Alexandra Rink
PhD, University of Toronto
At a Glance
- Brachytherapy treatment quality is a complex metric, dependent on many factors
- Factors affecting delivered dose range from accuracy of implant and target delineation, to organ motion, filling and displacement during treatment
- Understanding and accounting for these factors are critical in delivering high quality care
- Feedback mechanism with in-vivo dosimetry is a critical component in measuring impact of these uncertainties on dose delivered
Short Bio
Dr. Alexandra Rink is a board certified Medical Physicist at Princess Margaret Cancer Centre, an Associate Professor in the Departments of Radiation Oncology and Medical Biophysics, University of Toronto and a Clinician Scientist at the Princess Margaret Research Institute. She received her B.Sc. degree with honours in Chemical Physics from the College of Physical & Engineering Science at University of Guelph in 2003, and thereafter pursued a PhD in the Department of Medical Biophysics, University of Toronto. Her thesis, supported by the National Cancer Institute of Canada through a Terry Fox Foundation Research Studentship Award, focused on using polymer materials and optical fibre read-out in order to measure radiation dose remotely during the application of radiotherapy. Upon completion of graduate studies in 2008, Dr. Rink had commenced a Medical Physics Residency program at Princess Margaret Cancer Centre with the Department of Radiation Oncology. In 2010, Dr. Rink joined the Image-Guided Interventional Radiotherapeutics for Prostate Cancer group as a Clinical Physics Fellow and in 2012 the Radiation Physics department as staff. She has been leading the brachytherapy physics group at the Princess Margaret Cancer Centre since 2013, helping implement image-guided interstitial treatments for gynaecological and prostate cancers. Dr. Rink has started her own lab in 2019, with research interest in quality improvement of brachytherapy through dosimetric measurements using in-vivo optical fibre technology, understanding and monitoring organ motion and filling, target and applicator uncertainty and the impact on dose distribution, and implant accuracy and efficiency.
Research Synopsis
In Vivo Dosimetry
Radiotherapy treatments have become very sophisticated due to advances in technology and the increased complexity of the processes themselves. A robust, real-time in vivo radiation dosimeter is an important safety system for catching errors that cannot be detected by human vigilance and other quality assurance and quality control methods. My research involves investigation of various materials for use with fibre-optical readout for real-time patient dosimetry, as well as probe and system design. An important component of this work is the ability to implement the dosimetric device on patients and accurately predict real-time dose from a linear accelerator or remote brachytherapy afterloader in order to create a quality control tool. Immediate treatment interruption upon the detection of a threshold error is critical to avoid potential health consequences, and can only be achieved with real-time data feedback and comparison against the expected. Additionally, implementing a large-scale patient dosimetry program would provide the radiotherapy community with the statistics on treatment delivery deviations, including those not resulting in severe complications.
Improvement in Brachytherapy Patient Care
The paradigm of radiotherapy delivery is scan, plan and treat. The quality of treatment depends on the applicability of the scan to the time of treatment. While in external beam radiotherapy the standard practice is to account for planning and treatment uncertainties, this is rare in high dose-rate brachytherapy. Oedema from implant and organ filling and motion are just few of the factors that can contribute to a deviation from intended dose distribution. Understanding these factors and finding methods to account for these uncertainties, for example through implementation of planning margins or by following an organ filling protocol, can help improve quality of patients’ brachytherapy treatment. Non-dosimetric factors, such as the time it takes between patient scan and treatment, or the number of treatment catheters used in brachytherapy, also play an important part in the quality of patients’ brachytherapy treatment. My research explores methods to improve these factors, including image guidance and navigation for interstitial catheter positioning. Other opportunities include assisted contouring of targets and organs. My goal is to minimize patient’s time from scan to treatment and ensure interventions performed are necessary for optimal dose delivery.