Dr. Julia A. O'Hara Profile

Dr. Julia A. O'Hara

Research Scientist at Dartmouth Medical School

SPIE Involvement:

Author

Publications (31)

Proceedings Article | 9 March 2012 Paper

Histologic differences between orthotopic xenograft pancreas models affect Verteporfin uptake measured by fluorescence microscopy and spectroscopy

Julia O'Hara, Kimberley Samkoe, Alina Chen, Martin Isabelle, P. Hoopes, Tayyaba Hasan, Brian Pogue

Proceedings Volume 8210, 821014 (2012) https://doi.org/10.1117/12.913049

KEYWORDS: Tumors, Luminescence, Tissues, Blood vessels, Picosecond phenomena, Photodynamic therapy, Pancreas, Tissue optics, Liver, Laser induced fluorescence

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SPIE Journal Paper | 1 September 2011 Open Access

Protoporphyrin IX fluorescence contrast in invasive glioblastomas is linearly correlated with Gd enhanced magnetic resonance image contrast but has higher diagnostic accuracy

Kimberley Samkoe, Summer Gibbs-Strauss, Harold Yang, Paul Hoopes, Julia O'Hara, Brian Pogue, S. Khan Hekmatyar, Risto Kauppinen

JBO, Vol. 16, Issue 09, 096008, (September 2011) https://doi.org/10.1117/12.10.1117/1.3622754

KEYWORDS: Luminescence, Tumors, Green fluorescent protein, Magnetic resonance imaging, Gadolinium, Tissues, Image enhancement, Brain, Control systems, Diagnostics

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Proceedings Article | 9 March 2011 Paper

Quantifying receptor density in vivo using a dual probe approach with fluorescence molecular imaging

Kenneth Tichauer, Kimberley Samkoe, Julia O'Hara, Kristian Sexton, Scott Davis, Brian Pogue

Proceedings Volume 7965, 79650V (2011) https://doi.org/10.1117/12.891720

KEYWORDS: Tumors, Pancreas, Receptors, Tissues, Molecular imaging, Luminescence, Data modeling, In vivo imaging, Blood, Animal model studies

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Proceedings Article | 11 February 2011 Paper

In vivo validation of high frequency ultrasound-guided fluorescence tomography system to improve delivery of photodynamic therapy

Akshat Paliwal, Sason Torosean, Josiah Gruber, Julia O'Hara, Tayyaba Hasan, Brian Pogue, Edward Maytin

Proceedings Volume 7886, 788610 (2011) https://doi.org/10.1117/12.875629

KEYWORDS: Tumors, Photodynamic therapy, Skin, Fourier transforms, In vivo imaging, Luminescence, Skin cancer, Tissues, Picosecond phenomena, Image segmentation

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Proceedings Article | 11 February 2011 Paper

Determination of blood plasma fluorescence extinction coefficients for dyes used in three-compartment binding model

Kimberley Samkoe, Kristian Sexton, Kenneth Tichauer, Scott Davis, Julia O'Hara, Tayyaba Hasan, Brian Pogue

Proceedings Volume 7886, 78860A (2011) https://doi.org/10.1117/12.875408

KEYWORDS: Luminescence, Plasma, Blood, Receptors, Mass attenuation coefficient, Absorption, Tumors, Photodynamic therapy, Nonlinear filtering, Tissue optics

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Proceedings Article | 10 February 2011 Paper

Image contrast in fluorescence and magnetic resonance images for glioblastoma detection

Kimberley Samkoe, Summer Gibbs-Strauss, Harold Yang, S. Khan Hekmatyar, P. Jack Hoopes, Julia O'Hara, Risto Kauppinen, Brian Pogue

Proceedings Volume 7892, 78920O (2011) https://doi.org/10.1117/12.875425

KEYWORDS: Luminescence, Magnetic resonance imaging, Tumors, Diffusion, Green fluorescent protein, Brain, Gadolinium, Magnetism, Imaging systems, Image enhancement

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SPIE Journal Paper | 1 September 2010 Open Access

Comparing implementations of magnetic-resonance-guided fluorescence molecular tomography for diagnostic classification of brain tumors

Scott Davis, Kimberley Samkoe, Julia O'Hara, Summer Gibbs-Strauss, Keith Paulsen, Brian Pogue

JBO, Vol. 15, Issue 05, 051602, (September 2010) https://doi.org/10.1117/12.10.1117/1.3483902

KEYWORDS: Tumors, Luminescence, Brain, Tissues, Magnetic resonance imaging, Image segmentation, Tissue optics, Diagnostics, Spectroscopy, Image restoration

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SPIE Journal Paper | 1 May 2010 Open Access

Imaging targeted-agent binding in vivo with two probes

Brian Pogue, Kimberley Samkoe, Shannon Hextrum, Julia O'Hara, Michael Jermyn, Subhadra Srinivasan, Tayyaba Hasan

JBO, Vol. 15, Issue 03, 030513, (May 2010) https://doi.org/10.1117/12.10.1117/1.3449109

KEYWORDS: In vivo imaging, Tumors, Pancreas, Tissues, Luminescence, Receptors, Image processing, Plasma, Data modeling, Image visualization

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Proceedings Article | 5 March 2010 Paper

In vivo sampling of Verteporfin uptake in pancreas cancer xenograft models: comparison of surface, oral, and interstitial measurements

Martin Isabelle, Julia O'Hara, Kimberley Samkoe, P. Jack Hoopes, Sandy Mosse, Stephen Pereira, Tayyaba Hasan, Brian Pogue

Proceedings Volume 7551, 755116 (2010) https://doi.org/10.1117/12.852779

KEYWORDS: Picosecond phenomena, Tissues, Tissue optics, Laser induced fluorescence, Photodynamic therapy, Tumors, Pancreas, Natural surfaces, In vivo imaging, Luminescence

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Proceedings Article | 5 March 2010 Paper

In vivo PDT dosimetry: singlet oxygen emission and photosensitizer fluorescence

Seonkyung Lee, Kristin Galbally-Kinney, Brian Murphy, Steven Davis, Tayyaba Hasan, Bryan Spring, Yupeng Tu, Brian Pogue, Martin Isabelle, Julia O'Hara

Proceedings Volume 7551, 75510F (2010) https://doi.org/10.1117/12.846358

KEYWORDS: Oxygen, Photodynamic therapy, Picosecond phenomena, Semiconductor lasers, Luminescence, In vivo imaging, Sensors, Tumors, Imaging systems, Pulsed laser operation

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Proceedings Article | 3 March 2010 Paper

EGF targeted fluorescence molecular tomography as a predictor of PDT outcomes in pancreas cancer models

Kimberley Samkoe, Scott Davis, Subhadra Srinivasan, Martin Isabelle, Julia O'Hara, Tayyaba Hasan, Brian Pogue

Proceedings Volume 7551, 75510Q (2010) https://doi.org/10.1117/12.842934

KEYWORDS: Tumors, Photodynamic therapy, Magnetic resonance imaging, Luminescence, Pancreas, Imaging systems, Tissues, Fluorescence tomography, Tomography, Cancer

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SPIE Journal Paper | 1 March 2010 Open Access

System development for high frequency ultrasound-guided fluorescence quantification of skin layers

Josiah Gruber, Akshat Paliwal, Venkat Krishnaswamy, Hamid Ghadyani, Michael Jermyn, Julie O'Hara, Scott Davis, Joanna Kerley-Hamilton, Nicholas Shworak, Edward Maytin, Tayyaba Hasan, Brian Pogue

JBO, Vol. 15, Issue 02, 026028, (March 2010) https://doi.org/10.1117/12.10.1117/1.3374040

KEYWORDS: Luminescence, Tumors, Skin, Image segmentation, Ultrasonography, Tissues, Imaging systems, Signal detection, In vivo imaging, Fluorescence tomography

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Proceedings Article | 25 February 2010 Paper

Specific binding of molecularly targeted agents to pancreas tumors and impact on observed optical contrast

Kimberley Samkoe, Shannon Hextrum, Omar Pardesi, Julia O'Hara, Tayyaba Hasan, Brian Pogue

Proceedings Volume 7568, 75680H (2010) https://doi.org/10.1117/12.843009

KEYWORDS: Tumors, Tissues, Pancreas, Luminescence, Liver, Flow cytometry, In vivo imaging, Pancreatic cancer, Fluorescence tomography, Tissue optics

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Proceedings Article | 13 July 2009 Paper

Uptake of verteporfin by orthotopic xenograft pancreas models with different levels of aggression

Julia O'Hara, Kimberley Samkoe, Alina Chen, P. Jack Hoopes, Imran Rizvi, Tayyaba Hasan, Brian Pogue

Proceedings Volume 7380, 73805F (2009) https://doi.org/10.1117/12.823214

KEYWORDS: Tumors, Luminescence, Pancreas, Tissues, Liver, Photodynamic therapy, In vivo imaging, Pancreatic cancer, Spleen, Skin

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Proceedings Article | 13 July 2009 Paper

A singlet oxygen monitor as an in vivo photodynamic therapy dosimeter

S. Lee, K. Galbally-Kinney, M. Hinds, J. O'Hara, B. Pogue, A. Liang, T. Hasan, S. Davis

Proceedings Volume 7380, 738046 (2009) https://doi.org/10.1117/12.823030

KEYWORDS: Oxygen, Picosecond phenomena, Tumors, Photodynamic therapy, Luminescence, Semiconductor lasers, Sensors, Cameras, In vivo imaging, Imaging systems

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Proceedings Article | 13 July 2009 Paper

A study of MRI-guided diffuse fluorescence molecular tomography for monitoring PDT effects in pancreas cancer

Kimberley Samkoe, Scott Davis, Subhadra Srinivasan, Julia O'Hara, Tayyaba Hasan, Brian Pogue

Proceedings Volume 7380, 73803M (2009) https://doi.org/10.1117/12.823079

KEYWORDS: Luminescence, Magnetic resonance imaging, Tumors, Photodynamic therapy, Pancreas, Image segmentation, Abdomen, Fluorescence tomography, Optical fibers, Kidney

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SPIE Journal Paper | 1 May 2009 Open Access

Imaging of glioma tumor with endogenous fluorescence tomography

Dax Kepshire, Summer Gibbs-Strauss, Julia O'Hara, Michael Hutchins, Niculae Mincu, Frederic Leblond, Mario Khayat, Hamid Dehghani, Subhadra Srinivasan, Brian Pogue

JBO, Vol. 14, Issue 03, 030501, (May 2009) https://doi.org/10.1117/12.10.1117/1.3127202

KEYWORDS: Tumors, Luminescence, Fluorescence tomography, Tomography, Imaging systems, Signal detection, Tissues, Calibration, Fluorescence spectroscopy, Single photon detectors

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SPIE Journal Paper | 1 May 2009 Open Access

Errata: Imaging of glioma tumor with endogenous fluorescence tomography

Dax Kepshire, Summer Gibbs-Strauss, Julia O'Hara, Frederic Leblond, Subhadra Srinivasan, Brian Pogue, Michael Hutchins, Niculae Mincu, Mario Khayat, Hamid Dehghani

JBO, Vol. 14, Issue 03, 039802, (May 2009) https://doi.org/10.1117/12.10.1117/1.3157198

KEYWORDS: Tumors, Fluorescence tomography, Medical research, Physics, Roads, Diagnostics, Radiology

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Proceedings Article | 20 February 2009 Paper

Imaging protoporphyrin IX fluorescence with a time-domain FMT/microCT system

Frederic Leblond, Dax Kepshire, Julia O'Hara, Hamid Dehghani, Subha Srinivasan, N. Mincu, M. Hutchins, M. Khayat, B. Pogue

Proceedings Volume 7171, 717106 (2009) https://doi.org/10.1117/12.809267

KEYWORDS: Luminescence, Imaging systems, Signal detection, Sensors, Tomography, Quantum efficiency, Data acquisition, Diffusion, Computed tomography, Natural surfaces

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Proceedings Article | 18 February 2009 Paper

Magnetic resonance image-guided photodynamic therapy of xenograft pancreas tumors with verteporfin

Kimberley Samkoe, Alina Chen, Imran Rizvi, Julia O'Hara, P. Jack Hoopes, Tayyaba Hasan, Brian Pogue

Proceedings Volume 7164, 71640D (2009) https://doi.org/10.1117/12.809857

KEYWORDS: Tumors, Photodynamic therapy, Magnetic resonance imaging, Pancreas, Blood vessels, Therapeutics, Luminescence, Tissues, Pancreatic cancer, Magnetism

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Proceedings Article | 12 February 2009 Paper

Video-rate near infrared tomography for imaging thick tissue with dynamically varying absorption properties

Zhiqiu Li, Venkataramanan Krishnaswamy, Keith Paulsen, Brian Pogue

Proceedings Volume 7174, 71742G (2009) https://doi.org/10.1117/12.809875

KEYWORDS: Imaging systems, Charge-coupled devices, Tomography, Sensors, Tissues, Near infrared, Optical fibers, Signal detection, Tissue optics, Absorption

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SPIE Journal Paper | 1 January 2009 Open Access

Quantitative imaging of scattering changes associated with epithelial proliferation, necrosis, and fibrosis in tumors using microsampling reflectance spectroscopy

Venkataramanan Krishnaswamy, P. Jack Hoopes, Kimberley Samkoe, Julia O'Hara, Tayyaba Hasan, Brian Pogue

JBO, Vol. 14, Issue 01, 014004, (January 2009) https://doi.org/10.1117/12.10.1117/1.3065540

KEYWORDS: Tumors, Tissues, Scattering, Imaging systems, Absorption, Prostate, Pancreas, Blood, Reflectivity, Confocal microscopy

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SPIE Journal Paper | 1 January 2009 Open Access

Noninvasive measurement of aminolevulinic acid-induced protoporphyrin IX fluorescence allowing detection of murine glioma in vivo

Summer Gibbs-Strauss, Julia O'Hara, P. Jack Hoopes, Tayyaba Hasan, Brian Pogue

JBO, Vol. 14, Issue 01, 014007, (January 2009) https://doi.org/10.1117/12.10.1117/1.3065543

KEYWORDS: Tumors, Luminescence, Tissues, Brain, Spectroscopy, Fluorescence spectroscopy, In vivo imaging, Skin, Magnetic resonance imaging, Green fluorescent protein

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Proceedings Article | 25 February 2008 Paper

Noninvasive murine glioma detection improved following photobleaching of skin PpIX fluorescence

Summer Gibbs-Strauss, Scott Davis, Julia O'Hara, P. Jack Hoopes, Tayyaba Hasan, Brian Pogue

Proceedings Volume 6845, 68450D (2008) https://doi.org/10.1117/12.762997

KEYWORDS: Luminescence, Skin, Tumors, Brain, Spectroscopy, Imaging systems, Photodynamic therapy, Tissues, Visualization, Tissue optics

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Proceedings Article | 27 February 2007 Paper

Improved murine glioma detection following modified diet and photobleaching of skin PpIX fluorescence

Summer Gibbs, Julia O'Hara, P. Jack Hoopes, Brian Pogue

Proceedings Volume 6427, 64270D (2007) https://doi.org/10.1117/12.700456

KEYWORDS: Luminescence, Skin, Tumors, Tissues, Brain, Spectroscopy, Head, Imaging systems, Fluorescence spectroscopy, Tissue optics

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Proceedings Article | 6 March 2006 Paper

Analysis of cell line variation in biochemical production of protoporphyrin IX

Summer Gibbs, Bin Chen, Julia O'Hara, P. Jack Hoopes, Tayyaba Hasan, Brian Pogue

Proceedings Volume 6139, 61390A (2006) https://doi.org/10.1117/12.644787

KEYWORDS: Luminescence, Iron, Lithium, Flow cytometry, Cancer, Photodynamic therapy, Statistical analysis, Tissues, Prostate, Scatter measurement

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Protoporphyrin IX (PpIX) is produced via the heme synthesis pathway by the cell following administration of aminolevulinic acid (ALA). ALA synthase, the enzyme that produces ALA in the cell from glycine and succinyl-coenzyme A, is inhibited in a feedback mechanism by heme and thus is the rate limiting enzyme in the heme synthesis pathway. Since ALA is administered systemically, the rate limiting step that naturally exists in the cells is bypassed, however it is currently unclear why cells have different rate limiting steps in the ALA-PpIX synthesis pathway, and more specifically which types of cancer cells are most productive. It has been determined that when the same amount of ALA is administered to a wide panel of cancer cells in vitro that vastly differing amounts of PpIX are produced. The steps for the ALA-PpIX pathway occur in and around the mitochondria of the cell, but interestingly no correlation is seen between PpIX production and mitochondrial content of the cell, following ALA administration. However, total cell area shows positive correlation with PpIX production. Administration of the iron chelator, 1,2-dimethyl-3-hydroxy-4-pyridone (L1) in combination with ALA allows the final step in the heme synthesis pathway, conversion of PpIX to heme, to be delayed and thus increases the detectable amount of PpIX in each cell line. The cell lines that have the lowest PpIX production following administration of ALA alone show the largest increase in production following the combined administration of ALA and L1. PpIX fluorescence is thought to be a measure of cellular activity and the goal of the current study was to determine which cell lines would be the most promising targets for fluorescence detection or monitoring response to therapy. The results indicate that the cells with larger size and larger numbers of mitochondria may be good potential targets for this therapy. While this conclusion may appear obvious, it is not universally true, and cellular specific variations exist which are still not fully understood.

Proceedings Article | 13 June 2003 Paper

Effect of photodynamic therapy with verteporfin on tumor blood flow

Bin Chen, Brian Pogue, Isak Goodwin, Julia O'Hara, Carmen Wilmot, John Hutchins, P. Hoopes, Tayyaba Hasan

Proceedings Volume 4952, (2003) https://doi.org/10.1117/12.474082

KEYWORDS: Tumors, Photodynamic therapy, Blood circulation, Tissues, Doppler effect, Blood vessels, Oxygen, Luminescence, Laser systems engineering, Cancer

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Proceedings Article | 13 June 2003 Paper

Numerical light dosimetry in murine tissue: analysis of tumor curvature and angle of incidence effects upon fluence in the tissue

Chao Sheng, Brian Pogue, Hamid Dehghani, Julia O'Hara, P. Hoopes

Proceedings Volume 4952, (2003) https://doi.org/10.1117/12.474081

KEYWORDS: Tumors, Tissue optics, Tissues, Skin, Photodynamic therapy, Diffusion, Natural surfaces, Laser tissue interaction, Signal attenuation, Reflection

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Proceedings Article | 13 June 2003 Paper

Increasing oxygenation and radiation sensitivity following photodynamic therapy with verteporfin in the RIF-1 tumor

Brian Pogue, Julia O'Hara, Eugene Demidenko, Carmen Wilmot, Bin Chen, Harold Swartz, Tayyaba Hasan

Proceedings Volume 4952, (2003) https://doi.org/10.1117/12.473594

KEYWORDS: Tumors, Photodynamic therapy, Blood circulation, Radiotherapy, Oxygen, Tissues, Radiation effects, In vivo imaging, In vitro testing, Doppler effect

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