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Title: Dosimetric and Clinical Analysis of Spatial Distribution of the Radiation Dose in Gamma Knife Radiosurgery for Vestibular Schwannoma

Abstract

Objectives: We investigated variations in the distribution of radiation dose inside (dose inhomogeneity) and outside (dose falloff) the target volume during Gamma Knife (GK) irradiation of vestibular schwannoma (VS). We analyzed the relationship between some parameters of dose distribution and the clinical and radiological outcome of patients. Methods and Materials: Data from dose plans of 203 patients treated for a vestibular schwannoma by GK C using same prescription dose (12 Gy at the 50% isodose) were collected. Four different dosimetric indexes were defined and calculated retrospectively in all plannings on the basis of dose-volume histograms: Paddick conformity index (PI), gradient index (GI), homogeneity index (HI), and unit isocenter (UI). The different measures related to distribution of the radiation dose were compared with hearing and tumor outcome of 203 patients with clinical and radiological follow-up of minimum 2 years. Results: Mean, median, SD, and ranges of the four indexes of dose distribution analyzed were calculated; large variations were found between dose plans. We found a high correlation between the target volume and PI, GI, and UI. No significant association was found between the indexes of dose distribution calculated in this study and tumor control, tumor volume shrinkage, hearing worsening, loss ofmore » functional hearing, or complete hearing loss at last follow-up. Conclusions: Parameters of distribution of the radiation dose during GK radiosurgery for VS can be highly variable between dose plans. The tumor and hearing outcome of patients treated is not significantly related to these global indexes of dose distribution inside and around target volume. In GK radiosurgery for VS, the outcome seems more to be influenced by local radiation dose delivered to specific structures or volumes than by global dose gradients.« less

Authors:
 [1];  [2];  [1];  [2];  [1];  [2];  [1];  [2];  [1];  [2];  [1];  [2]
  1. Gamma Knife Center, Hospital Erasme, Brussels (Belgium)
  2. (Belgium)
Publication Date:
OSTI Identifier:
22054420
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 81; Journal Issue: 4; Other Information: Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; HEARINGS; IRRADIATION; NEOPLASMS; PATIENTS; PLANNING; RADIATION DOSE DISTRIBUTIONS; RADIATION DOSES; RADIOTHERAPY; SHRINKAGE; SPATIAL DISTRIBUTION; SURGERY

Citation Formats

Massager, Nicolas, E-mail: nmassage@ulb.ac.be, Neurosurgery-Department, Hospital Erasme, Brussels, Lonneville, Sarah, Neurosurgery-Department, Hospital Erasme, Brussels, Delbrouck, Carine, ENT-Department, Hospital Erasme, Brussels, Benmebarek, Nadir, Neurosurgery-Department, Hospital Erasme, Brussels, Desmedt, Francoise, Radiophysics, Bordet Institute, Brussels, Devriendt, Daniel, and Radiotherapy, Bordet Institute, Brussels. Dosimetric and Clinical Analysis of Spatial Distribution of the Radiation Dose in Gamma Knife Radiosurgery for Vestibular Schwannoma. United States: N. p., 2011. Web. doi:10.1016/J.IJROBP.2011.03.047.
Massager, Nicolas, E-mail: nmassage@ulb.ac.be, Neurosurgery-Department, Hospital Erasme, Brussels, Lonneville, Sarah, Neurosurgery-Department, Hospital Erasme, Brussels, Delbrouck, Carine, ENT-Department, Hospital Erasme, Brussels, Benmebarek, Nadir, Neurosurgery-Department, Hospital Erasme, Brussels, Desmedt, Francoise, Radiophysics, Bordet Institute, Brussels, Devriendt, Daniel, & Radiotherapy, Bordet Institute, Brussels. Dosimetric and Clinical Analysis of Spatial Distribution of the Radiation Dose in Gamma Knife Radiosurgery for Vestibular Schwannoma. United States. doi:10.1016/J.IJROBP.2011.03.047.
Massager, Nicolas, E-mail: nmassage@ulb.ac.be, Neurosurgery-Department, Hospital Erasme, Brussels, Lonneville, Sarah, Neurosurgery-Department, Hospital Erasme, Brussels, Delbrouck, Carine, ENT-Department, Hospital Erasme, Brussels, Benmebarek, Nadir, Neurosurgery-Department, Hospital Erasme, Brussels, Desmedt, Francoise, Radiophysics, Bordet Institute, Brussels, Devriendt, Daniel, and Radiotherapy, Bordet Institute, Brussels. Tue . "Dosimetric and Clinical Analysis of Spatial Distribution of the Radiation Dose in Gamma Knife Radiosurgery for Vestibular Schwannoma". United States. doi:10.1016/J.IJROBP.2011.03.047.
@article{osti_22054420,
title = {Dosimetric and Clinical Analysis of Spatial Distribution of the Radiation Dose in Gamma Knife Radiosurgery for Vestibular Schwannoma},
author = {Massager, Nicolas, E-mail: nmassage@ulb.ac.be and Neurosurgery-Department, Hospital Erasme, Brussels and Lonneville, Sarah and Neurosurgery-Department, Hospital Erasme, Brussels and Delbrouck, Carine and ENT-Department, Hospital Erasme, Brussels and Benmebarek, Nadir and Neurosurgery-Department, Hospital Erasme, Brussels and Desmedt, Francoise and Radiophysics, Bordet Institute, Brussels and Devriendt, Daniel and Radiotherapy, Bordet Institute, Brussels},
abstractNote = {Objectives: We investigated variations in the distribution of radiation dose inside (dose inhomogeneity) and outside (dose falloff) the target volume during Gamma Knife (GK) irradiation of vestibular schwannoma (VS). We analyzed the relationship between some parameters of dose distribution and the clinical and radiological outcome of patients. Methods and Materials: Data from dose plans of 203 patients treated for a vestibular schwannoma by GK C using same prescription dose (12 Gy at the 50% isodose) were collected. Four different dosimetric indexes were defined and calculated retrospectively in all plannings on the basis of dose-volume histograms: Paddick conformity index (PI), gradient index (GI), homogeneity index (HI), and unit isocenter (UI). The different measures related to distribution of the radiation dose were compared with hearing and tumor outcome of 203 patients with clinical and radiological follow-up of minimum 2 years. Results: Mean, median, SD, and ranges of the four indexes of dose distribution analyzed were calculated; large variations were found between dose plans. We found a high correlation between the target volume and PI, GI, and UI. No significant association was found between the indexes of dose distribution calculated in this study and tumor control, tumor volume shrinkage, hearing worsening, loss of functional hearing, or complete hearing loss at last follow-up. Conclusions: Parameters of distribution of the radiation dose during GK radiosurgery for VS can be highly variable between dose plans. The tumor and hearing outcome of patients treated is not significantly related to these global indexes of dose distribution inside and around target volume. In GK radiosurgery for VS, the outcome seems more to be influenced by local radiation dose delivered to specific structures or volumes than by global dose gradients.},
doi = {10.1016/J.IJROBP.2011.03.047},
journal = {International Journal of Radiation Oncology, Biology and Physics},
number = 4,
volume = 81,
place = {United States},
year = {Tue Nov 15 00:00:00 EST 2011},
month = {Tue Nov 15 00:00:00 EST 2011}
}