Gamma Knife Radiosurgery for Acoustic Schwannoma: Effects of Low Radiation Dose and Functional Prognosis

1996 ◽  
Vol 66 (1) ◽  
pp. 134-141 ◽  
Author(s):  
M. Hirato ◽  
H. Inoue ◽  
A. Zama ◽  
C. Ohye ◽  
T. Shibazaki ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Gamma Knife ◽  
Gamma Knife Radiosurgery ◽  
Low Radiation Dose ◽  
Acoustic Schwannoma

scholarly journals Vestibular Schwannoma Tumor Size and Growth Rate Predict Response with Gamma Knife Stereotactic Radiosurgery

2020 ◽  
Author(s):  
Daniel E. Killeen ◽  
Anthony M. Tolisano ◽  
Brandon Isaacson ◽  
J Walter Kutz ◽  
Samuel Barnett ◽  
...  
Keyword(s):  
Growth Rate ◽  
Radiation Dose ◽  
Gamma Knife ◽  
Tumor Volume ◽  
Gamma Knife Radiosurgery ◽  
Tumor Diameter ◽  
Linear Measurements ◽  
Level Of Evidence ◽  
Axial Diameter ◽  
Tumor Enlargement

Abstract Objective The aim of this study is to determine if pretreatment growth of sporadic vestibular schwannomas (VS) predicts postradiosurgery response. Methods This study was a retrospective chart review at a tertiary referral center of patients with VS that had at least two pretreatment magnetic resonance imaging (MRI) studies at least 6 months apart and underwent Gamma Knife radiosurgery with a minimum of 14 months postradiosurgery imaging surveillance. Tumor linear measurements and volumetric segmentation were assessed before and after radiosurgery. The main outcome measure was persistent enlargement following radiosurgery, defined as 2 mm enlargement in greatest axial diameter or 20% enlargement in volume without size regression. Results Thirty-five patients met the inclusion criteria. Patients were observed for median pre- and posttreatment intervals of 29.5 and 40.6 months, respectively. Median dose to the tumor margin was 13 Gy. Postradiosurgery enlargement occurred in six (17.1%) and nine (25.7%) patients based on linear and volumetric enlargement definitions, respectively. Pseudoprogression—defined as tumor enlargement—followed by linear or volumetric regression that occurred in 34.3% of tumors, reaching a maximum size at a median time of 6.3 months (3.3–8.4) postradiosurgery. When controlling for age, gender, and radiation dose, preradiosurgery tumor volume less than 0.3 cm3 (odds ratio [OR]: 59.7, p = 0.012) and preradiosurgery tumor diameter growth rate greater than or equal to 2.5 mm/year (OR: 19.3, p = 0.045) were associated with persistent postradiosurgery tumor enlargement. Conclusion Smaller pretreatment tumor volume and greater linear tumor growth rates were associated with postradiosurgery tumor enlargement when controlling for age, gender, and radiation dose. Level of Evidence :This study indicates that the level of evidence is V.

Linear accelerator radiosurgery for vestibular schwannoma

2001 ◽  
Vol 94 (1) ◽  
pp. 7-13 ◽  
Author(s):  
Roberto Spiegelmann ◽  
Zvi Lidar ◽  
Jana Gofman ◽  
Dror Alezra ◽  
Moshe Hadani ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Gamma Knife ◽  
Linear Accelerator ◽  
Imaging Modality ◽  
Gamma Knife Radiosurgery ◽  
Cranial Neuropathy ◽  
Content Type ◽  
Linac Radiosurgery ◽  
Acoustic Neuromas ◽  
Fine Print

Object. The use of radiosurgery in the treatment of acoustic neuromas has increased substantially during the last decade. Most published experience relates to the use of the gamma knife. In this report, the authors review the methods and results of linear accelerator (LINAC) radiosurgery in 44 patients with acoustic neuromas who were treated between 1993 and 1997. Methods. Computerized tomography scanning was selected as the stereotactic imaging modality for target definition. A single, conformally shaped isocenter was used in the treatment of 40 patients; two or three isocenters were used in four patients who harbored very irregular tumors. The radiation dose directed to the tumor border was the only parameter that changed during the study period: in the first 24 patients who were treated the dose was 15 to 20 Gy, whereas in the last 20 patients the dose was reduced to 11 to 14 Gy. After a mean follow-up period of 32 months (range 12–60 months), 98% of the tumors were controlled. The actuarial hearing preservation rate was 71%. New transient facial neuropathy developed in 24% of the patients and persisted to a mild degree in 8%. Radiation dose correlated significantly with the incidence of cranial neuropathy, particularly in large tumors (≥ 4 cm3). Conclusions. Single-isocenter LINAC radiosurgery proved to be an effective treatment for acoustic neuromas in this series, with results that were comparable with those reported for gamma knife radiosurgery and multiple isocenters.

scholarly journals Gamma knife radiosurgery for vestibular schwannomas: Results of hearing preservation in relation to the cochlear radiation dose

2009 ◽  
Vol 119 (6) ◽  
pp. 1076-1081 ◽  
Author(s):  
Ferdinand C. A. Timmer ◽  
Patrick E. J. Hanssens ◽  
Anniek E. P. van Haren ◽  
Jef J. S. Mulder ◽  
Cor W. R. J. Cremers ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Gamma Knife ◽  
Gamma Knife Radiosurgery ◽  
Hearing Preservation ◽  
Vestibular Schwannomas

Gamma Knife Radiosurgery for Patients with Acoustic Schwannoma

2015 ◽  
Vol 76 (S 02) ◽  
Author(s):  
Mustafa Hatiboglu ◽  
Mahmut Özgör ◽  
Enes Dik ◽  
Hakan Seyithanoglu ◽  
Saffet Tuzgen
Keyword(s):  
Gamma Knife ◽  
Gamma Knife Radiosurgery ◽  
Acoustic Schwannoma

Analysis of the causes of treatment failure in gamma knife radiosurgery for intracranial arteriovenous malformations

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 104-106 ◽  
Author(s):  
Yang Kwon ◽  
Sang Ryong Jeon ◽  
Jeong Hoon Kim ◽  
Jung Kyo Lee ◽  
Dong Sook Ra ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Treatment Failure ◽  
Gamma Knife ◽  
Arteriovenous Malformations ◽  
Gamma Knife Radiosurgery ◽  
Intracranial Arteriovenous Malformations ◽  
Content Type ◽  
The Mean ◽  
Fine Print

Object. The authors sought to analyze causes for treatment failure following gamma knife radiosurgery (GKS) for intracranial arteriovenous malformations (AVMs), in cases in which the nidus could still be observed on angiography 3 years postsurgery. Methods. Four hundred fifteen patients with AVMs were treated with GKS between April 1990 and March 2000. The mean margin dose was 23.6 Gy (range 10–25 Gy), and the mean nidus volume was 5.3 cm3 (range 0.4–41.7 cm3). The KULA treatment planning system and conventional subtraction angiography were used in treatment planning. One hundred twenty-three of these 415 patients underwent follow-up angiography after GKS. After 3 years the nidus was totally obliterated in 98 patients (80%) and partial obliteration was noted in the remaining 25. There were several reasons why complete obliteration was not achieved in all cases: inadequate nidus definition in four patients, changes in the size and location of the nidus in five patients due to recanalization after embolization or reexpansion after hematoma reabsorption, a large AVM volume in five patients, a suboptimal radiation dose to the thalamic and basal ganglia in eight patients, and radioresistance in three patients with an intranidal fistula. Conclusions. The causes of failed GKS for treatment of AVMs seen on 3-year follow-up angiograms include inadequate nidus definition, large nidus volume, suboptimal radiation dose, recanalization/reexpansion, and radioresistance associated with an intranidal fistula.

scholarly journals Gamma Knife Radiosurgery for Acoustic Schwannoma: Early Effects and Preservation of Hearing

1995 ◽  
Vol 35 (10) ◽  
pp. 737-741 ◽  
Author(s):  
Masafumi HIRATO ◽  
Hiroshi INOUE ◽  
Masaru NAKAMURA ◽  
Chihiro OHYE ◽  
Junko HIRATO ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Gamma Knife Radiosurgery ◽  
Acoustic Schwannoma ◽  
Early Effects

Fetal and ovarian radiation dose in patients undergoing gamma knife radiosurgery

2002 ◽  
Vol 58 (1) ◽  
pp. 32-41 ◽  
Author(s):  
Vladimir Ioffe ◽  
Richard S Hudes ◽  
David Shepard ◽  
J.Marc Simard ◽  
Lawrence S Chin ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Gamma Knife ◽  
Gamma Knife Radiosurgery

Skull base approaches and gamma knife radiosurgery for multimodality treatment of skull base tumors

2002 ◽  
Vol 97 ◽  
pp. 674-676 ◽  
Author(s):  
Paul C. Francel ◽  
Sumon Bhattacharjee ◽  
Paul Tompkins
Keyword(s):  
Radiation Dose ◽  
Skull Base ◽  
Gamma Knife ◽  
Gamma Knife Radiosurgery ◽  
Multimodality Treatment ◽  
Skull Base Tumor ◽  
Skull Base Tumors ◽  
Content Type ◽  
Fine Print

Object. The purpose of this study was to evaluate descriptive data obtained in patients who had received multimodality treatment with resection and gamma knife radiosurgery (GKS) for skull base tumors. Retrospective data were collected from 71 patients with skull base tumors who were treated from November 1996 to December 2000, all of whom underwent follow-up evaluation at 1 year or more. Methods. Data were collected from hospital charts and office records, including patient age, tumor type and location, number of tumors, maximum radiation dose, estimated radiation dose to the periphery, tumor volume, and percentage of patients with tumors smaller or the same size at follow-up evaluation. Conclusions. Of the 71 patients with 1 year or more of follow up, 93% had tumor either the same size or smaller and 34% of these patients had a smaller tumor size. It is concluded that: 1) GKS with multimodality treatment is effective for control of skull base tumors; 2) the radiosurgical team should consider the benefits of GKS for treatment of any skull base tumor to afford optimum patient management; and 3) neurosurgeons involved with the management of skull base tumors should either be trained and proficient in GKS or work closely with a colleague trained in the technique. This will ensure proper consideration of both options, resulting in overall improved patient treatment.

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