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Ryan Halter headshot

Ryan Halter

Associate Professor of Engineering

Adjunct Associate Professor of Surgery, Geisel School of Medicine

Education

  • BSc Engineering Science and Mechanics, Pennsylvania State University (1999)
  • MSc Engineering Mechanics, Pennsylvania State University (2001)
  • PhD Biomedical Engineering, Dartmouth College (2006)

Research Interests

Biomedical instrumentation; electrical impedance tomography and spectroscopy; medical imaging; tissue bioimpedance; cancer detection technologies; traumatic brain injury; medical robotics

Selected Publications

  • Halter RJ, Schned AR, Heaney JA, Hartov A, Paulsen KD, "Electrical properties of prostatic tissues: I. single frequency admittivity properties," Journal of Urology, 182:1600-1607, 2009.
  • Halter RJ, Schned AR, Heaney JA, Hartov A, Paulsen KD, "Electrical properties of prostatic tissues: II. Spectral admittivity properties," Journal of Urology, 182:1608-1613, 2009.
  • Halter RJ, Zhou T, Meaney PM, Hartov A, Barth, Jr RJ, Rosenkranz KM, Wells WA, Kogel CA, Borsic A, Rizzo EJ, Paulsen KD "Correlation of in vivo and ex vivo tissue dielectric properties to validate electromagnetic breast imaging: initial clinical experience," Physiological Measurement, 30:S121-S136, 2009.
  • Halter RJ, Hartov A, Paulsen KD, "Video Rate Electrical Impedance Tomography of Vascular Changes: Preclinical Development," Physiological Measurement, 29(3):349-364, 2008.
  • Halter RJ, Hartov A, Paulsen KD, "A broadband high frequency electrical impedance tomography system for breast imaging," IEEE Transactions on Biomedical Engineering, 55(2):650-659, 2008.

Awards

  • Prostate Cancer Research Training Grant: DoD CDMRP (2006-2008)
  • Loan Repayment Program for Clinical Research: NIH (2007-2012)
  • New Investigator Award in Prostate Cancer Research: DoD CDMRP (2009-2012)
  • RC1 Challenge Grant: NIH/NIBIB (2009-2011)
  • R21 Exploratory/Developmental Research Grant: NIH/NIBIB (2010-2012)
  • Research Robotic Fellowship: Intuitive Surgical, Inc (2009-2011)

Professional Activities

  • Member, Institue of Electrical & Electronic Engineers (IEEE)
  • Member, International Society for Electrical Bio-Impedance (ISEBI)
  • Member, Dartmouth's Committee for the Protection of Human Subjects (CPHS)

Courses

  • ENGS 169: Intermediate Biomedical Engineering
  • ENGS 76: Machine Engineering
  • ENGS 57: Intermediate Biomedical Engineering
  • ENGM 189.1: Medical Device Commercialization (.5 credit)

Patents

  • System and method of laryngoscopy surgery and imaging | 10,582,836
  • Systems and methods for cardiovascular-dynamics correlated imaging | 10,575,792
  • Surgical vision augmentation system | 10,568,522
  • System, method and device for monitoring the condition of an internal organ | 8,764,672

Startups

SynchroHealth
Co-Founder

Research Projects

  • Electrical bioimpedance

    Electrical bioimpedance

    Electrical bioimpedance measurements of tissue provide significant levels of contrast between benign and malignant pathologies due to the vastly different morphologies occurring between tissue types. Focal sensing or mapping of these properties can provide clinicians useful information regarding the extent and severity of diseases like cancer. Our group is currently developing technologies to couple bioimpedance sensors to clinical devices including: 1) intraoperative instruments for use in assessing surgical margins during tumor resection; and 2) standard biopsy needles for use in providing real-time pathological assessment of tissue.

  • Electrical impedance imaging for breast cancer screening

    Electrical impedance imaging for breast cancer screening

    Electrical impedance imaging for breast cancer screening is the process of imaging the electrical property (conductivity and permitivity) of tissue using electrodes located on the body surface. This project is one branch of the larger effort to develop innovative technologies for breast cancer detection.

  • Electrical impedance imaging for prostate cancer screening

    Electrical impedance imaging for prostate cancer screening

    Electrical impedance imaging for prostate cancer screening is the process of imaging non-invasively the electrical properties (conductivity and permittivity) of the prostate and its vicinity using electrodes mounted onto an intracavitary probe.

  • Combined ultrasound and electrical impedance tomography (EIT)

    Combined ultrasound and electrical impedance tomography (EIT)

    Combined ultrasound and electrical impedance tomography (EIT) puts 3-D ultrasound imaging together with EIT data in a co-registered volume. EIT relies on the mathematical processing of impedance data collected non-invasively from patients to reconstruct the 3-D distribution of the electrical properties of the tissues inside the patient. Combining ultrasound and EIT has the potential to greatly improve the quality and spatial resolution of the reconstructed electrical properties.

  • 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.
  • Enabling technologies for effective image-guided surgical navigation in trans-oral cancer surgery

    Enabling technologies for effective image-guided surgical navigation in trans-oral cancer surgery

    Throat cancers have been increasing in incidence worldwide. Despite advances in surgical and non-surgical management of these cancers, treatment continues to be associated with significant functional and cosmetic morbidity. More minimally invasive trans-oral surgical (TOS) approaches have reduced treatment morbidity and complications. However, one drawback of TOS is the difficulty in intraoperatively assessing tumor extent and locating major vascular structures. Surgical navigation with image guidance has shown improved safety and efficacy with other surgical procedures; however it is currently not feasible in TOS due to the soft tissue and airway deformation that occurs with placement of instruments needed to access the throat, thus rendering preoperative scans unusable in the intraoperative setting.

    The overarching objective of our research is to develop enabling technologies that allow for surgical navigation with image guidance for TOS. Our research strategy is to acquire intraoperative imaging during TOS in order to develop models of upper aerodigestive tract deformation that reflect the intraoperative state. This, in turn, would allow for registration of preoperative images to the intraoperative state. We are well equipped to solve this problem due to the unique intraoperative CT and MR imaging resources available at the Dartmouth Center for Surgical Innovation. We have successfully developed a 3D printable polymer laryngoscopy system which, unlike standard metal laryngoscopes, is CT and MRI compatible. We have also acquired preliminary intraoperative imaging data during laryngoscopy procedures. The next steps in this research will be to further quantify and characterize tissue deformation that occurs during TOS and ultimately develop a surgical navigation platform for trans-oral procedures.

  • Combined whole breast ultrasound and electrical impedance tomography

    Combined whole breast ultrasound and electrical impedance tomography

    Ultrasound is a supplemental screening technique that has good sensitivity in dense breasts, is inexpensive, and is widely available, but unfortunately, it has high rates of false positives. Electrical impedance tomography (EIT) is a second attractive modality that is low-cost and has shown promise for cancer detection and in differentiating fibrocystic tissues from other tissues. Combining automated whole breast ultrasound (ABUS), which is a recent improvement to standard ultrasound, with EIT may significantly reduce the number of false positives of ABUS. If successful, the combined ABUS/EIT system could become an important screening technology for women with dense breasts.

  • Electrical impedance tomography in pulmonary and cardiac applications

    Electrical impedance tomography in pulmonary and cardiac applications

    The most common application, so far, of electrical impedance tomography (EIT) has been pulmonary monitoring of patients. In particular, we have been pursuing EIT for cardiac output monitoring (a related application) and EIT as a surrogate for pulmonary function tests.

Videos

Seminar: Smart Devices and Systems for Surgical Guidance

Seminar: Surgical Enhancement: Using Electrical Bioimpedance to Improve Clinical Practice

Profile: Professor Ryan Halter

News

All Together Now
Apr 07, 2011