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PhD Thesis Proposal: Allaire Doussan



1:00pm - 2:00pm ET

DHMC Auditorium G/Online

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"An active electrode electrical impedance tomography probe for intraoperative surgical margin assessment in robotic-assisted radical prostatectomies"

Prostate cancer is the most common cancer among men and is the second most common cancer overall in the United States (US). In 2023, there were 288,300 new diagnoses of prostate cancer in the US and 1.4 million new cases globally. Of these patients, 40.5% are expected to undergo radical prostatectomy (RP). The primary goal of an RP is to remove the entire tumor and avoid positive surgical margins (PSM). However, there is a delicate balance between removing excess tissue to ensure wide margins for cancer eradication, sparing neurovascular tissue, and maintaining maximal urethral length to preserve erectile function and continence. This dichotomy leads to an incidence of PSMs in RP that varies from surgeon to surgeon, but overall rates have been reported to fall between 4% and 48% (average 21%). Patients with PSMs have a much higher rate of recurrence than patients with negative surgical margins and are often exposed to noxious adjuvant therapies to eradicate the remaining cancer. Not only are these treatments costly, they also typically have adverse morbidities that decrease the patient's quality of life. Currently, there is no widely accepted method to assess intraoperative margin status in real time.

Previous research has shown that the electrical impedance is sensitive to the cellular architecture and has successfully been used to distinguish between malignant and benign tissues in ex vivo prostate specimens. To this end, we have designed and characterized an active electrode based electrical impedance tomography (EIT) probe to identify PSMs intraoperatively. The probe was designed to interface with the Da Vinci surgical robotic system (Intuitive Surgical, Sunnyvale. CA). Proposed work includes finishing hardware development of the active electrode analog front end (AFE), interfacing the AFE with an EIT system to control it, and incorporating all the components into a laparoscopic compatible housing (≤12 mm diameter). Additional clinical validation includes continuing collection of ex vivo prostate data (currently N=23) to compare impedance data with histology along with starting to collect initial in vivo data with a simplified version of the probe.

Thesis Committee

  • Ryan Halter (Chair)
  • Ethan Murphy (Co-chair)
  • Kofi Odame
  • Lawrence Dagrosa
  • Gary Saulnier (University at Albany)


For more information, contact Julia Abraham at julia.s.abraham@dartmouth.edu.