Choice of Radiation Detector in Dosimetry of Stereotactic Radiosurgery-Radiotherapy
AbstractDosimetry of the small radiation fields used in radiosurgery is often difficult because of finite detector size and loss of lateral electronic equilibrium. However, small-field dosimetry is critical in radiosurgery where a relatively high dose in a single fraction is often delivered. Radiosurgery dosimetry varies significantly in small fields depending upon the choice of detector. Small-volume (0.015 cm3–0.125 cm3) cylindrical ion chambers, parallel-plate ion chamber, films (Kodak and CEA), thermoluminescent dosimeter (TLD), diamond detector, and Monte Carlo simulation were used to study the small-field ( ≤ 4 c...
Source: Journal of Radiosurgery - December 1, 2000 Category: Radiology Source Type: research
Radiosurgery for Intracranial Arteriovenous Malformations in Children
Conclusion: Radiosurgery is an effective noninvasive and safe therapeutic modality for the management of vascular malformations independent of location, size, or grade. (Source: Journal of Radiosurgery)
Source: Journal of Radiosurgery - December 1, 2000 Category: Radiology Source Type: research
Stability in Frameless Stereotactic Radiotherapy
AbstractThe development of fractionated stereotactic radiotherapy (SRT) has been hampered by slow and cumbersome relocation techniques. The Medtronic Sofamor Danek (MSD) frameless system is promoted as a fast, relocatable system. It relies upon the integrity of a bite tray system that is molded to the patient's upper dentition. Precise relocation of the bite tray is the key to accurate external placement of the fiducial reference frame. The optimum construction method for a stable reproducible tray is not described. We undertook a study to identify factors, which might influence the integrity of the bite tray system. Repro...
Source: Journal of Radiosurgery - December 1, 2000 Category: Radiology Source Type: research
Survival after Stereotactic Radiosurgery for Recurrent Glioblastoma Multiforme
AbstractThis retrospective analysis details the experience of a tertiary care center with survival and results for patients with recurrent glioblastoma multiforme (GBM) treated with stereotactic radiosurgery (SRS). Between August 1990 and June 1999, 23 patients were treated for recurrent GBM with SRS using either modified 6-MV linear accelerator (linac) or γ-knife. Twenty-two patients (96%) had an initial histological diagnosis of GBM, while 1 patient had an initial diagnosis of anaplastic astrocytoma that was biopsied at recurrence and found to have upgraded to GBM. The median Karnofsky performance score at the time of S...
Source: Journal of Radiosurgery - December 1, 2000 Category: Radiology Source Type: research
An Unusual Case of Liver Metastases from Glioblastoma Multiforme Following Radiosurgery
AbstractA rare case of isolated liver metastases in a patient with recurrent glioblastoma multiforme (GBM) treated with surgery, chemotherapy, external beam irradiation, and salvage stereotactic radiosurgery is described. Our review of literature has revealed only 8 other cases of isolated liver metastases in patients with GBM in the last three decades. Recent data suggest that stereotactic radiosurgery may alter the prognosis of specific subsets of patients with GBM. The potential for combined modality therapy, including radiosurgery to impact on the survival of GBM patients, and, hence, the natural history of this diseas...
Source: Journal of Radiosurgery - December 1, 2000 Category: Radiology Source Type: research
Choice of Radiation Detector in Dosimetry of Stereotactic Radiosurgery-Radiotherapy
Abstract
Dosimetry of the small radiation fields used in radiosurgery is often difficult because of finite detector size and loss of lateral electronic equilibrium. However, small-field dosimetry is critical in radiosurgery where a relatively high dose in a single fraction is often delivered. Radiosurgery dosimetry varies significantly in small fields depending upon the choice of detector. Small-volume (0.015 cm3–0.125 cm3) cylindrical ion chambers, parallel-plate ion chamber, films (Kodak and CEA), thermoluminescent dosimeter (TLD), diamond detector, and Monte Carlo simulation were used to study the ...
Source: Journal of Radiosurgery - December 1, 2000 Category: Radiology Source Type: research
Radiosurgery for Intracranial Arteriovenous Malformations in Children
Conclusion: Radiosurgery is an effective noninvasive and safe therapeutic modality for the management of vascular malformations independent of location, size, or grade. (Source: Journal of Radiosurgery)
Source: Journal of Radiosurgery - December 1, 2000 Category: Radiology Source Type: research
Stability in Frameless Stereotactic Radiotherapy
Abstract
The development of fractionated stereotactic radiotherapy (SRT) has been hampered by slow and cumbersome relocation techniques. The Medtronic Sofamor Danek (MSD) frameless system is promoted as a fast, relocatable system. It relies upon the integrity of a bite tray system that is molded to the patient's upper dentition. Precise relocation of the bite tray is the key to accurate external placement of the fiducial reference frame. The optimum construction method for a stable reproducible tray is not described. We undertook a study to identify factors, which might influence the integrity of the bi...
Source: Journal of Radiosurgery - December 1, 2000 Category: Radiology Source Type: research
Survival after Stereotactic Radiosurgery for Recurrent Glioblastoma Multiforme
Abstract
This retrospective analysis details the experience of a tertiary care center with survival and results for patients with recurrent glioblastoma multiforme (GBM) treated with stereotactic radiosurgery (SRS). Between August 1990 and June 1999, 23 patients were treated for recurrent GBM with SRS using either modified 6-MV linear accelerator (linac) or γ-knife. Twenty-two patients (96%) had an initial histological diagnosis of GBM, while 1 patient had an initial diagnosis of anaplastic astrocytoma that was biopsied at recurrence and found to have upgraded to GBM. The median Karnofsky performance s...
Source: Journal of Radiosurgery - December 1, 2000 Category: Radiology Source Type: research
An Unusual Case of Liver Metastases from Glioblastoma Multiforme Following Radiosurgery
Abstract
A rare case of isolated liver metastases in a patient with recurrent glioblastoma multiforme (GBM) treated with surgery, chemotherapy, external beam irradiation, and salvage stereotactic radiosurgery is described. Our review of literature has revealed only 8 other cases of isolated liver metastases in patients with GBM in the last three decades. Recent data suggest that stereotactic radiosurgery may alter the prognosis of specific subsets of patients with GBM. The potential for combined modality therapy, including radiosurgery to impact on the survival of GBM patients, and, hence, the natural h...
Source: Journal of Radiosurgery - December 1, 2000 Category: Radiology Source Type: research
Gamma Knife (GK) Radiosurgery for Pituitary Adenomas: Evaluation of a Series of 163 Patients
AbstractWe have analyzed a group of 163 patients with pituitary adenoma treated by the GK for 5 years. They were followed up for 12 –60 months (median 24 months) after irradiation. An antiproliferative effect has been achieved using the minimal dose 16–35 Gy with median of 20 Gy to the tumor margin in all of our patients who were controlled by MRI (n = 126 patients). One-half of these adenomas noticeably decreased in size. T his antiproliferative dose was safe for the surrounding structures. The effect was not dependent on the gender or age of the patient, on previous fractionated radiotherapy, or on the applied dose. ...
Source: Journal of Radiosurgery - September 1, 2000 Category: Radiology Source Type: research
Stereotactic Radiosurgery for Brainstem and Thalamic Metastases
This study reviews one institution's experience with the use of stereotactic radiosurgery (SRS) for brainstem and thalamic metastases to evaluate its efficacy in treating such lesions. Between October 1989 and January 1998, 20 patients (9 men, 11 women) underwent linear accelerator SRS for metastases in the brainstem or thalamus. A retrospective chart and radiographic analysis was performed on these patients. The mean patient age at the time of SRS was 55.9 years (range 34 –76). The median dose of SRS was 1600 cGy (range 1200–2000) to the 80% isodose line, although the isodose line varied somewhat. Of the 20 lesions, m...
Source: Journal of Radiosurgery - September 1, 2000 Category: Radiology Source Type: research
Metastatic Hepatoma to the Brain Treated with Stereotactic Radiosurgery
We report a case of hepatocellular carcinoma metastatic to the brain treated with stereotactic radiosurgery. This patient's tumors showed an excellent response to this modality and were successfully controlled for 13 months when she died of disseminated lung metastases. (Source: Journal of Radiosurgery)
Source: Journal of Radiosurgery - September 1, 2000 Category: Radiology Source Type: research
Permanent Iodine-125 Implants in the Treatment of Low-Grade Gliomas
We report a retrospective study on the use of the permanent iodine-125 (125I) implants in the management of low-grade gliomas. From July 1988 to July 1997, 16 patients with low-grade gliomas underwent permanent125I implants in the management of their lesions. There were 7 males and 9 females ranging in age from 4 to 48 years (mean 19). The location was in the cerebral hemisphere in 7 patients, brainstem in 5 patients and thalamus/basal ganglia in 4 patients. Prior to brachytherapy, 9 patients underwent surgical resection and 7 patients underwent stereotactic biopsy procedures. Fourteen patients were treated as part of the ...
Source: Journal of Radiosurgery - September 1, 2000 Category: Radiology Source Type: research
Two-Staged Radiosurgical Treatment of Large Arteriovenous Malformations
AbstractWhen the size of an arteriovenous malformation (AVM) in any one direction is more than 4 cm, an attempt is made to treat it in two stages, separated by 6 months. The first stage treats one-half of the AVM and the remainder is treated in the second stage, thus giving rise to a higher prescription dose for each stage. Therefore, the AVM, as a whole, could be given a higher dose than if the entire AVM were treated in a single fraction. In order to reproduce, in each stage, the isocenter coordinates determined from a pair of orthogonal films, two techniques are applied. One is the use of BrainLAB's mask system, which m...
Source: Journal of Radiosurgery - September 1, 2000 Category: Radiology Source Type: research
