CT images have been the gold standard for radiation treatment planning for more than 20 years. CT has superior spatial resolution and accuracy and provides necessary anatomic information needed for radiation therapy planning and delivery. However, modern radiation therapy relies more and more on other image modalities in order to obtain functional and other information for better treatment outcome.
In particular, MR-guided radiation therapy (MRgRT), where MR imaging is used to guide radiation therapy treatment planning and decision making, has increasingly been recognized as an important element for many types of cancers. Realizing the advantages of MRgRT and to bring the latest treatment options to our patients, the UF Department of Radiation Oncology has installed and commissioned a Philips Ambition 1.5 Tesla MR scanner exclusively for our patients.
The MR simulation is capable of generating synthetic CT for accurate dose calculation, thereby can be used directly for treatment planning and delivery, eliminating the geometric and positioning uncertainties compared to conventional image fusion-based treatment planning. Also, the superior soft tissue contrast of MR images allows our clinicians to better visualize and delineate target volumes.
In addition, our department has commissioned an Elekta Unity, a state-of-the-art combined 1.5 Tesla MR/Linac system (shown above, one of only 42 in clinical use worldwide and the first in the southeastern US), capable of reshaping the radiation dose based on daily changes in shape, size, and position of the tumor and surrounding healthy tissues. This system provides superior MR image quality prior/during the treatment. The daily adaptive capabilities of the Unity system will bring true personalized radiation therapy to our patients. Note that this is the only 1.5 Tesla MR LINAC system in the state of Florida.