On Target

Johnston-Willis’ Dr. K. Singh Sahni pinpoints brain tumors, other neurological disorders with new Gamma Knife Icon.

Dr. K. Singh Sahni

Photo courtesy of HCA Johnston-Willis Hospital

Modern oncology has become extremely effective at eradicating metastatic tumors throughout the body, with one exception: the brain. “The human body has a barrier between the brain and the body; it’s called the blood brain barrier,” says Richmond neurosurgeon Dr. K. Singh Sahni. This collection of tightly packed, specialized cells offers a natural defense mechanism against toxins. “But that same barrier applies when you’re trying to give some immunotherapies and most chemotherapies.”

As a result, Sahni, the chairman of neuroscience and medical director of the Gamma Knife Center at HCA Johnston-Willis Hospital, has experienced an increase in patients, especially those presenting with metastatic brain cancer—cancer that initially arose in another part of the body. Now, he’s able to treat more patients than before using the Leksell Gamma Knife Icon, which the hospital purchased in January. 

Johnston-Willis, the only Joint Commission Gold Seal brain tumor center in Virginia, first acquired its first Gamma Knife in 2004. Since then, its neurosurgeons have used it to treat more than 3,500 patients with primary or metastatic brain tumors and neurological disorders, such as trigeminal neuralgia. The only stereotactic radiosurgery system designed specifically to target brain tissue, the technology has long allowed an incredibly precise form of radiation for small tumors and those located in very sensitive areas, such as the brain stem, while fully protecting normal tissue. 

Now, the Icon has features that allow it to be used on those with larger tumors as well. According to Sahni, a new mask option means “we can treat patients with or without a frame, so you don’t have to put the head in the pins every time.” This enables fractionated treatment, or the reduction of large tumors over up to five visits. “In the past, if a tumor was bigger than, say, 3 centimeters, we would not treat it with Gamma Knife, because we would be afraid that it would cause swelling.” The feature also allows him to better treat claustrophobic patients and those on blood thinners.

A newly added high-definition motion management feature provides greater accuracy when the mask is on, because “it tracks the movement of a patient and it can stop or change what we’re doing with the patient.”

“The Gamma Knife Icon is helping us treat brain tumors in a very enhanced fashion,” and prolong the lives of those with previously untreatable cancers, he says. “I’ve treated patients with multiple brain tumors—sometimes 20 or more. As the brain tumors develop, we are taking care of them.” JohnstonWillisMed.com


This article originally appeared in our December 2018 issue.

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