Joseph Harmon

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:

• ERHS 712 Physics of Diagnostic Imaging
• ERHS 714 Radiation Therapy Physics

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:

• Development of new diagnostic medical imaging modalities
• Optimization of radiotherapy treatments

List of Major Laboratory Equipment:

1. Varian Trilogy linear accelerator
2. Diagnostic imaging units (CT, MRI, CR, radiographic, fluoroscopic, etc.)
3. 1 & 2-D water scanning systems
4. Variety of high-energy and low energy dosimetry devices and image quality phantoms
5. Radiochromic film analysis system, Varian Eclipse radiotherapy treatment planning system

Current Work/Projects:

1. Optimizing Canine Bladder Cancer Radiotherapy
2. Optimizing Canine Limb Radiosurgery: Use of Gafchromic Film for Evaluation of Skin Dose

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

Printer Friendly Page  |  View all Faculty / Researchers