Name of Investigator: Joseph F. Harmon, Jr.
Title: Medical Physicist/Assistant Professor (ERHS)
Contact Information:
Email Address: joseph.harmon@colostate.edu
Work Address (mailing): CSU Animal Cancer Center, Veterinary Teaching Hospital, 300 W. Drake Rd., Fort Collins, CO 80523
Office Location (Building/Room #): ACC 152
Office Phone Number: (970) 297-4063
Laboratory Location (Building/Room #): ACC 155
Biography:
Dr. Harmon is a clinical medical physicist
board certified in therapeutic and diagnostic radiological physics. He
began his physics career in the USAF as a nuclear science officer and
had the opportunity to begin a teaching career in the Physics
department of the USAF Academy. Midway through his USAF career he
transitioned into medical physics after obtaining a Ph.D. at the
university of Florida. After several clinical assignments at USAF
regional medical centers, he retired in 2003 and began working in
civilian medical centers. He enjoys the blend of physics and medicine
and the opportunity to improve radiotherapy treatments and diagnostic
image quality/safety. In 2007 he joined the CSU faculty and enjoy the
balanced mix of teaching, research and clinical duties and the unique
challenges/opportunities associated with veterinary patients.
Classes Taught/Currently Teaching:
Guest lecturer for: ERHS 300, ERHS 515, ERHS 632, ERHS 721, BIOM 470
Research Focus: Optimizing Canine Limb Radiosurgery.
Use of Gafchromic Film for Evaluation of Skin Dose.
Project Goals:
This project aims to assess the accuracy of the current Eclipse
radiosurgery skin dose calculations by comparison with measurements
utilizing a phantom, cadaver limb and actual clinical patients. If skin
dose calculation Vs measurement meets clinical accuracy requirements,
the clinician will have the confidence to increase tumor dose while
limiting skin dose to maximum tolerance. If the current Eclipse
algorithm cannot accurately predict the skin dose, a method applying
measurement based correction factors to the calculation will be
investigated. Additionally, a technique involving non-invasive in-vivo
gafchromic measurements will be established to confirm skin dose during
actual treatments. Such data will be critical to post treatment
follow-up visits and may permit target dose escalation for improved
tumor control.
Assessment of a Radiotherapy Patient Cranial Immobilization Device using Daily On-board Kilovoltage Imaging.
Project Goals:
The purpose of this study was to utilize state-of-the-art on-board
digital kilovoltage (kV) imaging to determine the systematic and random
set-up errors of an immobilization device designed for canine and
feline cranial radiotherapy treatments. The immobilization device is
comprised of a custom made support bridge, bite block, vacuum-based
foam mold and a modified thermoplastic mask attached to a commercially
available head rest designed for human radiotherapy treatments. The
immobilization device was indexed to a Varian exact couch-top designed
for image guided radiation therapy (IGRT). Daily orthogonal kV images
were compared to Eclipse treatment planning digitally reconstructed
radiographs (DRRs). The orthogonal kV images and DRRs were directly
compared online utilizing the Varian on-board imaging (OBI) system with
set-up corrections immediately and remotely transferred to the
treatment couch prior to treatment delivery. Off-line review of 124
patient treatments indicates systematic errors consisting of +0.18 mm
vertical, +0.39 mm longitudinal and -0.08 mm lateral. The random errors
corresponding to 2 standard deviations (95% CI) consist of 4.02 mm
vertical, 2.97 mm longitudinal and 2.53 mm lateral and represent
conservative CTV to PTV margins if kV OBI is not available. Use of
daily kV OBI along with the cranial immobilization device permits
reduction of the CTV to PTV margins to approximately 2.0.
Optimizing Canine Bladder Cancer Radiotherapy.
Project Goals:
Canine bladder cancer is a devastating disease usually resulting in
death within 3-12 months of diagnosis. Breeds particularly at risk for
this disease include Scottish Terriers, West Highland White terriers,
Wire Hair Fox Terriers, Shetland Sheepdogs, and Beagles. Treatment
options include surgery, chemotherapy and radiotherapy or a combination
approach. A key limitation of the radiotherapy approach is poor
radiographic bladder visualization which is required to correct for
variable bladder size/position and minimize dose to the adjacent
critical structures. Unfortunately, the bladder is practically
indistinguishable from normal soft tissues during treatment portal
imaging unless the bladder is filled with contrast material. However,
daily use of contrast is impractical and greatly increases the chance
of infection. A state-of-the-art Varian Trilogy linear accelerator
dedicated for use at the CSU Veterinary Teaching Hospital utilizes an
on-board cone-beam CT (CBCT) to provide images of the patient in the
treatment position. The real-time and high-contrast CBCT images provide
a 3-D snapshot of the treatment volume during every treatment session.
This project will analyze the available CBCT data in order to optimize
treatment margins for radiotherapy treatment planning thus permitting
maximum bladder dose and local control while minimizing the dose and
complications to nearby critical structures.
Future Direction:
List of Major Laboratory Equipment:
Current Work/Projects:
Publications:
M. Rowe, C. Chang, D. Thamm, S. Kraft, J. Harmon,
A. Vogt, B Sumerlin, S. Boyes, Tuning the Magnetic Resonance Imaging
Properties of Positive Contrast Agent Nanoparticles by Surface
Modification with RAFT Polymers, American Chemical Society, Langmuir, Aug 18; 25(16):9487-99.
J. Harmon, D. Van Uffelen, S. LaRue, Assessment of a Radiotherapy Patient Cranial Immobilization Device Using Daily On-Board Kilovoltage Imaging, Vet Radiol Ultrasound, Vol. 50, No. 2, 2009.
A. Dragun, E. Aguero, J. Harmon, J. Harper, J. Jenrette, “Chest Wall Dose in MammoSite™ Breast Brachytherapy: Radiobiologic Estimations of Late Complication Risk Based on Dose-Volume Considerations”, Brachytherapy, Vol. 4, Issue 4, 2005.
S. Meeks, J. Harmon, K. Langen et al., Performance characterization of megavoltage computed tomography imaging on a helical tomotherapy unit, Med Phys, Vol. 32, No. 8, 2005.
A. Dragun, J. Harmon, E. Aguero, “Defining Targets and Protecting Normal Tissues in Inverse-Planned IMRT for Prostate, Head and Neck, and Gynecologic Cancers: A Comparative Review”, Community Oncology, July/Aug 2005.
J. Harmon, F. Bova, S. Meeks, “Inverse Radiosurgery Treatment Planning Through Deconvolution and Constrained Optimization”, Medical Physics, Vol. 25, No. 10, 1998.
Post Doctorates/Graduate Students:
Name: Jerry Walters
Email Address: jlwalt@lamar.colostate.edu
Area of Study: MS, Health Physics
Graduation Date: SP 2009
Name: Jessica Nieset
Email Address: jessica.nieset@colostate.edu
Area of Study: Ph.D., Radiological Health Sciences
Graduation Date: SP 2010