Jump to content

Cyberknife (device): Difference between revisions

From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
AskJoanne (talk | contribs)
222 edits
Line 85: Line 85:
*[[Robotic surgery]]
*[[Robotic surgery]]
*[[NCI-designated Cancer Center]]s in the United States
*[[NCI-designated Cancer Center]]s in the United States
*[[South Florida Radiation Oncology (SFRO) ]]s in the South Florida


== References ==
== References ==

Revision as of 05:33, 23 March 2010

The CyberKnife is a frameless robotic radiosurgery system invented by John R. Adler, a Stanford University Professor of Neurosurgery and Radiation Oncology, and Peter and Russell Schonberg of Schonberg Research Corporation. The two main elements of the CyberKnife are (1) the radiation produced from a small linear particle accelerator and (2) a robotic arm which allows the energy to be directed at any part of the body from any direction.

The CyberKnife system is a method of delivering radiotherapy, with the intention of targeting treatment more accurately than standard radiotherapy.[1] It is not widely available, although the number of centres offering the treatment around the world has grown in recent years to over 150, particularly centered in North America, East Asia and Europe - the first UK CyberKnife was opened at The Harley Street Clinic [1] in February 2009.

The CyberKnife system is sold by the company Accuray, located in Sunnyvale, California. The CyberKnife system is used for treating benign tumors, malignant tumors and other medical conditions.[2][3]

The main features of the CyberKnife system, shown on a Fanuc robot

Main Features

Several generations of the CyberKnife system have been developed since its initial inception in 1990. There are two essential features of the CyberKnife system that set it apart from other stereotactic therapy methods.

Robotic Mounting

The first is the fact that the radiation source is mounted on a precisely controlled industrial robot. The original CyberKnife used a Japanese Fanuc robot[4], however the more modern systems use a German KUKA KR 240.[5] Mounted on the Robot is a compact X-band linac that produces 6MV X-ray radiation. The linac is capable of delivering approximately 600 cGy of radiation each minute - a new 800 cGy / minute model was announced at ASTRO[6][7] 2007. The radiation is collimated using fixed tungsten collimators (also referred to as “cones”) which produce circular radiation fields. At present the radiation field sizes are: 5, 7.5, 10, 12.5, 15, 20, 25, 30, 35, 40, 50 and 60 mm. ASTRO 2007 also saw the launch of the IRIS[7] variable-aperture collimator which uses two offset banks of six prismatic tungsten segments to form a blurred dodecagon field that is almost circular. The IRIS replicates the fixed collimator sizes without the need for exchanging the fixed collimators. Mounting the radiation source on the robot allows complete freedom to position the radiation within a space about the patient. The robotic mounting allows very fast repositioning of the source, which enables the system to deliver radiation from many different directions in a feasibly short treatment time.

Image Guidance

The image guidance system is the other essential item in the CyberKnife system. X-ray imaging cameras are located on supports around the patient allowing instantaneous X-ray images to be obtained.

6D Skull

The original (and still utilized) method is called 6D or skull based tracking. The X-ray camera images are compared to a library of computer generated images of the patient anatomy. Digitally Reconstructed Radiographs (or DRR's) and a computer algorithm determines what motion corrections have to be given to the robot because of patient movement. This imaging system allows the CyberKnife to deliver radiation with an accuracy of 0.5mm without using mechanical clamps attached to the patient's skull.[8] The use of the image guided technique is referred to as frameless stereotactic radiosurgery. This method is referred to as 6D because corrections are made for the 3 translational motions (X,Y and Z) and three rotational motions. It should be noted that it is necessary to use some anatomical or artificial feature to orient the robot to deliver X-ray radiation, since the tumor is never sufficiently well defined (if visible at all) on the X-ray camera images.

6D Skull tracking

Xsight

Additional image guidance methods are available for spinal tumors and for tumors located in the lung. For a tumor located in the spine, a variant of the image guidance called Xsight-Spine[9] is used. The major difference here is that instead of taking images of the skull, images of the spinal processes are used. Whereas the skull is effectively rigid and non-deforming, the spinal vertebrae can move relative to each other, this means that image warping algorithms must be used to correct for the distortion of the X-ray camera images.

A recent enhancement to Xsight is Xsight-Lung[10] which allows tracking of some lung tumors without the need to implant fiduciary markers.

Fiducial

For soft tissue tumors, a method known as fiducial tracking can be utilized.[11] Small metal markers (fiducials) made out of gold for bio-compatibility and high density to give good contrast on X-ray images are surgically implanted in the patient. This is carried out by an interventional radiologist, or neurosurgeon. The placement of the fiducials is a critical step if the fiducial tracking is to be used. If the fiducials are too far from the location of the tumor, or are not sufficiently spread out from each other it will not be possible to accurately deliver the radiation. Once these markers have been placed, they are located on a CT scan and the image guidance system is programmed with their position. When X-ray camera images are taken, the location of the tumor relative to the fiducials is determined, and the radiation can be delivered to any part of the body. Thus the fiducial tracking does not require any bony anatomy to position the radiation. Fiducials are known however to migrate and this can limit the accuracy of the treatment if sufficient time is not allowed between implantation and treatment for the fiducials to stabilize.[12][13]

Synchrony

The final technology of image guidance that the CyberKnife system can use is called the Synchrony system. The Synchrony system is utilized primarily for tumors that are in motion while being treated, such as lung tumors and pancreatic tumors.[14] The synchrony system uses a combination of surgically placed internal fiducials, and light emitting optical fibers (markers) mounted on the patient skin. Since the tumor is moving continuously, to continuously image its location using X-ray cameras would require prohibitive amounts of radiation to be delivered to the patients skin. The Synchrony system overcomes this by periodically taking images of the internal fiducials, and predicting their location at a future time using the motion of the markers that are located on the patient's skin. The light from the markers can be tracked continuously using a CCD camera, and are placed so that their motion is correlated with the motion of the tumor. A computer algorithm creates a correlation model that represents how the internal fiducial markers are moving compared to the external markers. The Synchrony system is therefore continuously predicting the motion of the internal fiducials, and therefore the tumor, based on the motion of the markers. The correlation model can be updated at any time if the patient breathing becomes in any way irregular. The advantage of the Synchrony system is that no assumptions about the regularity or reproducibility of the patient breathing have to be made. To function properly, the Synchrony system requires that for any given correlation model there is a functional relationship between the markers and the internal fiducials. The external marker placement is also important, and the markers are usually placed on the patient abdomen so that their motion will reflect the internal motion of the diaphragm and the lungs.

RoboCouch

A new robotic six degree of freedom patient treatment couch called RoboCouch[15] has been added to the CyberKnife which provides the capability for significantly improving patient positioning options for treatment.

Frameless

The frameless nature of the CyberKnife also increases the clinical efficiency. In conventional frame-based radiosurgery, the accuracy of treatment delivery is determined solely by connecting a rigid frame to the patient which is anchored to the patient’s skull with invasive aluminum or titanium screws. The CyberKnife is the only radiosurgery device that does not require such a frame for precise targeting.[16] Once the frame is connected, the relative position of the patient anatomy must be determined by making a CT or MRI scan. After the CT or MRI scan has been made, a radiation oncologist must plan the delivery of the radiation using a dedicated computer program, after which the treatment can be delivered, and the frame removed. The use of the frame therefore requires a linear sequence of events that must be carried out sequentially before another patient can be treated. Staged CyberKnife radiosurgery is of particular benefit to patients who have previously received large doses of conventional radiation therapy and patients with gliomas located near critical areas of the brain. Unlike whole brain radiotherapy, which must be administered daily over several weeks, radiosurgery treatment can usually be completed in 1-5 treatment sessions. Radiosurgery can be used alone to treat brain metastases, or in conjunction with surgery or whole brain radiotherapy, depending on the specific clinical circumstances.[17]

By comparison, using a frameless system, a CT scan can be carried out on any day prior to treatment that is convenient. The treatment planning can also be carried out at any time prior to treatment. During the treatment the patient need only be positioned on a treatment table and the predetermined plan delivered. This allows the clinical staff to plan many patients at the same time, devoting as much time as is necessary for complicated cases without slowing down the treatment delivery. While a patient is being treated, another clinician can be considering treatment options and plans, and another can be conducting CT scans.

In addition, very young patients (pediatric cases) or patients with fragile heads because of prior brain surgery cannot be treated using a frame based system.[18] Also, by being frameless the CyberKnife can efficiently re-treat the same patient without repeating the preparation steps that a frame-based system would require.

The delivery of a radiation treatment over several days or even weeks (referred to as fractionation) can also be beneficial from a therapeutic point of view. Tumor cells typically have poor repair mechanisms compared to healthy tissue, so by dividing the radiation dose into fractions the healthy tissue has time to repair itself between treatments.[19] This can allow a larger dose to be delivered to the tumor compared to a single treatment.[20]

Comparison with other Stereotactic systems

Gamma Knife

One of the most widely known stereotactic radiosurgery systems is the Gamma Knife. The Gamma Knife was originally developed by Lars Leksell, remains the gold standard method for delivery of stereotactic radiosurgery to the brain and is manufactured by Elekta. John Adler, the inventor of the CyberKnife system spent time training with Lars Leksell in Stockholm at the Karolinska Institute in 1985. The GammaKnife system uses 201 Cobalt-60 sources located in a ring around a central treatment point ("isocenter"). The Gamma Knife system is equipped with a series of 4 collimators of 4mm, 8mm, 12mm and 16mm diameter, and is capable of submillimeter accuracies. The Gamma Knife system does however require a head frame to be bolted onto the skull of the patient, and is only capable of treating cranial lesions. As a result of frame placement, treatment with Gamma Knife does not require real time imaging capability as the frame does not allow movement during treatment. This is the reason that the Gamma Knife system is likely to be more accurate than Cyber Knife.[21] The Cyberknife Society and Accuray maintain that there are no peer-reviewed published papers that establish Gamma Knife as being more accurate than CyberKnife.[22][23]

Novalis

Another popular Stereotactic system is the Novalis produced by Brainlab.[24] The Novalis radiosurgery system utilizes a small computer controlled micro Multi Leaf Collimator mMLC, that can produce many complicated shapes. The maximum radiation field size that the Novalis can produce is 98 mm x 98 mm, and the minimum is 3mm x 3mm allowing a considerable range of tumors to be treated. The Novalis system also has X-ray imaging using amorphous silicon flat panel X-ray detectors. A 2D/3D image fusion of the patient setup X-rays with digitally reconstructed radiographs from a planning CT scan quickly determines a correction vector for the patients position. Infrared fiducial markers attached to the patient then allow precise tracking of the correction vector's application to the patient's position via an infrared camera and a couch that can move in all six dimensions enables the precise positioning of the patient. Patient immobilization can also be performed framelessly using the patients internal anatomy as the frame of reference. An implanted marker based respiratory tracking option known as ExacTrac Gating is also an option. BrainLAB's Novalis has become a leading player in the world of neurosurgery.[25]

Conventional Linac

Conventional X-ray therapy linear accelerators can be utilized for radiosurgery, either by the use of additional blocking cones or by a removable or built in micro MLC system. Examples of removable micro MLC units are the Ergo from 3D line],[26] the mMLC manufactured by Brainlab,[24] and the AccuKnife produced by Direx.[27], or the Novalis TX

Clinical uses

Since August 2001, the CyberKnife system has FDA clearance for treatment of tumors in any location of the body.[28] Some of the tumors treated include: pancreas,[29][30] liver,[31] prostate,[32][33] Spinal Lesions,[34] head and neck cancers,[35] and benign tumors.[36]

None of these studies have shown any general survival benefit over conventional treatment methods. By increasing the accuracy with which treatment is delivered there is a potential for dose escalation, and potentially a subsequent increase in effectiveness, particularly in local control rates. However the studies cited are so far limited in scope, and more extensive research will need to be completed in order to show any effects on survival.[30]

In 2008 actor Patrick Swayze was among the people to be treated with Cyberknife radiotherapy.[37]

Cyberknife worldwide locations

CyberKnife systems have been installed in over 150 locations worldwide,[38] including 100 hospitals in the United States.[39][40][41][42][43] For example, in the US, they are installed at St Mary's-Duluth Clinic in Duluth, Minnesota http://www.smdc.org, the The Community Cancer Center http://www.cancercenter.org/ between OSF St. Joseph Medical Center and BroMenn Regional Medical Center in Bloomington-Normal, Illinois. Stanford University Medical Center (Blake Wilbur Cyberknife Center) and the Comprehensive Cancer Center at Stanford University, Georgetown University Hospital, UCSF Medical Center, St. Mary's of Michigan [2], Kennestone Hospital in Georgia, Baylor University Medical Center, St. Luke's Episcopal Hospital, the University of Pittsburgh, and CyberKnife of Southern California[3]at Vista, Apollo Specialty Hospitals, India, , Healthcare Global (HCG) at Bangalore, India [4]. Additional locations in the United States include the Denver CyberKnife in Colorado, Cyberknife Center at Capital Health [5] in Trenton, New Jersey, Philadelphia CyberKnife[6], Rocky Mountain CyberKnife in Boulder, Colorado [7], Salt Lake CyberKnife [8], Reno CyberKnife [9], CyberKnife St. Louis - St. Louis University Hospital - St. Louis, MO [10] and Oklahoma CyberKnife in Tulsa, Oklahoma.[11]. The first CyberKnife outside of Stanford University where it was developed was installed at Newport Diagnostic Center (NDC) in Newport Beach, Calif. [[12]]. In January, 2010, NDC installed the latest CyberKnife, the G4800 MU. The CyberKnife at Mercy Hospital in Miami[[13]], Florida was installed in January, 2010 and the first patient was treated on January 14, 2010.

Stanford University has treated over 2,500 patients using the Cyberknife system, and worldwide over 40,000 patients have been treated.[44][45]

Overlook Hospital in Summit, New Jersey was the first hospital in the New York metro area to offer the CyberKnife Stereotactic Radiosurgery System. Today, Overlook has performed the second most treatments of prostate cancer with the cyberknife in the world. [46]

There are 19 centers in Japan, 5 in China, 5 in South Korea, 5 in Taiwan ROC, 3 in France, 3 in Italy, 3 in Canada (1 each in Montreal, Ottawa, and Hamilton), 2 in Turkey, and 1 each in Germany, Greece,[47] Spain,[48] Netherlands, Switzerland,[49], United Kingdom- the first UK CyberKnife was opened at The Harley Street Clinic in February 2009: http://www.cyberknifecentrelondon.co.uk ,[50][51][52] India,[53] Malaysia, Thailand in Ramathibodi Hospital and Vietnam.

Several Cyberknife video clips can be found on YouTube.[54][55]

See also

References

  1. ^ Dr Nick Plowman, Senior Clinical Oncologist, London HCA - How CyberKnife Works
  2. ^ http://med.stanford.edu/neurosurgery/patient_care/radiosurgery.html Stanford Neurosurgery
  3. ^ Robotic Whole Body Stereotactic Radiosurgery: Clinical Advantages of the CyberKnife Integrated System. . . . Reprinted by permission from The International Journal of Medical Robotics and Computer Assisted Surgery - Robotics Online
  4. ^ Fanuc Robotics http://www.fanucrobotics.com/
  5. ^ Kuka Roboter GmbH http://www.kuka.com/en/
  6. ^ ASTRO annual meeting website
  7. ^ a b Accuray announce 4 new products at ASTRO
  8. ^ An Analysis of the Accuracy of the 6D Tracking With CyberKnife Inoue M, Sato K, Koike I International Journal of Radiation Oncology, Biology, Physics 01 November 2006 (Vol. 66, Issue 3 (Supplement), Page S611)
  9. ^ Accuray::Xsight Spine Tracking System
  10. ^ Accuray::Xsight Lung Tracking System
  11. ^ CyberKnife Radiosurgery - Fiducial Overview
  12. ^ Fuller CD, and Scarbrough TJ, MD Fiducial Markers in Image-guided Radiotherapy of the Prostate. U S ONCOLOGICAL DISEASE 2006 75-78
  13. ^ Murphy MJ. Fiducial-based targeting accuracy for external-beam radiotherapy. Medical Physics March 2002 Volume 29, Issue 3, pp. 334–344
  14. ^ Phase I study of stereotactic radiosurgery in patients with locally advanced pancreatic cancer Koong AC, Le QT, Ho A, Fong B, Fisher G, Cho C, Ford J, Poen J, Gibbs IC, Mehta VK, Kee S, Trueblood W, Yang G, Bastidas JA International Journal of Radiation Oncology*Biology*Physics 15 March 2004 (Vol. 58, Issue 4, Pages 1017–1021)
  15. ^ Accuray::RoboCouch Patient Positioning System
  16. ^ Rocky Mountain CyberKnife Center - Brain Metastases
  17. ^ Chang SD, Min W, Martin DP, Gibbs IC, Heilbrun MP. An analysis of the accuracy of the CyberKnife: A robotic frameless stereotactic radiosurgical system. Neurosurgery. 2003; 52: 140-147.
  18. ^ http://biz.yahoo.com/bw/070115/20070115005165.html?.v=1
  19. ^ Radiobiology for the Radiologist Eric J. Hall Lippincott Williams & Wilkins; 5th edition (2000)
  20. ^ Comparisons between Gamma Knife, BrainLAB’s Novalis and Cyberknife
  21. ^ Gamma Knife vs. CyberKnife :: Gamma Knife Center :: Wake Forest University Baptist Medical Center
  22. ^ Radiosurgery CyberKnife Overview
  23. ^ Yu, C, Main W, Taylor D, Kuduvalli G, Apuzzo M, Adler J, Wang M: An Anthropomorphic Phantom Study of the Accuracy of CyberKnife Spinal Radiosurgery. Neurosurgery, 55(5):1138–1149, 2004
  24. ^ a b Brainlab http://www.brainlab.com/
  25. ^ BBC news - Aug 2003 - Curing cancer with computers
  26. ^ 3D line http://www.3dline.com/
  27. ^ Direx http://www.direx.co.il/accu.htm
  28. ^ "CyberKnife::Reimbursement Information." CyberKnife. Web. 10 Mar. 2010.<http://www.cyberknife.com/reimbursement-insurance/index.aspx>
  29. ^ Phase I study of stereotactic radiosurgery in patients with locally advanced pancreatic cancer. Koong AC, Le QT, Ho A, Fong B, Fisher G, Cho C, Ford J, Poen J, Gibbs IC, Mehta VK, Kee S, Trueblood W, Yang G, Bastidas JA. International Journal of Radiation Oncology*Biology*Physics, 15 March 2004 (Vol. 58, Issue 4, Pages 1017–1021)
  30. ^ a b Phase II study to assess the efficacy of conventionally fractionated radiotherapy followed by a stereotactic radiosurgery boost in patients with locally advanced pancreatic cancer. Koong AC, Christofferson E, Le QT, Goodman KA, Ho A, Kuo T, Ford JM, Fisher GA, Greco R, Norton J, Yang GP. International Journal of Radiation Oncology*Biology*Physics, 01 October 2005 (Vol. 63, Issue 2, Pages 320-323)
  31. ^ Phase I Dose Escalation Study of CyberKnife Stereotactic Radiosurgery for Liver Malignancies. Lieskovsky YC, Koong A, Fisher G, Yang G, Ho A, Nguyen M, Gibbs I, Goodman K.International Journal of Radiation Oncology*Biology*Physics, 01 October 2005 (Vol. 63, Issue (Supplement 1), Page S283)
  32. ^ 2206: Hypofractionated Stereotactic Radiotherapy for Prostate Cancer: Early Results. Hara W, Patel D, Pawlicki T, Cotrutz C, Presti J, King C. International Journal of Radiation Oncology, Biology, Physics, 01 November 2006 (Vol. 66, Issue 3 (Supplement), Pages S324-S325)
  33. ^ Wall street Journal - November 2008 - Is CyberKnife Ready for Prime Time in Prostate Cancer?
  34. ^ Cyberknife frameless real-time image-guided stereotactic radiosurgery for the treatment of spinal lesions. Gerszten PC, Ozhasoglu C, Burton SA, Vogel WJ, Atkins BA, Kalnicki S, Welch WC. International Journal of Radiation Oncology*Biology*Physics, 01 October 2003 (Vol. 57, Issue 2 (Supplement), Pages S370-S371)
  35. ^ CyberKnife Fractionated Stereotactic Radiosurgery for the Treatment of Primary and Recurrent Head and Neck Cancer. Liao JJ, Judson B, Davidson B, Amin A, Gagnon G, Harter K. International Journal of Radiation Oncology*Biology*Physics, 01 October 2005 (Vol. 63, Issue (Supplement 1), Page S381)
  36. ^ Cyberknife frameless radiosurgery for the treatment of benign tumors. Bhatnagar AK, Gerzsten PC, Agarwal A, Ozhasoglu CW, Vogel WJ, Kalnicki S, Welch WC, Burton SA. International Journal of Radiation Oncology*Biology*Physics, September 2004 (Vol. 60, Issue 1 (Supplement), Page S548)
  37. ^ Patrick-Swayze has Cyberknife radiotherapy
  38. ^ Reuters -December 2008 - Accuray Achieves Milestone of 150th CyberKnife System Installed Worldwide
  39. ^ Accuray Reaches 100th U.S. CyberKnife System Installation
  40. ^ Cyberknife worldwide locations
  41. ^ Patrick Swayze US Cyberknife treatment
  42. ^ Cyberknife at Georgetown University Hospital, Washington
  43. ^ Georgetown University Hospital in Washington
  44. ^ Maverick in a mind field - Silicon Valley / San Jose Business Journal:
  45. ^ Accuray FAQ
  46. ^ Atlantic Health
  47. ^ Cyberknife, Athens
  48. ^ Cyberknife, Madrid
  49. ^ March 2009, Zurich cyberknife
  50. ^ Cyberknife Harley Street, London
  51. ^ Cyberknife Centre London
  52. ^ BBC news - 30/12/08 - Cyberknife boost to cancer care
  53. ^ Reuters - January 2008 - CyberKnife Radiosurgery Expands to India
  54. ^ YouTube - 數碼導航刀 Accuray CyberKnife System
  55. ^ YouTube - Packard Children's Opens First Pediatric-Focused Cyberknife

External links

Retrieved from "https://en.wikipedia.org/w/index.php?title=Cyberknife_(device)&oldid=351514795"