Gamma knife surgery refers to a radiation therapy used in the treatment of tumours among other disorders in the brain. This type of therapy is unique in the sense that it delivers exceedingly focused radiation beams to a specific target in the brain; actually, 201 distinct beams converge to a single focal point.

The kind of radiation source in use is referred to as cobalt. The sources are usually positioned in a hemisphere manner so that all the beams can converge on one desired point. The shape along with the prescription of the radiation is adjusted to target only a single point. This is done carefully in such a way that other healthy tissues are not damaged.

The Process and Steps Involved

Gamma knife surgical procedure is reported to be a four-step process, including: attaching of the frame, imaging (MRI, Angiography, and CT), treatment planning (dose planning), and the actual treatment (radiation delivery). The frame is positioned to the patient’s head by screwing it at four locations. The frame’s functionality is to provide target coordinate determination, and to immobilise as well as position the patient’s head in the collimator helmet during treatment.

Imaging provides the basis for treatment planning, and they are normally obtained through magnetic resonance imaging, computerized tomography, and angiography. A sum of imageries are taken, and then transferred to the treatment planning system. After the images have been exported to the treatment planning system, the lesion is thereafter outlined. The actual treatment, which involves radiation delivery, is initiated when the patient is placed on the couch.

The patient’s head is normally positioned in the fitting collimator helmet corresponding to specific coordinates. At this stage, the stereotactic frame is used in positioning the lesion at the focal point of the 201 cobalt beams. The bed then moves into the gamma unit to start radiation delivery with a characteristic treatment period lasting for about an hour’s time. The duration is dependent on the complexity of treatment planning. The bed pulls out of the gamma unit when radiation delivery is over.

After the gamma knife surgery, there is usually a follow-up procedure. The effects of the surgery do occur over time. The therapy is intended to stop the growth of tumours. Therefore, the effects are seen over a period of time, maybe weeks or months. The Australian doctor will stay in contact with the patient in order to follow up on the patient’s progress. The follow up session may involve angiography images, CT or MRI.

Gamma Knife Surgery is Solution to?

Gamma knife surgery is intended to treat Australian patients with the following disorders: brain metastasis originating from other parts of the body, including melanoma, breast and lungs; acoustic neuroma, including benign tumour; meningioma, including noncancerous tumour of protective membranes situated nearby the brain as well as the spinal cord; and pituitary adenoma, including noncancerous tumour of the hormone secreting, pituitary glands. Other disorders that gamma knife surgery can be used to treat consist of but are not limited to: cavernous malformations, trigeminal neuralgia, and epilepsy.

References:

1) What is Gamma Knife Surgery (GKS)?: http://www.muh.org.au/servicesspecialties/gammaknife/forpatients/faqs.aspx

2) Gamma knife radiosurgery: http://www.msac.gov.au/internet/msac/publishing.nsf/Content/12C5978F6F65151CCA2575AD0082FDA9/$File/1028-Gamma-knife-radiosurgery-Assessment-Report.pdf