The Cyberknife is an innovative technology for Radiosurgery, with the aim of offering both patients with tumor lesions and not, a broader spectrum of action for treating the disease, alongside the already established practice surgical and radiation therapy provided by Hospitals and more from General Medicine. This new technique of treatment called Cyberknife, offers the possibility of sending high doses of radiation to targets located anywhere in the body. In this way you can destroy solid tumor lesions or to treat functional disorders such as epilepsy, Parkinson’s disease, chronic pain pharmaco refractory (e.g. trigeminal neuralgia) and many other disorders. The system is completely non-invasive treatment with a median duration of approximately 1 hour. The treatment can be performed in outpatients without hospitalization or even on a purely outpatient basis. Cyberknife Radiosurgery is one of the most complex and effective technologies available today in the medical field and is spreading all over the world with impressive speed. About 200 units have been purchased to date (about 100 in the U.S. alone), although impressive considering that the ‘unit has been on the market only 5 years ago. The Cyberknife was invented and developed by Professor John Adler, a neurosurgeon at Stanford University, using a series of technological innovations readily available at this center located in the heart of Silicon Valley. Some of the most interesting of the Cyberknife clinical applications (for example the possibility of treating functional indications such as trigeminal neuralgia, the epilepsy, etc. ..) have been developed at Stanford by an Italian student of Prof. Adler, Dr Pantaleo Romanelli ( see references below). To date, the Stanford University has treated over 3000 patients with cancer of any district or functional body and remains the principal international point of reference for the Cyberknife Radiosurgery. The Stanford University is open to full cooperation in order to develop research protocols in this area.
Radio-surgery and CyberKnifeTM System.
The Radiosurgery uses high doses of radiation to target the lesion precisely, with the aim to have the same effect of open surgery, hence the term “radio-surgery.” A treatment can take place in single session radio-surgery or hypo fractionated regime, i.e. in 2-5 fractions. It differs from radiation therapy, which instead uses much lower doses delivered in several sessions, typically 30, as a technique far less precise. Besides affecting the cancer cells it is necessary to protect the critical organs and surrounding healthy tissue and this can only be obtained with high accuracy radiation doses or by administering non-lethal for healthy organs and tissues.
The accuracy required for the use of high doses of radiation has historically been achieved for the treatment of intracranial lesions by using a system of rigid immobilization, stereotactic helmet. This, screwed to the patient’s head using local anesthesia, allows fixing the position of the head during treatment and provides a reference system to locate the coordinates of the lesion during treatment planning and treatment. However, this approach, typical of the Gamma Knife and linear accelerator conventional treatment does not allow to split (if not particularly complex cases and loss of accuracy), or to treat extra cranial lesions with the same definition of accuracy required for radio-surgery. With the evolution of technology, radio-surgery is now feasible without the need for a fixed disk as the stereotactic helmet, but using a reference system even more reliable because the lesion than static in nature: the skull itself.
CyberKnife Robotic Radiosurgery System TM is the technological evolution. It is a compact linear accelerator mounted on a robotic arm with six degrees of freedom driven by computers.
Thanks to a guidance system using X-ray images, the CyberKnifeTM system identifies and follows the position of the lesion to be treated during the entire treatment. This provides sub-millimeter accuracy required, because any movement of the patient is offset by a correction of the beam by the robot. The total clinical accuracy of the CyberKnife is less than 0.95mm from specific injuries to fix. It includes all the possible errors resulting from the CT scan on which prepares the treatment plan, the errors due to the accuracy of the imaging system in the identification of the target position, the pointing error and mechanical repositioning of the robot.
Published tests performed on a puppet show how the accuracy is generally better than that specific (Yu C, Main W, Taylor D, Kuduvalli G, Wang M, Apuzzo M, Adler J. An Anthropomorphic Phantom Study of the Accuracy of CyberKnife Spinal Radiosurgery. Neurosurgery 55 (5):1138-1149, November 2004). The data show that the accuracy achieved by the imaging system is comparable to that obtained with the use of stereotactic helmet. The benefits are enormous, including the abolition of the helmet:
greater patient comfort and acceleration of the time of the clinical procedure,
possibility of splitting the treatment,
possibility of extending to the whole body this kind of treatment.
While a system like the Gamma Knife treatment is possible only on the first intracranial and cervical vertebrae in a single session, with the CyberKnife Radiosurgery is applicable not only to the district head, but all along the spine, massive facial, lung , liver, pancreas and prostate. It ‘also possible to divide the treatment it is vital in many cases where the lesion is adjacent to critical structures such as the spinal cord or when the patient has already undergone radiation and normal tissues can not receive further dose in quantities harmful.
All this represents an absolute innovation in the field of Radiosurgery and the CyberKnife differs from any other device on the market today.
The clinical applications, initially developed in neurosurgery, are now growing in relation to all other parts of the body. To date, in the world, the 50% of treatments cover extra cranial sites, also saw the continued development of this technology to make more reliable and accurate treatment of lesions that move with the breath and still located outside of the skull. The CyberKnife, thanks to the module SynchronyTM, is the only system in the world with an accuracy of 1.5mm in the treatment of lesions that move with the breath.
The data show that the weight of the extra cranial applications is important, alongside purely neurosurgical realm, for the realization of a unit Radiosurgery that provides a wide range of possibilities for each type of patient. Are given below the graphs showing the trend of patients treated with CyberKnife in the world for different parts of the body.
Nowadays, to think about Radiosurgery as a technique suitable only in brain field or applicable only to this, it is considered a limitation. Epidemiological data relating to cancer in Italy – similar to what happens in the world – show that the incidence is higher for lung lesions, prostate, breast. The Italian Association of Cancer Registries, AIRTUM (www.registri-tumori.it) says 253,000 incidents of cancer cases estimated in Italy in 2006 (age 0-84 years). The data obtained through the Registers between 1998 and 2002 show the top five cancers in terms of frequency, by age, reported in the table
A clear idea of the development of tumors in different locations of the body is outlined by the underlying data.
Statistically 1 man on 15 and 1 woman on 71 developed lung cancer, 1 man on 16 developed prostate cancer, 1 man on 139 and 1 woman on 188 developed cancer of the central nervous system.
Table 03: development of tumors in different body locations
Epidemiological data prefer a device that allows to treat the greatest number of diseases and especially that allows to face the large extra cranial series with the same practice than intracranial.
Another aspect not to be underestimated is the organizational one. Radiosurgery eliminates the long lead times typical of hospitalization for surgery, but the patient preparation, drawing up a plan of care and treatment that requires good organization and an optimization of the time for each operator. The flexibility in the clinical planning becomes a key point. The need to fix a stereotactic helmet to the head of the patient means to prepare the patient, perform imaging, implement the treatment plan and treat the patient in a single day and all into subsequent steps and tight. The CyberKnife provides the ability to program each of these points at times or different days, depending on the case.
Regarding the number of treatments that can be made daily with the CyberKnife System, these may be 2 to 3 patients (with a maximum of 4).
List of publications.
Romanelli P, Chang D, Koong A, Adler J: Cyberknife extra cranial Radiosurgery using the, Techniques in Neurosurgery, September 2003
Romanelli P, Heit G, Chang S, Pham C, Martin D, Adler J: Frameless Radiosurgery for trigeminal neuralgia, stereotactic and Functional Neurosurgery, January 2004
Romanelli P, Esposito V, Adler J: Neuroablative procedures for chronic pain,
Neurosurgery Clinics of North America, July 2004
Lim M, Villavicencio A Burneikiene S, Chang S, Romanelli P and others: CyberKnife Radiosurgery for Idiopathic Trigeminal Neuralgia, Neurosurgery Focus, May 2005
Lim, M, Cotrutz C, Romanelli P, Schaal D, Gibbs I, Chang S, Adler J: CT stereotactic Radiosurgery Using Cisternography Isocentric Planning and Non-Treatment of Trigeminal Neuralgia for the, Minimally Invasive Neurosurgery, Giugno2005
Romanelli P, Schweikard A, Schlaefer A, Adler J: Computer-aided robotic Radiosurgery. Computer Aided Surgery, June 2006.
Romanelli P, Anschel D: Radiosurgery for epilepsy. Lancet Neurology, June 2006.
Stancanelli J, Romanelli P, Modugno N, Cantore GP: Atlas-based identification of targets for functional Radiosurgery, Medical Physics, July 2006.
Romanelli P, Schaal D, Adler J: Image-guided intracranial and extra cranial lesions radio ablation for. Technology in Cancer Research, August 2006
Romanelli P, Adler J, Cantore G: Radiosurgery for spinal lesions, Nature Clinical Practice Oncology, in press
Villavicentio A, Lim M, Burneikine S, Romanelli P, et al: Cyberknife Radiosurgery for trigeminal neuralgia, Neurosurgery, in press.