The Impact of a Clinical Electron Accelerator on the Advancement of Veterinary Oncology and Translational Cancer Research

Cancer is a leading cause of death in veterinary patients. Forms of radiation therapy were used to treat these patients as early as 1896. Dr. Edward Gillette spearheaded veterinary oncology at Colorado State University (CSU). He recognized that a successful program would require well trained personnel together with modern modalities. His motivation presented a dilemma since fiscal realities in veterinary practice are modest compared to clinical practices in humans. In 1981 the CSU College of Veterinary Medicine and Biomedical Sciences commissioned the first clinical linear accelerator dedicated to the treatment of naturally occurring tumors in veterinary patients and translational research. This refurbished Varian Clinac 6 was capable of delivering photon and electron beams generated in an isocentric gantry with flexible beam collimation. Commercially available clinical accelerators are designed exclusively for human medicine. This paper chronicles the adaption of this early electron accelerator to veterinary patients without compromising the accuracy and precision expected in human radiation therapy. Broad challenges were encountered in dosimetry, treatment planning and patient positioning. Dr. Thomas Borak and Mr. Robert Scott formed a team approach to medical physics, engineering and maintenance. Translational research focuses on treatment of pet animals to evaluate novel therapeutics and foster an understanding of mechanisms impacting tumor control. The clinical accelerator, together with scientists, technicians and students at CSU pioneered translational research in radiation oncology. Veterinary oncology today is a mature and thriving discipline, based on modern clinical capabilities for cancer treatment in animals as well as a strong research component that benefits both veterinary and human medicine.