Cyberknife is a streotactic radiosurgery device and it is the brand name given by manufacturer.
As a definition, stereotactic radiosurgery is a treatment option that combines highly advanced radiation therapy, imaging method, image processing programs and robotic systems. Although the term “surgery” is expressed in the definition, it does not require incision and anesthesia. After the location of the target is determined and three dimensional images are created, high-dose radiation is delivered. Since CyberKnife can deliver radiation beams with very high precision, healthy tissue around the diseased area is exposed to minimal dose.
Although Cyberknife is more commonly used in the treatment of brain and spinal tumors (primary or metastatic), stereotactic body radiotherapy can be planned for tumors of liver, adrenal glands, prostate, lung and other organs.
CyberKnife radiosurgery system basically consist of a linear accelerator that generates 6 MV X-ray and a patient or treatment bed. The reported precision of the robot is 0.13 mm. Unlike the conventional radiotherapy methods, target identification by continuous imaging and guiding system is combined with computer controlled robotic system throughout the CyberKnife treatment and thus, tumors are irradiated with a very high precision.
Cyberknife system uses advanced software and imaging techniques to deliver radiation beams precisely by monitoring movements of tumor and patient and guiding radioactive beams accordingly. Therefore, the other radiosurgery systems needs to a skull frame to be secured on cranium under local anesthesia for intracranial pathologies, while CyberKnife uses a thermoplastic mask. This mask is far better tolerated by patients, while the dose can be divided into daily doses or 2 to 5 fractions for large tumors that cannot be treated by other radiosurgery systems due to concerns about side effects. Considering extracranial pathologies, the robotic system can treat moving tumors with a precision even below one milliliter with the help of intraoperative imaging. This tracking system used only in CyberKnife eliminates the need to techniques that influence patient comfort negatively, such as screwing a skull frame to the cranium to eliminate movement of patients or restricting the breathing to minimize movements of tumor – all required by other radiosurgery devices.
Since the robotic arm allows a wide range of movements, CyberKnife system can deliver radiation beams to tumors that are located in any part of the body, including but not limited to brain, head and neck, the spine, lungs, prostate, liver, pancreas, breast and other soft tissues.
On the other hand, diseases treated with CyberKnife are considered in two major groups; intracranial (inside the cranium) and extracranial (outside of the cranium). Intracranial pathologies, vascular pathologies (Arteriovenous Malformation, Cavernous Malformation), malignant tumors (Brain Metastasis, Glial Tumors (Grade II, III and IV), Ependymoma, Medulloblastoma, Chondrosarcoma), Benign Tumors (Vestibular Schwannoma, Meningioma, Glial Tumors (Grade I),Craniopharyngioma, Pituitary Adenoma, Glomus Jugulare Tumor, Hemangioblastoma, Other schwannomas, Central Neurocytoma, Cordoma) and neuropsychiatric pathologies (Trigeminal Neuralgia, Epilepsy, Cluster Headache, Parkinson's Disease, Essential Tremor, Uncontrolled Pain, Obsessive-Compulsive Disorder).
Extracranial pathologies; head and neck cancers, lung cancers, liver cancers, pancreatic cancers, soft tissue tumors, spinal tumors, prostate cancers, metastatic cancers, recurrent cancers.
With the help of Cyberknife System, treatment can be completed within 1 to 5 days, while patients need to attend treatment sessions for 5 to 7 weeks in a conventional radiation therapy. In addition, it provides a treatment option for patients who are inoperable, require complex surgeries or seek alternatives to surgery. There is no any age limitation for this therapy. No medical condition or disorder contraindicates this therapy.
Advantages of CyberKnife in treatment of cancer and other pathologies are as follows:
• Painless treatment.
• Noninvasive approach.
• No anesthesia requirement.
• Opportunity of treatment at outpatient settings.
• Unique precision protects healthy tissue and organs that are located around the tumor.
• There is no recovery period.
• Patient may resume routine activities of daily life immediately after the therapy
• It does not need to fix head or body with a frame.
• The techniques that decrease patient comfort are not needed, such as holding breath.
Because no incision is made and no anesthesia is administered in CyberKnife, the risk profile of the procedure is very low.
Possible risks include tiredness and fatigue as well as skin reactions (redness, tenderness and rarely temporary hair loss). Since said risks are directly related with the target body part, your doctor will explain the risks in detail that apply to you. Moreover, your doctor will plan the required treatment for possible risks and prescribe the medicines to control these risks.
However, most patients can easily engage in activities of daily life after this outpatient treatment.
CyberKnife therapy is planned as an outpatient treatment and an appointment is scheduled.
Your doctor may instruct you to stop eating or drinking a certain time before the CyberKnife therapy or your doctor may ask you to avoid particular foods. In addition, if you have chronic diseases such as diabetes and hypertension, your regular medicines will also be taken into consideration.
For CyberKnife therapy, it would be wise to wear comfortable clothes. Although it is an outpatient treatment, preparations and the treatment phase can cover a large part of the day.
Your history of allergy against contrast media will be addressed, as imaging studies, such as CT and MRI, are used in CyberKnife treatment. If you have ever developed an allergic reaction in an imaging study, you should absolutely inform your doctor. Besides, if you have pacemaker, neurostimulator or stent in your body, you should inform your doctor.
Treatment is planned using results of imaging studies before the treatment is actually started. This phase of the treatment is largely related with the target body part. After the location of the target is determined and three dimensional images are created, the dose you will receive is planned. All these procedures are performed in the place, called simulation room. Since this phase needs a certain time, you will usually be discharged after the data required for planning the treatment are collected, and the date and time of the actual treatment is notified to you.
After you are admitted to the CyberKnife room, you will be placed on the treatment bed. A vascular access is established. This vascular access will be used both for infusing fluid and administering necessary medicines.
After all relevant data are transferred to the linear accelerator device, the location of the tumor is marked. However, this marking process is not required for all cancers. Images are acquired to verify that you are correctly positioned.
When the treatment begins, you can feel movements of both radiotherapy device and the treatment bed. However, the healthcare personnel in the command room can see and hear you throughout the treatment. Therefore, you do not need to worry. After the radiation dose is delivered, your treatment will be completed.
Although CyberKnife has no serious side effects, it is reasonable to a family member or a friend to accompany you after the treatment.
Your doctor will explain the issues (such as washing the skin at target area with warm water and mild soap, drying with a soft towel, protection of the skin at target area from excess heat and cold, wearing baggy and cotton clothes- including underwear) that you need to take care after treatment.
If you have questions about radiation therapy and post-treatment care, please ask your doctor.
On the other hand, even though you will be prescribed for likely side effects, if you have symptoms that you think related with your treatment, you should absolutely contact your doctor.