Medicine and Health Sciences Commons^™

Using Natural Language Processing And Sentiment Analysis To Augment Traditional User-Centered Design: Development And Usability Study, Curtis L. Petersen, Ryan Halter, David Kotz, Lorie Loeb, Summer B. Cook, Dawna M. Pidgeon, Brock Christensen, John A. Batsis

Dartmouth Scholarship

Background: Sarcopenia, defined as the age-associated loss of muscle mass and strength, can be effectively mitigated through resistance-based physical activity. With compliance at approximately 40% for home-based exercise prescriptions, implementing a remote sensing system would help patients and clinicians to better understand treatment progress and increase compliance. The inclusion of end users in the development of mobile apps for remote-sensing systems can ensure that they are both user friendly and facilitate compliance. With advancements in natural language processing (NLP), there is potential for these methods to be used with data collected through the user-centered design process.

Objective: This study aims …

Optimization Of Fluorescent Imaging In The Operating Room Through Pulsed Acquisition And Gating To Ambient Background Cycling, Kristian J. Sexton, Yan Zhao, Scott C. Davis, Shudong Jiang, Brian Pogue

Dartmouth Scholarship

The design of fluorescence imaging instruments for surgical guidance is rapidly evolving, and a key issue is to efficiently capture signals with high ambient room lighting. Here, we introduce a novel time-gated approach to fluorescence imaging synchronizing acquisition to the 120 Hz light of the room, with pulsed LED excitation and gated ICCD detection. It is shown that under bright ambient room light this technique allows for the detection of physiologically relevant nanomolar fluorophore concentrations, and in particular reduces the light fluctuations present from the room lights, making low concentration measurements more reliable. This is particularly relevant for the light …

Raman Spectroscopy Detects Distant Invasive Brain Cancer Cells Centimeters Beyond Mri Capability In Humans, Michael Jermyn, Joannie Desroches, Jeanne Mercier, Karl St-Arnaud

Dartmouth Scholarship

Surgical treatment of brain cancer is limited by the inability of current imaging capabilities such as magnetic resonance imaging (MRI) to detect the entirety of this locally invasive cancer. This results in residual cancer cells remaining following surgery, leading to recurrence and death. We demonstrate that intraoperative Raman spectroscopy can detect invasive cancer cells centimeters beyond pathological T1-contrast-enhanced and T2-weighted MRI signals. This intraoperative optical guide can be used to detect invasive cancer cells and minimize post-surgical cancer burden. The detection of distant invasive cancer cells beyond MRI signal has the potential to increase the effectiveness of surgery and directly …

Multiobjective Guided Priors Improve The Accuracy Of Near-Infrared Spectral Tomography For Breast Imaging, Jinchao Feng, Shudong Jiang, Junqing Xu, Yan Zhao, Brian W. Pogue, Keith D. Paulsen

Dartmouth Scholarship

An image reconstruction regularization approach for magnetic resonance imaging-guided near-infrared spectral tomography has been developed to improve quantification of total hemoglobin (HbT) and water. By combining prior information from dynamic contrast enhanced (DCE) and diffusion weighted (DW) MR images, the absolute bias errors of HbT and water in the tumor were reduced by 22% and 18%, 21% and 6%, and 10% and 11%, compared to that in the no-prior, DCE- or DW-guided reconstructed images in three-dimensional simulations, respectively. In addition, the apparent contrast values of HbT and water were increased in patient image reconstruction from 1.4 and 1.4 (DCE) or …

Effects Of Breast Density And Compression On Normal Breast Tissue Hemodynamics Through Breast Tomosynthesis Guided Near-Infrared Spectral Tomography, Kelly E. Michaelsen, Venkataramanan Krishnaswamy, Linxi Shi, Srinivasan Vedantham, Andrew Karellas, Brian W. Pogue, Keith D. Paulsen, Steven P. Poplack

Dartmouth Scholarship

Optically derived tissue properties across a range of breast densities and the effects of breast compression on estimates of hemoglobin, oxygen metabolism, and water and lipid concentrations were obtained from a coregistered imaging system that integrates near-infrared spectral tomography (NIRST) with digital breast tomosynthesis (DBT). Image data were analyzed from 27 women who underwent four IRB approved NIRST/DBT exams that included fully and mildly compressed breast acquisitions in two projections—craniocaudal (CC) and mediolateral-oblique (MLO)—and generated four data sets per patient (full and moderate compression in CC and MLO views). Breast density was correlated with HbT (r=0.64, p=0.001), water (r=0.62, p=0.003), …

Microdose Fluorescence Imaging Of Aby-029 On An Operating Microscope Adapted By Custom Illumination And Imaging Modules, Jonathan T. Elliott, Alisha V. Dsouza, Kayla Marra, Brian W. Pogue, David Roberts, Keith Paulsen

Dartmouth Scholarship

Fluorescence guided surgery has the potential to positively impact surgical oncology; current operating microscopes and stand-alone imaging systems are too insensitive or too cumbersome to maximally take advantage of new tumor-specific agents developed through the microdose pathway. To this end, a custom-built illumination and imaging module enabling picomolar-sensitive near-infrared fluorescence imaging on a commercial operating microscope is described. The limits of detection and system specifications are characterized, and in vivo efficacy of the system in detecting ABY-029 is evaluated in a rat orthotopic glioma model following microdose injections, showing the suitability of the device for microdose phase 0 clinical trials.

Review Of Fluorescence Guided Surgery Systems: Identification Of Key Performance Capabilities Beyond Indocyanine Green Imaging, Alisha V. Dsouza, Huiyun Lin, Eric R. Henderson, Kimberley S. Samkoe

Dartmouth Scholarship

There is growing interest in using fluorescence imaging instruments to guide surgery, and the leading options for open-field imaging are reviewed here. While the clinical fluorescence-guided surgery (FGS) field has been focused predominantly on indocyanine green (ICG) imaging, there is accelerated development of more specific molecular tracers. These agents should help advance new indications for which FGS presents a paradigm shift in how molecular information is provided for resection decisions. There has been a steady growth in commercially marketed FGS systems, each with their own differentiated performance characteristics and specifications. A set of desirable criteria is presented to guide the …

Design Of Nanoparticle-Based Carriers For Targeted Drug Delivery, Xiaojiao Yu, Ian Trase, Muqing Ren, Kayla Duval, Xing Guo, Zi Chen

Dartmouth Scholarship

Nanoparticles have shown promise as both drug delivery vehicles and direct antitumor systems, but they must be properly designed in order to maximize efficacy. Computational modeling is often used both to design new nanoparticles and to better understand existing ones. Modeled processes include the release of drugs at the tumor site and the physical interaction between the nanoparticle and cancer cells. In this paper, we provide an overview of three different targeted drug delivery methods (passive targeting, active targeting, and physical targeting) and compare methods of action, advantages, limitations, and the current stages of research. For the most commonly used …

Portable, Parallel 9-Wavelength Near-Infrared Spectral Tomography (Nirst) System For Efficient Characterization Of Breast Cancer Within The Clinical Oncology Infusion Suite, Yan Zhao, Brian W. Pogue, Steffen J. Haider, Jiang Gui, Roberta Diflorio-Alexander, Keith Paulsen, Shudong Jiang

Dartmouth Scholarship

A portable near-infrared spectral tomography (NIRST) system was developed with simultaneous frequency domain (FD) and continuous-wave (CW) optical measurements for efficient characterization of breast cancer in a clinical oncology setting. Simultaneous FD and CW recordings were implemented to speed up acquisition to 3 minutes for all 9 wavelengths, spanning a range from 661nm to 1064nm. An adjustable interface was designed to fit various breast sizes and shapes. Spatial images of oxy- and deoxy-hemoglobin, water, lipid, and scattering components were reconstructed using a 2D FEM approach. The system was tested on a group of 10 normal subjects, who were examined bilaterally …

Improved Sensitivity To Fluorescence For Cancer Detection In Wide-Field Image-Guided Neurosurgery, Michael Jermyn, Yoann Gosselin, Pablo A. Valdes, Mira Sibai, Kolbein Kolste

Dartmouth Scholarship

In glioma surgery, Protoporphyrin IX (PpIX) fluorescence may identify residual tumor that could be resected while minimizing damage to normal brain. We demonstrate that improved sensitivity for wide-field spectroscopic fluorescence imaging is achieved with minimal disruption to the neurosurgical workflow using an electron-multiplying charge-coupled device (EMCCD) relative to a state-of-the-art CMOS system. In phantom experiments the EMCCD system can detect at least two orders-of-magnitude lower PpIX. Ex vivo tissue imaging on a rat glioma model demonstrates improved fluorescence contrast compared with neurosurgical fluorescence microscope technology, and the fluorescence detection is confirmed with measurements from a clinically-validated spectroscopic probe. Greater PpIX …

Calibration And Optimization Of 3d Digital Breast Tomosynthesis Guided Near Infrared Spectral Tomography, Kelly E. Michaelsen, Venkataramanan Krishnaswamy, Linxi Shi, Srinivasan Vedantham, Steven Poplack, Andrew Karellas, Brian Pogue, Keith Paulsen

Dartmouth Scholarship

Calibration of a three-dimensional multimodal digital breast tomosynthesis (DBT) x-ray and non-fiber based near infrared spectral tomography (NIRST) system is challenging but essential for clinical studies. Phantom imaging results yielded linear contrast recovery of total hemoglobin (HbT) concentration for cylindrical inclusions of 15 mm, 10 mm and 7 mm with a 3.5% decrease in the HbT estimate for each 1 cm increase in inclusion depth. A clinical exam of a patient's breast containing both benign and malignant lesions was successfully imaged, with greater HbT was found in the malignancy relative to the benign abnormality and fibroglandular regions (11 μM vs. …

Review Of Fluorescence Guided Surgery Visualization And Overlay Techniques, Jonathan T. Elliott, Alisha V. Dsouza, Scott C. Davis, Jonathan D. Olson, Keith Paulsen, David Roberts, Brian Pogue

Dartmouth Scholarship

In fluorescence guided surgery, data visualization represents a critical step between signal capture and display needed for clinical decisions informed by that signal. The diversity of methods for displaying surgical images are reviewed, and a particular focus is placed on electronically detected and visualized signals, as required for near-infrared or low concentration tracers. Factors driving the choices such as human perception, the need for rapid decision making in a surgical environment, and biases induced by display choices are outlined. Five practical suggestions are outlined for optimal display orientation, color map, transparency/alpha function, dynamic range compression, and color perception check.

Logarithmic Intensity Compression In Fluorescence Guided Surgery Applications, Alisha V. Dsouza, Huiyun Lin, Jason Gunn, Brian W. Pogue

Dartmouth Scholarship

The use of fluorescence video imaging to guide surgery is rapidly expanding, and improvements in camera readout dynamic range have not matched display capabilities. Logarithmic intensity compression is a fast, single-step mapping technique that can map the useable dynamic range of high-bit fluorescence images onto the typical 8-bit display and potentially be a variable dynamic contrast enhancement tool. We demonstrate a ∼4.6  times improvement in image quality quantified by image entropy and a dynamic range reduction by a factor of ∼380 by the use of log-compression tools in processing in vivo fluorescence images.

Review Of Biomedical Čerenkov Luminescence Imaging Applications, Kaveh Tanha, Ali Mahmoud Pashazadeh, Brian W. Pogue

Dartmouth Scholarship

Čerenkov radiation is a fascinating optical signal, which has been exploited for unique diagnostic biological sensing and imaging, with significantly expanded use just in the last half decade. Čerenkov Luminescence Imaging (CLI) has desirable capabilities for niche applications, using specially designed measurement systems that report on radiation distributions, radiotracer and nanoparticle concentrations, and are directly applied to procedures such as medicine assessment, endoscopy, surgery, quality assurance and dosimetry. When compared to the other imaging tools such as PET and SPECT, CLI can have the key advantage of lower cost, higher throughput and lower imaging time. CLI can also provide imaging …

Molecular Dyes Used For Surgical Specimen Margin Orientation Allow For Intraoperative Optical Assessment During Breast Conserving Surgery, David M. Mcclatchy, Venkataramanan Krishnaswamy, Stephen C. Kanick, Jonathan T. Elliott, Wendy A. Wells, Richard J. Barth Jr., Keith D. Paulsen, Brian W. Pogue

Dartmouth Scholarship

A variety of optical techniques utilizing near-infrared (NIR) light are being proposed for intraoperative breast tumor margin assessment. However, immediately following a lumpectomy excision, the margins are inked, which preserves the orientation of the specimen but prevents optical interrogation of the tissue margins. Here, a workflow is proposed that allows for both NIR optical assessment following full specimen marking using molecular dyes which have negligible absorption and scattering in the NIR. The effect of standard surgical inks in contrast to molecular dyes for an NIR signal is shown. Further, the proposed workflow is demonstrated with full specimen intraoperative imaging on …

Macroscopic-Imaging Technique For Subsurface Quantification Of Near-Infrared Markers During Surgery, Michael Jermyn, Kolbein Kolste, Julien Pichette, Guillaume Sheehy, Leticia Angulo-Rodriguez, Keith D. Paulsen, David W. Roberts, Brian C. Wilson, Kevin Petrecca, Frederic Leblond

Dartmouth Scholarship

Obtaining accurate quantitative information on the concentration and distribution of fluorescent markers lying at a depth below the surface of optically turbid media, such as tissue, is a significant challenge. Here, we introduce a fluorescence reconstruction technique based on a diffusion light transport model that can be used during surgery, including guiding resection of brain tumors, for depth-resolved quantitative imaging of near-infrared fluorescent markers. Hyperspectral fluorescence images are used to compute a topographic map of the fluorophore distribution, which yields structural and optical constraints for a three-dimensional subsequent hyperspectral diffuse fluorescence reconstruction algorithm. Using the model fluorophore Alexa Fluor 647 …

Next-Generation Raman Tomography Instrument For Non-Invasive In Vivo Bone Imaging, Jennifer-Lynn H. Demers, Francis W. L. Esmonde-White, Karen A. Esmonde-White, Michael D. Morris, Brian Pogue

Dartmouth Scholarship

Combining diffuse optical tomography methods with Raman spectroscopy of tissue provides the ability for in vivo measurements of chemical and molecular characteristics, which have the potential for being useful in diagnostic imaging. In this study a system for Raman tomography was developed and tested. A third generation microCT coupled system was developed to combine 10 detection fibers and 5 excitation fibers with laser line filtering and a Cytop reference signal. Phantom measurements of hydroxyapatite concentrations from 50 to 300 mg/ml had a linear response. Fiber placement and experiment design was optimized using cadaver animals with live animal measurements acquired to …

Macroscopic Optical Imaging Technique For Wide-Field Estimation Of Fluorescence Depth In Optically Turbid Media For Application In Brain Tumor Surgical Guidance, Kolbein K. Kolste, Stephen C. Kanick, Pablo A. Valdés, Michael Jermyn, Brian C. Wilson, David W. Roberts, Keith D. Paulsen, Frederic Leblond

Dartmouth Scholarship

A diffuse imaging method is presented that enables wide-field estimation of the depth of fluorescent molecular markers in turbid media by quantifying the deformation of the detected fluorescence spectra due to the wavelength-dependent light attenuation by overlying tissue. This is achieved by measuring the ratio of the fluorescence at two wavelengths in combination with normalization techniques based on diffuse reflectance measurements to evaluate tissue attenuation variations for different depths. It is demonstrated that fluorescence topography can be achieved up to a 5 mm depth using a near-infrared dye with millimeter depth accuracy in turbid media having optical properties representative of …

Quantitative Spatial Frequency Fluorescence Imaging In The Sub-Diffusive Domain For Image-Guided Glioma Resection, Mira Sibai, Israel Veilleux, Jonathan T. Elliott, Frederic Leblond, Brian Wilson

Dartmouth Scholarship

Intraoperative 5- aminolevulinic acid induced-Protoporphyrin IX (PpIX) fluorescence guidance enables maximum safe resection of glioblastomas by providing surgeons with real-time tumor optical contrast. However, visual assessment of PpIX fluorescence is subjective and limited by the distorting effects of light attenuation and tissue autofluorescence. We have previously shown that non-invasive point measurements of absolute PpIX concentration identifies residual tumor that is otherwise non-detectable. Here, we extend this approach to wide-field quantitative fluorescence imaging by implementing spatial frequency domain imaging to recover tissue optical properties across the field-of-view in phantoms and ex vivo tissue.

Hybrid Photomultiplier Tube And Photodiode Parallel Detection Array For Wideband Optical Spectroscopy Of The Breast Guided By Magnetic Resonance Imaging, Fadi El-Ghussein, Michael A. Mastanduno, Shudong Jiang, Brian W. Pogue, Keith D. Paulsen

Dartmouth Scholarship

A new optical parallel detection system of hybrid frequency and continuous-wave domains was developed to improve the data quality and accuracy in recovery of all breast optical properties. This new system was deployed in a previously existing system for magnetic resonance imaging (MRI)-guided spectroscopy, and allows incorporation of additional near-infrared wavelengths beyond 850 nm, with interlaced channels of photomultiplier tubes (PMTs) and silicon photodiodes (PDs). The acquisition time for obtaining frequency-domain data at six wavelengths (660, 735, 785, 808, 826, and 849 nm) and continuous-wave data at three wavelengths (903, 912, and 948 nm) is 12 min. The dynamic ranges …

Sensitivity Of Mri-Guided Near-Infrared Spectroscopy Clinical Breast Exam Data And Its Impact On Diagnostic Performance, Michael A. Mastanduno, Junqing Xu, Fadi El-Ghussein, Shudong Jiang, Hong Yin, Yan Zhao, Kelly E. Michaelson, Ke Wang, Fang Ren, Brian W. Pogue, Keith D. Paulsen

Dartmouth Scholarship

In this study, data from breast MRI-guided near infrared spectroscopy (NIRS) exams delivered to 44 patients scheduled for surgical resection (ending in 16 benign and 28 malignant diagnoses) were analyzed using a spatial sensitivity metric to quantify the adequacy of the optical measurements for interrogating the tumor region of interest, as derived from the concurrent MRI scan. Along with positional sensitivity, the incorporation of spectral priors and the selection of an appropriate regularization parameter in the image reconstruction were considered, and found to influence the diagnostic accuracy of the recovered images. Once optimized, the MRI/NIRS data was able to differentiate …

Structured Light Scatteroscopy, Venkataramanan Krishnaswamy, Jonathan T. Elliott, David M. Mcclatchy, Richard J. Barth Jr., Wendy A. Wells, Brian W. Pogue, Keith D. Paulsen

Dartmouth Scholarship

A new imaging approach, structured light scatteroscopy (SLS), is demonstrated, which offers rapid wide-field imaging of microscopic morphological variations in bulk tissue surfaces. Elastic scattering of light offers exquisite sensitivity to ultrastructural changes at multiple size scales ranging from nanometers to millimeters, but in bulk tissues the confounding effects of molecular absorption and strong multiple scattering of light often lead to a dramatic reduction in scatter contrast and specificity. It is demonstrated that the SLS using structured high spatial frequency illumination and detection to probe the tissue achieves direct, absorption-independent, high-resolution maps of the scattering response. The scattering response is …

Comparison Of Magnetic Resonance Imaging-Compatible Optical Detectors For In-Magnet Tissue Spectroscopy: Photodiodes Versus Silicon Photomultipliers, Fadi El-Ghussein, Shudong Jiang, Brian W. Pogue, Keith D. Paulsen, Brian W. Pogue

Dartmouth Scholarship

Tissue spectroscopy inside the magnetic resonance imaging (MRI) system adds a significant value by measuring fast vascular hemoglobin responses or completing spectroscopic identification of diagnostically relevant molecules. Advances in this type of spectroscopy instrumentation have largely focused on fiber coupling into and out of the MRI; however, nonmagnetic detectors can now be placed inside the scanner with signal amplification performed remotely to the high field environment for optimized light detection. In this study, the two possible detector options, such as silicon photodiodes (PD) and silicon photomultipliers (SiPM), were systematically examined for dynamic range and wavelength performance. Results show that PDs …

Dual-Channel Red/Blue Fluorescence Dosimetry With Broadband Reflectance Spectroscopic Correction Measures Protoporphyrin Ix Production During Photodynamic Therapy Of Actinic Keratosis, Stephen Chad Kanick, Scott C. Davis, Yan Zhao, Tayyaba Hasan, Edward V. Maytin, Brian W. Pogue, M Shane Chapman

Dartmouth Scholarship

Dosimetry for aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) photodynamic therapy of actinic keratosis was examined with an optimized fluorescence dosimeter to measure PpIX during treatment. While insufficient PpIX generation may be an indicator of incomplete response, there exists no standardized method to quantitate PpIX production at depths in the skin during clinical treatments. In this study, a spectrometer-based point probe dosimeter system was used to sample PpIX fluorescence from superficial (blue wavelength excitation) and deeper (red wavelength excitation) tissue layers. Broadband white light spectroscopy (WLS) was used to monitor aspects of vascular physiology and inform a correction of fluorescence for …

Extraction Of Intrinsic Fluorescence From Single Fiber Fluorescence Measurements On A Turbid Medium: Experimental Validation, U. A. Gamm, C. L. Hoy, F. Van Leeuwen - Van Zaane, H. J. C. M. Sterenborg, S. C. Kanick, D J. Robinson, A. Amelink

Dartmouth Scholarship

Abstract

The detailed mechanisms associated with the influence of scattering and absorption properties on the fluorescence intensity sampled by a single optical fiber have recently been elucidated based on Monte Carlo simulated data. Here we develop an experimental single fiber fluorescence (SFF) spectroscopy setup and validate the Monte Carlo data and semi-empirical model equation that describes the SFF signal as a function of scattering. We present a calibration procedure that corrects the SFF signal for all system-related, wavelength dependent transmission efficiencies to yield an absolute value of intrinsic fluorescence. The validity of the Monte Carlo data and semi-empirical model is …

Anthropomorphic Breast Phantoms With Physiological Water, Lipid, And Hemoglobin Content For Near-Infrared Spectral Tomography, Kelly E. Michaelsen, Venkataramanan Krishnaswamy, Adele Shenoy, Emily Jordan, Brian W. Pogue, Keith D. Paulsen

Dartmouth Scholarship

Breast mimicking tissue optical phantoms with sufficient structural integrity to be deployed as stand-alone imaging targets are developed and successfully constructed with biologically relevant concentrations of water, lipid, and blood. The results show excellent material homogeneity and reproducibility with inter- and intraphantom variability of 3.5 and 3.8%, respectively, for water and lipid concentrations ranging from 15 to 85%. The phantoms were long-lasting and exhibited water and lipid fractions that were consistent to within 5% of their original content when measured 2 weeks after creation. A breast-shaped three-compartment model of adipose, fibroglandular, and malignant tissues was created with water content ranging …

Advances In Optics For Biotechnology, Medicine And Surgery, Maryann Fitzmaurice, Brian W. Pogue, Guillermo J. Tearney, James W. Tunnell

Dartmouth Scholarship

The guest editors introduce a Biomedical Optics Express feature issue that includes contributions from participants at the 2013 conference on Advances in Optics for Biotechnology, Medicine and Surgery XIII.

An Imaging-Based Platform For High-Content, Quantitative Evaluation Of Therapeutic Response In 3d Tumour Models, Jonathan P. Celli, Imran Rizvi, Adam R. Blanden, Iqbal Massodi, Iqbal Massodi, Michael D. Glidden, Brian Pogue, Tayyaba Hasan

Dartmouth Scholarship

While it is increasingly recognized that three-dimensional (3D) cell culture models recapitulate drug responses of human cancers with more fidelity than monolayer cultures, a lack of quantitative analysis methods limit their implementation for reliable and routine assessment of emerging therapies. Here, we introduce an approach based on computational analysis of fluorescence image data to provide high-content readouts of dose-dependent cytotoxicity, growth inhibition, treatment-induced architectural changes and size-dependent response in 3D tumour models. We demonstrate this approach in adherent 3D ovarian and pancreatic multiwell extracellular matrix tumour overlays subjected to a panel of clinically relevant cytotoxic modalities and appropriately designed controls …

Spatial Frequency Analysis Of Anisotropic Drug Transport In Tumor Samples, Stewart Russell, Kimberley S. Samkoe, Jason R. Gunn, P Jack Hoopes, Thienan A. Nguyen, Milo J. Russell, Robert R. Alfano, Brian W. Pogue

Dartmouth Scholarship

Directional Fourier spatial frequency analysis was used on standard histological sections to identify salient directional bias in the spatial frequencies of stromal and epithelial patterns within tumor tissue. This directional bias is shown to be correlated to the pathway of reduced fluorescent tracer transport. Optical images of tumor specimens contain a complex distribution of randomly oriented aperiodic features used for neoplastic grading that varies with tumor type, size, and morphology. The internal organization of these patterns in frequency space is shown to provide a precise fingerprint of the extracellular matrix complexity, which is well known to be related to the …

Contrast Enhanced-Magnetic Resonance Imaging As A Surrogate To Map Verteporfin Delivery In Photodynamic Therapy, Kimberley S. Samkoe, Amber Bryant, Jason R. Gunn, Stephen P. Pereira, Tayyaba Hasan, Brian W. Pogue

Dartmouth Scholarship

The use of in vivo contrast-enhanced magnetic resonance (MR) imaging as a surrogate for photosensitizer (verteporfin) dosimetry in photodynamic therapy of pancreas cancer is demonstrated by correlating MR contrast uptake to ex vivo fluorescence images on excised tissue. An orthotopic pancreatic xenograft mouse model was used for the study. A strong correlation ([i]r=0.57 ) was found for bulk intensity measurements of T1-weighted gadolinium enhancement and verteporfin fluorescence in the tumor region of interest. The use of contrast-enhanced MR imaging shows promise as a method for treatment planning and photosensitizer dosimetry in human photodynamic therapy (PDT) of pancreas …