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History of Stereotactic Radiosurgery
by
Stephen
B.
Tatter, M.D., Ph.D.
Crossfire Proton-beam Treatments
In 1946, Wilson first proposed the clincial use of
charged-particle beams because of their unique characteristics.14
Lars Leksell adressed the theoretical and many practical aspects
of stereotactic radiosurgery in 1951.9 Using the Uppsala
University cyclotron Leksell and Borje Larsson, a radiobiologist,
used a cross fired proton beam in intial experiments in animals
and in the first treatments of human patients.8 These treatments
used the plataeu ionization portion of the beam's energy rather
than the focal Bragg peak at its end.
Early Bragg-peak Proton Radiosurgery
In 1954, John Lawrence began to use the Berkely cyclotron's Bragg
peak to irradiate the pituitaries of patients with metastatic
breast cancer for hormonal suppression.12 The first thirty
patients were treated with protons and thereafter helium ions were
used.
In 1961 Raymond Kjellberg began treating patients using the Bragg
peak of protons from the Harvard Cyclotron Laboratory.7 This was
soon followed by similar efforts led by V.S. Koroshkov in Moscow.
Early Experience with Pituitary Radiosurgery
Pituitary lesioning and subsequently treatment of adenomas were
the first successful applications of radiosurgery because of the
ability to localize the sella turcica on plane radiographs. The
main risks of such treatment was injury to the cranial nerves.13
Late hypopituitarism is also confirmed as an expected result of
successful control of secretory and non-functioning adenomas.
The Kjellberg Risk Prediction Curve
Ateriovenous malformations were the first parenchymal lesions on
which radiosurgery was extensively evaluated. Development of
single-dose radiation for this type of lesion required
determination of the tolerance of normal brain and of the brain
surrounding AVMs to radiosurgical doses. Using a combination of
clinical and experimental observations, Kjellberg proposed the
standard dose effect curves for radiation necrosis in proton
therapy of the brain.6 It is of particular note that Kjellberg's
one percent dose-diameter line for radiation necrosis also serves
as the basis for gamma knife and linear accelerator dosimetry.4,
11
Evolution of Imaging and Treatment Planning Techniques
Initial attempts at proton radiosurgery were limited by
neuroradiologic techniques which prevented successful three
dimensional treatment planning. These limitations were first
overcome for proton radiosurgery of the pituitary because of its
midline symmetry and because of the presence of reliable bony
landmarks visible on conventional radiographs. Stereotactic
treatment of arteriovenous malformations began in 1963 and was
based on a stereotactic guidance device and angiograms.6 Some
tumors including skull base lesions could be adequately localized
by pneumoencephelography. Leksell performed the first such
treatment, radiating a vestibular schwannoma in 1969.10 Treatment
of the majority of intracranial tumors required the ability to
image three dimensionally and awaited the widespread availability
of computed tomography and magnetic resonance imaging.
Evolution of Beam Delivery and Patient Positioning
Intital efforts at beam delivery used conventional radiographs and
stereotactic immobilization to identify targets. Three-dimensional
stereotactic techniques were then applied to radiosurgery, but
required continuous immobilization of the patient in the
sterotactic apparatus from the time of imaging to the completion
of the treatment. Transposition of three-dimensional imaging
information to conventional X-ray stereotactic space was possible
but somewhat inconvenient and occassionally inaccurate.3 More
recently, implanted skull fiducials have been employed to allow
reproducible correlation of conventional radiographs with
three-dimensional imaging.1, 5 This makes fractionated proton
therapy practicle and may allow a further increase in the
risk-to-benefit ratio of particle beam radiosurgery.
Beam scanning is another technique under development to allow
optimization of delivery. Current proposals involve using
electromagnetic beam modulators to move the single Bragg peak
through the entire treament volume rather than using a fixed
number of static beams.
A patient positioning system known as STAR (stereotactic alignment
for radiosurgery) is currently in use at the Harvard Cyclotron.2
It uses the target-centered principle, allowing complete
rotational freedom once the linear coordinates of the target have
been defined. It is compatible with any orthogonal or radial
stereotactic coordinate system and accepts targets obtained
directly from computed tomography, magnetic resonance imaging, and
angiography. This arrangement is required to allow the
implementation of line-of-sight treament planning because the
Harvard beam is limited to the horizontal position. Another
solution to this challenge used by some new medically-dedicated
particle beams are designs that allow protons to be delivery from
arbitrary angles rather than from a horizontal beam.
References
* Butler WE, Ogilvy CS, Chapman PH, Verhy L , Zervas NT. "Stereotactic
alignment for Bragg peak radiosurgery." In Radiosurgery: Baseline and
Trends, ed. L. Steiner. 85-91. New York: Raven Press, 1992.
* Chapman PH, Ogilvy CS , Butler WE. "A new stereotactic alignment system
for charged-particle radiosurgery at the Harvard Cyclotron Laboratory,
Boston." In Stereotactic Radiosurgery, ed. Eben Alexander III, Jay S.
Loeffler, and L. Dade Lunsford. 105-108. New York: McGraw-Hill, 1993.
* De Salles AA, Asfora WT, Abe M, Kjellberg RN: Transposition of target
information from the magnetic resonance and computed tomography scan
images to conventional X-ray stereotactic space. Applied
Neurophysiology 50:23-32, 1987.
* Flickinger JC: The integrated logistic formula and predictions of
complications from radiosurgery. Int J Radiat Oncol Biol Phys
23:879-85, 1989.
* Gall KP, Verhey LJ, Wagner M: Computer-assisted positioning of
radiotherapy patients using implanted radiopaque fiducials. Medical
Physics 20:1153-9, 1993.
* Kjellberg RN, Hanamura T, Davis KR, Lyons SL , Adams RD: Bragg-peak
proton-beam therapy for arteriovenous malformations of the brain. New
England Journal of Medicine 309:269-74, 1983.
* Kjellberg RN, Shintani A, Frantz AG, Kliman B: Proton-beam therapy in
acromegaly. New England Journal of Medicine 278:689-95, 1968.
* Larsson B, Leksell L, Rexed B , et al: The high energy proton beam as a
neurosurgical tool. Nature 182:1222-3, 1958.
* Leksell L: The stereotaxic method and radiosurgery of the brain. Acta
Chir Scand 102:316-19, 1951.
* Leksell L: A note on the treatment of acoustic tumors. Acto Chir Scand
137:763-5, 1969.
* Saunders WM, Winston KR, Siddon RL , et al: Radiosurgery for
arteriovenous malformations of the brain using a standard linear
accelerator. Rationale and technique. Int J Radiat Biol Phys 15:441-7,
1988.
* Tobias CA, Lawrence JH, Born JL , et al: Pituitary irradiation with
high-energy proton beams. A preliminary report. Cancer Res 18:121-34,
1958.
* Urie MM, Fullerton B, Tatsuzaki H, Birnbaum S, Suit HD, Convery K,
Skates , Goitein M: A dose response analysis of injury to cranial
nerves and/or nuclei following proton beam radiation therapy.
International Journal of Radiation Oncology, Biology, Physics 23:27-39,
1992.
* Wilson RR: Radiological use of fast protons. Radiology 47:487-91, 1946.
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by MGH Neurosurgical Service 1998
