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At least 289 records · Page 16Linked to original sources
PubMed2001

[Radiosurgery of the brain at the beginning of the 21st century: gamma knife with C-table].

The goal of stereotactic radiosurgery by definition is "the delivery of a single, high dose of radiation allowing the precise and complete destruction of chosen target structures containing healthy and/or pathological cells, without significant concomitant or late radiation damage to adjacent tissues". This effect is obtained by the precise focusing of multiple low energy radiation beams crossing at the target. Three different techniques can be used for radiosurgery: linear accelerator (LINAC) based radiosurgery, Bragg-peak (proton) therapy and Gamma Knife radiosurgery. Leksell Gamma Knife (LGK) is a dedicated neurosurgical device for brain surgery to destroy predetermined intracranial targets through the intact skull. It operates via the radiobiological effect of stereotactically directed, highly focused ionizing gamma-beams of 201 cobalt-60 sources. The LGK offers the best precision of target during irradiation. The mechanical accuracy is about 0.3 mm, which makes it particularly suitable for highly sophisticated neurosurgical interventions. Radiosurgery was originally developed to treat functional neurological disorders, but soon after its introduction cerebral arteriovenous malformations, and brain tumors became the main targets for the technique. Since the first LGK installation at the Sophiahemmet Hospital, Stockholm, Sweden in 1967, over 150,000 patients have already been treated in more than 150 units worldwide. The accumulated clinical experience with the LGK has established this method as the "golden standard" of radiosurgery. In December 1999, a new development, the LGK Model-C was installed at the Centre Gamma Knife, Université Libre de Bruxelles, Hôpital Académique Erasme, Brussels, Belgium. This was followed by completion of two similar units in Krefeld, Germany, and at the Presbyterian University Hospital, Pittsburgh, Pennsylvania, U.S.A. The major innovation in the design of the LGK Model-C is the robotic Automatic Positioning System, which allows computer-controlled automatic and sequential positioning of multiple shots during treatment. Thus all steps of the procedure are performed through an unbroken digital chain, from stereotactic image acquisition to the control of the irradiation sequence. This represents a significant achievement which increases the accuracy and practicality of the treatment. The technical details of the method are described, and the main treatment indications are reviewed.

Brain Neoplasms↗
PubMedDate not supplied

Focal enhancement of cranial nerve V after radiosurgery with the Leksell gamma knife: experience in 15 patients with medically refractory trigeminal neuralgia.

BACKGROUND AND PURPOSE: Gamma knife radiosurgery is an alternative for the treatment of medically refractory trigeminal neuralgia. Few reports of posttreatment MR imaging appearance of cranial nerve V exist. Our purpose was to define MR imaging characteristics in cranial nerve V after gamma knife radiosurgery. METHODS: We retrospectively reviewed MR images of 15 patients who underwent gamma knife radiosurgery for trigeminal neuralgia. Radiation doses were 35-45 Gy at the 50% isodose line. Thin-section T2-weighted images and contrast-enhanced and nonenhanced T1-weighted images were obtained the day of radiosurgery and within the next 5 mo. Images were scored for enhancement and hyperintensity on T2-weighted images. Time to follow-up imaging and radiation dose were recorded. RESULTS: Mean time to follow-up imaging was 61 +/- 29 d. Posttreatment T2-weighted images showed stable signal intensity in all cases, with radiosurgical target site enhancement in 10. All five patients whose images did not show treatment-related enhancement received radiation doses of 35 Gy. The data suggested a correlation between enhancement with radiation dose (P =.06). No correlation of enhancement with treatment response or time to follow-up existed (P >.05). CONCLUSION: The trigeminal nerve often enhances at the target site after radiosurgery. Lack of trigeminal nerve enhancement occurred only with lower doses (35 Gy at 50%). MR imaging may be useful to confirm the presence and location of the treatment site after gamma knife radiosurgery for trigeminal neuralgia.

Adult↗
PubMedDate not supplied

Controversies in the management of multiple brain metastases: the roles of radiosurgery and radiation therapy.

Multiple brain metastases (BrM) are a common challenge to patients with cancer. Tumour resection is used mainly for patients with large tumours that cause acute neurological syndromes. The prognosis, even after treatment with whole brain radiation therapy (WBRT), is poor with average expected survivals less than six months. For this reason, numerous centres have evaluated the role of stereotactic radiosurgery (SRS) in patients with solitary or multiple tumours. We conducted a randomised trial that compared radiosurgery plus WBRT to WBRT alone. The rate of local failure at one year was 100% after WBRT alone but only 8% in patients who had boost radiosurgery. The median time to local failure was six months after WBRT alone in comparison to 36 months after WBRT plus radiosurgery (p=0.0005). The median time to any brain failure was improved in the radiosurgery group (p=0.002). Survival was related to extent of extracranial disease (p=0.02). Combined WBRT and radiosurgery for patients with two to four BrM significantly improves control of brain disease. WBRT alone, for years the standard treatment, does not appear to provide lasting and effective care for most patients. Controversies remain in patient selection, number of BrM suitable for treatment, concomitant management of extracranial disease, and timing of therapy.

Brain Neoplasms↗
PubMed2002

[Prognostic factors for deep situated malignant gliomas treated with linac radiosurgery].

BACKGROUND & OBJECTIVE: Though radiosurgery has been used for more than 10 years, the value of radiosurgery for malignant glioma has not been clarified. This paper was designed to investigate efficacy of radiosurgery to malignant glioma by analyzing the prognostic factors affecting prognosis of malignant gliomas treated with linac radiosurgery. METHODS: Fifty-eight patients with deep situated malignant gliomas, 28 anaplastic astrocytomas(AA) and 30 glioblastomas (GBM), aged from 7 to 70 years, were analyzed. The mean volume of tumor was 12.08 cm3, and mean prescription dose for linac radiosurgery was 19.42 Gy. The results were analyzed with Kaplan-Meier curve and Cox regression. RESULTS: There were 44.8% of the tumors shrank. Median tumor local control interval was 10 months(15 months for AA and 9 months for GBM). Tumor local control probability was 37.9% for 1 year and 10.3% for 2 years. Median survival was 22.5 months for AA and 13 months for GBM and 15 months for all patients. The survival probability was 79.3% at 1 year and 20.6% at 2 years. Isocenter numbers and tumor volume were the prognostic factors for tumor control, but conformity index was prognostic factor for survival as determined by Cox regression analysis. Considered of pathology, only isocenter number and target volume significantly affected the tumor control interval. Complication appeared in 44.8% of the patients and the median interval of complication onset was 8 months. Symptomatic cerebral edema was observed in 31.0% of the patients. CONCLUSION: Linac radiosurgery can effectively improve tumor local control and elongate survival for the patients with deep situated malignant gliomas. Tumor volume is the prognostic factor for tumor control, while conformity index is prognostic factor for survival.

Adolescent↗
PubMed2003

[Accuracy and precision of X-ray radiosurgery treatment for tumors in eyeball].

BACKGROUND & OBJECTIVE: Localization error in X-ray radiosurgery for tumors in eyeball was common due to the rotation of eyeball. The accuracy and precision of X-ray radiosurgery was studied by fixing the eyeball with micro-vacuo-certo-contacting ophthalmophanto (MVCCOP) to reduce the error in this article. METHODS: CT localization accuracy of X-ray radiosurgery system was measured using special markers in skull phantom. The eyeballs were fixed using MVCCOP, which was designed by the authors, and then the eyeball fixation accuracy and target localization accuracy were measured by comparing the CT localization coordinates and verification coordinates of corresponding points. RESULTS: The mean error of CT localization of BRW head-ring was 0.65 mm and maximum error was 1.09 mm. The mean error of fixation of eyeball using MVCCOP was 0.84 mm and maximal error was 1.17 mm. The accuracy of tumor localization in eyeball was 0.87 mm averagely and 1.19 mm maximally. The mean error of SRS200 was 0.22 mm and maximum error was 0.32 mm. The total error was 1.40 mm and 95 percentile confidence error was 2.12 mm. CONCLUSION: The accuracy and precision of X-ray radiosurgery using MVCCOP has come up to the standard of quality control of stereotactic radiosurgery. This localization method can reduce the localization errors in radiosurgery caused by the rotation of eyeball.

Child↗
PubMed2004

[In vivo evaluation of tumor response to radiosurgery: application to vestibular schwannomas].

Imaging follow-up of vestibular schwannomas (VS), such as CT or MR, does not allow assessing the response of the tumor tIssue to radiosurgery. Changes in contrast enhancement are frequently observed, with a loss of contrast enhancement within the treated VS. However, this typical aspect does not anticipate the long-term success of radiosurgery for VS. New functional and metabolic image modalities could be useful to assess in vivo radiosurgery-induced tIssue changes. Such data already exist, using techniques such as MR spectroscopy, positron emission tomography (PET) and SPECT, but they concern almost exclusively the evaluation of primary SNC tumors and metastases of systemic cancers. There are, however, very sparse metabolic and functional data concerning the in vivo evaluation of the response of the tumor tIssue to radiosurgery. Moreover, such information is only anecdotal in VS. In other disorders, PET and MR spectroscopy data suggest interesting new directions for the assessment of radiosurgery follow-up. Based on the predictive information provided by PET and MR spectroscopy in primary CNS tumors, it would be worthwhile to design a prospective study evaluating the role of these imaging modalities for in vivo assessment of radiosurgery-treated SV.

Brain↗
PubMed2004

Use of stereotactic PET images in dosimetry planning of radiosurgery for brain tumors: clinical experience and proposed classification.

UNLABELLED: We developed a technique that allows the routine integration of PET in stereotactic neurosurgery, including radiosurgery. We report our clinical experience with the combined use of metabolic (i.e., PET) and anatomic (i.e., MRI and CT) images for the radiosurgical treatment of brain tumors. We propose a classification describing the relative role of the information provided by PET in this multimodality image-guided approach. METHODS: Between December 1999 and March 2003, 57 patients had stereotactic PET as part of their image acquisition for the planning of gamma knife radiosurgery. Together with stereotactic MRI and CT, stereotactic PET images were acquired on the same day using either (18)F-FDG or (11)C-methionine. PET images were imported in the planning software for the radiosurgery dosimetry, and the target volume was defined using the combined information of PET and MRI or CT. To analyze the specific contribution of the PET findings, we propose a classification that reflects the strategy used to define the target volume. RESULTS: The patients were offered radiosurgery with PET guidance when their tumor was ill-defined and we anticipated some limitation of target definition on MRI alone. This represents 10% of the radiosurgery procedures performed in our center during the same period of time. There were 40 primary brain lesions, 7 metastases, and 10 pituitary adenomas. Abnormal PET uptake was found in 62 of 72 targets (86%), and this information altered significantly the MRI-defined tumor in 43 targets (69%). CONCLUSION: The integration of PET in radiosurgery provides additional information that opens new perspectives for the optimization of the treatment of brain tumors.

Adolescent↗
PubMed2005

[Gamma knife radiosurgery for large trigeminal schwannomas].

OBJECTIVE: To evaluate the role of gamma knife (GK) radiosurgery in controlling large trigeminal schwannoma. METHODS: The clinical data of 30 patients suffering from large trigeminal schwannoma with a maximum diameter of 39.0 mm (31.0 to 53.0 mm), who underwent GK radiosurgery, used as the primary treatment modality in 20 patients and used to cure the residuals of tumor after microsurgery in 10 patients, with the maximum irradiation dose to tumor of 25.8 Gy (20.0 to 33.0 Gy) and a tumor margin dose of 12.2 Gy (9.0 to 14.0 Gy), were analyzed respectively. RESULTS: The 30 patients had been followed up for 78 months (24 to 136 months). Twenty-nine of the 30 patients were alive, and one patient with malignant trigeminal schwannoma died of tumor progression 36 months after the GK radiosurgery. Neurological deficits were improved in 24 patients and 3 patients' condition remained stable. Two patients' symptoms worsened 5 and 30 months after the GK radiosurgery respectively because of tumor swelling and tumor cyst enlarging. Then these two patients underwent microsurgery and their tumors were subtotally removed. Disappearance of tumor occurred in 4 patients, a marked decrease in tumor volume was observed in 20 patients, three tumors kept unchanged or slightly regressed in volume, and 3 tumors, including that of the patient who died, progressed. The tumor-growth control rate was 90% (27/30). Two patients underwent craniotomy after GK radiosurgery and one of these 2 resected specimens underwent histopathological examination. The histopathological findings of this tumor resected 30 months after GK radiosurgery revealed that most of the tumor tissue necrosed and was full of microcysts, the residual tumor cells in peripheral areas underwent hyaline degeneration, and the nuclei showed pyknosis. CONCLUSION: GK may be a good alternative treatment for selective patients suffering from large trigeminal schwannoma with a maximum diameter <or= 40 mm.

Adult↗
PubMed2005

[The usefulness of adjuvant therapy using gamma knife radiosurgery for the recurrent or residual nonfunctioning pituitary adenomas].

We evaluated the treatment results of nonfunctioning pituitary adenomas in the era of radiosurgery. Between January 1994 and December 2003, we operated on 44 patients with nonfunctioning pituitary adenomas. 43 patients were operated on by transsphenoidal surgery and one patient was operated on by the transcranial approach. Total removal was able to be achieved in 13 patients (30%). Gamma knife radiosurgery was performed for residual tumor in 26 patients and for recurrence in 2 patients. The mean tumor diameter at the gamma knife radiosurgery was 18.2 mm (7.9 to 26.3 mm). The treatment dose was a mean of 12.3 Gy (8 to 16 Gy) to the tumor margin. The mean follow-up period after radiosurgery was 36.4 months. Tumor growth control was able to be achieved in 26 patients (93%). Two patients (7%) required adrenal and thyroid hormonal replacement during the follow-up period after radiosurgery due to radiation-induced endocrinopathy. None of the patients suffered from new cranial nerve deficits. This included optic neuropathy. Surgical resection using transsphenoidal surgery and subsequent gamma knife radiosurgery for residual and recurrent tumor proved to have a highly effective tumor growth control rate, and maintained the quality of life in patients with nonfunctioning pituitary adenomas.

Adenoma↗
PubMed1992

Radiobiologic models for radiosurgery.

A series of initial radiobiologic investigations have been performed using three animal models. The baboon model proved to be a valuable technique to assess the in vivo radiobiologic response of single-fraction irradiation doses delivered to the primate brain stem. Multimodality neurodiagnostic testing, including CT, MR imaging, xenon-enhanced CT, evoked potential studies, and analysis of CSF myelin basic protein levels, all of which eventually were correlated with neuropathologic examination, enabled detection of lesions produced with high-dose (150 Gy) radiosurgery as early as 6 weeks. Within the first 6 months after radiosurgery, lower doses (20 Gy, 50 Gy) did not result in clinically or neurodiagnostically detectable lesions. The rat arteriovenous fistula model permits analysis of the delayed histopathologic effects of radiosurgery on an experimentally created fistula designed to mimic an AVM. The rat C6 glioma model is designed to evaluate the effect of radiosurgery in an infiltrative tumor that simulates a human malignant brain tumor. These studies are intended eventually to increase our knowledge about the safety and efficacy of radiosurgery in both the normal and tumor-implanted brains. We believe that such fundamental studies ultimately will improve our ability to reach the goals of radiosurgery: to destroy the target and spare the surrounding brain. Eventually, it may become feasible to achieve these goals by combining radiosurgical technique with both radiation sensitizers (for the treated volume) and brain protectors.

Animals↗
PubMed1992

Physics for radiosurgery with linear accelerators.

Radiosurgery had a long development period and, for more than three decades, was used only in a few specialized centers around the world. The development of LINAC-based radiosurgical techniques combined with the concurrent advances in imaging modalities during the 1980s, however, caused so much interest in this treatment modality that most major radiotherapy centers now offer this service or at least plan to offer it in the near future. When considering a LINAC for radiosurgical use, one should remember that technical and clinical requirements for accurate radiosurgery are far more stringent than those applied to standard radiotherapy. This is because in radiosurgery, the targeted volumes are much smaller and the dose is usually delivered in a single irradiation session, whereas in radiotherapy, the dose is delivered to a relatively large target volume on a fractionated basis. Linear accelerator-based radiosurgery broadens the scope of radiotherapy departments. The impetus to introduce this service at a medical center usually comes from neurosurgeons, however. Even after the service becomes routine at an institution, it is the neurosurgeon who refers the patient and who plays the most important role in determining the target volume and its location within the brain. The decision on the choice of isodose surface and the prescribed dose, however, belongs to the radiotherapist. It is becoming clear that radiosurgery is a complex treatment modality for which a successful outcome requires a collaborative team effort by several hospital-based professionals, including neurosurgeons, radiation oncologists, neuroradiologists, and medical physicists. As in standard radiotherapy, physics plays an important role in radiosurgery, not only in the development of target localization, treatment-planning, and dose delivery techniques, but also in the actual patient contact, from the diagnostic target localization procedures, through treatment planning, to patient preparation on the device and dose delivery.

Brain Neoplasms↗
PubMed2006

[A case of cerebral arteriovenous malformation revealing repeated intranidal hemorrhage accompanying neovascularization after stereotactic radiosurgery].

We report a patient with cerebral arteriovenous malformation (AVM) revealing growing mass lesion after stereotactic radiosurgery. This 12-year-old female presented headache. CT scan showed hematoma at the head of the right caudate nucleus and angiography showed AVM at the site. LINAC-based stereotactic radiosurgery was performed with the patient. Twenty-three months after the radiosurgery the patient complained headache and CT scan showed hematoma again at the same site, although angiography did not show AVM. Thirty-five months after the radiosurgery mass lesion with enhancement effect was observed at the site and the mass lesion grew gradually thereafter. Thirty-nine months after the radiosurgery the mass lesion was evacuated. Histological examination revealed fibrotic core and surrounding neovascularized area with hemorrhage. The histology shows a new etiology of growing mass lesion after radiosurgery for AVM.

Basal Ganglia↗
PubMed1990

Introduction to radiosurgery.

Although radiosurgery treatments began more than 30 years ago and thousands of patients have been treated, the role of radiosurgery in the treatment of intracranial lesions is continuing to evolve. For AVM several groups have reported favorable angiographic response rates. Further information, however, is needed to establish the relationship between this objective measure of response and the risk of subsequent hemorrhage. Ideally this relationship might be established through randomized trials. For ethical reasons, however, such trials are unlikely to be undertaken. Although radiosurgery may finally prove useful in the treatment of lesions other than AVM, currently available retrospective data do not allow firm conclusions in most cases. Various techniques can be used to deposit the dose accurately in a predetermined intracranial volume. Nonetheless, it frequently is difficult to define the three-dimensional configuration of the volume requiring treatment accurately. This difficulty is independent of the radiosurgical technique used and, together with dose prescription and patient selection, is probably of greater importance than possible differences in dose distribution produced by different systems. Because many patients will have radiosurgery in nontrial clinical settings, it is important that future reports provide sufficient information to allow meaningful interpretation. At minimum, reports must contain an accounting of all patients treated, including number followed and number lost to follow-up evaluation or otherwise lacking repeat radiologic studies or clinical evaluation. (The statement that 1000 patients were treated is not useful in the absence of this accounting and may cast doubt on reported results.) Beyond accounting it is helpful if reports provide (1) information on dimensions and intracranial location of lesions treated and correlation with dose and outcome, (2) quantitative information on dose prescribed, including minimum and maximum dose to the target, especially when multiple isocenters are used (when isodose contours from individual isocenters must be summed), (3) detailed information on patients developing complications (in what ways did their presentation or treatment differ from that of other patients?), and (4) thorough data analysis using modern statistical techniques. The number of radiosurgery facilities is increasing rapidly. Whether the number of patients treated in each facility will continue to rise each year as more new facilities are open is conjectural and will depend on the evolution of indications for radiosurgery and on the evolution of referral patterns as techniques, facilities, and results become established.

Brain Neoplasms↗
PubMed1995

[Stereotactic radiosurgery using a linear accelerator (LINAC): simulation and positioning].

Stereotactic radiosurgery using a Gamma unit obtains good results for small intracranial diseases, arteriovenous malformation (AVM) and acoustic neurinoma. In stereotactic radiosurgery using a linear accelerator (LINAC), many fundamental problems are to be solved. 1) accuracy of a LINAC, 2) making the collimators for high energy X-ray narrow beams, 3) dosimetry for high energy X-ray narrow beams, 4) irradiation methods for stereotactic radiosurgery, 5) fixation of a patient's head and 6) simulation of a target. The usefulness of our method for simulation of a target and for positioning for radiosurgery was investigated. High energy X-ray narrow beams obtained with the collimators for narrow beams (field sizes: 9mm phi, 18mm phi and 27mm phi) satisfy clinical requirements for stereotactic radiosurgery, as indicated by dose profiles and isodose curves. No dosimetry method for high energy X-ray narrow beams has been established yet. Of the main irradiation methods for stereotactic radiosurgery, the method using multiple non-coplanar converging arcs needs no drastic reconstruction for use with LINAC. A patient's head was completely fixed by the stereotactic frame (Patil stereotaxic system or Leksell micro-stereotactic system). Simulation of a target was performed under CT scan. On CT image, the center of a target was determined and the three-dimensional coodinate on the stereotactic head frame target was settled so that the target would be reached. The three-dimensional coordinate for the target was coincided with the isocenter of a LINA by the laser beams of three-directional pointers. Afterwards, the target position was finely adjusted, by using the target positioner manipulator system.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1993

Combined embolization and gamma knife radiosurgery for cerebral arteriovenous malformations.

In a study of 46 patients with cerebral arteriovenous malformations (AVMs) the value of combining embolization and gamma knife radiosurgery was assessed. In 35 patients with large grade III to V AVMs (Spetzler-Martin system) staged combined treatment was planned. In 11 patients, radiosurgery complemented embolization for a residual AVM. The number of embolization sessions ranged from 1 to 7 (median 2). Twenty-six patients needed multiple embolization sessions. In 28 patients the grade of AVMs decreased as a result of embolization. In 16 patients collateral feeding vessels developed after embolization which made delineation of the residual nidus difficult. The time lag between the last embolization and radiosurgery ranged from 1 to 24 months (median 4). Nineteen of 35 large grade III to V AVMs were possible to treat by radiosurgery following embolization. In the 46 patients complications occurred in 9 from embolization and in 2 from radiosurgery. Two patients had transient and 9 had permanent neurologic deficits. It is concluded that embolization facilitates radiosurgery for some large AVMs and therefore this combined treatment has a role in the management of AVMs.

Adolescent↗
PubMedDate not supplied

Endovascular treatment of cerebral arteriovenous malformations following radiosurgery.

PURPOSE: Previous reports of embolization of cerebral arteriovenous malformations (AVMs) have evaluated the technique as adjunctive therapy prior to surgery or radiosurgery; our aim is to assess the role of embolization following radiosurgery. PATIENTS: Six patients previously treated with radiosurgery and showing no response as judged by cerebral angiography were embolized 24 to 55 months (mean 34.3 months) after initial radiosurgery. RESULTS: In five of six, a significant volume reduction was achieved ranging from 60%-100% (mean 74%). One patient was treated with embolization alone and the AVM has remained fully thrombosed 2 years after treatment. Three patients underwent surgical resection for cure after embolization, and two patients had repeat radiosurgery to a significantly smaller AVM volume. One patient had an asymptomatic carotid dissection at embolization; however, no clinically apparent complications occurred in the treatment group. CONCLUSION: Embolization can be used after radiosurgery to assist in the management of those AVMs that have not responded to initial treatment.

Adolescent↗
PubMed1996

Stereotactic radiosurgery for glial neoplasms of childhood.

We evaluated the role of stereotactic radiosurgery (SRS) in 25 children with surgically incurable brain tumors of glial origin. Histological diagnoses were obtained at the time of craniotomy and attempted removal (n = 20) or by stereotactic biopsy (n = 5). Thirteen children had tumors with benign histological characteristics (pilocytic and low-grade astrocytomas), whereas 12 children had tumors with malignant characteristic (malignant astrocytomas and ependymomas). Eleven (10 with malignant tumors) of the 25 children had received fractionated irradiation before SRS. Radiosurgical doses (range to margin, 11-20 Gy) were calculated on the basis of tumor volume and location, with consideration given to prior radiation dose. Follow-up for the 13 children with benign tumors ranged from 6 to 48 months (median, 21 mo). Eleven of the 13 children with "benign" glial neoplasms had tumor control with SRS alone (no evidence of tumor, n = 4; decreased tumor, n = 5; and unchanged tumor, n = 2), and all 13 remain alive. Five children with malignant tumors are alive at 12, 45, 50, 72, and 72 months after radiosurgery. The other seven children with malignant tumors are dead, with a median survival of 6 months after radiosurgery. Three of 12 children with malignant glial neoplasms had tumor control after SRS. Two of these three children received fractionated irradiation as an adjunct to SRS. Complications occurring in four children were transient, associated with peritumoral edema, and responsive to oral glucocorticoids. There was no relationship between tumor volume and local control after radiosurgery. Radiosurgery alone is a safe and effective treatment modality for unresectable benign gliomas of childhood. Radiosurgery may have a role in the adjuvant management of unresectable malignant glial neoplasms of childhood if other therapies (irradiation or chemotherapy) are available.

Adolescent↗
PubMedDate not supplied

Radiosurgery as a treatment alternative for dural arteriovenous fistulas of the cavernous sinus.

PURPOSE: Radiosurgery is an effective treatment for cerebral arteriovenous malformations. We conducted the present study to investigate the feasibility and efficacy of gamma knife radiosurgery for dural arteriovenous fistulas (DAVFs) of the cavernous sinus. METHODS: Eighteen patients (12 women and six men; 29-75 years old [mean age, 55 years]) with DAVFs of the cavernous sinus (Barrow's type B:1, C:7, and D:10) treated by gamma knife radiosurgery were enrolled in the study. DAVFs were bilateral in six patients and unilateral in 12. Stereotactic X-ray angiography and MR imaging were performed for targeting the radiosurgery. Areas of arteriovenous communication targeted for irradiation were first outlined on the X-ray angiograms. The target regions were then transferred to and displayed on the MR images. Dose planning was based on findings on the integrated images. Prescribed maximum target doses were 22 to 38 Gy (mean, 28 Gy). The targets were covered by 50% to 90% isodose levels. Radiation doses to the surrounding optic apparatus were kept to less than 8 Gy. The patients were followed up with color Doppler sonography and MR imaging. When noninvasive imaging suggested obliteration, X-ray angiography was performed to verify the results. RESULTS: The DAVFs were totally obliterated in 12 (80%) of the 15 patients. In the other three, one was almost completely obliterated at 14 months and two were partially obliterated at 19 and 27 months, respectively, after radiosurgery. No complications or symptom worsening occurred during the follow-up period. CONCLUSION: Gamma knife radiosurgery is a feasible, effective, and safe treatment for DAVFs of the cavernous sinus. Integration of stereotactic X-ray angiography and MR imaging not only aids treatment efficacy but also protects the relevant vital structures, especially the optic apparatus, from the hazards of radiation.

Adult↗