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Encyclopedia > Proton therapy

Proton therapy is a kind of external beam radiotherapy where protons are directed to a tumor site. External beam radiotherapy otherwise known as teletherapy, is the mostfrequently used form of radiotherapy. ... // For alternative meanings see proton (disambiguation). ... Tumor or tumour literally means swelling, and is sometimes still used with that meaning. ...

Contents

Indications

Proton therapy is of interest because of its ability to accurately target and kill tumors, both near the surface and deep seated within the body, while minimizing damage to the surrounding tissues. For this reason, it is favored for treating certain kinds of tumors where conventional X-ray radiotherapy would damage surrounding radio-sensitive tissues to an unacceptable level (optical nerve, spinal cord, central nervous system, head & neck prostate, isolated brain metastases, pituitary adenomas, arteriovenous malformations, meningiomas, acoustic neuroma, chordoma, chondrosarcoma, uveal melanomas, macular degeneration, nasopharynx, sinus, oropharynx, lung, breast, liver). This is of particular importance in the case of pediatric patients where long term side effects such as residual occurrence of secondary tumors resulting from the overall radiation dose to the body are of great concern. Because of the lower dose to healthy tissue protons have less severe collateral side-effects than conventional radiation therapy. Biological tissue is a collection of interconnected cells that perform a similar function within an organism. ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... Radiation therapy (or radiotherapy) is the medical use of ionizing radiation as part of cancer treatment to control malignant cells (not to be confused with radiology, the use of radiation in medical imaging and diagnosis). ... The optic nerve is the nerve that transmits visual information from the retina to the brain. ... The Spinal cord nested in the vertebral column. ... A diagram showing the CNS: 1. ... Male Anatomy The prostate is an exocrine gland of the male mammalian reproductive system. ... Meningiomas are tumors arising from the outer part of the arachnoid mater in the meninges of the brain or the spinal cord. ... Acoustic neuroma (or Vestibular Schwannoma) is a benign tumor of the myelin forming cells called Schwann cells of the 8th cranial nerve, known as the acoustic nerve, (or more properly the vestibulocochlear nerve) just after it has left the brainstem, in the pontine angle; also at the point where the... Spinal tumors are neoplasms located in the spinal cord. ... A chondrosarcoma is a cancer of the cartilage. ... Listen to this article · (info) This audio file was created from an article revision dated 2005-07-19, and may not reflect subsequent edits to the article. ... The pharynx is the part of the digestive system of many animals immediately behind the mouth and in front of the esophagus. ... The term sinus (Latin for bay, pocket, curve or bosom) is used in various contexts. ... The pharynx is the part of the digestive system of many animals immediately behind the mouth and in front of the esophagus. ... The lungs flank the heart and great vessels in the chest cavity. ... A pregnant womans breasts. ... The liver is an organ in some animals, including mammals (and therefore humans), birds, and reptiles. ... Clinac 2100 C100 accelerator Radiation therapy (or radiotherapy) is the medical use of ionizing radiation as part of cancer treatment to control malignant cells (not to be confused with radiology, the use of radiation in medical imaging and diagnosis). ...


The logic for treating common cancers (especially lung, head/neck etc) with proton therapy is the same as saying that surgery alone should cure most lung cancers, as surgery is the Definitive Local Treatment. Of course, surgery does not - because most cancers spread microscopically very early beyond the tumor ('local') site. A cardiothoracic surgeon performs a mitral valve replacement at the Fitzsimons Army Medical Center. ...


Historically, one area where proton therapy had considerable early successful application was in treating choroidal malignant melanomas, a type of eye cancer for which the only known treatment was enucleation (removal of the eye). Today, proton therapy is one of the techniques that are capable of treating this tumor without mutilation. (see article in French) The choroid, also known as the choroidea or choroid coat, is the vascular layer of the eye lying between the retina and the sclera. ... Melanoma is a malignant tumor of melanocytes. ... A human eye. ... It has been suggested that Cancerous tumor be merged into this article or section. ... surgical removal of the eye This page is a candidate for speedy deletion. ...


How it works

Proton therapy, like all forms of radiotherapy, works by aiming, energetic ionizing particles (in this case, protons) onto the target tumor. These particles damage the DNA of cells and thus ultimately cause their death. Because of their high rate of division, and their reduced ability to repair damaged DNA, cancerous cells are particularly vulnerable to this attack on their DNA. ... // For alternative meanings see proton (disambiguation). ... The structure of part of a DNA double helix. ...


As protons scatter less easily in the tissue there is very little lateral dispersion; the beam stays focused on the tumor shape without much lateral damage to surrounding tissue. All protons of a given energy have a certain range; no proton penetrates beyond that distance. Furthermore, the dosage to tissue is maximum just over the last few millimeters of the particle’s range, this maximum is called the Bragg Peak. This depth depends on the energy to which the particles were accelerated by the proton accelerator, which can be adjusted to the maximum rating of the accelerator. It is therefore possible to focus the cell damage due to the proton beam at the very depth in the tissues where the tumor is situated; tissues situated before the Bragg peak receive some reduced dose, and tissues situated after the peak receive none. Bragg Peak When a fast charged particle moves through matter, it produces an ionisation dose by depositing energy and ionizing along its path. ...


Proton therapy, however, needs heavy equipment. For instance, the Orsay proton therapy center, in France, uses a synchrocyclotron weighing 900 tons in total. Such equipment was formerly only available within centers studying particle physics; and in the case of the Orsay installation, the treatment machine was converted from particle research usage to medical usage. The same situation is in Italy where the CATANAproton therapy facility is installed inside the Laboratori Nazionali del Sud of National Institute for Nuclear Physics. CATANA is, actually, the unique italian proton therapy center. It started the operation in collaboration with the Physics Department of Catania University and Policlinico Universitario and, up to now, 114 patients have been treated. However, there are now several dedicated proton therapy centers in operation or under construction in North America, Europe, and Asia. Proton beam radiation therapy has had remarkable success in the treatment of many types of cancer, including brain and spinal tumors, as well as prostate cancer. Recent breakthroughs in antimatter research have suggested that antiprotons may be much more effective at killing cancer cells than their proton opposites. Musée dOrsay Exterior view in the afternoon Musée dOrsay Inside the main hall The Musée dOrsay is a museum in Paris, situated on the left bank of the River Seine. ... A part of a magnet from the Orsay synchrocyclotron, now used by the proton therapy center (to be replaced in 2008 by newer technologies) A synchrocyclotron is a cyclotron in which the frequency of the driving RF electric field is varied to compensate for the mass gain of the accelerated... Thousands of particles explode from the collision point of two relativistic (100 GeV per nucleon) gold ions in the STAR detector of the Relativistic Heavy Ion Collider. ...


History of Proton Therapy in the United States

The first suggestion that energetic protons could be an effective treatment method was made by Robert R. Wilson in a paper published in 1946 while he was involved in the design of the Harvard Cyclotron Laboratory (HCL). The first treatments were performed at Particle accelerators built for physics research, notably at Uppsala in Sweden and Berkeley Radiation Laboratory in the late 1950s. In 1961, a collaboration began between HCL and the Massachusetts General Hospital (MGH) to pursue proton therapy. Over the next 41 years this program refined and expanded these techniques while treating 9,116 patients before the Cyclotron was shut down in 2002. Following this pioneering work, the first hospital based proton treatment center in the United States was built in 1990 at Loma Linda University Medical Center in Loma Linda, California (LLUMC). This was followed by The Northeast Proton Therapy Center at Massachusetts General Hospital (recently renamed the Francis H. Burr Proton Therapy Center), to which the HCl treatment program was transferred in 2001-2002. Proton therapy for ocular tumors is also available in Sacramento at the UC Davis Proton Facility, a facility operated exclusively by the UC San Francisco Department of Radiation Oncology. It is estimated that over 44,000 patients have been effectively treated with proton therapy. Now on line as well is the Midwest Proton Radiotherapy Institute at Indiana University. In the summer of 2006 treatment started at two new facilities: the for profit [1] [2] University of Texas M. D. Anderson Cancer Treatment Center [3], Houston, Texas and the Florida Proton Therapy Institute at the University of Florida Shands Medical Center in Jacksonville, Florida. Robert Rathbun Wilson (March 4, 1914–January 16, 2000) was an American physicist who was the youngest group leader of the Manhattan Project, a sculptor, and an architect of Fermi National Laboratory (Fermilab), where he was also the director from 1967-1978. ... Harvard University is a private university in Cambridge, Massachusetts, USA, and a member of the Ivy League. ... A particle accelerator uses electric fields to propel charged particles to great energies. ... The Berkeley Lab is perched on a hill overlooking the Berkeley central campus and San Francisco Bay. ... Massachusetts General Hospital (often abbreviated to Mass General or just MGH) is a teaching hospital of Harvard Medical School and biomedical research facility in Boston, Massachusetts. ...


Therapy equipment suppliers

Following firms are currently supplying or developing proton therapy equipment: Optivus (USA), IBA (Belgium), Hitachi (Japan), ACCEL (Germany).[4]


M.D. Anderson Cancer Center's for profit [5] Proton therapy Center (Houston) is now accepting patients for proton treatment. The Florida Proton Therapy Institute (Jacksonville) will start treating patients in early August of 2006.


References

  • "Radiological Use of Fast Protons", R. R. Wilson, Radiology, 47:487-491 (1946)
  • "Use of Protons for Radiaotherapy", A.M. Koehler, Proc. of the Symposium on Pion and Proton Radiotherapy, Nat. Accelerator Lab., (1971)
  • "Protons in Radiation Therapy: comparative Dose Distributions for Protons, Photons and Electrons, A.M. Koehler, W.M. Preston, Radiology, 104(1):191-195 (1972)
  • "Bragg Peak Proton Radiosurgery for Arteriovenous Malformation of the Brain" R.N. Kjelberg, presented at First Int. Seminar on the Use of Proton Beams in Radiation Therapy, Moskow (1977)
  • "Fractionated Proton Radiation Therapy of Cranial and Intracrainial Tumors" Austin-Seymor, M.J. Munzenrider, et al. Am.J.of Clinical Oncology 13(4):327-330 (1990)
  • "Proton Radiotherapy", Hartford, Zietmean, et al. in Radiotheraputic Management of Carcinoma of the Prostate, A. D'Amico and G.E. Hanks. London,UK, Arnold Publishers: 61-72 (1999)

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  Results from FactBites:
 
FOXNews.com - Proton Therapy Used More to Treat Cancer - Health News | Current Health News | Medical News (863 words)
But he said studies have shown proton therapy allows a higher level of radiation on the tumor, with less damage to healthy tissue and fewer side effects, such as loss of appetite, diarrhea and headaches."That was the breakthrough, what changed my mind,"he said.
Proton therapy has been around since the mid-1950s but was done mostly at research facilities, according to the National Association for Proton Therapy.
But proton therapy, which is covered by Medicare and most insurance companies, is about three times more expensive than traditional radiation, in part because of the cost of the facilities, Cox said.
Proton Therapy Takes Aim in Prostate Cancer Battler (622 words)
For the past seven years, proton therapy, a superior type of radiation therapy that permits a more precise delivery of a higher dose of tumor destroying energy, has been successfully used at the Loma Linda University Proton Treatment Center in Southern California.
Proton therapy is often referred to as "bloodless surgery" since it has a surgical precision that leaves vital organs and healthy tissue near the tumor unaffected, allowing for a speedier recovery for most of the patients.
Proton therapy is being used in more than 20 cancer sites, and is also being used to treat other diseases.
  More results at FactBites »

 
 

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