CyberKnife

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 methods, image processing programs, and robotic systems. Although "surgery" is expressed in the definition, it does not require incision and anesthesia. After determining the target's location and creating three-dimensional images, high-dose radiation is delivered. Since CyberKnife can deliver radiation beams with very high precision, healthy tissue around the diseased area is exposed to a 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 the liver, adrenal glands, prostate, lung, and other organs.

CyberKnife radiosurgery system consists of a linear accelerator that generates 6 MV X-rays and a patient or treatment bed. The robot's reported precision is 0.13 mm. Unlike the conventional radiotherapy methods, target identification by continuous imaging and the guiding system is combined with a controlled robotic system throughout the CyberKnife treatment. Thus, tumors are irradiated with very high precision.

The cyberknife system uses advanced software and imaging techniques to deliver radiation beams precisely by monitoring the movements of the tumor and patient and guiding radioactive beams accordingly. Therefore, the other radiosurgery systems need a skull frame to be secured on the cranium under local anesthesia for intracranial pathologies, while CyberKnife uses a thermoplastic mask. Patients far better tolerate this mask, while the dose can be divided into daily doses or 2 to 5 fractions for large tumors that other radiosurgery systems cannot treat due to concerns about side effects.

Considering extracranial pathologies, the robotic system can treat moving tumors with precision, even below one milliliter, with the help of intraoperative imaging. This tracking system used only in CyberKnife eliminates the need for techniques that influence patient comfort negatively, such as screwing a skull frame to the cranium to stop movement of patients or restricting breathing to minimize movements of tumors – all required by other radiosurgery devices. Since the robotic arm allows a wide range of movements, the CyberKnife system can deliver radiation beams to tumors that are located in any part of the body, including but not limited to the brain, head and neck, 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, and recurrent cancers.

With the help of the Cyberknife System, treatment can be completed within 1 to 5 days, while patients need to attend treatment sessions for 5 to 7 weeks in conventional radiation therapy. In addition, it provides a treatment option for inoperable patients who require complex surgeries or seek alternatives to surgery. There is no 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.
• There is 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.
• Techniques that decrease patient comfort, such as breathing, are unnecessary.

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, fatigue, and skin reactions (redness, tenderness, and rarely temporary hair loss). Since said risks are directly related to the target body part, your doctor will explain the risks that apply to you in detail. Moreover, your doctor will plan the required treatment for possible risks and prescribe the medicines to control these risks.

However, after this outpatient treatment, most patients can easily engage in daily activities.

CyberKnife therapy is planned as an outpatient treatment, and an appointment is scheduled.

Your doctor may instruct you to stop eating or drinking at a specific time before CyberKnife therapy or 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 much 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. You should inform your doctor if you have ever developed an allergic reaction in an imaging study. Besides, if you have a pacemaker, neurostimulator, or stent in your body, you should inform your doctor

Treatment is planned using the results of imaging studies before the therapy is started. This phase of the treatment is primarily related to the target body part. After the target's location is determined and three-dimensional images are created, your desired dose is planned. All these procedures are performed in a place called a simulation room. Since this phase needs a specific 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 are notified to you.

You will be placed on the treatment bed after you are admitted to the CyberKnife room. Vascular access is established. This vascular access will be used to infuse fluid and administer necessary medicines.
The tumor's location is marked after all relevant data are transferred to the linear accelerator device. 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 the movements of the radiotherapy device and the 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 severe side effects, it is reasonable for a family member or a friend to accompany you after the treatment. Your doctor will explain the issues (such as washing the skin in the target area with warm water and mild soap, drying with a soft towel, protecting the skin in the target area from excess heat and cold, and wearing baggy and cotton clothes- including underwear) that you need to take care after treatment. Please ask your doctor if you have questions about radiation therapy and post-treatment care. On the other hand, even though you will be prescribed for likely side effects, if you have symptoms related to your treatment, you should contact your doctor.