UVA Earns Grant to Develop Tomo® Stereotactic Program
Recently ranked as one of the top 40 Cancer Centers in the country,* the University of Virginia Cancer Center offers high-quality patient care in an integrated, comprehensive treatment environment. A TomoTherapy Center of Excellence, the Department of Radiation Oncology at UVA has been treating patients with the TomoTherapy Hi·Art System® since October 2004, and the quality care patients receive there is enhanced and supported by the department’s pioneering research.
One focus of that research has been extracranial stereotactic radiation therapy - using the TomoTherapy Hi·Art System to deliver extremely high doses of carefully targeted radiation in a single or a few treatment fractions. The Department was recently awarded funding by the University of Virginia to develop TomoTherapy for this purpose.
Paul Read, MD PhD, is Assistant Professor and Vice Chair of the Department of Radiation Oncology, and is one of the people instrumental in obtaining the grant.
“We are working closely with the MRI group here at UVA,” explains Dr. Read, “using dynamic MRI scans to develop patient-specific PTV expansions to account for respiratory motion of lung tumors.”
Figure 1: Treatment plan for TomoTherapy SBRT for lung metastasis.
Dr. Read describes one case involving a woman who had a 1 cm breast cancer metastasis in the right lung as the only site of disease, and who opted for stereotactic body radiation therapy (SBRT) with TomoTherapy instead of surgery.
When planning the treatment, the oncologists used dynamic MRI to account for the full range of tumor motion (see Figure 1). After treatment of the patient with 3 fractions, CT images taken 2, 3, and 6 months later (Figure 2) show the tumor’s response and the accuracy of treatment delivery as evidenced by the small region of pulmonary fibrosis in the 6 month scan surrounding the remaining 2 mm nidus.
Figure 2: CT scans showing tumor response and treatment accuracy of TomoTherapy SBRT.
Accounting for organ motion and distortion during treatment delivery is called 4D planning (“time” is the fourth dimension), and is important for maintaining accurate treatment delivery in cases such as lung tumors. Dr. James Larner, Associate Professor of Radiation Oncology and Internal Medicine, is one of the physicians involved in developing UVA’s stereotactic lung radiation therapy program, and UVA also has plans to collaborate with TomoTherapy on 4D treatment planning.
In addition to the grant project, Dr. Tyvin Rich, Professor of Radiation Oncology, is developing protocols for TomoTherapy treatment of liver tumors and other GI malignancies. The department is also developing a combined clinic with neurosurgery and orthopedics for evaluation and TomoTherapy treatment of patients with spinal and paraspinal tumors.
Dr. Read notes that the department is also fortunate to have Ke Sheng, PhD, as a medical physicist in the department. A recent graduate of the University of Wisconsin Medical Physics program, Dr. Sheng worked extensively with Dr. “Rock” Mackie on the development of aspects of the Hi·Art System. “Dr. Sheng has been instrumental in all of the projects at UVA,” states Dr. Read.
The department will be presenting two abstracts at ASTRO next month describing some of their TomoTherapy research. One abstract will offer a dosimetric analysis using the TomoTherapy Hi·Art System for stereotactic liver radiation therapy. The other abstract, covering a dose comparison study for oropharyngeal cancer using the TomoTherapy Hi·Art System vs. standard IMRT, finds that the TomoTherapy system offers a significant improvement in dose conformality. Following this dosimetric study, Dr. Read moved the head and neck cancer IMRT program almost entirely to the TomoTherapy system.
“The TomoTherapy Hi·Art System is a wonderful image-guided instrument,” notes Dr. Read. “From TBI [total body irradiation] to very focused, small-volume stereotactic treatments, it’s tremendously versatile in its applications.”
* US News and World Report, “Best Hospitals 2005.”
23 Sep 2005
