Risk analysis of Leksell Gamma Knife Model C with automatic positioning system

2002 ◽  
Vol 52 (3) ◽  
pp. 869-877 ◽  
Author(s):  
Steven J Goetsch
Keyword(s):  
Risk Analysis ◽  
Gamma Knife ◽  
Positioning System ◽  
Model C ◽  
Automatic Positioning

A comparison of the gamma knife model C and the Automatic Positioning System with Leksell model B

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 25-28 ◽  
Author(s):  
Daniela Tlachacova ◽  
Michal Schmitt ◽  
Josef Novotny ◽  
Josef Novotny ◽  
Mustafa Majali ◽  
...  
Keyword(s):  
Radiation Exposure ◽  
Gamma Knife ◽  
Positioning System ◽  
Content Type ◽  
Ocular Lesions ◽  
Significant Difference ◽  
Model C ◽  
Automatic Positioning ◽  
Fine Print

Object. The authors sought to compare the quality of treatment planning, radiation protection, and the time taken for treatment in the Leksell gamma knife model B with that using the model C Automatic Positioning System (APS). Methods. Data were obtained in 463 patients treated with the B model and 518 patients treated with the C model. Data were analyzed in patients in whom the following diagnoses had been made: vestibular schwannoma, pituitary adenoma, meningioma, solitary metastasis, and other benign and malignant solitary tumors. Patients with arteriovenous malformations, ocular lesions, and functional diagnoses were excluded from this study. Conclusions. With the C model there was a better conformity for most treated targets, such as vestibular schwannomas (p = 0.005) and meningiomas (p = 0.015). The level of radiation exposures to personnel was significantly decreased when using the model C (p < 0.001). There was no significant difference in radiation exposure of extracranial structures for the same number of shots in patients treated by both models. The mean time saved using the C model with the APS was 41 minutes per treatment. It would seem that the gamma knife model C permits better dose conformity, shorter treatment times, and less radiation exposure to personnel.

Gamma knife model C with the automatic positioning system and its impact on the treatment of vestibular schwannomas

2002 ◽  
Vol 97 ◽  
pp. 450-455 ◽  
Author(s):  
Gerhard A. Horstmann ◽  
Albertus T. C. J. Van Eck
Keyword(s):  
Gamma Knife ◽  
Target Volume ◽  
Vestibular Schwannomas ◽  
Positioning System ◽  
Content Type ◽  
Loss Of Hearing ◽  
Model C ◽  
Automatic Positioning ◽  
Fine Print

Object. The aim of this study was to assess the effects of the gamma knife automatic positioning system (APS) on the treatment of patients, particularly effects of this system on the treatment of patients with vestibular schwannomas (VSs), with a view to reducing loss of hearing. Methods. The dose delivery with an increased number of shots was checked with GAFChromic Film for various numbers of shots (one to 129). The results in the first 549 patients were recorded. In addition a series of 59 patients with VSs treated with 13 Gy to the 65% isodose is presented. The authors have termed this the “13 on 65” concept. The film dosimetry showed that a large number of small shots did not materially affect the dose and dose distribution produced by gamma knife treatment. The APS was used alone in 72% of arteriovenous malformations, 71% of meningiomas, 94% of VSs, and 84% of pituitary adenomas. Metastatic tumors were accessible in a pure APS mode in 59% of all cases, glioma in 58%, and uveal melanoma in 10% of the cases. Thus two thirds of patients could be treated using APS alone. It was possible to use the APS and manual systems together for complex or very eccentrically placed targets. The APS resulted in the use of a larger number of isocenters. After a mean follow-up period of 15 months, the results in patients with the VSs in whom 13 Gy was delivered to the 65% isodose were similar to those in patients treated with the more conventional 50% margin isodose. There was no change in the incidence of hearing loss within the study period, and the incidence of trigeminal and facial neuropathies remained unchanged after treatment as well. Conclusions. The APS encourages the design of more conformal dose plans. The greater use of smaller collimators results in a steeper dose gradient with a smaller amount of radiation outside the target volume. Because the APS is able to apply a large number of smaller isocenters in an acceptable time, the number of isocenters used is increased. An increased number of isocenters can also be used to reduce the maximum radiation dose and increase the homogeneity in a given dose plan.

The commissioning and quality assurance of the Automatic Positioning System on the Leksell gamma knife

2002 ◽  
Vol 97 ◽  
pp. 574-578 ◽  
Author(s):  
Tracy Soanes ◽  
Anna Hampshire ◽  
Paul Vaughan ◽  
Christopher Brownett ◽  
Jeremy Rowe ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Base Plate ◽  
Positioning System ◽  
Positional Accuracy ◽  
Content Type ◽  
Test Tool ◽  
Test Treatments ◽  
Model C ◽  
Automatic Positioning ◽  
Fine Print

Object. The authors describe a series of commissioning checks that were developed following the installation of the Automatic Positioning System (APS) on the model C gamma knife. Methods. System reliability was checked by performing a series of test treatments using the APS. A phantom was designed to enable the exposure of small pieces of Gaf Chromic film at 40 different predefined x, y, and z coordinates. The phantom consisted of a base plate with a series of film holders to facilitate the exposures using a 4-mm field, the center of which was marked. A spreadsheet calculation was performed to verify the conversion from Leksell coordinates to the APS coordinates when the treatment angle (gamma angle) is other than 90°. A number of APS plans were prepared and the coordinate transformation verified. Precision measurements were performed to verify the correct positioning of the high bars when attached to the frame. The Gaf Chromic films were exposed, and the APS plans were used when confined to positions within the high bar range. A test tool to verify accurate location of the high bars on the frame was also designed. Conclusions. The performance of APS was verified independently of the manufacturer by using specially designed tools, phantoms, and spread sheets. At all points tested, the positional accuracy was found to be within specification. Conversion to APS coordinates was verified as correct.

Stereotactic radiosurgery of essential trigeminal neuralgia using Leksell Gamma Knife model C with automatic positioning system

2011 ◽  
Vol 34 (4) ◽  
pp. 497-508 ◽  
Author(s):  
Motohiro Hayashi ◽  
Mikhail Chernov ◽  
Noriko Tamura ◽  
Takaomi Taira ◽  
Masahiro Izawa ◽  
...  
Keyword(s):  
Trigeminal Neuralgia ◽  
Stereotactic Radiosurgery ◽  
Gamma Knife ◽  
Positioning System ◽  
Model C ◽  
Automatic Positioning

A comparison of the gamma knife model C and the Automatic Positioning System with Leksell model B

2005 ◽  
Vol 102 ◽  
pp. 25-28 ◽  
Author(s):  
Daniela Tlachacova ◽  
Michal Schmitt ◽  
Josef Novotny ◽  
Josef Novotny ◽  
Mustafa Majali ◽  
...  
Keyword(s):  
Radiation Exposure ◽  
Gamma Knife ◽  
Positioning System ◽  
Content Type ◽  
Ocular Lesions ◽  
Significant Difference ◽  
Model C ◽  
Automatic Positioning ◽  
Fine Print

Object.The authors sought to compare the quality of treatment planning, radiation protection, and the time taken for treatment in the Leksell gamma knife model B with that using the model C Automatic Positioning System (APS).Methods.Data were obtained in 463 patients treated with the B model and 518 patients treated with the C model. Data were analyzed in patients in whom the following diagnoses had been made: vestibular schwannoma, pituitary adenoma, meningioma, solitary metastasis, and other benign and malignant solitary tumors. Patients with arteriovenous malformations, ocular lesions, and functional diagnoses were excluded from this study.Conclusions.With the C model there was a better conformity for most treated targets, such as vestibular schwannomas (p = 0.005) and meningiomas (p = 0.015). The level of radiation exposures to personnel was significantly decreased when using the model C (p < 0.001). There was no significant difference in radiation exposure of extracranial structures for the same number of shots in patients treated by both models. The mean time saved using the C model with the APS was 41 minutes per treatment. It would seem that the gamma knife model C permits better dose conformity, shorter treatment times, and less radiation exposure to personnel.

Impact of the model C and Automatic Positioning System on gamma knife radiosurgery: an evaluation in vestibular schwannomas

2002 ◽  
Vol 97 ◽  
pp. 588-591 ◽  
Author(s):  
Jean Régis ◽  
Motohiro Hayashi ◽  
Denis Porcheron ◽  
Christine Delsanti ◽  
Xavier Muracciole ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Gamma Knife Radiosurgery ◽  
Positioning System ◽  
Major Advance ◽  
Content Type ◽  
Group I ◽  
The Mean ◽  
Model C ◽  
Automatic Positioning ◽  
Fine Print

Object. The technical advances associated with the model C gamma knife include a robotized system enabling automatic positioning of the stereotactic coordinates. The purpose of this study was to analyze the clinical impact of this technical modification. Methods. The authors studied a sample of patients with vestibular schwannoma (VS). This sample included three groups treated using gamma knife radiosurgery. Group I comprised 21 patients with VS treated just before the installation of the Automatic Positioning System (APS). Group II included patients in Group I with new dose plans created using the APS (in other words, simulated dose plans). Group III consisted of a control group of 20 patients matched for tumor grade with the previous group and treated recently with the APS. Treatment times were calculated after correcting the time for each shot according to the age of the sources after reloading. The treatment times, including total time, irradiation time, and duration of the neurosurgical procedure, were analyzed. In addition, dose planning including number of isocenters, number of different collimators, malfunctions, and the conformity and selectivity indices were recorded. The trend was to reduce the mean number of collimator runs from 7.9 to 1.2 and to increase the mean number of shots from 7.9 to 15.6, mostly by using the 4-mm collimator exclusively. The APS-related conformity and selectivity were improved from 95 to 97% and from 78 to 84%, respectively. The total treatment time was reduced by 53%, and time required to interact with the patient in the room was considerably reduced (75%), giving the neurosurgeon greater freedom to perform other tasks during the treatment period. The reduction of the time spent by the neurosurgeon at work in the room was 84%. The total radiation time was increased by 54%. Conclusions. The preliminary results of this study indicate that the robotization of the gamma knife is likely a major advance in radiosurgery.

First clinical experience with the automatic positioning system and Leksell gamma knife Model C

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 193-197 ◽  
Author(s):  
Gerhard A. Horstmann ◽  
Hans Schöpgens ◽  
Albertus T. C. J. van Eck ◽  
Hans-Jürg Kreiner ◽  
Wolfgang Herz
Keyword(s):  
Gamma Knife ◽  
Clinical Experience ◽  
Positioning System ◽  
Content Type ◽  
The Future ◽  
Narrow Space ◽  
Model C ◽  
Automatic Positioning ◽  
Fine Print

✓ In May of 1999, the first Leksell Model C gamma knife was installed at the Gamma Knife Zentrum in Krefeld, Germany. The authors recount their experience with this latest technical gamma knife development. Until the end of 1999, extensive physical and technical tests were performed and the system's hardware and software were continuously improved and adapted to the user's needs. By the end of 1999, 163 GKSs had been performed using the new functionality of the Model C in manual or “trunnion” mode. The trunnions, the two parts of the system that fix the patient headframe to the gamma knife when the isocenter positions, are checked manually. During the same period the new automatic positioning system (APS) was extensively tested and refined so that the first APS treatment could be performed in January 2000. Fifty GKSs have been performed with the APS capability of the Model C. It was possible to use APS alone in 74% of surgeries whereas in 14% some shots were given with APS and some with trunnions. In 12%, GKS was scheduled and planned for APS, but due to unexpected technical (6%) or mechanical (6%) reasons the treatment had to be performed manually. At present there are some spatial restrictions with Model C in APS mode when compared with the Model B. The most significant restriction is the narrow space for the patient's shoulders, especially when deep-seated lesions are treated. Through mechanical changes of the APS motor housing and some modifications of and to the motor driven couch adjustment, these limitations will be reduced in the future. The APS treatment runs smoothly and fast. In no case did any relevant safety error occur during GKS. The more stringent mechanical limitations of the APS compared with the Model B means that frame placement on the head is more critical than before.

scholarly journals Use of the Leksell gamma knife C with automatic positioning system for the treatment of meningioma and vestibular schwannoma

2003 ◽  
Vol 14 (5) ◽  
pp. 1-5 ◽  
Author(s):  
Marc Levivier ◽  
Jose Lorenzoni ◽  
Nicolas Massager ◽  
Salvador Ruiz ◽  
Daniel Devriendt ◽  
...  
Keyword(s):  
Success Rate ◽  
Gamma Knife ◽  
Vestibular Schwannoma ◽  
Treatment Success ◽  
Treatment Success Rate ◽  
Positioning System ◽  
Significant Difference ◽  
Evolutionary Step ◽  
The Mean ◽  
Automatic Positioning

Object The authors report their experience using the Leksell gamma knife C (GK-C) for the treatment of meningioma and vestibular schwannoma (VS). Methods In December 1999, the first commercially available clinical GK-C was installed at the Université Libre de Bruxelles (Erasme Hospital, Brussels, Belgium). In January 2000, the system was upgraded and equipped with the automatic positioning system (APS). Between February 2000 and February 2003, the APS-equipped GK-C was used to perform 532 radiosurgical treatments, including those in 97 meningiomas and 101 VSs. Meningioma and VS represent 18 and 19%, respectively, of lesions in patients treated with GK-C at the authors' center. The mean number of isocenters per lesion was 9.5 (range 1–36): 18.1 (range 1–36) for meningioma and 12.8 (range 1–27) for VS. In 77.6% of the cases, the authors used a single helmet of collimators (55.5% in meningioma and 74.3% in VS). The most frequently used collimator size was 4 mm (46.7%). Whereas it was 4 mm in cases of VS (64.3%), it was 8 mm in cases of meningioma (41.6%). The APS could be used in 86% of the cases, either alone (79%) or in combination with trunnions (7%). There was a difference in the APS-based treatment success rate in meningiomas (85%) and VSs (94%). A significant difference was also noted in the conformity of the radiosurgical treatments between the two lesions. Conclusions The APS-equipped GK-C represents an evolutionary step in radiosurgery. It requires adjustments by the treating team for its specific limitations, which vary among indications, as exemplified by the differences inherent between meningioma and VS in this series.

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