Melanie Cole, MS (Host): Welcome to  UF Health MedEd Cast with UF Health Shands Hospital. I'm Melanie Cole. And we have a panel for you today for our discussion that focuses on understanding radiosurgery.

Joining me is Dr. Frank Bova, he's a medical physicist and a distinguished professor in the Department of Neurologic Surgery at the University of Florida College of Medicine, and Dr. William Friedman, he's a neurosurgeon and professor of Neurologic Surgery at the University of Florida College of Medicine.

Doctors, thank you so much for joining us today. Dr. Friedman, I'd like to start with you. Tell us how you began. The two of you began this collaborative work, which led to the development of the University of Florida Radiosurgery System.

William A. Friedman, MD: In 1985, one of my mentors came back from a neurosurgery meeting and he had heard about a new treatment technique called radiosurgery that at the time was only available in Stockholm, Sweden, and it was called the Gamma Knife. He encouraged me to look into it and consider bringing that technology to UF and to the United States. So, I rapidly found out that it was a team effort, and I needed to work with the Department of Radiation Oncology, and specifically with a medical physicist. And that's when I met Frank Bova.

Shortly after that, Frank and I got on a plane with one of the Shands Hospital administrators, and we flew to Stockholm, and we looked carefully at the the Gamma Knife. Later that year, we flew to Boston and we looked at a prototype system for radiosurgery using a different type of radiation-producing device called a linear accelerator. And after some deliberation, we decided together that the linear accelerator option was more future-looking.

Frank then came up with an invention for significantly improving the accuracy of the linear accelerator, and also for greatly improving the computer planning, which makes this treatment possible. So, we embarked on about a two-year period of research and development, and came up with what was later known as the University of Florida Radiosurgery System. That system was patented by the University of Florida, and it was licensed by UF to a series of companies that installed this device in hundreds of hospitals around the world. We treated our first patient in May of 1988. And a few months ago, we passed our 6,000th patient landmark.

Melanie Cole, MS: Dr. Bova, help us to understand the radiosurgery paradigm. Explain the basic paradigm. So, we've covered a number of principles for us of radiosurgery, how it differs from conventional radiation therapy, as Dr. Friedman was just discussing computer planning and the technology involved. Please expand on that for us and differentiate it.

Frank Bova, PhD: In routine radiation therapy, there are two principles that are employed to make the treatments safe and effective. One is the ability to focus the radiation and try to limit it to just the tissues at risk. And the other one is the fact that normal tissue is less susceptible to radiation than tumor tissue. So when you treat tumor tissue and normal tissue together, the normal tissue after about four to six hours goes through a healing process, the DNA repairs itself. And this is necessary because of the large volumes that are involved in treatment.

The radiosurgery paradigm basically utilizes a much more focused radiation, coming from many, many different directions to create a very, very high intensity spot of radiation and to spare the normal tissue. And by geometrically sparing the normal tissue, the radiobiology, the repair mechanism that radiation oncology relies on is not needed, and much higher doses can be administered to the patients. But to do this, you need to be extremely more accurate than the machines at the time when we started, and you need to have planning systems, which do literally hundreds of times more calculations in order to optimize these treatments. And so, the obstacle was to develop a system that was an order of magnitude more accurate, than the current versions of medical linear accelerators, and also to develop a computer system that was literally hundreds of times faster.

Once that was accomplished, then we could actually target things much more precisely. We could use what's called non-coplanar beam planning, which allows us to hit targets from many, many different angles, concentrating the radiation much more effectively over the target tissues. Once we got that all accomplished, we were able to then start looking at applying this, using a linear accelerator with the same kind of accuracy that was previously available through the older technologies.

Melanie Cole, MS: What an exciting time in your field, Dr. Friedman. What type of tumors are we talking about? What are most commonly treated with radiosurgery? And speak about whether metastatic tumors can now be looked at that way as well.

William A. Friedman, MD: In any tumor practice, metastatic tumors are going to predominate because they're much, much more common than tumors that start within the brain itself. Let me just start by saying a few words about the radiosurgery paradigm. So, this is a one-time outpatient treatment that replaces what could be difficult surgery with a prolonged hospital stay. We start by numbing up four spots on the patient's head, we attach a metal ring, we connect them to the machine, and we shoot hundreds of very small beams of radiation from different angles. All the beams come together at the tumor so the dose is concentrated there and the dose to the normal brain is minimal.

Once the treatment is over, the ring comes off and the patient goes home the same day. And then, we follow them with serial MRI scans, usually every three months. So, metastatic brain tumors are tumors that spread from elsewhere in the body to the brain. The most common primary tumors are lung cancers and breast cancers. And they spread through the bloodstream to the brain, they grow rapidly, and they can become life-threatening.

Previously, our best methods for treating these were open surgery, which we still use for larger tumors and conventional radiation therapy, which generally involves irradiating the entire brain at a significantly lower dose of radiation than we can do with radiosurgery and results in poorer tumor control and high rates of damage to normal brain.

The use of the radiosurgery outpatient one-time paradigm has literally revolutionized the treatment of metastatic brain tumors. We have about an 80-85% cure rate of these metastatic tumors. And as treatments with various medications, immunotherapy in particular, have become more successful at controlling the primary cancers, radiosurgery has significantly extended patients' lifespans and, in many cases, produce cures.

Now, there are many other tumors that start within the brain itself, usually benign tumors like vestibular schwannomas or pituitary tumors or meningiomas, and they also can be treated with radiosurgery. If they originate in locations that are felt to be particularly difficult for open surgery, radiosurgery should definitely be considered.

Melanie Cole, MS: Dr. Bova, what's UF's role in training clinicians or developing protocols for radiosurgery? How has this influenced broader clinical practice?

Frank Bova, PhD: Once we were able to deliver these significantly higher doses safely and accurately to patients, the the ability of, looking at tumors that were not responding to the routine fractionated therapies was then possible. And over the years, numerous protocols have been developed to treat the tumors that Dr. Friedman really just enumerated. So when we started back in 1988, the doses that we needed, the treatment approaches were all new and being developed. And as the community of radiosurgery grew and national protocols and also protocols at the University of Florida started establishing safety and efficacy for treating these tumors, the ability to actually go through and start offering these treatments safely and effectively to patients became possible. This really is a question for Dr. Friedman. I'd like him to actually just enumerate on them.

William A. Friedman, MD: I would just add to what Dr. Bova said that our work in Radiosurgery, we had the first FDA-approved linear accelerator radiosurgery system in the United States. So, our work was truly pioneering. It resulted in 175 publications, hundreds of talks at national and international meetings, and dozens of visitors to the University of Florida, all of whom came to learn from us how to do radiosurgery.

So, fortunately, because we started in the very early days of Radiosurgery in the United States and in the world, we were able, by carefully studying our patients and publishing and speaking about our results, to establish the standards for Radiosurgery that are used around the world today.

Melanie Cole, MS: Thank you both so much. I'd love to give you each a chance for a final thought. So, Dr. Bova, what would you like key messages to be about Radiosurgery at the University of Florida College of Medicine and UF Health Shands Hospital? What would you like other providers to know about the groundbreaking work that you both have done?

Frank Bova, PhD: Being part of this field since the 1980s has allowed us to not only do some pioneering work in the field, and as Dr. Friedman mentioned, host numerous visits of neurosurgeons from around the world. It's been very gratifying to be able to offer this treatment safely and effectively to so many patients.

Melanie Cole, MS: Dr. Friedman, last word to you as we look forward to the future. Your vision for the program, for the future of radiosurgery training, incoming residents. Where do you see this going? Give us a little blueprint and also what you hope to see happen.

William A. Friedman, MD: I think radiosurgery is very well established now. Of course, there are always technological advances that we probably don't have time to go into in this particular presentation. I would like to just emphasize access. If you have a brain tumor, whether it's a malignant metastatic tumor or a benign brain tumor, you want to be seen and taken care of right away. And I want all the providers who might be listening to this, to know that if you call the University of Florida Radiosurgery Program, we will absolutely see you within a week and get your problem taken care of.

Melanie Cole, MS: Well, it certainly is. And thank you so much. Both of you for joining us today and sharing your incredible expertise. To learn more about this and other healthcare topics at UF Health Shands Hospital, please visit innovation.ufhealth.org. And to listen to more podcasts from our experts, please visit ufhealth.org/medmatters.

That concludes today's episode of  UF Health MedEd Cast with UF Health Shands Hospital. I'm Melanie Cole. Thanks so much for joining us today.