The CyberKnife is an exciting, innovative new approach to radiosurgery. Unlike previous radiosurgery methods that rely on mechanical immobilization and manipulation of the patient and machine, the CyberKnife utilizes fully automated image guided robotics to achieve stereotactic accuracy not only in the head but also in sites throughout the body. It has all the advantages of traditional stereotactic radiosurgery yet it spares the patient the inconvenience and risk of having a metal frame screwed to the skull. The CyberKnife employs image guidance technology in the place of the metal frame previously noted. Treatments can be given in a single session or in several sessions on successive days, whichever will optimize the effectiveness of the therapy and minimize the risk of complications. In addition and most significantly, the benefits of radiosurgery can now be made available to patients with disease outside the brain (eg in the neck or spine).
The CyberKnife is the only radiosurgery system that continually checks and compensates for patient position and movement through an image-guidance system during treatment. The scientific principles involved are similar to those used in guiding cruise missiles. This is made possible by incorporating a low dose X-ray camera system consisting of diagnostic X-ray tubes and cameras as shown in the diagram below. The cameras use detectors linked to an image registration computer. Data is then transferred to the computer controlled robot, updating the robot gantry position to assure that the treatment beam from the Linac points at the intended location within the patient with millimeter accuracy. CyberKnife is able to respond virtually in real time to any patient movement during treatment. The patient meanwhile lies on the couch while the CyberKnife moves around the patient delivering the treatment dose. The operator controls the progress of the treatment from outside the room via video monitors and an intercom, thereby assuring the patient’s safety.
|
The CyberKnife uses a 6MV compact linear accelerator (Linac) mounted on the robot (Gantry). The Linac produces a high energy X-ray beam that is capable of penetrating deep into the patient to deliver a precisely defined, desired dose of radiation in the patient. The robot points the X-ray beam from multiple positions and angles to deliver a series of up to 1248 radiosurgical beams one after another precisely to the target tissue in the patient as is shown in the drawing below where beams are represented by red line; the patient’s head is grey; the target is blue, and a critical structure to be avoided (the optic chiasm in the case shown) is purple. The combined effect of all the beams coming together in the target is a high and effective dose of radiation in the target tissue with minimal radiation exposure to surrounding healthy tissue.
|
Treatment planning is done based on fused MRI, PET and CT data sets using a computer program on a Silicon Graphics workstation integrated with the treatment delivery system. Plans are developed by a multidisciplinary team including a surgeon, radiation oncologist, and physicist. Since most clinical targets are irregular in shape, plans are developed using an inverse planning algorithm that employs linear programing to devise an individualized set of small beams each directed to treat a portion of the target in the patient. The program adjusts the dose delivered by each beam so that a uniform dose of radiation will conform to the shape of the target. Superior homogeneity and conformality of dose is achieved by this means.
The guidance system uses images of the patient digitally reconstructed from the planning CT data set in the geometry of the imaging system. These are compared in real time to live images of the patient in the treatment position. New robot coordinates are then calculated and communicated automatically to the robot computer. The robot then directs the beam to the planned location in the patient. To assist the patient to maintain a stable position (but not a rigidly fixed position), a thermoplastic mask is worn during the treatment. The mask is individually made for each patient.
For treatment sites in the spine, an alternative approach is employed. In this case, tiny stainless steel screws or gold markers are percutaneously inserted into the bone near the target in an outpatient procedure prior to the planning CT study. During treatment, the guidance system automatically locates these markers and calculates new robot coordinates based on their actual position. The appearance of the markers in the planning CT scan is shown in the images below where the marker is shown at the intersection of colored crosshairs; the clinical target is shown outlined in red, and the spinal cord is in green.
The CyberKnife is the only system available which can compensate for patient movement to ensure highly accurate delivery of radiation during treatment.
CyberKnife is distinguished by the following features:
|
| The robotic arm is able to direct radiation beams to reach tumors previously considered untreatable with surgery or radiation.
|
|
|
| No painful head frame is screwed to the patient’s skull.
|
|
|
| Better quality of life is experienced by the patient during and after treatment.
|
|
|
| Stereotactic radiosurgery can be done in one or several sessions, depending on the needs of the patient.
|
|
|
| Radiosurgery can be done with stereotactic accuracy anywhere in the body.
|
|
|
| The CyberKnife at Newport Diagnostic Center can non-invasively achieve a surgical-like outcome for lesions of the brain and spine.
|
|
|
| The CyberKnife is the first and only commercial application of robotic stereotactic radiosurgery for the spine and the spinal cord.
|
|
|
| No frame
|
|
|
| No incision for radiosurgery in the head
|
|
|
| No sedation during treatment
|
|
|
| No risk of infection for brain radiosurgery
|
|
|
| Treatment provided on an outpatient basis
|
|
|
| Reduced pain
|
|
|
| Minimal to no perceivable recovery period
|
|
|
| Lower risk of complications
|
|
|
| Treatment planning scans can be scheduled at the patient’s convenience, up to several days before the treatment
|
|
|
| Treatment of lesions untreatable by open surgery or other radiosurgical systems
|
|
|
| Lesions that have previously undergone the maximum allowed dose of radiation can be treated
|
Physician referral is necessary for patients to begin the evaluation process. Our Tumor Board carefully reviews each potential patient's clinical condition to determine whether CyberKnife is an appropriate treatment option. This is done in close consultation with a patient's personal physician. If you're interested in CyberKnife as a treatment option, ask your physician to contact our medical staff at (949) 467-3063.
Patients who wish to be evaluated for CyberKnife radiosurgery should be prepared to have the following information available:
|
|
| A signed records release form which is available upon request or can be downloaded from our site (records release form).
|
|
|
| Original films from their most recent MRI scan, and prior MRI studies for comparison
|
|
|
| Records of any prior tests, medical or surgical treatments, radiation treatments
|
|
|
| Audiogram results (if applicable -- ask your physician)
|
|
|
| Vision tests (if applicable)
|
|
|
| Endocrine studies (if applicable)
|
|
|
| Chemotherapy or radiation therapy reports (if applicable)
|
CyberKnife treatment consists of the following:
Evaluation
All patients who come to the Center will receive a comprehensive evaluation by our team of medical specialists which include surgeons, radiation oncologist and a medical physicist. Our physicians will sit down with you to review your medical history in detail. It is best if you know the dates of any medical procedures (including surgery, radiation or chemotherapy) related to your condition.
If you have any questions about preparing for your consultation, please call us or consult your doctor.
Once a recommendation of CyberKnife radiosurgery has been made by the multidisciplinary Tumor Board, a special MRI study is usually needed to properly define the treatment area. MR spectroscopy and/or PET/CT is often used and is available at NDC for physician and patient convenience.
Treatment Planning
Treatment planning, for those patients being treated for tumors or conditions in the head, begins with creation of a thermoplastic mask which is custom made for them on-site at NDC.
Those patients who have tumors or conditions in the spine or elsewhere in the body outside the head will have markers inserted through a small incision in the skin under local or general anesthetic and is performed as an outpatient procedure at a local area hospital.
All patients will undergo a high resolution CT with contrast for treatment planning purposes.
Actual treatment planning is done by team members consisting of surgeons and radiation oncologists along with a medical physicist.
Treatment
Most patients receive treatment in a single session (usual) or, when needed for medical reasons, 3 to 5 (but occasionally as many as 30) sessions on successive days. The patient lies comfortably on the treatment couch and wears the mask, when applicable, while the robotic arm delivers the radiation. Most treatments last from one to two hours. Patient can go home immediately after the procedure and resume normal day-to-day activities.
Follow-up
It is of paramount importance that patients agree to cooperate in having their follow-up examinations at Newport Diagnostic Center or by returning to their referring physicians. Patients are responsible for making sure their records and diagnostic studies are sent to us if they receive follow-up elsewhere.
Physicians interested in referring patients for CyberKnife treatment should call the CyberKnife Department at (949) 467-3060 to discuss patient prognosis and treatment options. The referring physician and those participating in the management of the patient will be kept up to date as treatment is administered. Often we get patients who send films and records for an opinion and we would like ask that these patients to consult their personal physician and have them contact us to assist in determining whether they are suitable candidates for radiosurgery.
Cancer including
|
|
| Metastases to the brain from cancers such as lung cancer, breast cancer, melanoma, synovial cell
|
|
|
| Metastases to the spine from cancers such as lung cancer, breast cancer, prostate cancer, thyroid cancer
|
|
|
| Recurrent or residual primary cancer of the brain such as glioblastoma multiforme, epenymoma
|
|
|
| Recurrent or residual primary cancer in or adjacent to the spine or spinal cord such as sarcoma, malignant chordoma
|
|
|
| Benign tumors in the brain, base of the skull, and spine including
|
|
| Meningioma
|
|
|
| Schwannoma including acoustic neuroma and, in select cases, NF2
|
|
|
| Glomus jugulare
|
|
|
| Chordoma
|
|
|
| Pituitary adenomas
|
|
|
| Craniopharyngioma
|
|
|
| Hemangioblastoma
|
|
|
|
| Malformations of the blood vessels including
|
|
| Arteriovenous malformation in the brain
|
|
|
| Arteriovenous malformation in the spinal cord
|
|
|
|
| Functional diseases such as Trigeminal neuralgia
|
|
|
| Lumbar radiculopathy (only on a research protocol)
|
Top