Mark Foley

Ollscoil na Gaillimhe – University of Galway

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Christoph Kleefeld

Ollscoil na Gaillimhe – University of Galway

Majed Alharbi

Al Jouf University

Michael Martyn

Galway Clinic

Jamie Goggins

Ollscoil na Gaillimhe – University of Galway

Sinéad O’Keeffe

University of Limerick

Marta Fuente

Laboratoire des Sciences du Climat et de l'Environnement

Tuathan O’Shea

Royal Marsden NHS Foundation Trust

Mohammed Alaswad

King Fahd Medical City

Le Chi Hung

Ollscoil na Gaillimhe – University of Galway

Magdalena Bazalova‐Carter

University of Victoria

Cooperative Institutions

Ollscoil na Gaillimhe – University of Galway

University Hospital Galway

National University of Ireland

Trinity College Dublin

McGill University

University of Maryland, Baltimore

Royal Marsden NHS Foundation Trust

Saolta University Health Care Group

University of Victoria

Universidad de Cantabria

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Off‐axis dose distribution with stand‐in and stand‐off configurations for superficial radiotherapy treatments

Journal of Applied Clinical Medical Physics (2019)

Keith Davey Margaret Moore Sinéad Cleary Christoph Kleefeld Mark Foley

Current practice when delivering dose for superficial skin radiotherapy is to adjust the monitor units so that the prescribed dose is delivered to the central axis of the superficial unit applicator. Variations of source-to-surface distance due to patient's anatomy protruding into the applicator or extending away from the applicator require adjustments to the monitor units using the inverse square law. Off-axis dose distribution varies significantly from the central axis dose and is not currently being quantified. The dose falloff at the periphery of the field is not symmetrical in the anode-cathode axis due to the heel effect. This study was conducted to quantify the variation of dose across the surface being treated and model a simple geometric shape to estimate a patient's surface with stand-in and stand-off. Isodose plots and color-coded dose distribution maps were produced from scans of GAFChromic EBT-3 film irradiated by a Gulmay D3300 orthovoltage x-ray therapy system. It was clear that larger applicators show a greater dose falloff toward the periphery than smaller applicators. Larger applicators were found to have a lower percentage of points above 90% of central axis dose (SA90). Current clinical practice does not take this field variation into account. Stand-in can result in significant dose falloff off-axis depending on the depth and width of the protrusion, while stand-off can result in a flatter field due to the high-dose region near the central axis being further from the source than the peripheral regions. The central axis also received a 7% increased or decreased dose for stand-in or stand-off, respectively.

10.1002/acm2.12730

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Challenges and opportunities for a CAMPEP-accredited medical physics graduate program

Physica Medica (2018)

Christoph Kleefeld Mark Foley

10.1016/j.ejmp.2018.06.047

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Comparison of the T descriptor of the 7th and 8th editions of the TNM staging system for non-small cell lung cancer after radiotherapy: An analysis from the TCP modelling perspective

Physica Medica (2021)

Mohammed Alaswad Christoph Kleefeld Mark Foley

TNM staging system

10.1016/j.ejmp.2021.01.053

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Radiation dose intensity and local tumour control of non-small cell lung cancer: A radiobiological modelling perspective

Journal of Physics Conference Series (2019)

Mohammed Alaswad C. Kleefeld Mark Foley

Abstract Several clinical situations call for the use of radiobiological principles as powerful clinical tools. The aim of this project is to examine the effect of radiotherapy dose intensity on local tumour control for non-small cell lung cancer (NSCLC) using the biological effective dose (BED) concept. A two-year tumour control probability (TCP) model was developed based on the linear-quadratic cell concept combined with Poisson statistics. The two-year local control outcome was analysed for the radiotherapy dose using the BEDs. The BED calculations and the TCP model were fitted to a series of NSCLC patients drawn from the literature. The investigation is based on the two-year local tumour control rate for stage I-II NSCLC for a dose fractionation size that varied from 1.5-20 Gy per fraction delivered via three radiotherapy treatments: 3D-conformal radiation therapy (3D-CRT), continuous hyperfractionated accelerated radiotherapy (CHART) and stereotactic ablative body radiotherapy (SABR). The BED values of 2,280 patients were computed and analysed as a function of local tumour control. To quantitatively assess the correlation between the BED and local tumour control, a residuals analysis and linear regression were performed. Higher radiotherapy doses were associated with improved local tumour control and survival rates for NSCLC, as suggested by the coefficient of the correlation R 2 statistical test: 0.83 for the 3D-CRT and 0.91 for the SABR treatment.

Hyperfractionation

10.1088/1742-6596/1248/1/012071

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An investigation of radiomic image feature repeatability with time and depth in a CT phantom study

Physica Medica (2021)

M. G. Moran Parisa Tahery Christoph Kleefeld Mark Foley Brendan Tuohy

Repeatability

Feature (linguistics)

10.1016/j.ejmp.2021.01.061

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Monte Carlo investigation of the dosimetric effect of the Autoscan ultrasound probe for guidance in radiotherapy

Michael Martyn Tuathan O' Shea Emma Harris Jeffrey C. Bamber Mark Foley

The aim of this study was to quantify the dosimetric effect of the Autoscan^TM ultrasound probe, which is a 3D transperineal probe used for real-time tissue tracking during the delivery of radiotherapy. CT images of a solid water phantom, with and without the probe placed in contact with its surface, were obtained (0.75 mm slice width, 140 kVp). CT datasets were used for relative dose calculation in Monte Carlo simulations of a 7-field plan delivered to the phantom. The Monte Carlo software packages BEAMnrc and DOSXYZnrc were used for this purpose. A number of simulations, which varied the distance of the radiation field edge from the probe face (0 mm to 5 mm) were performed. Perineal surface doses as a function of distance from the radiation field edge, with and without the probe in place, were compared. The presence of the probe was found to result in negligible dose differences when the radiation field is not delivered through the probe. A maximum surface dose increase of ≈1% was found when the probe face to field edge distance was 0 mm. Surface doses with and without the probe in place agreed within Monte Carlo simulation uncertainty at distances ≥ 3 mm. Using data from three patient volunteers, a typical probe face to field edge distance was calculated to be ≈20 mm. Our results therefore indicate that the presence of the probe does not adversely affect a typical patient treatment, due to the relatively large probe face to field edge distance.

10.1117/12.2216653

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Initial evaluation of the performance of novel inorganic optical fibre dosimeters using the CyberKnife system

Physica Medica (2024)

Majed Alharbi Jameel Bashehab S. Alhujaili Saleh T. Alanezi Z.A. Alrowaili

Cyberknife

10.1016/j.ejmp.2024.103261

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Radon mitigation by soil depressurisation case study: Radon concentration and pressure field extension monitoring in a pilot house in Spain

The Science of The Total Environment (2019)

Marta Fuente Daniel Rábago Jamie Goggins Ismael Fuente Merino Carlos Sáinz

Soil gas

10.1016/j.scitotenv.2019.133746

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Abstract 5392: Mesenchymal stem cell (MSC) mediated delivery of the sodium iodide symporter (NIS) supports radionuclide imaging and treatment of breast cancer

Cancer Research (2011)

Róisín M. Dwyer James Ryan Ronan J. Havelin John C. Morris Cathal O’Flatharta

Abstract Mesenchymal Stem Cells (MSCs) have the ability to migrate specifically to tumours in vivo, and coupled with their capacity to bypass immune surveillance, are potentially attractive vehicles for tumor-targeted delivery of therapeutic agents. The aim of this study was to determine the potential of MSC-mediated expression of the sodium iodide symporter (NIS) for in vivo imaging and therapy of breast tumours. Expression of NIS allows cells to concentrate radionuclides including technetium-99m (Tc-99m) and 131-Iodine (131-I). This could potentially support imaging of NIS-expressing MSCs following engraftment, and 131-I therapy of surrounding tumour tissue based on the bystander effect of the radionuclide. Methods: Tumor bearing animals (MDA-MB-231 flank) were given an intravenous or intratumoral injection of NIS expressing human MSCs (MSC-NIS), followed by imaging 3, 7, 10 or 14 days later. Imaging was performed using a Bazooka SPECT γ-camera, following intraperitoneal injection of 2mCi/74MBq Tc-99m. Following imaging, animals were sacrificed and organs harvested for analysis of hNIS expression by RQ-PCR. A second group of animals received an intraperitoneal injection of 1mCi/37MBq 131-I or saline (controls) 14 days following intratumoral or intravenous injection of MSC-NIS, and tumour volume was tracked for 8 weeks. Results: Bazooka SPECT imaging of animals revealed uptake of tracer (Tc-99m) in the mouse thyroid/salivary glands and stomach, representing native NIS expression. Following injection of MSC-NIS, an image of animal intestines was also observed at D3, with a weak image of the tumour also visible. By Day14, uptake of tracer was visible at the site of the tumour with no significant image of non-target tissue observed. Expression of hNIS in harvested organs supported the imaging data, with hNIS detected in the intestines, heart, lungs and tumour at early timepoints. While NIS expression depleted in non-target tissues by D7, gene expression persisted at the tumour site. Based on imaging/biodistribution data, animals were given a therapeutic dose of 131-I 14 days following MSC-NIS injection to avoid toxicity to non-target organs. No adverse effect of injection of MSC-NIS or radionuclide was observed. Tracking of tumour volume revealed a significant reduction in tumour growth in animals that had received an intravenous injection of 131-I 14days following MSC-NIS injection (Mean ± SEM, 236 ± 62mm3 versus 665 ± 204 mm3 in controls). Following intratumoral injection of MSC-NIS + 131-I, although tumour size was reduced compared to controls (472 ± 80 mm3), the difference in volume was not significant. Conclusion: The ability to non-invasively track MSC migration and transgene expression in real time prior to therapy is a major advantage to this strategy. This promising data supports the viability of this approach as a novel therapy for metastatic breast cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5392. doi:10.1158/1538-7445.AM2011-5392

Sodium-iodide symporter

Radionuclide therapy

Spect imaging

Intraperitoneal injection

Imaging agent

10.1158/1538-7445.am2011-5392

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Citations (2)

Rosemount Eco-Green Business Park Feasibility Study

Elise Maxwell Mark Foley Joe Braman Josh Sopeth Ryan Marty

Report completed by students enrolled in MBA 6504: Carlson Consulting Enterprise, taught by Toby Nord in spring 2015.

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