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Gamma Knife Radiosurgery

The Gamma Knife is not a knife in the usual sense. Rather, it is a knife without a blade; a form of neurosurgery that requires no incision. The physicians and radiation oncologists at Wayne State University, the Detroit Medical Center, and Karmanos Cancer Institute are proud to offer Gamma Knife radiosurgery as an outpatient procedure.

Harper Hospital, in the internationally recognized Detroit Medical Center, is one of the few facilities in the nation to provide Gamma Knife radiosurgery.

Until the development of the Gamma Knife, the primary treatment for tumors and blood vessel abnormalities in the brain was usually a combination of conventional brain surgery and intensive radiation treatment. Although in many cases this may be the preferred method, the Gamma Knife offers an alternative option, called radiosurgery, which makes treatment possible without incision. The Wayne State University Neurosurgery faculty, acknowledged pioneers in the technology of radiosurgery, were among the first to introduce the linear accelerator and the infrared-based, computer-assisted tracking system. With the introduction of Gamma Knife radiosurgery, the team further demonstrates its commitment to bring to the community the latest technical advances which offer the potential for not only improved results of therapy, but also a reduction in the side-effects of those therapies.

What Is The Gamma Knife?

This technologically-advanced, multi-million dollar, 20-ton machine allows surgeons to operate on abnormal areas of the brain, such as tumors or arteriovenous malformations (AVMs) with radiation instead of scalpels. This procedure is called radio-surgery. The Gamma Knife uses gamma rays directed by highly sophisticated computer technology to destroy targeted lesions while sparing the tissue surrounding the tumor or brain disorder. Patients do not experience pain and often may resume their usual lifestyle the day after treatment.

How Does The Gamma Knife Work?

The Gamma Knife causes the gamma radiation emitted from 201 sources of cobalt-60 to converge precisely on and destroy a tumor, blood vessel abnormality (arteriovenous malformation or AVM) or other abnormal brain tissue with a 0.1 mm accuracy. The surrounding normal brain is left virtually unaffected because the individual beams are too weak to damage normal tissues en route to the target. However, when the 201 beams are precisely focused by our computer technology and the Gamma Knife, the targeted abnormality is destroyed.

The Gamma Knife was developed by Swedish neurosurgeon Lars Leksell in 1968 and is considered state-of-the-art due to advanced computer software, which allows the machine to pinpoint brain lesions with exquisite accuracy. The Gamma Knife has been used to successfully treat thousands of patients worldwide.

For treating surgically inaccessible tumors and AVMs, no other procedure has had the impressive results that the Gamma Knife has had. Many years of well-documented research, clinical use and clinical evaluation support the Gamma Knife technology.

How Does Radiosurgery Differ From Conventional Surgery?

Gamma Knife radiosurgery differs from conventional neurosurgery in several ways. No incision or cut is made, the patient's head is not shaved and the treatment is virtually painless. The patient lies on a cushioned, hydraulic table, which moves to and from the shielded dome that houses the gamma ray sources. Adult patients do not require general anesthesia; only local anesthesia to place the guiding frame and a mild sedative are administered. The patient receives one or more applications, or doses, of gamma radiation in a single treatment and is usually hospitalized only overnight. Normally, patients can resume their usual activities the next day. The risks of surgical complications, such as those from general anesthesia, infection or bleeding, are practically eliminated. There are no scars and less psychological trauma for the patient. Further, radiosurgery is more cost effective than conventional surgery for patients and their insurance companies, since patients can return almost immediately to work or other activities.

Which Patients Can Benifit From Gamma Knife Surgery?

Radiosurgery is being used by our neurosurgeons and radiation oncologists to help patients with vascular lesions such as arteriovenous malformations and for both benign and malignant brain tumors. Many times, this procedure also is effective for treating disorders that otherwise are inaccessible by conventional neurosurgery or for patients in whom conventional procedures are medically inadvisable, perhaps diabetic, elderly or hypertensive patients.

Radiosurgery is an especially valuable approach for patients whose advanced age or poor medical condition places them at an unacceptable high risk for anesthesia and conventional surgery. It also is beneficial for patients whose lesions are situated in an inaccessible or functionally critical area within the brain, making a surgical approach difficult or impossible by conventional neurosurgical techniques.

Patients who may benefit from Gamma Knife radiosurgery are those with benign tumors (acoustic neuromas, meningiomas, pituitary adenomas, craniopharyngiomas or tumors at the skull base or pineal region) and those with malignant tumors or vascular abnormalities.

Carefully selected cases with movement disorders, such as Parkinson's disease, essential tremor, patients with intractable pain, such as trigeminal neuralgia and disseminated carcinoma, and those with medically intractable epilepsy may obtain relief with Gamma Knife treatment.

The Referring Physician

The referring physician is an active partner in the treatment process. Each patient's case is reviewed by a multidisciplinary team of neurosurgeons, neurologists, radiation oncologists, neuroradiologists, medical physicists, nurses, and computer specialists. All treatment, follow-up, progress and patient outcome studies are done in conjunction with the patient's referring physician.

The Gamma Knife Team

A multidisciplinary approach focuses a broad range of medical expertise on each case before Gamma Knife radiosurgery is performed. The Gamma Knife team includes the neurosurgeon, neurologist, radiation oncologist, neuroradiologist, medical physicist, nurse and computer specialist. The team works together to provide optimal individualized care for each patient undergoing treatment. The patient's referring physician also contributes to the multidisciplinary approach.

Gamma Knife Treatment

What The Patient Can Expect - You will be admitted to Harper Hospital for your treatment. Blood tests will be performed, as before any operation. Before your treatment you will be seen by the Gamma Knife team, which most often will include the radiation oncologist, neurosurgeon and others who will help plan your treatment.

On the morning of your treatment, you may receive a mild sedative. You then will be taken to the Gamma Knife suite. There, after you receive a local anesthetic, a guiding device (stereotactic frame) will be attached to your head with four pins. This will take about 20 minutes. Certain measurements of the shape of your head will be made to help plan the dose for your treatment.

Immediately, after these measurements are made, MRI or CT imaging or a cerebral angiogram will be performed to precisely locate, within less than one millimeter, the targets for radiation treatment. These diagnostic tests may take one to four hours. While your individualized dose is being computed, you will wait in the Gamma Knife area. Dosimetry planning generally takes one to two hours, depending on the lesion and the number of doses needed to treat it. Then you will be moved into the treatment room where you will be positioned on the couch of the Gamma Knife unit. The couch slides into the Gamma Knife unit where the stereotactic frame on your head will attach to a large steel helmet that has many holes to focus radiation on the exact area of treatment.

The treatment session may last 30 minutes to three hours, depending on the amount of radiation necessary. You will not feel any different when the treatment is given and you will not experience any pain. Throughout treatment, you will be observed by closed-circuit television and will be able at all times to talk with the doctor and nurse in attendance by two-way intercom. After treatment, the helmet and guiding device will be removed and you will be taken back to your room, where you may eat your normal diet and resume taking the medications you were on before the procedure. Occasionally, one or more postoperative tests will be performed before you are discharged the following day. You will be able to return to your normal routine, including work or school, the day after treatment.

Neurosurgery at Wayne State University

Through the years, Wayne State Neurosurgery has been a prominent leader in the care and treatment of patients with neurosurgical disorders. The department is internationally recognized for its excellent clinical skills, innovative research and advanced education in the neurosciences.

Today, the department remains committed to the advancement of neurosurgical expertise through its involvement in vital international research and education of the medical professional. The neurosurgical staff is comprised of the brightest and most talented group of physicians and ancillary staff dedicated to a continuum of neuroscience care that strives to exceed the expectations of those we serve.

The Wayne State Department of Neurosurgery is dedicated to bringing first-class patient care, education and research to our community, our nation and our world.