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The Proton Beam Unit was founded in 1962 and has the largest experience with stereotactic radiosurgery of any center in the United States. Information regarding non-invasive proton beam radiosurgery and fractionated radiosurgery for brain and spinal tumors and arteriovenous malformations.
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Proton Beam Radiosurgery Comparison of Charged Particles

History of Stereotactic Radiosurgery

by Stephen B. Tatter, M.D., Ph.D.

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Comparison of Charged ParticlesComparison of
Charged Particles (e. g. Protons) and Photons (Gamma particles)

    Photons produced in Gamma Knife® and linear accelerator radiosurgery units do not produce a peak of interaction of a single beam with tissue as do charged particles such as protons. There is also no rapid fall off after the target is reached. Thus, with Gamma Knife and LINAC radiosurgical doses must be achieved by superimposing a large number of beams on the target while only a small number of beams reach other areas. The large number of different target paths required makes milling of individual collimators impractical, a limitation that will not be overcome until variably-gated (or dynamically-collimated) linear accelerators are widely available.

    The circular collimators currently in use in photon radiosurgery units result in roughly spherical or elliptical target volumes. Most lesions can still be satisfactorily covered using multiple superimposed ellipsoids. However, this may significantly increase the dose inhomgeneity leading to the potential for side effects in regions recieving particularly high doses. This also suggetsts that proton radiosurgery will be particularly appealing in applications where dose fractionation is of benefit, since no portion of target in a proton field is expected to receive a complication producing dose because of superimposition of high dose areas. Fractionated particle beam radiosurgery is, therefore, an area of active current research.

    The Proton Beam Unit was founded in 1962 and has the largest experience with stereotactic radiosurgery of any center in the United States. Proton beam offers certain theoretical advantages over other modalities of stereotactic radiosurgery (i.e. Gamma Knife® and linear accelerators) because it makes use of the quantum wave properites of protons to reduces doses to surrounding tissue beyond the target to a theoretical minimum of zero. In practice, the proton facility offers advantages for the treatment of unusually shaped brain tumors and arteriovenous malformations. The homogeneous doses delivered also makes fractionated therapy possible. Proton beam radiosurgery also has the ability to treat tumors outside of the cranial cavity. These properties make it the ideal post-resection therapy for many chordomas and certain chondrosarchomas of the spine and skull base as well as an excellent mode of therapy for many other types of tumors.


  • Rand R: The stereotactic Cobalt 60 Gamma Unit in the treatment of acoustic neuromas. in Brackmann DE (ed): Neurological Surgery of the Ear and Skull base. 1982, pp 379-389
  • Thomsen J, Tos M, Borgesen SE: Gamma Knife: Hydrocephalus as a complication of stereotactic radiosurgical treatment of an acoustic neuroma. Am J Otol 11:330-333, 1990
  • Ganz JC, Backlund EO, Thorsen FA: The results of Gamma Knife surgery of meningiomas, related to size of tumor and dose. Stereotactic and Func Neurosurg 61:23-29, 1993
  • Kondziolka D, Lunsford LD, Coffey RJ, Flickinger JC: Gamma Knife radiosurgery of meningiomas. Stereotactic and Func Neurosurg 57:11-21, 1991
  • Steiner L, Lindquist C, Steiner M: Meningiomas and Gamma Knife radiosurgery, in Al Mefty O (ed): Meningiomas. Raven Press, New York, 1991, pp 263-272
  • Coffey, R.J., D.A. Nichols, and E.G. Shaw, Stereotactic radiosurgical treatment ofcerebral arteriovenous malformations. Gamma Unit Radiosurgery Study Group[see comments]. Mayo Clin Proc, 1995. 70(3): p. 214-22.
  • Coffey RJ, Lunsford LD: Stereotactic gamma radiosurgery for brainstem AVM. Neurosurgeon 10:238-246, 1991
  • Fukuoka S; Suematsu K; Nakamura J [Gamma knife radiosurgery for arteriovenous malformation Nippon Rinsho 1993 Dec;51 Suppl: 353-8.
  • Guo WY, Lindquist C, Karlsson B, Kihlstrom L, Steiner L: Gamma Knife surgery of cerebral arteriovenous malformations: Serial MR imaging studies after radiosurgery. Int J Radiat Oncol Biol Phys 25:315-323, 1993
  • Guo WY, Wikholm G, Karlsson B, Lindquist C, Svendsen P, Ericson K: Combined embolization and Gamma Knife radiosurgery for cerebral arteriovenous malformations. Acta Radiologica 34:600-606, 1993
  • Guo W, Lindquist M, Lindquist C, Ericson K, Nordell B, Karlsson B, Kihlstrom L: Stereotaxic angiography in Gamma Knife radiosurgery of intracranial arteriovenous malformations. Am Journal Neuroradiol 13:1107-1114, 1992
  • Guo W: Radiological aspects of Gamma Knife radiosurgery for arteriovenous malformations and other non-tumoural disorders of the brain. Acta Radiologica Supplementum 34:388, 1993
  • Lunsford LD, Coffey RJ, Bissonette D, Flickinger JC: Stereotactic radiosurgery for arteriovenous malformations. Case selection and initial results from the first North American Gamma Unit. Proc Harvard Radiosurgery Update. Boston, 1990
  • Lunsford LD, Kondziolka D, Pollock BE, Maitz A, Flickinger JC: Gamma knife stereotactic radiosurgery for brain arteriovenous malformations: What we have learned. Neurosurgeons (in press): 1994
  • Flickinger JC, Lunsford LD, Linskey ME, Duma CM, Kondziolka D: Gamma Knife radiosurgery for acoustic tumors: Multivariate analysis of four year results. Radiotherapy & Oncol 27:91-98, 1993
  • Kamerer DB, Lunsford LD, Moller M: Gamma Knife. An alternative treatment for acoustic neurinomas. Ann Otol Rhinol Laryngol 97:631-635, 1988
  • Kobayashi T, Tanaka T, Kida Y: The early effects of Gamma Knife on 40 cases of acoustic neuroma. Proc ISRS. Stockholm, 1993
  • Noren G, Greitz A, Lax I: Gamma Knife surgery in acoustic tumors. Acta Neurochir (Wien) 58:104-107, 1993
  • Noren G, Greitz D, Hirsch A, Lax I: Gamma Knife radiosurgery in acoustic neurinoma, in L. Steiner (ed): Radiosurgery: Baseline and Trends. Raven Press, New York, 1992, pp 141-148
  • Noren G: Gamma Knife radiosurgery in acoustic neurinomas, in Haid CT (ed): Vestibular Diagnosis and Neuro-Otosurgical Management of the Skull Base. Demeter Verlag, Grfelfing, 1991, pp 43-47
  • Ogunrinde OK, Lunsford LD, Flickinger JC, Maitz AH, Kondziolka D: Facial nerve preservation and tumor control after Gamma Knife radiosurgery of unilateral acoustic tumors. Skull Base Surg 4(2):87-92, 1994
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