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Tennessee dog benefits from stereotactic radiosurgery to treat brain tumor at University of Florida

Thanks to University of Florida veterinarians, Tennessean Marc Mandeville once again celebrated the holidays with his beloved boxer, Sirus, who is recuperating at home in Knoxville after successful treatment last fall for a brain tumor.

“Sirus loves Christmas,” said Mandeville, who gave his 6-year-old boxer plenty of Frisbees and other favorite toys and treats this year. “The night before, he is always restless because he knows there will be presents under the tree for him.”

So far Sirus is doing well and is seizure-free, Mandeville said.

“His medication has him hungry and thirsty, but beyond that, there are no recurring issues,” Mandeville said.

The procedure Sirus received in Gainesville at UF's Veterinary Medical Center — known as stereotactic radiosurgery, or SRS — is not available anywhere else in the Southeast.

Sirus' problems first became apparent in October 2007 when Mandeville, a district sales representative for Socket Mobile, returned home with him after their morning walk. Sirus typically would lie down on the tile kitchen floor while Mandeville began working from his home office. But that day, he came over and leaned against Mandeville, giving him a strange look. Almost immediately, the dog collapsed on his side and went into a seizure.

When the seizures continued, Mandeville took Sirus to the University of Tennessee 's College of Veterinary Medicine. A CT scan of Sirus' brain revealed a mass, which a biopsy and an ultrasound identified as an oligodendrocytoma of the left forebrain, an aggressive tumor common in boxers.

Mandeville searched the Internet to learn more about treatment options and discovered an article about an advanced method of obliterating tumors and lesions with a single session of potent and precisely pinpointed radiation that UF veterinarians are using to help animals through a unique relationship the veterinary school has with UF's McKnight Brain Institute.

He asked Dr. Sarita Miles, an intern at UT and a 2007 UF veterinary graduate who helped treat Sirus, about the procedure. Miles put Mandeville in touch with UF neurology resident Rossi House to determine whether Sirus was a candidate.

“I told him this was probably Sirus' best chance for long-term survival,” House said.

Dr. Chris Mariani, a former adjunct clinical professor of veterinary neurology and neurosurgery at UF who is now on the faculty at North Carolina State University 's College of Veterinary Medicine, has given several talks describing SRS and its use in treating dogs with brain tumors.

A study he conducted at UF was the focus of one such presentation given during the American College of Veterinary Internal Medicine's annual meeting in 2005.

“In a nutshell, the 25 or so dogs I kept track of for the UF study seemed to do about as well or better than those that received conventional radiation therapy, but SRS has several important advantages over conventional radiation,” Mariani said. “It's a single treatment, which means one anesthesia, and it's potentially an outpatient procedure or one overnight stay as compared to weeks of treatment and multiple anesthesias.”

The side effects associated with SRS are almost nonexistent, particularly when compared with conventional treatment, UF veterinarians say.

Almost 20 years after Dr. Frank Bova and Dr. William Friedman, professors in the UF College of Medicine's department of neurosurgery, initiated radiosurgery treatments in people using their patented system known as the LINAC Scalpel, SRS has evolved to become the treatment of choice for people with certain types of intracranial tumors. In the past seven years, UF veterinarians, working in close collaboration with Bova and his staff at the McKnight Brain Institute, have treated nearly 100 cases, including animals with tumors located not only within the brain but also within the nose and mouth, and even osteosarcomas of the limbs.

“We will irradiate any tumor within the cranial vault regardless of what type we think it is,” said Dr. Tom Schubert, chief of the UF veterinary college's neurology service. “The last one we did (in another procedure Nov. 9) was instead of regular surgery because despite the fact that it was accessible, the owners did not want their dog to go through the pain of standard surgery.”

Neurology cases receiving SRS have CT and MRI images taken. Those images then are merged and analyzed with special software, so veterinarians can precisely pinpoint the tumor and determine the proper dose of radiation to be administered.

In the early days, a head frame was used to help veterinary radiologists obtain accurate targeting images. The process was cumbersome, however, and a new method was devised that makes use of a dental mechanism known as a biteplate. The method was developed at UF for human use and then readapted at the McKnight Brain Institute for use in veterinary radiosurgery cases. The biteplate is custom molded to the animal's upper teeth and a set of reference markers are then attached. At the time of treatment, these markers are tracked by a stereoscopic infrared camera and software developed at UF.

“The combined system allows the delivery of small high-intensity radiation beams to the tumor, with an accuracy of approximately .25 millimeters,” Bova said. “This system also allows normal tissues to be avoided with the same precision.”

Mandeville and his wife, who do not have children, said they view Sirus as a family member.

“He is, in sense our child,” Mandeville said. “He is a very loving dog and has always been the neighborhood's favorite dog, both in Tennessee and when we lived in Florida. In fact, it's not unusual for kids to come by and knock on the door to ask if Sirus can play, even when most of the kids have their own dogs.

“In our minds, the cost was a small price to pay for a member of our family,” he added. “What we do know is that we did everything that we could have possibly done to help him, and that we feel good about. When it comes right down to it, we weren't ready to give up.”