Radiation therapy is a highly effective, potent treatment option for many types of cancer. Over the last few decades, radiation has become increasingly precise. With the advent of stereotactic radiosurgery (SRS), we can often target tumors with focused beams of radiation as a minimally invasive alternative to whole-brain radiation or traditional surgical excision.
Among the most advanced SRS tools available is the Gamma Knife Icon, an innovative machine that delivers nearly 200 pinpoint beams of radiation that converge on a tumor and spare healthy tissue.
UT Southwestern is the largest radiosurgery program and the only Gamma Knife program in North Texas. I serve as co-director of our Gamma Knife training program – one of just four in the U.S. Within the UT Southwestern Gamma Knife program, we conduct groundbreaking research and instruct physicians and medical physicists from all over world in the latest radiosurgery techniques.
Because of its precision, Gamma Knife is an excellent option for patients with malignant or benign tumors, especially those adjacent to critical nerves and eloquent areas of the brain – including those that control sight, speech, and other important daily functions.
For patients with brain metastases, improvements in Gamma Knife technology have been particularly important. In years past, only patients with a limited number of brain metastases were eligible for radiosurgery, with many patients receiving whole-brain radiation instead. While effective in eliminating tumors, whole-brain radiation risks damaging healthy brain tissue and causing cognitive impairments.
Fortunately, with improvements in Gamma Knife technology, we can now treat patients with many brain metastases (even more than 10), drastically reducing the need for whole-brain radiation and potentially improving a patient's outcomes.
Successful radiosurgery requires an extremely precise radiation plan and a multidisciplinary team of experts. The Gamma Knife radiosurgery team at UT Southwestern combines decades of expertise in neurosurgery, radiation oncology, neuro-otology, and medical physics.
Our radiosurgery team follows a four-step collaborative process that gives every patient the best chance for a positive outcome.
4 layers of radiosurgery teamwork for every patient
1. A full spectrum of experts
When a patient is identified as a good candidate for Gamma Knife – by a neurosurgeon, neuro-otologist, or radiation oncologist – we communicate as a group about next steps in their treatment plan. Each member of the team brings specific expertise to the patient’s care plan:
- Neurosurgeons have completed advanced training in human anatomy, with a subspecialty in understanding the intricacies of the brain's functionality and how anatomical changes (from tumors and treatments) can impact a patient's quality of life – today and long term.
- Neuro-otologists have advanced training in tumors within the skull base and expertise in how careful treatment can minimize side effects for patients with favorable tumors.
- Radiation oncologists are experts in the application of modern, potent radiotherapy of cancerous and benign tumors, and they create safe, effective treatment plans throughout a patient’s course of care.
2. A team that collaborates on treatment day
In our Gamma Knife center, radiation oncologists, surgeons, and physicists work together to review all the custom treatment plans to be implemented that day.
On the day of the patient’s Gamma Knife procedure, the patient arrives at the center and we prepare them for radiosurgery, including establishing an immobilization device with a mask or frame and acquiring advanced imaging. The neurosurgeon and/or neuro-otologist delineates the tumors and critical structures in the brain, and the radiation oncologist uses that information to make a radiation plan to treat the tumor.
Then, the surgeon, radiation oncologist, and medical physicist review the plan together. This collaborative approach helps the team accurately target the tumors while avoiding damage to eloquent structures and healthy tissue.
Get a closer look at the Gamma Knife technology
Cancer specialists work alongside physicians from the Spine Center and the O’Donnell Brain Institute to deliver high-quality care for people with tumors of the central nervous system (the brain and spinal cord). We bring the latest evidence-based methods for diagnosis and treatment from the research lab to our patients.
3. Quality assurance by a medical physicist
Medical physicists are the guardians of safety of our advanced radiosurgery machines, which rely on physics – the science of motion, energy, and force – to function properly. This highly sensitive equipment requires daily quality assurance testing.
The medical physicist conducts quality checks on the Gamma Knife machine itself, as well as the science of implementing the treatment plan. This layer of checks and balances ensures the highest level of precise radiation therapy and is only available at high-volume radiation centers such as ours.
4. Tumor board conferences
Every week, approximately 30 of our brain cancer experts meet to discuss our patients' diagnoses and treatment plans. The team includes:
- Ear, nose, and throat surgical experts (otolaryngologists)
- Head and neck cancer specialists
- Medical physicists
- Radiation and medical oncologists
In these forums, we discuss the nuances of complex patient cases and proposed treatment plans, looking at them from every angle to maximize treatment and minimize risk.
The future of radiosurgery for brain cancer
UT Southwestern is at the forefront of radiosurgery clinical care, education, and research. We continue to expand our knowledge through clinical trials that take the gold-standard approaches to the next level.
We currently are enrolling patients in several clinical trials. The first is looking to determine if we can even further improve the control rates in patients with a limited number of brain metastases by increasing the dose of radiation.
A second trial is seeking to show that patients with a significant number of brain metastases who undergo distributed radiosurgery rather than whole brain radiotherapy can have a better quality of life with decreased loss of short-term memory. Each patient will have a neuropsychological evaluation prior to receiving radiation therapy and in follow-up.
This study will give us more information about the extent to which radiosurgery can benefit patients with multiple metastatic tumors, both in terms of cognitive outcomes and in tumor elimination.
As the science of radiosurgery becomes even more refined, our procedures – and our patients' outcomes – will continue to improve. Gamma Knife technology has been a game-changer in metastatic brain cancer treatment, and our radiosurgery team continues to push advancement and innovation in this evolving field.
Using radiosurgery to deliver precision cancer care
Dr. Robert Timmerman, Professor and Vice Chair of the Department of Radiation Oncology at UT Southwestern, is a nationally recognized expert in the use of SABR, a precise radiation technique that targets and shrinks tumors – and sometimes destroys them – all while damaging very little of the surrounding tissue.