Philip McGeachy
Medical Physicist, MCCPM
Adjunct Assistant Professor
Adjunct Assistant Professor
Medical Physics Residency (CAMPEP accredited)
Ph.D Radiation Oncology Physics (CAMPEP accredited)
B.Sc (Honours) Physics
Contact information
Phone
Location
Research and teaching
Research Interest
A couple of decades ago a new technique of external beam radiotherapy (EBRT) that allowed for the spatial modulation of the photon fluence (intensity) of a treatment beam was introduced. This modality, called intensity modulated radiotherapy (IMRT), allowed sculpting of the radiation dose distribution such that it improved the dose conformity to the tumour (target) and significantly reduced injury to the healthy tissue. A limitation to IMRT is that a single photon energy spectrum (6 MV) is used for all treatment beams. The single photon energy spectrum (6 MV) used in IMRT deposits the majority of its energy closer to the surface of the medium than higher energy photons. A typical treatment plan consists of a set of beams at various angles about the patient, with each beam traversing a different pathlength to reach the tumour. This variability in pathlength beckons for the use of various photon beam energies when determining the optimal treatment plan to further tailor the dose distribution to the target structure. My research focuses on formulating and solving an optimization problem that, given any organ geometry and set of radiation beam angles, will find the optimal photon beam energy and fluence. This optimal solution in terms of photon energy and fluence may result in a dose distribution that is as close as possible to the one desired by the radiation oncologist. The development of this novel and enhanced radiation therapy modality will be called modulated photon radiotherapy (XMRT).
Publications
(2010-2015):
Characterizing 3D Printing in the Fabrication of Variable P Density Phantoms for Quality Assurance of Radiotherapy
J. Madamesila, P. McGeachy, E. Villarreal- Barajas, R. Khan
Physica Medica 32(1) 242-247 (2016).
Modulated photon radiotherapy (XMRT): An algorithm for the simultaneous optimization of photon beamlet energy and intensity in external beam radiotherapy (EBRT) planning
P. McGeachy, E. Villarreal- Barajas, Y. Zinchenko, R. Khan
Phys. Med. Biol. 61(4) 1476-1498 (2016).
Abstracts & Presentations (2012-2015):
Assessing fit of rigid 3D-printed bolus for sarcoma of the knee in radiotherapy treatments
P. McGeachy, A. Yarschenko, C. Schinkel, E. Kurien, W. Smith, T. Meyer
Med Phys 45(6), e318 (2018). AAPM 60th Annual Meeting, Nashville TN, July 29 - Aug 2, 2018
Smoothing constraints in Modulated Photon Radiotherapy (XMRT) fluence map optimization
P McGeachy, E Villarreal Barajas, Y Zinchenko
Phys. Med. Biol. 43(8) 4949 (2016)
Deliverability Considerations in Modulated Photon Radiotherapy (XMRT) (Poster Presentation)
P McGeachy, S Weppler, E Villarreal Barajas, Y Zinchenko, and R Khan
Phys. Med. Biol. 43(6) 3539 (2016)
Fluence Delivery Optimization with Multileaf Collimation
S. Weppler, P. McGeachy, E. Villarreal-Barajas, R. Khan
Med. Phys. 43(6) 3587 (2016)
Dosimetry and Practical Therapy Solutions On 3D Fabrication of Phantoms and Experimental Verification of Patient Dose Computation Algorithms
R. Khan, R. Zavan, P. McGeachy, E. Villarreal- Barajas
Med. Phys. 43(6) 3587 (2016)
A preliminary study on the effect of Modulated Photon Radiotherapy (XMRT) for prostate cancer treatment planning
P. McGeachy, E. Villarreal- Barajas, Y. Zinchenko, P. Shirvani, R. Khan
Proceedings for the IUPESM World Congress on Medical Physics and Biomedical Engineering. Presented at IUPESM World Congress on Medical Physics and Biomedical Engineering, Toronto, ON, June 8-12, 2015.
Evaluating Dosimetric Outcome of Modulated Photon Radiotherapy (XMRT) Optimization for Head and Neck Patients
P. McGeachy, E. Villarreal-Barajas, Y. Zinchenko, R. Khan
Med. Phys. 42(6), 3418 (2015). Presented at AAPM Annual Meeting, Anaheim, CA July 12-16, 2015.
Characterizing 3D Printing in the Fabrication of Variable Density Phantoms
J. Madamesila, P. McGeachy, E. Villarreal-Barajas, R. Khan
Med. Phys. 42(6), 3188 (2015). Presented at AAPM Annual Meeting, Anaheim, CA July 12-16, 2015.
Modulated Photon Radiotherapy (XMRT): The impact of incorporating energy modulation into Intensity Modulated Radiotherapy (IMRT) optimization.
P. McGeachy, R. Khan
Med Phys 41(6), 277 (2014). Presented at AAPM Annual Meeting, Jul 20th – 24th , 2014. Austin, TX
The impact of intensity- and energy-modulated photon radiotherapy (XMRT) optimization on a variety of organ geometries.
P. McGeachy, Y. Zinchenko, J.E. Villarreal-Barajas, and R. Khan
Med. Phys 41(8), 14. Presented at COMP Annual scientific meeting, Banff, AB, July 9-12, 2014.
A linear programming approach for incorporating photon beam-energy modulation into Intensity Modulated Radiotherapy (IMRT) optimization.
P. McGeachy, Y. Zinchenko, J.E. Villarreal-Barajas, and R. Khan
High-performance numerical methods supporting radiation therapy treatment planning II workshop, May 10th- 11th, 2014. Bethlehem, PA
Developing photon beamlet energy optimization criteria for modulated photon radiotherapy (XMRT)
P. McGeachy, and R. Khan
Radiotherapy and Oncology 108, S269 (2013). Presented at COMP-CARO Joint meeting, Montreal, QB, Sept 18-21, 2013.
Incorporating photon beamlet energy in optimization of intensity modulated beams
P. McGeachy, and R. Khan
Medical Physics 40 (6), 291 (2013). Presented at AAPM Annual Meeting, Indianapolis, IN, Aug 4-8, 2013.
Comparison of an open source genetic algorithm to the commercially used ISA for generation of seed distributions in LDR prostate brachytherapy
P. McGeachy, and R. Khan
Medical Physics 39(7), 4625 (2012). Presented at COMP Annual Meeting, Halifax, NS, Jul 11-14, 2012.
An open source genetic algorithm for seed distributions in prostate brachytherapy
P. McGeachy, and R. Khan
Canadian Association of Physics (CAP) Congress; Calgary, Canada Jun 11-15, (2012)
Monoenergetic photon beamlet optimization in Intensity Modulated Radiotherapy (IMRT)
P. McGeachy, and R. Khan
Alberta Cancer Foundation (ACF) Cancer Research Conference; Banff, Canada Nov 1-3, (2012)
Optimization of photon beamlet energy for Intensity Modulated Radiotherapy (IMRT) in a simple geometric tumour model
P. McGeachy,and R. Khan
Southern Alberta Cancer Research Institute (SACRI) Research Day; Calgary, Canada, Sept 28, (2012)