What is GK? It is a single treatment modality unit which emits 201 Gamma Ray beams stereotactically and precisely to the brain lesion without harming the surrounding tissues. It was invented by Professor Lars Leksell in 1968 at the Karolinska Institute, Stockholm, in Sweden.
It is a great medical contribution to humanity, and is now widely acknowledged as the best choice for the treatment of many brain diseases. This treatment requires highly trained and knowledgeable staff including physicians, nurses, medical physicists and technologists.
The technology of GK itself is a major breakthrough. It maximizes its accuracy and capacity by using imaging techniques like CT, MRI, and Cerebral Angiogram which enable a physician and medical physicist to precisely locate the lesion, and then calculate the volume and strength of the required radiation.
For treatment, the stereo-tactic frame is applied to the precise spot of the lesion to treat it. When an application session is finished, the frame will gradually degenerate, and the entire treatment procedure will be completed. The actual treatment usually lasts 30 minutes up to 2 hours. After completion of the treatment procedures, the physicians at the hospital will observe the patient for a night before discharge.
Knife Features of Key Gamma :
- Gamma Knife is not really a knife. There is no anesthesia and no incision except for certain cases that require local anesthesia for the frame fixation. It is a bloodless and almost painless procedure.
- It uses Gamma rays that is powerful enough to destroy the undesirable tissues in the brain, such as a tumor or arterio-venous malformation (AVM).
- GK treats a lesion precisely without harming surrounding brain tissues, scalp hair or skull. The precision is so high and definite that a small lesion in a range of 1 to 2 millimeters is treatable.
- The radiation can access almost any particular area of the brain. It is therefore very useful for the treatment of deeper parts or the base of the brain, which are very difficult to reach by conventional open surgery.
- The volume, strength and direction of the radiation beam are controllable so that it can be adjusted to fit the patient’s condition, and diverted from the undesirable area as required.
- There is no chance of infection or need for blood transfusion. No shaving of hair or scar on the scalp results from this treatment.
- There is no lengthy post-operative care or loss of productive life. The patient can return to normal life only a day after surgery.
- It is relatively cheap compared to long hospitalization, antibiotic therapy, rehabilitation process etc. for an open brain operation.
- No death or disability related to the GK procedure.
How GK treatment is given. The following are the step by step procedures for GK therapy :
1. Frame Fixation: The stereo-tactic frame, which is fully adjustable, is applied to the patient’s head. This is like a motorcyclist’s helmet, albeit a larger one.
2. Imaging of the Lesion: CT scan, MRI or Angiogram is conducted to draw up 3D images of the lesion(s).
3. Computing Treatment Plan: The information obtained from the imaging devices is loaded into a computer program to generate a treatment plan. Radiation dosage is then calculated according to patients’ specific situation.
4. Treatment: The patient is brought into the treatment room. Helmet and frame will be applied to the patient’s head and then the radiation process will commence. The calculated dosage will be automatically emitted into the brain. The treatment process takes only 30-120 minutes.
5. Rest and observation: Usually the patient will be observed for a night after treatment. But in many instances it is not necessary to do so.
Indications of GK treatment :
According to Dr Dittapong, GK is used for a wide variety of brain conditions. While some of them have very good responses, the physicians are perfecting treatment modalities for the others. In short, the established indications for GK treatment are as follows:
1. Vascular disorders: At present Arteriovenous Malformation (AVM) of the brain is the main target of GK therapy. Over 80% of patients resulted in total obliteration of the lesion in two years. It is very difficult to treat AVM by open brain surgery, so GK is now becoming the primary choice of treatment. In recent years, vascular aneurysm and other vessel disorders are also treated by GK.
2. Benign tumors: Over one-third of all GK treatment were applied on various types of benign brain tumors e. g. acoustic neuroma, meningioma, pituitary tumor or macroadenoma, pineal tumor, trigeminal neuroma etc. 90-95% of patients have had very good control of tumor growth. Facial nerves are consistently preserved in almost all of the cases unlike conventional open surgery, which often resulted in facial paralysis. Also, 80% of acoustic neuroma cases treated by GK did not lose hearing after GK although it is very common to occur after an open surgery.
3. Malignant tumors: Brain Metastasis (single or multiple) can be surgically radiated by Gamma Knife and has resulted in good control of tumor growth. Up to 8 lesions can be treated simultaneously by GK. This is almost impossible to do by an open surgery. Glial (malignant) tumors are increasingly treated by GK because of much better results than open surgery. Recently, progress has been made in the treatment of ocular melanoma by GK.
4. Functional targets: Response to GK treatment for Trigeminal Neuralgia is quite good in patients with intractable (severe) pain. With medications alone, some patients suffer from severe pain and disability for long time. GK is also promising results for the treatment of Parkinson’s disease, epilepsy, intractable pain and even some psychoneurotic conditions.
Why a patient should choose GK treatment :
GK is truly an alternative for the treatment of brain diseases, particularly for the treatment of tumors, AVM, various types of brain lesions, and functional disorders. As compared to conventional surgery, it is much safer and easier for the patient. He summarizes the followings as some of the advantages of GK:
For a deep lesion such as a brain stem lesion, Gamma Knife surgery is a better and less risky alternative because the radiation can access the location of the lesion for treatment without harming the surrounding tissues. There is very high risk in treating a deep lesion through conventional open surgery.
Gamma Knife surgery does not require anesthesia. This greatly reduces the risks for the elderly and patients with heart or lung diseases. Conventional open surgery requires general anesthesia.
A maximum of two days of hospitalization may be required. Conventional surgery may require intensive care, and more than 10-20 days of hospitalization. In comparison, there is no risk of blood loss, infection or pain, no incision, no scar or hair shaving. It is inexpensive and requires no post-surgery care.
How widely GK is used : At present, there are approximately 180 Gamma Knife centers worldwide. Most of these centers located in developed countries like USA, Japan, Europe and Australia. In Southeast Asia such facilities are available in Japan, Korea, Thailand and Singapore.