Keith D. Paulsen

Research Interests

Biomedical engineering; numerical methods in electromagnetics; cancer therapeutics; medical imaging methodologies; bioelectromagnetics

Education

• BSc, Biomedical Engineering, Duke University 1981
• MS, Engineering Sciences, Dartmouth College 1984
• PhD, Engineering Sciences, Dartmouth College 1986

Awards

• Fellow of OSA
• Fellow of SPIE
• Fellow of AIMBE
• Fellow of IEEE
• Fellow of NAI
  

Startups

Research Projects

• Image-based registration and intraoperative updating for guiding spine surgery

  Image-based registration and intraoperative updating for guiding spine surgery

  This project develops and evaluates image-based registration methods involving stereovision for registration and image updating during open spine surgeries for degenerative spondylolisthesis.

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• Preoperative image updating for guidance during brain tumor resection

  Preoperative image updating for guidance during brain tumor resection

  The goal of this project is to optimize and validate, in human and animal studies, intraoperative image updating methods that assimilate intraoperative data acquired with stereovision and ultrasound with computational modeling to update preoperative MRI in order to maintain image registration accuracy throughout surgery.

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• Quantitative scatter imaging

  Quantitative scatter imaging

  Quantitative scatter imaging makes use of the fact that normal functioning cells and cancerous cells show differences both in the components within the cells and in the structural organization of the cells within the tissue. These physical distinctions in biological structure have been shown to scatter light differently. This study develops a new approach to imaging scatter-based contrast over a wide field of view in tissue using high frequency structured light. These scattering features may provide a method to diagnostically identify abnormal tissue without the need to administer targeted compounds. This approach has the potential to generate new diagnostic screenings and new approaches for surgical guidance.

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• Image-guided neurosurgery

  Image-guided neurosurgery

  Image-guided neurosurgery gives the surgeon the ability to track instruments in reference to subsurface anatomical structures. Using clinical brain displacement data, a computational technique is being developed to model the brain deformation that typically occurs during neurosurgery. The resulting deformation predictions are then used to update the patient's preoperative magnetic resonance images seen by the surgeon during the procedure.

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• Non-linear image reconstruction techniques

  Non-linear image reconstruction techniques

  Non-linear image reconstruction techniques is at the core of the medical imaging projects. Excitation-induced measurements from each instrument are compared with calculations from corresponding numerical models to compute updated property images of the biological target. As the images are progressively updated (or refined) in a non-linear iterative process, important features and functional information related to the objects physiological status—tumor, benign tissue, etc.—become more apparent. The computational core of the breast imaging project works synergistically with all four groups to improve our fundamental understanding of these mathematical systems to improve overall image quality and resolution. These processes have been developed for both 2D and 3D geometries in each modality and are being expanded to exploit emerging parallel computing capabilities.

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• Fluorescence-guided surgery

  Fluorescence-guided surgery

  Fluorescence-guided surgery is important for the resection of some types of cancerous tumors where the tumor and normal tissue are similar in appearance and texture, and patient prognosis depends heavily on the completeness of resection. By selectively tagging tumor tissue with fluorescent dyes, it becomes possible to visually discriminate between normal and tumor tissues and improve significantly the completeness of tumor resection.

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• Therapy monitoring

  Therapy monitoring

  Therapy monitoring is an important emerging application of imaging modalities. These and other current research topics include:

  • near-infrared imaging of brain tissue;
  • near-infrared spectroscopy for diagnosing peripheral vascular disease;
  • electrical impedance spectroscopy for radiation therapy monitoring;
  • magnetic resonance elastography for detecting brain or prostate lesions; to follow the progression of diabetic damage in the foot; and to answer basic questions of wave propagation in tissue;
  • microwave imaging spectroscopy for hyperthermia therapy monitoring, brain imaging, and detection of early-stage osteoporosis;
  • electrical impedance tomography for monitoring traumatic brain injury progression and therapy.

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• Optical molecular imaging

  Optical molecular imaging

  Optical molecular imaging is being used to provide molecular guidance in cancer surgery. Fluorescent contrast agents are in pre-clinical and clinical studies to image cancer tumors in vivo, with a dual focus, first on getting more accurate information out of the tissue, and secondly to provide better information about the specificity of the molecules as markers. Systems and algorithms for diffuse fluorescence imaging of tissue are studied, both as a stand-alone system, and as coupled to magnetic resonance imaging and computed tomography imaging. Tracer kinetic modeling is also being developed to allow quantitative imaging of molecular binding in vivo.

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• Microwave imaging spectroscopy

  Microwave imaging spectroscopy

  Microwave imaging spectroscopy (also commonly referred to as microwave computed tomography) presents the challenge of measuring the signal data necessary to produce meaningful images. Development of site-specific antenna arrays along with improved electronic signal detection technology is rapidly making this measurement feasible for breast cancer detection. A second-generation tomographic breast imaging system has been completed and the data are being used to recover permittivity and conductivity maps of the breast for evaluation by a clinician.

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• Magnetic resonance elastography

  Magnetic resonance elastography

  Magnetic resonance elastography is being developed as a technique to measure the elasticity of tissue in vivo by gently shaking the tissue in a magnetic resonance imager. The displacements measured are used to determine tissue mechanical properties which can help identify and classify breast lesions. See also Discovering at Thayer School.

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• Near-infrared imaging

  Near-infrared imaging

  Near-infrared imaging (NIR) provides a way to quantify blood and water concentrations in tissue, as well as structural and functional parameters. Since normal tissue, benign tumors, and malignant tumors each carry different concentrations of both hemoglobin and water, and have different levels of oxygen demand and ultrastructural scattering, NIR spectroscopy can be combined into standard imaging systems as an effective method of to provide additional information for breast cancer detection and diagnosis. Work is ongoing to improve techniques for better image reconstruction, display and integration with magnetic resonance imaging (MRI) and computed tomography (CT) imaging.

  See also Center for Imaging Medicine

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Courses

• ENGS 205: Computational Methods for Partial Differential Equations II
• ENGG 325: Introduction to Surgical Innovation
• ENGS 105: Computational Methods for Partial Differential Equations I
• ENGM 189.1: Medical Device Commercialization (.5 credit)
• ENGM 189.2: Medical Device Development (.5 credit)
• ENGG 189.1: Medical Device Commercialization (.5 credit)
• ENGG 189.2: Medical Device Development (.5 credit)

Books

"Estimation of intraoperative brain deformation" in Studies in Mechanobiology, Tissue Engineering and Biomaterials Book 11

Springer, 2012

"Brain Shift Compensation via Intraoperative Imaging and Data Assimilation" in Handbook of Imaging in Biological Mechanics

CRC Press, 2015

Alternative Breast Imaging: Four Model-Based Approaches

Springer, 2004

Videos

News

Dartmouth SYNERGY Wins $28 Million in NIH Funding
Aug 27, 2024

Dartmouth Engineering Leads Team Selected for ARPA-H Award to Develop Novel Technologies for Precise Tumor Removal
Aug 13, 2024

Dartmouth Researchers File Patent for Device to Advance Breast Cancer Detection and Monitoring
May 10, 2023

Kudos: Team Effort
Jul 01, 2022

Dartmouth Startup's Invention Wins NH Product of the Year
Oct 28, 2021

Lab Report: Clearer Cancer Imaging
Aug 01, 2020

$3 Million Grant May Result in Fewer Unnecessary Breast Biopsies
Mar 06, 2020

Paulsen Elected to National Academy of Inventors
Dec 03, 2019

Dartmouth Engineering Professor Elected Senior Member of the National Academy of Inventors
Feb 11, 2019

New Imaging System Makes Back Surgery Safer, Faster and Less Expensive
Apr 25, 2018

Dartmouth Is Helping Brain Surgeons See Tumors More Clearly
Mar 06, 2017

Dartmouth Wins FDA Approval for Aid to Guide Cancer Surgery
Oct 11, 2016

Food Dye, Near Infrared Light Can Aid in Breast Resection
May 12, 2015

The Center for Surgical Innovation at Dartmouth-Hitchcock
Dec 01, 2014

Dartmouth Team Receives Best Paper Award for Breast Imaging Research
Sep 09, 2014

MRI and Optical Scanning During Surgery Accurately Locate Small Breast Cancer Tumors
Apr 02, 2014

DHMC inaugurates unique intraoperative MRI and CT suite
Mar 19, 2014

Researchers Developing New Approach for Imaging Dense Breasts for Abnormalities
Jan 26, 2014

Dartmouth Engineering Professor Elected SPIE Fellow
Jan 07, 2013

What is the Future of Microwave Technology in Diagnostic Imaging?
Dec 11, 2012

Dartmouth Discovery: Journals
Sep 19, 2012

New Probe Provides Vital Assist in Brain Cancer Surgery
Jul 25, 2012

Research Reveals a More Complete Picture of Breast Tissue
Mar 06, 2011

Alternative / supplemental breast imaging methods tested
Mar 06, 2011

Dartmouth's alternative breast imaging techniques sort abnormal from normal tissue
Mar 06, 2011

NCI Awards $12.8 Million to Dartmouth Center of Cancer Nanotechnology Excellence
Mar 06, 2011

Dartmouth researchers test new technique to examine breast tissue
Mar 06, 2011

Paulsen awarded Pritzker Chair
Mar 04, 2011

In the News