151
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Graham JD, Nahum AE, Brada M. A comparison of techniques for stereotactic radiotherapy by linear accelerator based on 3-dimensional dose distributions. Radiother Oncol 1991; 22:29-35. [PMID: 1947210 DOI: 10.1016/0167-8140(91)90066-p] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In order to establish the appropriate beam arrangement for use in stereotactic radiotherapy using a linear accelerator, dose volume distributions were calculated for a number of spherical targets in a head phantom and assessment was made by dose sparing of normal tissue outside the target volume. Using a single isocentre, fixed beam arrangements were compared with single and multiple non-coplanar isocentric arc rotations at target sizes from 10 to 55 mm diameter on a 6 MV Philips linear accelerator. From the dose-volume histograms produced, an arrangement of 3 or 4 arcs of rotation proved most suitable, in terms of sparing of normal tissue outside the target volume to high dose irradiation, across the range of target sizes studied. There was little further benefit with increasing the number of arcs beyond this. At target sizes greater than 20 mm diameter an arrangement of 6 static non-coplanar beams achieved sparing equivalent to multiple arc rotations and may have considerable advantages in the treatment of irregular volumes where customised beam shaping could be employed.
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Affiliation(s)
- J D Graham
- Academic Unit of Radiotherapy & Oncology, Institute of Cancer Research, Surrey, U.K
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152
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Tsai JS, Buck BA, Svensson GK, Alexander E, Cheng CW, Mannarino EG, Loeffler JS. Quality assurance in stereotactic radiosurgery using a standard linear accelerator. Int J Radiat Oncol Biol Phys 1991; 21:737-48. [PMID: 1869467 DOI: 10.1016/0360-3016(91)90694-y] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Methods have recently been developed for using standard linear accelerators to perform stereotactic radiosurgery. The accuracy necessary to perform this procedure requires an intensive quality assurance program to encompass all aspects of dose calibration and mechanical integrity of the treatment unit, the treatment planning process, and treatment delivery. The programs developed at the Joint Center for Radiation Therapy (JCRT) include testing of the linear accelerator and the stereotactic system, cross checking of the treatment planning process, and a quality assurance check list of the treatment delivery procedure. This report outlines in detail the quality assurance program currently in use at the JCRT.
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Affiliation(s)
- J S Tsai
- Joint Center for Radiation Therapy, Harvard Medical School, Boston, MA 02115
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153
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Kooy HM, Nedzi LA, Loeffler JS, Alexander E, Cheng CW, Mannarino EG, Holupka EJ, Siddon RL. Treatment planning for stereotactic radiosurgery of intra-cranial lesions. Int J Radiat Oncol Biol Phys 1991; 21:683-93. [PMID: 1907960 DOI: 10.1016/0360-3016(91)90687-y] [Citation(s) in RCA: 97] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Stereotactic radiosurgery of intra-cranial lesions is a treatment modality where a well defined target volume receives a high radiation dose in a single treatment. Our technique delivers this dose using a set of non-coplanar arcs and small circular collimators. We use a standard linear accelerator in our treatments, and the adjustable treatment parameters are: isocenter location, gantry arc rotation interval, couch angle, collimator field size, and dose. The treatment planning phase of the treatment determines these parameters such that the target volume is sufficiently irradiated, and dose to surrounding healthy tissue and critical, dose-limiting structures is minimized. The attachment of a BRW localizing frame to the patient's cranium combined with CT imaging (and optionally MRI or angiography) provides the required accuracy for localizing individual structures in the treatment volume. The treatment is fundamentally 3-dimensional and requires a volumetric assessment of the treatment plan. The selection of treatment arcs relies primarily on geometric constraints and the beam's eye view concept to avoid irradiating critical structures. The assessment of a treatment plan involves isodose distributions throughout the volume and integral dose-volume histograms. We present the essential concepts of our treatment planning approach, and illustrate these in three clinical cases.
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Affiliation(s)
- H M Kooy
- Joint Center for Radiation Therapy, Harvard Medical School, Boston, MA 02115
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154
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Delannes M, Daly NJ, Bonnet J, Sabatier J, Tremoulet M. Fractionated radiotherapy of small inoperable lesions of the brain using a non-invasive stereotactic frame. Int J Radiat Oncol Biol Phys 1991; 21:749-55. [PMID: 1869468 DOI: 10.1016/0360-3016(91)90695-z] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Arteriovenous malformations (AVMs) and benign or low grade, small malignant tumors can be treated by stereotactic radiotherapy in a single fraction. This report describes a technique for stereotactic treatment of small lesions using conventional, fractionated, photon beam irradiation. The Laitinen's stereoadapter, non-invasive head frame was used. This device was tested for accuracy by serial mountings and found to be accurate within 1 mm. The accuracy of the dose delivered was within 2%. Adaptation of this device to the linear accelerator required the design of secondary circular collimators which decreased the penumbra from 3-4 mm to 2-3 mm. The dose fall off outside the target volume is steep enough when using two non-coplanar arcs (90 to 10% within 1 cm). Thermoluminescent dosimetry (TLD) in a humanoid phantom showed good correlation with the calculated dose. This system permits delivery of fractionated radiation therapy to small volumes, easily and accurately, under stereotactic conditions.
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Affiliation(s)
- M Delannes
- Department of Radiotherapy, Hopital Purpan, Toulouse, France
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155
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Gehring MA, Mackie TR, Kubsad SS, Paliwal BR, Mehta MP, Kinsella TJ. A three-dimensional volume visualization package applied to stereotactic radiosurgery treatment planning. Int J Radiat Oncol Biol Phys 1991; 21:491-500. [PMID: 2061126 DOI: 10.1016/0360-3016(91)90801-a] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A comprehensive software package has been developed for visualization and analysis of 3-dimensional data sets. The system offers a variety of 2- and 3-dimensional display facilities including highly realistic volume rendered images generated directly from the data set. The package has been specifically modified and successfully used for stereotactic radiosurgery treatment planning. The stereotactic coordinate transformation is determined by finding the localization frame automatically in the CT volume. Treatment arcs are specified interactively and displayed as paths on 3-dimensional anatomical surfaces. The resulting dose distribution is displayed using traditional 2-dimensional displays or as an isodose surface composited with underlying anatomy and the target volume. Dose volume histogram analysis is an integral part of the system. This paper gives an overview of volume rendering methods and describes the application of these tools to stereotactic radiosurgery treatment planning.
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Affiliation(s)
- M A Gehring
- Department of Human Oncology, University of Wisconsin, Madison 53792
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156
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Schell MC, Smith V, Larson DA, Wu A, Flickinger JC. Evaluation of radiosurgery techniques with cumulative dose volume histograms in linac-based stereotactic external beam irradiation. Int J Radiat Oncol Biol Phys 1991; 20:1325-30. [PMID: 1904411 DOI: 10.1016/0360-3016(91)90245-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Radiosurgery at UCSF is performed with a 6-MV linear accelerator with tertiary collimation for improved small field definition. The dose delivery to the target relative to normal tissue is influenced by the number of arcs, the arc geometry, field size, and beam energy. The impact of arc number, arc geometry, and field size on the dose distribution from 6-MV X rays in a 16 cm spherical phantom has been evaluated through the use of cumulative dose volume histograms. Dose volume histograms were calculated for a) 1-5 and 10 arcs, and b) collimator sizes of 1.25, 2.0, and 3.0 cm. Differences between techniques were found at the 5-10% level for field sizes from 1.25 to 2.0 cm. It was shown that the finite dimension of the sphere and, by extension, head diminishes the differences between techniques for the larger field sizes. The effect of treating with two isocenters is also analyzed and an approach for improving the dose distribution is presented.
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Affiliation(s)
- M C Schell
- Department of Radiation Oncology, University of California, San Francisco
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157
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Gillies C, Hochman C. Technical and therapeutic aspects of dynamic stereotactic radiosurgery. Med Dosim 1991; 16:85-91. [PMID: 1907831 DOI: 10.1016/0958-3947(91)90051-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A treatment procedure that results in a uniform dose in a single fraction over the entire treatment volume while minimizing the dose to other tissues has been developed to treat intracranial lesions such as arteriovenous malformations (AVMs). This technique is called dynamic stereotactic radiosurgery. Its main characteristic is simultaneous and continuous gantry and couch motion during the treatment procedure. It employs an isocentrically mounted linear accelerator as the source of radiation. Target localization is determined by digital subtraction angiography and CT. From results obtained in other centres, this technique has shown that an AVM less than 2.5 cm in diameter has an 85% chance of being completely obliterated within two years after a single treatment of stereotactic radiosurgery. This technique is suitable for those patients with inoperable, surgically inaccessible lesions, or whose current medical profile shows them to be high-risk candidates for surgical intervention.
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Affiliation(s)
- C Gillies
- Ontario Cancer Foundation, Toronto-Bayview Regional Cancer Centre, Canada
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158
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Abstract
Eighty-five patients with acoustic neurinomas underwent stereotactic radiosurgery with the gamma unit at the University of Pittsburgh (Pittsburgh, PA) during its first 30 months of operation. Neuroimaging studies performed in 40 patients with more than 1 year follow-up showed that tumors were smaller in 22 (55%), unchanged in 17 (43%), and larger in one (2%). The 2-year actuarial rates for preservation of useful hearing and any hearing were 46% and 62%, respectively. Previously undetected neuropathies of the trigeminal (n = 12) and facial nerves (n = 14) occurred 1 week to 1 year after radiosurgery (median, 7 and 6 months, respectively), and improved at median intervals of 13 and 8 months, respectively, after onset. Hearing loss was significantly associated with increasing average tumor diameter (P = 0.04). No deterioration of any cranial nerve function has yet developed in seven patients with average tumor diameters less than 10 mm. Radiosurgery is an important treatment alternative for selected acoustic neurinoma patients.
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Affiliation(s)
- J C Flickinger
- Department of Radiation Oncology, University of Pittsburgh School of Medicine, Joint Radiation Oncology Center
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159
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External Stereotactic Focal Irradiation of Arteriovenous Malformations by a Routinely Used Linear Accelerator. ACTA ACUST UNITED AC 1991. [DOI: 10.1007/978-3-642-84163-7_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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160
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Razek A, Ragab AH, Kim TH. Management of Childhood Gliomas. GLIOMA 1991. [DOI: 10.1007/978-3-642-84127-9_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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161
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Flickinger JC, Lunsford LD, Wu A, Kalend A. Predicted dose-volume isoeffect curves for stereotactic radiosurgery with the 60Co gamma unit. Acta Oncol 1991; 30:363-7. [PMID: 2036248 DOI: 10.3109/02841869109092387] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Mathematical models were developed to predict tolerance of brain tissue to stereotactic radiosurgery. The use of these formulas for predicting symptomatic brain necrosis from stereotactic radiosurgery with the 60Co gamma unit is discussed. Predicted dose-response curves for different collimator sizes were calculated. Dose-volume isoeffect curves for a 3% risk of brain necrosis from a single fraction radiosurgery were then derived. Dose-volume isoeffect curves for combinations of fractionated whole brain irradiation with radiosurgery boosts were also calculated. The predicted dose-volume isoeffect curves provide useful tolerance guidelines for the practice of stereotactic radiosurgery.
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Affiliation(s)
- J C Flickinger
- Department of Radiation Oncology, University of Pittsburgh School of Medicine, Pennsylvania
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162
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163
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Souhami L, Olivier A, Podgorsak EB, Pla M, Pike GB. Radiosurgery of cerebral arteriovenous malformations with the dynamic stereotactic irradiation. Int J Radiat Oncol Biol Phys 1990; 19:775-82. [PMID: 2120160 DOI: 10.1016/0360-3016(90)90509-i] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
From December 1986 through December 1988, 33 patients with inoperable arteriovenous malformation (AVM) were treated in our center with the dynamic stereotactic radiosurgery, which uses a standard 10 MV isocentric linear accelerator. There were 18 females and 15 males with a median age of 26 years (range: 9-69) and a median follow-up time of 16 months (range: 7-32). The arteriovenous malformation volumes treated ranged from 0.2 to 42 cm3. The prescribed doses at the isocenter varied from 50 to 55 Gy and were given as a single fraction in the majority of the patients (31/33). Late complications consisting of intracranial bleeding and/or hemiparesis were observed in three patients. To date, 21 patients underwent repeat angiographic studies at 1 year post-treatment. A complete obliteration of the lesion was achieved in 38% of these patients. For the patients whose arteriovenous malformation nidus was covered by a minimum dose of 25 Gy, the total obliteration rate was 61.5% (8/13), whereas none of the patients who had received less than 25 Gy at the edge of the nidus obtained a total obliteration. Our preliminary analysis at 1 year post-radiosurgery reveals results comparable to those previously reported for other radiosurgical techniques for the same follow-up period.
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Affiliation(s)
- L Souhami
- Dept. of Radiation Oncology, McGill University, Montréal, Canada
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164
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Flickinger JC, Maitz A, Kalend A, Lunsford LD, Wu A. Treatment volume shaping with selective beam blocking using the Leksell gamma unit. Int J Radiat Oncol Biol Phys 1990; 19:783-9. [PMID: 2120161 DOI: 10.1016/0360-3016(90)90510-q] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The Leksell gamma unit at the University of Pittsburgh uses 201 highly focused 60Co beams arranged in a hemispherical array. Selective beam blocking can be used to modify the treatment volume into ellipsoid shapes oriented in different directions to match better the shape of the target volume. Dose distributions for different blocking patterns were calculated using specially developed computerized 3-D treatment planning software. The changes in dose distribution with different blocking patterns predicted by computer were verified by film densitometry. Techniques for using selective beam blocking to match more closely the treatment volume to the intended target volume have the potential of reducing the likelihood of complications for radiosurgery with the Leksell gamma unit and need to be further developed.
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Affiliation(s)
- J C Flickinger
- University of Pittsburgh School of Medicine, Joint Radiation Oncology Center, PA
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165
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Flickinger JC, Schell MC, Larson DA. Estimation of complications for linear accelerator radiosurgery with the integrated logistic formula. Int J Radiat Oncol Biol Phys 1990; 19:143-8. [PMID: 2199419 DOI: 10.1016/0360-3016(90)90146-b] [Citation(s) in RCA: 116] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Radiosurgery techniques permit high doses of single fraction irradiation to be administered to small volumes of tumor with relative sparing of surrounding brain tissue. The tolerance of surrounding normal brain tissue to dose distributions from linear accelerator radiosurgery with different collimator sizes is an important factor that must be estimated by anyone using these treatment techniques. The exponential and linear quadratic versions of the integrated logistic formula were used to estimate the probability of brain necrosis at different doses for radiosurgical dose distributions administered by a 6 MV linear accelerator with a 5 arc technique for collimator sizes from 12.5 to 30 mm in diameter. Dose-volume isoeffect curves for a 3% risk of brain necrosis from linear accelerator radiosurgery were then calculated. These curves approximate those calculated for gamma knife radiosurgery and a published 1% dose-volume isoeffect line predicted for proton beam irradiation. Similar dose-volume isoeffect curves were calculated for single fraction radiosurgery boosts administered after 30 Gy of whole brain irradiation in 12 fractions. The integrated logistic formula appears to be a useful tool for estimating tolerance and providing guidelines for prescribing radiation doses for linear accelerator radiosurgery.
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Affiliation(s)
- J C Flickinger
- Department of Radiation Oncology, University of Pittsburgh School of Medicine, PA 15213
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166
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Souhami L, Olivier A, Podgorsak EB, Hazel J, Pla M, Tampieri D. Dynamic stereotactic radiosurgery in arteriovenous malformation. Preliminary treatment results. Cancer 1990; 66:15-20. [PMID: 2354401 DOI: 10.1002/1097-0142(19900701)66:1<15::aid-cncr2820660104>3.0.co;2-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
From December 1986 through August 1988, 25 patients with intracranial arteriovenous malformations underwent radiosurgery with the dynamic stereotactic irradiation technique. The prescribed dose at isocenter ranged from 50 Gy to 55 Gy, given as a single fraction in 92% of the patients. Field sizes, defined at the 90% isodose surface, varied from 5 mm to 25 mm and were chosen in order to deliver 20 to 25 Gy at the periphery of the malformation. To date, 14 angiographic studies were repeated at 1 year posttreatment. In six patients (43%) a complete obliteration of the lesion was achieved. Late side effects were observed in three patients. Our initial analysis, at 1 year posttreatment, suggests that our results are comparable with those previously reported for other radiosurgical techniques. The linac-based dynamic stereotactic technique appears to be a valid alternative to radiosurgery with the Gamma unit or with heavy-charged particle beams.
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Affiliation(s)
- L Souhami
- Department of Radiation Oncology, McGill University, Montréal, Québec, Canada
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167
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Flickinger JC, Lunsford LD, Wu A, Maitz AH, Kalend AM. Treatment planning for gamma knife radiosurgery with multiple isocenters. Int J Radiat Oncol Biol Phys 1990; 18:1495-501. [PMID: 2370199 DOI: 10.1016/0360-3016(90)90326-f] [Citation(s) in RCA: 119] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Many arteriovenous malformations and tumors suitable for radiosurgical treatment have non-spherical or irregular shapes. Forty-eight percent of the first 156 patients treated with the gamma unit at the University of Pittsburgh required treatment with two or more isocenters to optimize dose distributions. Dose distributions for combining gamma knife treatments to two or more isocenters were systematically investigated. High speed computerized dosimetry was performed using specially developed software and dose distributions were confirmed with film densitometry. We have developed guidelines for treatment to two or more isocenters which help reduce treatment planning time, and facilitate selection of treatment doses and optimum dose distributions. These guidelines include maintaining an account of the distances between all isocenters, using a catalogue of sample two-isocenter isodose plans, comparing dose volume histograms, and calculating complication probabilities using the integrated logistic formula.
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Affiliation(s)
- J C Flickinger
- Department of Radiation Oncology, University of Pittsburgh School of Medicine, PA 15213
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168
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Abstract
A new technique for stereotactic radiosurgery by use of a patient rotator is described. Using the rotator with a small collimated beam of 6 MV x-rays, a small well-defined region of the brain can be irradiated to a high dose with rapid fall off of the dose outside the target volume. Since the linear accelerator gantry does not move during therapy the possibility of a collision between the gantry and the patient or stereotactic equipment is eliminated. The system is also independent of the rotational stability of the linear accelerator gantry axis and turntable axis. Dose distributions measured in a Lucite head phantom with film exhibited properties well suited for radiotherapy. Tests carried out to evaluate the ability to irradiate a selected target point within the brain with the rotator system showed a maximum positional error of 1.0 and 2.0 mm for angiography and CT localisation respectively.
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Affiliation(s)
- P H McGinley
- Emory Clinic, Division of Radiation Therapy, Atlanta, GA 30322
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169
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Laperriere NJ. Critical appraisal of experimental radiation modalities for malignant astrocytomas. Can J Neurol Sci 1990; 17:199-208. [PMID: 2192790 DOI: 10.1017/s0317167100030456] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The management of patients with supratentorial malignant astrocytomas has remained a major problem. Patients continue to die from a lack of local control in 90% of cases despite an improvement of median survival seen with the use of postoperative radiation therapy. Because of this, there has been considerable interest in exploring novel ways of possibly improving results. This paper reviews the rationale and clinical results with the use of altered fractionation schemes, brachytherapy, radiation sensitizers, hyperthermia, particle therapy, and radiosurgery in the treatment of these patients. Currently, there is no demonstrated advantage with the use of these experimental modalities in the initial management of patients. There would appear to be some benefit for selected patients who are treated with brachytherapy at recurrence, but its efficacy as part of initial management remains to be determined determined in ongoing randomized prospective trials.
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Affiliation(s)
- N J Laperriere
- Department of Radiation Oncology, Princess Margaret Hospital, Toronto, Ontario, Canada
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170
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Podgorsak EB, Pike GB, Pla M, Olivier A, Souhami L. Radiosurgery with photon beams: physical aspects and adequacy of linear accelerators. Radiother Oncol 1990; 17:349-58. [PMID: 2343151 DOI: 10.1016/0167-8140(90)90008-k] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The question of the adequacy of isocentric linear accelerators (linacs) for use in radiosurgery is addressed. The general physical requirements for radiosurgery, mainly a high spatial and numerical accuracy of dose delivery, reasonable treatment time, and low skin and leakage dose as well as cost considerations are examined. Various linac-based procedures are analyzed in view of their ability to meet these requirements and are contrasted with the clinically proven system of the Gamma unit. It is shown that the linac-based multiple converging arcs techniques and the dynamic rotation meet the stringent physical requirements on dose delivery and are thus viable alternatives to radiosurgery with the commercially available and dedicated Gamma unit.
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Affiliation(s)
- E B Podgorsak
- Department of Radiation Oncology, McGill University, Montréal, Québec, Canada
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171
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Hariz MI, Henriksson R, Löfroth PO, Laitinen LV, Säterborg NE. A non-invasive method for fractionated stereotactic irradiation of brain tumors with linear accelerator. Radiother Oncol 1990; 17:57-72. [PMID: 2108476 DOI: 10.1016/0167-8140(90)90049-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A new technique for fractionated stereotactic irradiation of intracranial lesions is described. The treatment is based on a versatile, non-invasive interface for stereotactic localization of the brain target imaged by computed tomography (CT), angiography or magnetic resonance tomography (MRT), and subsequent repetitive stereotactic irradiation of the target using a linear accelerator. The fractionation of the stereotactic irradiation was intended to meet the requirements of the basic principles of radiobiology. The radiophysical evaluation using phantoms, and the clinical results in a small number of patients, demonstrated a good reproducibility between repeated positionings of the target in the isocenter of the accelerator, and a high degree of accuracy in the treatment of brain lesions.
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Affiliation(s)
- M I Hariz
- Department of Neurosurgery, University Hospital, Umeå, Sweden
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172
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Comparison of different radiation types and irradiation geometries in stereotactic radiosurgery. Int J Radiat Oncol Biol Phys 1990; 18:211-20. [PMID: 2404918 DOI: 10.1016/0360-3016(90)90286-s] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Recent interest in stereotactic radiosurgery of intracranial lesions, and the development of stereotactic irradiation techniques has led to the need for a systematic and complete comparison of these methods. A method for conducting these comparisons is proposed and is applied to a set of currently-used stereotactic radiosurgical techniques. Three-dimensional treatment planning calculations are used to compare dose distributions for several different radiation types and irradiation geometries. Calculations were performed using charged particles (H, He, C, and Ne ions) and the irradiation geometry currently used at Lawrence Berkeley Laboratory. Photons in the Gamma Knife configuration and the Heidelberg Linac arc method are used. The 3-dimensional dose distributions were evaluated by means of dose-volume histograms and integral doses to the target volume and to normal brain. The effects of target volume, shape and location are studied. The charged particle dose distributions are more favorable than those of the photon methods. The differences between charged particles and photons increase with increasing target volume. The differences between different charged particle species are small, as are the effects of target shape and location.
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173
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Abstract
A new, linear accelerator based radiosurgical system has been designed and tested. It incorporates a mechanical system of precision bearings to control all patient and accelerator movements. The dosimetry system allows near real-time examination of the isodose distributions in any computed tomography plane such that any treatment plan can be quickly optimized. Extensive testing shows a radiation beam accuracy of .2 +/- .1 mm. The dose gradient between the 90% and 10% isodose distributions compares favorably with any previously published radiosurgical method.
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Affiliation(s)
- W A Friedman
- Department of Neurological Surgery, University of Florida College of Medicine, Gainesville 32610
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174
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Flickinger JC. An integrated logistic formula for prediction of complications from radiosurgery. Int J Radiat Oncol Biol Phys 1989; 17:879-85. [PMID: 2777680 DOI: 10.1016/0360-3016(89)90082-5] [Citation(s) in RCA: 246] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
An integrated logistic model for predicting the probability of complications when small volumes of tissue receive an inhomogeneous radiation dose is described. This model can be used with either an exponential or linear quadratic correction for dose per fraction and time. Both the exponential and linear quadratic versions of this integrated logistic formula provide reasonable estimates of the tolerance of brain to radiosurgical dose distributions where there are small volumes of brain receiving high radiation doses and larger volumes receiving lower doses. This makes it possible to predict the probability of complications from stereotactic radiosurgery, as well as combinations of fractionated large volume irradiation with a radiosurgical boost. Complication probabilities predicted for single fraction radiosurgery with the Leksell Gamma Unit using 4, 8, 14, and 18 mm diameter collimators as well as for whole brain irradiation combined with a radiosurgical boost are presented. The exponential and linear quadratic versions of the integrated logistic formula provide useful methods of calculating the probability of complications from radiosurgical treatment.
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Affiliation(s)
- J C Flickinger
- Department of Radiation Oncology, University of Pittsburgh School of Medicine, PA
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175
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Loeffler JS, Alexander E, Siddon RL, Saunders WM, Coleman CN, Winston KR. Stereotactic radiosurgery for intracranial arteriovenous malformations using a standard linear accelerator. Int J Radiat Oncol Biol Phys 1989; 17:673-7. [PMID: 2674079 DOI: 10.1016/0360-3016(89)90123-5] [Citation(s) in RCA: 119] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We have previously described the development of a technique which utilizes a standard linear accelerator to provide stereotactic, limited field radiation. The radiation is delivered using a modified and carefully calibrated 6 MV linear accelerator. Precise target localization and patient immobilization is achieved using a Brown-Roberts-Wells (BRW) stereotactic head frame which is in place during angiography, CT scanning, and treatment. Seventeen arteriovenous malformations (AVMs) have been treated in 16 patients from February 1986 to July 1988. Single doses of 1500-2500 cGy were delivered using multiple non-coplanar arcs with small, sharp edged x-ray beams to lesions less than 2.7 cm in greatest diameter. The dose distribution from this technique has a very rapid dropoff of dose beyond the target volume. Doses were prescribed at the periphery of the AVMs, typically to the 80-90% isodose line. Eleven of 16 patients have been followed by repeat angiography at least 1 year following treatment. Five of 11 have had complete obliteration of their AVM in 1 year and an additional three patients have achieved complete obliteration by 24 months. There have been no incidences of rebleeding or serious complications in any patient. We conclude that stereotactic radiosurgery using a standard linear accelerator is an effective and safe technique in the treatment of intracranial AVMs and the results compare favorably to the more expensive and elaborate systems that are currently available for stereotactic treatments.
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Affiliation(s)
- J S Loeffler
- Department of Radiation Therapy, Harvard Medical School, Boston, MA 02115
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176
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Affiliation(s)
- M Brada
- Academic Radiotherapy Unit, Institute of Cancer Research, Sutton, Surrey, UK
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177
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Lyman JT, Phillips MH, Frankel KA, Fabrikant JI. Stereotactic frame for neuroradiology and charged particle Bragg peak radiosurgery of intracranial disorders. Int J Radiat Oncol Biol Phys 1989; 16:1615-21. [PMID: 2656604 DOI: 10.1016/0360-3016(89)90971-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The application of heavy charged particle Bragg peak radiosurgery for the treatment of intracranial vascular and other disorders requires a system of precise patient immobilization and stereotactic localization of defined intracranial targets. The process of using stereotactic neuroradiological procedures (including cerebral angiography, CT scanning and magnetic resonance imaging) for target definition and localization, and complex treatment planning constrain such a system to be adaptable and reusable. This paper describes a removable stereotactic frame-mask system that is used to immobilize and reposition the patient during stereotactic neuroradiological procedures and charged particle radiosurgery. It consists of four parts--(a) a plastic mask for immobilizing the patient's head; (b) a lucite-graphite mounting frame; (c) a set of fiducial markers; and (d) interfaces between the frame for immobilization and fixation to various diagnostic and therapeutic patient couches. The relationship between each component and the radiosurgical procedure is discussed. This system has proven to be safe, reliable, and noninvasive and it does not require fixation to the bones of the face or skull. When integrated into the radiosurgical treatment planning and localization procedures developed at Lawrence Berkeley Laboratory, it is capable of reliably repositioning the patient to 1 mm in each of three planes and contouring the intracranial target reliably to this accuracy. The application of this stereotactic system in heavy charged particle radiosurgery of intracranial arteriovenous malformations is described in other reports.
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Affiliation(s)
- J T Lyman
- Lawrence Berkeley Laboratory, University of California, Berkeley 94720
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178
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Pastyr O, Hartmann GH, Schlegel W, Schabbert S, Treuer H, Lorenz WJ, Sturm V. Stereotactically guided convergent beam irradiation with a linear accelerator: localization-technique. Acta Neurochir (Wien) 1989; 99:61-4. [PMID: 2667285 DOI: 10.1007/bf01407778] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A stereotactic convergent beam irradiation technique using a linear accelerator has been developed in order to precisely apply single high doses of up to 50 gray and more to brain lesions (radiosurgery). Accurate positioning of the patient and the target point of irradiation is an absolute requirement for this method. The stereotactic localization system developed for this purpose is described.
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Affiliation(s)
- O Pastyr
- Institute for Radiology and Pathophysiology, German Cancer Research Centre, Heidelberg, Federal Republic of Germany
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179
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Podgorsak EB, Pike GB, Olivier A, Pla M, Souhami L. Radiosurgery with high energy photon beams: a comparison among techniques. Int J Radiat Oncol Biol Phys 1989; 16:857-65. [PMID: 2493438 DOI: 10.1016/0360-3016(89)90506-3] [Citation(s) in RCA: 102] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The presently known radiosurgical techniques with high energy photon beams are based either on the commercially available Gamma unit utilizing 201 stationary cobalt beams or on isocentric linear accelerators. The techniques using linear accelerators are divided into the single plane rotation, the multiple non-coplanar arcs, and the dynamic rotation. A brief description of these techniques is given, and their physical characteristics, such as precision of dose delivery, dose fall-off outside the target volume, and isodose distributions are discussed. It is shown that the multiple non-coplanar arcs technique and the dynamic rotation give dose distributions similar to those of the Gamma unit, which makes these two linear accelerator based techniques attractive alternatives to radiosurgery with the Gamma unit.
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