John Kildea

McGill University | McGill · Department of Medical Physics

Background: Dose-surface maps (DSMs) are an increasingly popular tool to evaluate spatial dose-outcome relationships for the rectum. Recently, DSM addition has been proposed as an alternative method of dose accumulation from deformable registration-based techniques. In this study, we performed the first experimental investigation of the accuracy a...

Background Dose‐outcome studies in radiation oncology have historically excluded spatial information due to dose‐volume histograms being the most dominant source of dosimetric information. In recent years, dose‐surface maps (DSMs) have become increasingly popular for characterization of spatial dose distributions and identification of radiosensitiv...

Radiomics-based machine learning classifers have shown potential for detecting bone metastases (BM) and for evaluating BM response to radiotherapy (RT). However, current radiomics models require large datasets of images with expert-segmented 3D regions of interest (ROIs). Full ROI segmentation is time consuming and oncologists often outline just...

Despite the known importance and necessity of the standardized collection and use of patient-reported outcomes (PROs), there remain challenges to successful clinical implementation. Facilitated through a quality improvement initiative spearheaded by the Canadian Partnership for Quality Radiotherapy (CPQR), and now guided by the Canadian Association...

Theoretical evaluations indicate the radiation weighting factor for thermal neutrons differs from the current International Commission on Radiological Protection (ICRP) recommended value of 2.5, which has radiation protection implications for high-energy radiotherapy, inside spacecraft, on the lunar or Martian surface, and in nuclear reactor workpl...

BACKGROUND Individuals diagnosed with COVID-19 are instructed to self-isolate at home. However, during self-isolation, they may experience anxiety and insufficient care. Some patient portals can allow patients to self-monitor and share their health status with healthcare professionals for remote follow-up, but little data is available on the feasib...

Background: Individuals diagnosed with COVID-19 are instructed to self-isolate at home. However, during self-isolation, they may experience anxiety and insufficient care. Patient portals can allow patients to self-monitor and share their health status with healthcare professionals for remote follow-up, but little data is available on the feasibili...

Purpose/Objective(s) The COVID-19 pandemic has shifted practices in oncology to prioritize patient and healthcare staff safety while maintaining necessary treatment delivery. We obtained feedback from both patients and healthcare staff on pandemic-based practices in our radiotherapy department to adapt policies and procedures to improve safety and...

Purpose: To develop a Natural Language Processing (NLP) and Machine Learning (ML) pipeline that can be integrated into an Incident Learning System (ILS) to assist radiation oncology incident learning by semi-automating incident classification. Our goal was to develop ML models that can generate label recommendations, arranged according to their li...

Neutron exposure poses a unique radiation protection concern because neutrons have a large, energy-dependent relative biological effectiveness (RBE) for stochastic effects. Recent computational studies on the microdosimetric properties of neutron dose deposition have implicated clustered DNA damage as a likely contributor to this marked energy depe...

PurposeOpal is a new patient-centered mobile application that gives cancer patients access to their real time medical data in conjunction with disease- and treatment-specific patient education material. Few studies have focused on patients’ experiences with such mobile applications. This study’s objectives were to (1) explore cancer patients’ perce...

Objective The majority of cancer patients suffer from severe pain at the advanced stage of their illness. In most cases, cancer pain is underestimated by clinical staff and is not properly managed until it reaches a critical stage. Therefore, detecting and addressing cancer pain early can potentially improve the quality of life of cancer patients....

This study examines if single-cell DNA sequencing may be used to study the mutational effects of ionizing radiation. As the action of ionizing radiation is a stochastic process, each cell in an irradiated sample experiences its own unique radiation-induced DNA damage. As a result, conventional sequencing methods such as bulk cell sequencing cannot...

The COVID-19 pandemic has shifted oncology practices to prioritize patient safety while maintaining necessary treatment delivery. We obtained patient feedback on pandemic-based practices in our radiotherapy department to improve quality of patient care and amend policies as needed. We developed a piloted questionnaire which quantitatively and quali...

Opal (opalmedapps.com), a patient portal in use at the Cedars Cancer Centre of the McGill University Health Centre (MUHC) (Montreal, Canada), gives cancer patients access to their medical records, collects information on patient-reported outcome measures (PROMs), and has demonstrated patient satisfaction with care. This feasibility study aims to ev...

Nested Neutron SpectrometersTM (NNS) can be used to measure neutron fluence rate spectra under diverse circumstances with a working principle similar to Bonner sphere systems. Conventionally, the NNS consists of an active-readout He-3 detector core and concentric moderator shells. In environments where the neutron fluence rate exceeds ∽10⁴ neutrons...

Craniospinal irradiation (CSI) is a complex radiation therapy technique that is used for patients, often children and teenagers/young adults, with tumors that have a propensity to spread throughout the central nervous system such as medulloblastoma. CSI is associated with important long-term side effects, the risk of which may be affected by numero...

High-energy electron treatment procedures in radiotherapy pose a potential iatrogenic cancer risk as well as a critical health risk to patients with cardiac implantable electronic devices due to the generation of secondary neutrons in the linac head, the treatment room, and the patient. It may be argued that the neutron production from photons is w...

Background: Inter-observer variations (IOVs) arising during contouring can potentially impact plan quality and patient outcomes. Regular assessment of contouring IOV is not commonly performed in clinical practice due to the large time commitment required of clinicians from conventional methods. This work uses retrospective information from past tr...

Nuclear reactions induced during high-energy radiotherapy produce secondary neutrons that, due to their carcinogenic potential, constitute an important risk for the development of iatrogenic cancer. Experimental and epidemiological findings indicate a marked energy dependence of neutron relative biological effectiveness (RBE) for carcinogenesis, bu...

The spectrum of secondary neutrons generated by a medical linear accelerator (linac) during high-energy radiation therapy must be accurately determined in order to assess the carcinogenic risk that these neutrons pose to patients. Neutron spectrometers such as the Nested Neutron Spectrometer (NNS) can be used to measure neutron fluence spectra but...

Purpose Chest wall pain is an uncommon but bothersome late complication following lung stereotactic body radiation therapy. Despite numerous studies investigating predictors of chest wall pain, no clear consensus has been established for a chest wall constraint. The aim of our study was to investigate factors related to chest wall pain in a homogen...

221 Background: Patient portals are software products that provide care recipients (patients) with access to some or all of their personal health information (PHI) within a healthcare institution’s electronic medical record (EMR). Most patient portals are just that–windows into an EMR. However, in today’s connected world, a patient portal can offer...

Purpose: Neutrons are an unavoidable by-product of high-energy radiation therapy treatments that deliver unwanted nontarget dose to patients. Use of attening-filter-free (FFF) photon beams has been shown to significantly reduce photoneutron production per monitor unit (MU) of dose delivered. The purpose of this investigation was to characterize th...

BACKGROUND Patient portals are increasingly accepted as part of standard medical care. However, to date, most patient portals provide just passive access to medical data. The use of modern technology such as smartphones and data personalization algorithms offers the potential to make patient portals more person-centered and enabling. OBJECTIVE The...

Background Patient portals are increasingly accepted as part of standard medical care. However, to date, most patient portals provide just passive access to medical data. The use of modern technology such as smartphones and data personalization algorithms offers the potential to make patient portals more person-centered and enabling. Objective The...

Thermal neutrons are found in reactor, radiotherapy, aircraft, and space environments. The purpose of this study was to characterize the dosimetry and microdosimetry of thermal neutron exposures, using three simulation codes, as a precursor to quantitative radiobiological studies using blood samples. An irradiation line was designed employing a pyr...

Purpose: Collaborative incident learning initiatives in radiation therapy promise to improve and standardize the quality of care provided by participating institutions. However, the software interfaces provided with such initiatives must accommodate all participants and thus are not optimized for the workflows of individual radiation therapy cente...

Figure. S1. (a) Summary of an incident reporting and learning survey of RTTs in our radiation therapy center (questions 1‐4). (b) Summary of an incident reporting and learning survey of RTTs in our radiation therapy center (questions 5‐8). Figure. S2. (a) Preliminary incident reporting and learning newsletter circulated in our radiation therapy cen...

We report on the development and clinical deployment of an in-house incident reporting and learning system that implements the taxonomy of the Canadian National System for Incident Reporting – Radiation Treatment (NSIR-RT). In producing our new system, we aimed to: • • Analyze actual incidents, as well as potentially dangerous latent conditions. •...

We describe a method for predicting waiting times in radiation oncology. Machine learning is a powerful predictive modelling tool that benefits from large, potentially complex, datasets. The essence of machine learning is to predict future outcomes by learning from previous experience. The patient waiting experience remains one of the most vexing c...

We describe an electronic waiting room management system that we have developed and deployed in our cancer centre. Our system connects with our electronic medical records systems, gathers data for a machine learning algorithm to predict future patient waiting times, and is integrated with a mobile phone app. The system has been in operation for ove...

We describe the measurements of neutron spectra that we undertook around a scanning proton beam at the Skandion proton therapy clinic in Uppsala, Sweden. Measurements were undertaken using an extended energy range Nested Neutron Spectrometer (NNS, Detec Inc., Gatineau, QC) operated in pulsed and current mode. Spectra were measured as a function of...

We describe Opal (Oncology portal and application), the mobile phone app and patient portal that we have developed and are deploying for Radiation Oncology patients at our cancer centre. Opal is a novel tool to empower patients with their own personal medical data, including appointment schedules, consultation notes, test results, radiotherapy trea...

Purpose:Waiting times remain one of the most vexing patient satisfaction challenges facing healthcare. Waiting time uncertainty can cause patients, who are already sick or in pain, to worry about when they will receive the care they need. These waiting periods are often difficult for staff to predict and only rough estimates are typically provided...

Purpose: Out-of-field neutron doses resulting from photonuclear interactions in the head of a linear accelerator pose an iatrogenic risk to patients and an occupational risk to personnel during radiotherapy. To quantify neutron production, in-room measurements have traditionally been carried out using Bonner sphere systems (BSS) with activation fo...

During high-energy radiotherapy treatments, neutrons are produced in the head of the linac through photonuclear interactions. This has been a concern for many years as photoneutrons contribute to the accepted, yet unwanted, out-of-field doses that pose an iatrogenic risk to patients and an occupational risk to personnel. Presently, in-room neutron...

We describe development of automated, web-based, electronic health record (EHR) auditing software for use within our paperless radiation oncology clinic. By facilitating access to multiple databases within the clinic, each patient's EHR is audited prior to treatment, regularly during treatment, and post treatment. Anomalies such as missing doc...

We describe DepDocs, a web-based platform that we have developed to manage the committee meetings, policies, procedures and other documents within our otherwise paperless radiotherapy clinic. DepDocs is essentially a document management system based on the popular Drupal content management software. For security and confidentiality, it is hosted on...

Purpose With the emergence of flattening filter free (FFF) photon beams, several authors have noted many advantages to their use. One such advantage is the decrease in neutron production by photonuclear reactions in the linac head. In the present work we investigate the reduction in neutrons from a Varian TrueBeam linac using the Nested Neutron Spe...

The Whipple Observatory 10 m γ-ray telescope has been used to survey the error boxes of EGRET unidentified sources in an attempt to find counterparts at energies of 350 GeV and above. Twenty-one unidentified sources detected by EGRET (more than 10% of the total number) have been included in this survey. In no case is a statistically significant sig...

The first atmospheric Cherenkov telescope of VERITAS (the Very Energetic Radiation Imaging Telescope Array System) has been in operation since February 2005. We present here a technical description of the instrument and a summary of its performance. The calibration methods are described, along with the results of Monte Carlo simulations of the tele...

Stephen Hawking's prediction that black holes should radiate like black bodies has several important consequences, including the possibility of the detection of small (similar to 10(15) g) black holes created in the very early universe. The detection of such primordial black holes ( PBHs) would be an important discovery, not only confirming Hawking...

Blazars have traditionally been separated into two broad categories based on their optical emission characteristics. Blazars with faint or no emission lines are referred to as BL Lacertae objects ( BL Lacs), and blazars with prominent, broad emission lines are commonly referred to as flat-spectrum radio quasars (FSRQs). The spectral energy distribu...

We present results from observations of 29 BL Lacertae objects, taken with the Whipple Observatory 10 m gamma-ray telescope between 1995 and 2000. The observed objects are mostly at low redshift (z<0.2), but observations of objects of up to z=0.444 are also reported. Five of the objects are EGRET sources and two are unconfirmed TeV sources. Three o...

We report a possible detection of TeV gamma rays from the Galactic center by the Whipple 10 m gamma-ray telescope. Twenty-six hours of data were taken over an extended period from 1995 through 2003 resulting in a total significance of 3.7 sigma. The measured excess corresponds to an integral flux of 1.6 x 10(-8) +/- 0.5 x 10(-8) (stat) +/- 0.3 x 10...

Details are presented of the Whipple Observatory's 10 m atmospheric Cherenkov telescope and camera, as it evolved during the period 1997 until 2006. The design of the telescope and camera's optical and electronic systems is discussed together with a detailed description of the four-stage GRANITE (Gamma-RAy New Imaging TElescope) upgrade program, un...

Gamma-ray burst (GRB) observations at very high energies (VHE; E > 100 GeV) can impose tight constraints on some GRB emission models. Many GRB afterglow models predict a VHE component similar to that seen in blazars and plerions, in which the GRB spectral energy distribution has a double-peaked shape extending into the VHE regime. VHE emission coin...

Photoneutrons are a major component of the equivalent dose in the maze and near the door of linac bunkers. Physical measurements and Monte Carlo (MC) calculations of neutron dose are key for validating bunker design with respect to health regulations. We attempted to use bubble detectors and a (3)He neutron spectrometer to measure neutron equivalen...

Innovation/Impact: We describe the web-based QA infrastructure under development and in use within our paperless radiation oncology clinic. Our framework comprises a centralized web-server that facilitates simultaneous and seamless access to multiple databases within the clinic. All activities, including treatment planning, patient appointments and...

Multiwavelength observations of the high-frequency-peaked blazar 1ES 2344+514 were performed from 2007 October to 2008 January. The campaign represents the first contemporaneous data on the object at very high energy (VHE, E >100 GeV) γ-ray, X-ray, and UV energies. Observations with VERITAS in VHE γ-rays yield a strong detection of 20σ with 633 exc...

Multiwavelength observations of the high-frequency-peaked blazar 1ES2344+514 were performed from 2007 October to 2008 January. The campaign represents the first contemporaneous data on the object at very high energy (VHE, E >100 GeV) {\gamma}-ray, X-ray, and UV energies. Observations with VERITAS in VHE {\gamma}-rays yield a strong detection of 20...

Purpose: To describe a framework for comprehensive web‐based QA in medical physics and radiation oncology through centralized access to multiple databases. We believe that this form of centralized QA represents the future direction for data analysis and visualization in increasingly data‐driven radiation oncology and medical physics practises. Meth...

We present results of very-high-energy gamma-ray observations (E > 160 GeV) of two high-frequency-peaked BL Lac (HBL) objects, 1ES 1218+304 and H 1426+428, with the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE). Both sources are very-high-energy gamma-ray emitters above 100 GeV, detected using ground-based Cherenkov telescopes. STACE...

We describe a framework for comprehensive electronic QA currently under development in the department of Radiation Oncology at the Montreal General Hospital. When complete, the system will incorporate all data generated within the department. It will allow for easy access to all aspects of a patient's treatment and to the state of all relevant equi...

Gamma-ray bursts (GRBs) are the most powerful explosions known in the universe. Sensitive measurements of the high-energy spectra of GRBs can place important constraints on the burst environments and radiation processes. Until recently, there were no observations during the first few minutes of GRB afterglows in the energy range between 30 GeV and...

Shielding design calculations used in megavoltage radiation therapy essentially reduce to determination of barrier thicknesses. A shielding barrier serves to attenuate the radiation dose from a high level produced inside a therapy room to a lower “design goal” level at a point‐of‐interest outside. The calculation must account for both radiation phy...

Older bunkers designed for dual energy linacs were often constructed with both a maze and high energy door. The door provides both radiation safety and access control, however, it may be desirable to limit use of the high energy door to reduce mechanical wear and improve workflow. We conducted a feasibility study to determine if our high energy lin...

Imaging atmospheric Cherenkov telescopes (IACTs) used for ground-based gamma-ray astronomy at TeV energies use reflectors with areas on the order of as their primary optic. These tessellated reflectors comprise hundreds of mirror facets mounted on a space frame to achieve this large area at a reasonable cost. To achieve a reflecting surface of suff...

This thesis describes a study of shielding design techniques used for radiation therapy facilities that employ megavoltage linear accelerators. Specifically, an evaluation of the shielding design formalism described in NCRP report 151 was undertaken and a feasibility study for open-door 6 MV radiation therapy treatments in existing 6 MV, 18 MV trea...

Although Galactic cosmic rays (protons and nuclei) are widely believed to be mainly accelerated by the winds and supernovae of massive stars, definitive evidence of this origin remains elusive nearly a century after their discovery. The active regions of starburst galaxies have exceptionally high rates of star formation, and their large size-more t...

Black Hole Energy Boost More than 20 galaxies are known to emit photons with energies a trillion times higher than those of visible light, but it is not known where this emission originates. These galaxies are part of a class of active galactic nuclei believed to harbor supermassive black holes in their centers from which relativistic plasma jets e...

We present results from a long-term monitoring campaign on the TeV binary LSI +61° 303 with VERITAS at energies above 500 GeV, and in the 2-10 keV hard X-ray bands with RXTE and Swift, sampling nine 26.5 day orbital cycles between 2006 September and 2008 February. The binary was observed by VERITAS to be variable, with all integrated observations r...

We have used the STACEE high-energy gamma-ray detector to look for fast blue-green laser pulses from the vicinity of 187 stars. The STACEE detector offers unprecedented light-collecting capability for the detection of nanosecond pulses from such lasers. We estimate STACEE's sensitivity to be approximately 10 photons per square meter at a wavelength...

HESS J0632+057 is one of only two unidentified very-high-energy gamma-ray sources which appear to be point-like within experimental resolution. It is possibly associated with the massive Be star MWC 148 and has been suggested to resemble known TeV binary systems like LS I +61 303 or LS 5039. HESS J0632+057 was observed by VERITAS for 31 hr in 2006,...

We present evidence that the very high energy (VHE, E > 100 GeV) gamma-ray emission coincident with the supernova remnant IC 443 is extended. IC 443 contains one of the best studied sites of supernova remnant/molecular cloud interaction and the pulsar wind nebula CXOU J061705.3+222127, both of which are important targets for VHE observations. VERIT...

The VERITAS collaboration reports the detection of very-high-energy (VHE) gamma-ray emission from the high-frequency-peaked BL Lac object 1ES 1218+304 located at a redshift of z=0.182. A gamma-ray signal was detected with a statistical significance of 10.4 standard deviations (10.4 sigma) for the observations taken during the first three months of...

The intermediate-frequency peaked BL Lacertae (IBL) object 3C 66A is detected during 2007 - 2008 in VHE (very high energy: E > 100 GeV) gamma-rays with the VERITAS stereoscopic array of imaging atmospheric Cherenkov telescopes. An excess of 1791 events is detected, corresponding to a significance of 21.2 standard deviations (sigma), in these observ...

The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) is a ground-based telescope that uses the wave-front-sampling technique to detect very high energy (VHE) gamma rays. STACEE's sensitivity in the energy range near 100 GeV permits useful observations of pulsars with the potential to discriminate between various proposed mechanisms for...

Since September 2005, the Whipple 10m Gamma-ray Telescope has been operated primarily as a blazar monitor. The five Northern Hemisphere blazars that have already been detected at the Whipple Observatory, Markarian 421, H1426+428, Markarian 501, 1ES 1959+650 and 1ES 2344+514, are monitored routinely each night that they are visible. We report on the...

The high-frequency-peaked BL-Lacertae object \objectname{1ES 0806+524}, at redshift z=0.138, was observed in the very-high-energy (VHE) gamma-ray regime by VERITAS between November 2006 and April 2008. These data encompass the two-, and three-telescope commissioning phases, as well as observations with the full four-telescope array. \objectname{1ES...

The accretion of matter onto a massive black hole is believed to feed the relativistic plasma jets found in many active galactic nuclei (AGN). Although some AGN accelerate particles to energies exceeding 1012 electron volts and are bright sources of very-high-energy (VHE) γ-ray emission, it is not yet known where the VHE emission originates. Here w...

We present optical, X-ray, high-energy (30 GeV) and very high energy (100 GeV; VHE) observations of the high-frequency peaked blazar Mrk 421 taken between 2008 May 24 and June 23. A high-energy γ-ray signal was detected by AGILE with between June 9 and 15, with F(E>100 MeV) = 42+14–12× 10–8 photons cm–2 s–1. This flaring state is brighter than the...

We report on observations of the blazar W Com (ON+231) with the Solar Tower Atmospheric Cerenkov Effect Experiment (STACEE), a wave front-sampling atmospheric Cerenkov telescope, in the spring of 2003. In a data set comprising 10.5 hr of on-source observing time, we detect no significant emission from W Com. We discuss the implications of our resul...

The detection of spectral variability of the γ-ray blazar Mrk 421 at TeV energies is reported. Observations with the Whipple Observatory 10 m γ-ray telescope taken in 2000/2001 revealed exceptionally strong and long-lasting flaring activity. Flaring levels of 0.4-13 times that of the Crab Nebula flux provided sufficient statistics for a detailed st...

We report results from an intensive multiwavelength monitoring campaign on the TeV blazar Mrk 421 over the period of 2003-2004. The source was observed simultaneously at TeV energies with the Whipple 10 m telescope and at X-ray energies with the Rossi X-Ray Timing Explorer (RXTE) during each clear night within the Whipple observing windows. Support...

We present observations of the dwarf galaxies Draco and Ursa Minor, the Local Group galaxies M32 and M33, and the globular cluster M15 conducted with the Whipple 10 m gamma-ray telescope to search for the gamma-ray signature of self-annihilating weakly interacting massive particles (WIMPs), which may constitute astrophysical dark matter (DM). We re...

A survey of binary systems containing pulsars was conducted, with the intention of detecting Galactic sources of very high energy γ-ray emission. Observations were carried out with the Whipple 10 m imaging atmospheric Cerenkov telescope. Standard analysis techniques were applied to these sources to search for steady, unpulsed emission. Periodic tes...

We report on a multiwavelength campaign on the TeV γ-ray blazar Mrk 421 performed during 2002 December and 2003 January. These target of opportunity observations were initiated by the detection of X-ray and TeV γ-ray flares with the All Sky Monitor (ASM) on board the Rossi X-Ray Timing Explorer (RXTE) and the 10 m Whipple γ-ray telescope. The campa...