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  • Benjamin Côté

    Project Title: Arrow: A probe-format graphite calorimeter for absolute dosimetry of high-energy small fields photon beams .

  • Cédric Bélanger

    Project Title: Optimisation et reconstruction de trajectoires non-parallèles d’aiguilles ou de
    cathéters pour procédures thérapeutiques avec guidage robotique .

  • Christopher Lund

    Project Title: Investigation of neutron-induced DNA damage using track structure simulations .

  • Danahé LeBlanc

    Project Title: To be added

  • David Santiago Ayala Alvarez

    Project Title: Dosimetric studies on the INTRABEAM electronic brachytherapy source .

  • Faiçal Alaoui Abdalaoui Slimani

    Project Title: Méthodes d’apprentissage statistique pour la segmentation des images tomodensitométriques .

  • Felix Mathew

    Project Title: To Be Added

  • Gabriel Couture

    Project Title: Analyse de la dynamique du taux de l’antigene prostatique spécifique en contexte post-traitement en curiethérapie

  • Joseph DeCunha

    Project Title: Computation of microdosimetric energy distributions to heterogeneous compartment sizes .

  • Julien Bancheri

    Project Title: To Be Added

  • Julien Mégrourèche

    Project Title: Microcavity-enhanced hydrated electron dosimeter: A miniature in-vivo radiation detector.

  • Li Ming Tony Wang

    Project Title: The development of a system for the quantification of pulmonary fibrosis progression via changes in CT densities

  • Liam Carol

    Project Title: Non-invasive positron detection to enable dynamic PET .

  • Marie Anne Lebel Cormier

    Project Title: Conception d’un dosimètre avec un capteur à réseaux de Bragg .

  • Reza Moosavi Askari

    Project Title: Therapeutic approaches.

  • Ximeng Mao

    Project Title: System and methods for fast radiation calculations .

    Marie Anne Lebel Cormier Abstract

    Les dosimètres à fibre optique offrent de nombreux avantages pour l’utilisation clinique. Leur taille leur procure l’avantage d’être peu invasif tout en étant flexible et en offrant une excellente résolution spatiale. Un dosimètre à fibre offre la possibilité de mesurer la radiation précisément en un point donnée ou en quelques points donnés, ce qui rend impossible la mesure d’un profil de dose pour une unique irradiation. Avec des plans de traitements de plus en plus complexes, cette mesure devient indispensable afin d’effectuer des contrôles de qualité. Un dosimètre à fibre optique permettant de mesurer un profil de dose s’avérerait donc être un outil remarquable. Les capteurs à réseau de Bragg sont tout indiqués pour cet usage. En effet, plusieurs réseaux de Bragg peuvent être fabriqués au sein d’une fibre optique afin de mesurer simultanément la radiation à différentes positions. Les capteurs à réseaux de Bragg s’avèrent être efficaces pour mesurer de hautes doses de radiation, mais leur comportement à faible dose a été peu étudié. En effet, la radiation génère des défauts dans la fibre optique composant le capteur, ce qui provoque un décalage de la longueur d’onde de Bragg. Pour des doses suffisamment importantes, ce décalage est mesurable. Le projet vise, dans un premier temps, à choisir un capteur à réseau de Bragg permettant une lecture de dose suffisamment faible pour être utilisé pour des traitements de radiothérapie. Dans un second temps, le projet vise à caractériser le dosimètre .

    Marie Anne Lebel Cormier Publications

    1) To Be Added .

    Danahé LeBlanc Abstract

    To be added .

    Danahé LeBlanc Publications

    1) To Be Added .

    Cedric Belanger Abstract

    Le projet consiste en la création d’un nouvel algorithme d’optimisation de planification de traitement en curiethérapie permettant des insertions non parallèles de cathéters et la validation de l’applicabilité d’une insertion de cathéters par guidage robotique sur des géométries similaires à celles rencontrées en clinique.

    Pour ce faire, l’algorithme de reconstruction 3D des trajectoires des cathéters dans le repère de l’anatomie d’un patient devra être implémenté pour des configurations arbitraires. Trois principales configurations particulières seront étudiées et validées. Par la suite, les résultats dosimétriques obtenus à partir des configurations non parallèles de cathéters seront comparés à des résultats dosimétriques de configurations parallèles standards de cathéters afin d’évaluer les bénéfices de cette nouvelle approche. Le volet expérimental du projet consistera à tester la reconstruction dynamique des cathéters lorsque ceux-ci sont insérés dans un fantôme à l’aide d’un robot de manière à simuler une planification de traitement guidée par robot.
    .

    Cédric Bélanger Publications

    To Be Added.

    Tony Wang Abstract

    Currently, the identification and quantification of pulmonary fibrosis, resulting from
    contemporary treatment modalities in lung radiotherapy, is largely dependent on physician
    apraisals and patient reports. As a result, pulmonary fibrosis, and it’s progression, are often
    poorly identified and, more importantly, poorly quantified. Using the analysis of clinical and
    diagnostic imaging we will attempt to extract lung image densities by quantifying, in HU, the
    changes in densities between the beginning of treatment and end of treatment. Then, using
    physician appraisals for imaged pulmonary fibrosis, we will attempt to correlate changes in
    densities with changes in reported severity of pulmonary fibrosis. Depending on he robustness of
    this proposed method, we may ultimately try to correlate density changes with changes in
    clinical presentation of pulmonary fibrosis as well as ultimately correlating density changes
    with known biomarkers, relating to pulmonary fibrosis, and cancer metastasis. Ultimately we hope
    to develop a better method of describing, characterizing and quantifying pulmonary fibrosis.

    Reza Moosavi Askari Abstract

    One of the therapeutic approaches that has attracted much of attention owing to its significant role in different types of widespread cancers, such as breast and prostate cancers, is brachytherapy. In that procedure, a high dose of radiation is applied to cancerous target tissue by positioning enclosed sources of radiations in the vicinity or inside of tumors without affecting the neighboring healthy tissues. Radionuclides such as 137Cs and 192Ir in the shape of seeds or wires are usually used as the brachytherapy sources. Precise knowledge of dose distribution around brachytherapy sources is essential to ameliorate the assessment of treatment quality and results. Achieving this goal has always been challenged by other effects such as
    the influence of tissue heterogeneity and interseed attenuation. Monte Carlo (MC) particle transport methods can be used to provide us with an accurate understanding of dose distribution encompassing brachytherapy sources. Nevertheless, another challenge stems from overlapping of the radiation sources with the patient geometry. To overcome that, we use an object-oriented MC simulation toolkit, called GEANT4, which simulates the passage of particles throughout the matter and enable us to generate parallel geometries in a single application.GEANT4 will equip us with the whole range of functionality such as geometry characterization, navigator classes, tracking, and physical interaction models for a great range of particles with energies from 250 eV up to the TeV .

    Reza Moosavi Askari Publications

    1) To Be Added

    Julien Mégrourèche Abstract

    Radiation treatments for cancer promise a targeted approach that treats tumours while avoiding irradiation of healthy tissue. Such treatment requires a careful calibration of the radiation dose, with excellent spatial resolution, using a measurement device (dosimeter) that ideally does not affect the path of the radiation. By exploiting optical microcavity technology originally developed to trap photons in quantum optics experiments, we propose to create a compact, highly sensitive, and fast dosimeter.
    The optical microcavity greatly enhances interactions between light and water, allowing measurement of the radiation-induced changes in water’s optical absorption in a microscopic volume. Moreover, the microcavity is located on the tip of an optical fiber, which means that the fundamental dimensions of the dosimeter are comparable to those of a human hair. This small size not only translates to good spatial resolution, but also facilitates in vivo measurements – that is, dosimetry conducted while the patient is actually receiving treatment. Constructed of materials that minimally impact the radiation path, and measuring radiation dose in a substance (water) very close to human tissue, the dosimeter will overcome limitations of current devices while allowing sub-millimeter spatial resolution .

    Julien Mégrourèche Publications

    To Be Added

    Julien Bancheri Abstract

    To Be Added

    Julien Bancheri Publications

    To Be Added

    Tony Wang Publications

    To Be Added

    Joseph DeCunha Abstract

    Biological factors alone cannot explain differences in radio sensitivity between various cancers. Some aspects of radio sensitivity are related to physical factors, namely the size of nuclei and cells. Microdosimetry is the branch of dosimetry concerning itself with an understanding of energy deposition events to volumes with sizes on the order of micrometers. The lineal energy (energy per mean chord length of a volume) delivered to a cell receiving the average dose is an important factor related to the biological effectiveness of a radiation beam to a given target. We determine accurate size distributions of cancerous and healthy cells and nuclei derived from pathology slides. Using cell size distributions, three dimensional models of patient tissue are developed. Distributions of energy deposited in individual cells and nuclei are then determined using a Monte Carlo dose calculation engine. Distributions of specific and lineal energy corresponding to a given pathology slide can then be determined. Microdosimetric energy distributions will be investigated for various brachytherapy sources (existing and proposed) .

    Joseph DeCunha Publications

    1. Joseph DeCunha†, S. A. Enger (2018) A new delivery system to resolve dosimetric issues in intravascular brachytherapy, Brachytherapy 17(3): 634-643. https://doi.org/10.1016/j.brachy.2018.01.012. Published online March 5, 2018.

    Faiçal Alaoui Abdalaoui Slimani Abstract

    Résumé : La segmentation d’image est une technique qui vise à classifier des pixels selon des critères préalablement définis. Il s’agit d’un problème difficile à résoudre pour lequel aucun algorithme de segmentation n’est conçu pour résoudre un problème spécifique.

    En plus, les approches actuellement utilisées pour l’extraction des informations à partir des images tomodensitométriques (TDM) reposent principalement sur les outils d’analyse d’images classiques, qui ne se prêtent pas à un traitement automatique rapide et fiable de plusieurs images.

    Dans le cadre de mon projet, on va définir un agent qui va apprendre d’une manière automatique à prendre des décisions à partir des différents descripteurs d’observations des images TDM. L’action de cet agent se traduit par une segmentation automatique des images pour aider le médecin dans sa prise de décision dans un diagnostic, le choix du traitement, la radiothérapie, etc.

    Faiçal Alaoui Abdalaoui Slimani Publications

    To Be Added

    Gabriel Couture Abstract

    Résumé : L’antigéne prostatique spécifique (APS), une protéine se retrouvant en petite quantité dans le sang, est un biomarqueur pour le cancer de la prostate. En radiothérapie , ce biomarqueur est échantillonne à intervalle régulier après le traitement pour surveiller l’ évolution de la maladie. Une décroissance de l’APS vers des valeurs faibles est généralement observée après le traitement , tandis qu’une remontée peut être annonciatrice d’une récidive.

    Le comportement des courbes d’évolution du taux d’APS est potentiellement porteur d’information prognostique. Il pourrait être envisageable, par exemple, de prévoir la récidive de la maladie à partir de la dynamique des courbes d’APS.
    Pour ce faire, des méthodes numériques pour extraire des informations des courbes d’APS devront être élaborées. Ces informations pourront par la suite être utilisées pour faire des prédictions via un algorithme d’apprentissage automatique. Le projet a le potentiel d’aboutir en un outil d’aide à la décision pour les radio-oncologues, qui pourront utiliser la dynamique de l’APS comme un indicateur de succès ou d’échec du traitement.

    Gabriel Couture Publications

    To Be Added

    Christopher Lund Abstract

    Although recognized as highly carcinogenic, the exact nature of neutron-induced DNA damage and its energy dependence is not well understood. With new advancements in computer modeling of DNA and its interactions with radiation, a revisiting of this problem is possible. However, for any new model of neutron-induced DNA damage to be accepted, extensive validation by radiobiological experiments is required. It is indeed this latter point that separates the research proposed here from other groups that have attempted similar research. The Neutron-Induced Carcinogenic Effects (NICE) group, of which this project forms a part, will be the first to employ whole-genome sequencing (WGS) as a means of investigating DNA damage. WGS provides vastly improved information about the extent of DNA damage to an irradiated cell compared to the other techniques used in this field. In combination with NICE’s unique expertise in neutron spectrometry, WGS will thus serve as a valuable source of both insight and feedback during the creation of a new model of the energy dependence of neutron-induced DNA damage. For example, WGS returns the number of mutations directly; therefore, proposed probabilistic models of DNA repair machinery can be implemented and tested in a meaningful way. While this is fundamental research, it is not without real-world consequences. During high-energy radiotherapy, patients are subjected to an unavoidable neutron dose. Without a reliable model of the carcinogenic potential of neutrons, an accurate assessment of the increased secondary cancer risk to the patient can not be made and considered.

    Christopher Lund Publications

    To Be Added

    Felix Mathew Abstract

    To Be Added

    Felix Mathew Publications

    To Be Added

    Benjamin Côté Abstract

    The goal of the project is to miniaturize the Aerrow probe that was developed by James Renaud and associate in order to be usable in small field dosimetry in a clinical environment. The probe uses temperature changes in a graphite core to deduce the received dose. With a thermal isolation provided by 2 layers of aerogel and 2 other layers of graphite who are thermally controlled, good thermal accuracy can be achieved. With a optimization of the component density and thickness, correction factor importance can reduce, therefore increasing the accuracy of the measurement .

    Benjamin Côté Publications

    To Be Added

    Liam Carol Abstract

    The reconstruction of dynamic PET images requires the acquisition of arterial total activity curves also called the arterial input function (AIF). The current gold-standard to acquire these AIFs involves sampling of the arterial blood through the PET scan. This technique requires specialized equipment and personnel and represent a significant financial investment, thus limiting dynamic PET to large academic centres. We are developing a novel positron detector that is wrist-mounted and non-invasive, eliminating the need for invasive sampling. The detector is based off of a coiled plastic scintillating fibre that can detect positrons escaping from the patient’s wrist.A dual read-out system will allow for coincidence counting to be performed and will allow for a high spatial resolution to be achieved. First patient trials were performed on a cohort of 7 patients receiving 150-labelled water chest scans. The scans were performed with the detector in place and were also analyzed using image derived AIFs. The measured data was compared to the image derived AIFs and shows a good agreement save for some background contribution. Further tests will be performed to determine the nature of the measured background signal and the detector will be modified to shield against it. Once this detector is complete, it will allow dynamic PET to be performed with any PET scanner at any PET centre without the need for further equipment or expertise .

    Liam Carol Publications

    To Be Added

    Ximeng Mao Abstract

    Background: Monte Carlo method is the most accurate dose calculation methods and gold standard. However, Monte Carlo based dose calculation engines, both in external beam radiation therapy and brachytherapy can be slow to be used in a clinical workflow. We have developed AI based System and methods for fast radiation calculations. The system comprises methods for fast radiation calculations, with applications including, but not limited to, radiation dose calculation for medical therapies, radiation calculation for non-destructive testing of materials, radiation calculation related to imaging, and radiation calculations related to radiation shielding and protection. This system and methods enables radiation calculations that are comparably accurate to the state of the art methods, but significantly faster to execute.

    What is novel? The method for calculation uses a data-based algorithm to model the underlying physics of the radiation interactions rather than a standard first-principles, physics based model.

    Significance: The significance of this invention is as a novel method of calculating certain physical properties of radiation is a way that is comparable in accuracy to previously known, gold-standard methods, but executed much quicker, which is key to many applications of radiation calculations .

    Ximeng Mao Publications

    To Be Added

    David Santiago Ayala Alvarez Abstract

    Abstract: Miniature kV x-ray tubes for electronic brachytherapy are used in intraoperative radiotherapy (IORT) applications to improve the outcome of targeted populations of cancer patients. The implemented low-energy electronic method is found to be a convenient alternative to interstitial brachytherapy with radionuclides, reducing the inherent safety risks and shielding, yet with a higher dose rate. The Intrabeam system is one of the most distributed examples of these sources, which is calibrated using the manufacturer’s own protocol. A comprehensive and feasible in the clinic dosimetry protocol for electronic brachytherapy is essential and is in active research. In this project, a brachytherapy dosimetry model based on a modified version of the TG-43 protocol for the Intrabeam source will be developed. In addition, the absorbed dose to water will be determined with the Exradin A20 parallel plate ionization chamber, which presents improved characteristics over the PTW 34013 such as precisely defined dimensions and the inclusion of a guard ring. Monte Carlo models for both methods will be validated based on measurements in water. The validated methods will be used to calculate dose to patient tissues and to establish optimized combinations of INTRABEAM with EBRT, studying the radiobiological implications.

    David Santiago Ayala Alvarez Publications

    To Be Added

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