10/20/2025
By Toni Roth

The College of Sciences, Department of Graduate Studies, invites you to attend a Doctoral Dissertation defense by Toni M. Roth titled “Physician Simulator as a Teaching Module for Rectal Spacer Insertions."

Defense Date: Wednesday, Oct. 22
Time: 2 - 4 p.m.
Location: This will be a virtual defense on Zoom (link upon request)

Advisors:

  • Angélica Pérez-Andújar, Ph.D., Department of Medical Physics, Memorial Sloan Kettering Cancer Center
  • Erno Sajo, Ph.D., Department of Physics and Applied Physics, University of Massachusetts Lowell

Committee Members:

  • Romy Guthier, Ph.D., Department of Physics and Applied Physics, University of Massachusetts Lowell
  • Lynne Gauthier, Ph.D., Department of Physical Therapy and Kinesiology, University of Massachusetts Lowell
  • Antonio Damato, Ph.D., Department of Medical Physics, Memorial Sloan Kettering Cancer Center
  • Ashley Cetnar, Ph.D., Department of Radiation Oncology, The Ohio State University - James Cancer Hospital
  • Matthew Belley, Ph.D., Evolv Technology
  • Gil'ad Cohen, M.S., Department of Radiation Oncology, NYU Grossman School of Medicine

Abstract:
Rectal spacer insertion is an interventional procedure whereby a hydrogel is placed between the prostate and rectum in a region called Denonvilliers’ fascia. The procedure occurs prior to external beam radiotherapy or brachytherapy treatments of the prostate and can be performed in either the outpatient clinic or hospital setting by Radiation Oncologists or Urologists under transrectal ultrasound (TRUS) guidance. The aim of the rectal spacer insertions is to provide additional displacement between the prostate and rectum allowing for both dose escalation to the prostate and a dose reduction to the rectum. This simultaneous dose escalation to the prostate and dosimetric reduction to the rectum, generally considered the dose-limiting structure, allows for improved clinical outcomes with reduced rectal and gastrointestinal toxicity as shown in the prospective randomized clinical trial by Hamstra Da, et al. However, the dosimetric sparing of the rectum is dependent on appropriate spacer insertion and vendor training is not focused on the quality of the insertion. There is a need for physician training to expedite the time to competency and provide feedback that both measures and trends rectal insertion quality. In this three-volume dissertation, a gaming experience (simulator) is designed to train and teach the physician how to perform a successful rectal spacer insertion using a hepatically realistic and patient-specific phantom.