.142024

KEYWORDS: Photomultipliers, Electrodes, Computer aided design, Fused deposition modeling, Ray tracing, Signal detection, 3D modeling, Finite difference methods, Phase modulation, Visualization

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Showing 5 of 7 publications

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