The effect of gamma knife irradiation on functions of striatum in rats

2005 ◽  
Vol 102 ◽  
pp. 42-48 ◽  
Author(s):  
Osamu Tokumaru ◽  
Mihoko Tomida ◽  
Yoko Katayama ◽  
Mootohiro Hayashi ◽  
Yoriko Kawakami ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Time Course ◽  
Magnetic Resonance Images ◽  
High Dose ◽  
Nigrostriatal Pathway ◽  
Histological Changes ◽  
Dorsoventral Axis ◽  
Target Region ◽  
Content Type ◽  
Fine Print

Object.An animal model has been developed to study the effect of gamma knife surgery(GKS) on cerebral function.Methods.A rat was fixed in a newly developed Régis—Valliccioni frame that enables the target region to be planned directly on the magnetic resonance images. The left striatum was irradiated with 150 Gy via a 4-mm collimator of the Leksell gamma knife. Apomorphine (dopamine agonist) was administered to elicit a circling behavior (apomorphine test) after the GKS so as to examine the time course of the changes in dopaminergic functions of irradiated striatum. After a series of behavioral analyses, irradiated brains were subjected to histological examination.Necrosis was observed in the irradiated area surrounded by hemorrhage and gliosis. The distance between the histologically estimated and planned centers of the irradiation areas was 1.0 ± 0.5 mm. The extent of the distance was due to errors along dorsoventral axis. The distribution of the irradiation areas influenced the activity and the circling behaviors in apomorphine test, which was suggestive of involvement of the nigrostriatal pathway.Conclusions.Targeting by using the Régis—Valliccioni frame was very accurate compared with targeting with coordinates based on brain maps used hitherto. Although targeting improved the accuracy, further effort will still be necessary to reduce errors along dorsoventral axis. The apomorphine test indicated a reduced dopaminergic function of the irradiated area including striatum, which accompanied histological changes after a high dose of irradiation (150 Gy).

The effect of gamma knife irradiation on functions of striatum in rats

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 42-48 ◽  
Author(s):  
Osamu Tokumaru ◽  
Mihoko Tomida ◽  
Yoko Katayama ◽  
Mootohiro Hayashi ◽  
Yoriko Kawakami ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Time Course ◽  
Magnetic Resonance Images ◽  
High Dose ◽  
Nigrostriatal Pathway ◽  
Histological Changes ◽  
Dorsoventral Axis ◽  
Target Region ◽  
Content Type ◽  
Fine Print

Object. An animal model has been developed to study the effect of gamma knife surgery(GKS) on cerebral function. Methods. A rat was fixed in a newly developed Régis—Valliccioni frame that enables the target region to be planned directly on the magnetic resonance images. The left striatum was irradiated with 150 Gy via a 4-mm collimator of the Leksell gamma knife. Apomorphine (dopamine agonist) was administered to elicit a circling behavior (apomorphine test) after the GKS so as to examine the time course of the changes in dopaminergic functions of irradiated striatum. After a series of behavioral analyses, irradiated brains were subjected to histological examination. Necrosis was observed in the irradiated area surrounded by hemorrhage and gliosis. The distance between the histologically estimated and planned centers of the irradiation areas was 1.0 ± 0.5 mm. The extent of the distance was due to errors along dorsoventral axis. The distribution of the irradiation areas influenced the activity and the circling behaviors in apomorphine test, which was suggestive of involvement of the nigrostriatal pathway. Conclusions. Targeting by using the Régis—Valliccioni frame was very accurate compared with targeting with coordinates based on brain maps used hitherto. Although targeting improved the accuracy, further effort will still be necessary to reduce errors along dorsoventral axis. The apomorphine test indicated a reduced dopaminergic function of the irradiated area including striatum, which accompanied histological changes after a high dose of irradiation (150 Gy).

Gamma knife radiosurgery in patients with advanced breast cancer undergoing bone marrow transplant

2002 ◽  
Vol 97 ◽  
pp. 663-665 ◽  
Author(s):  
Kenneth J. Levin ◽  
Emad F. Youssef ◽  
Andrew E. Sloan ◽  
Rajiv Patel ◽  
Rana K. Zabad ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Advanced Breast Cancer ◽  
Gamma Knife ◽  
Gamma Knife Radiosurgery ◽  
High Dose Chemotherapy ◽  
Advanced Breast ◽  
High Dose ◽  
Initial Management ◽  
Content Type ◽  
Fine Print

Object. Recent studies have suggested a high incidence of cognitive deficits in patients undergoing high-dose chemotherapy, which appears to be dose related. Whole-brain radiotherapy (WBRT) has previously been associated with cognitive impairment. The authors attempted to use gamma knife radiosurgery (GKS) to delay or avoid WBRT in patients with advanced breast cancer treated with high-dose chemotherapy and autologous bone marrow transplantation (HDC/ABMT) in whom brain metastases were diagnosed. Methods. A retrospective review of our experience from 1996 to 2001 was performed to identify patients who underwent HDC/ABMT for advanced breast cancer and brain metastasis. They were able to conduct GKS as initial management to avoid or delay WBRT in 12 patients following HDC/ABMT. All patients were women. The median age was 48 years (range 30–58 years). The Karnofsky Performance Scale score was 70 (range 60–90). All lesions were treated with a median prescription dose of 17 Gy (range 15–18 Gy) prescribed to the 50% isodose. Median survival was 11.5 months. Five patients (42%) had no evidence of central nervous system disease progression and no further treatment was given. Four patients were retreated with GKS and three of them eventually received WBRT as well. Two patients were treated with WBRT as the primary salvage therapy. The median time to retreatment with WBRT was 8 months after the initial GKS. Conclusions. Gamma knife radiosurgery can be effectively used for the initial management of brain metastases to avoid or delay WBRT in patients treated previously with HDC, with acceptable survival and preserved cognitive function.

Radiosurgery for Cushing's disease after failed transsphenoidal surgery

2000 ◽  
Vol 93 (5) ◽  
pp. 738-742 ◽  
Author(s):  
Jonas M. Sheehan ◽  
Mary L. Vance ◽  
Jason P. Sheehan ◽  
Dilantha B. Ellegala ◽  
Edward R. Laws
Keyword(s):  
Gamma Knife ◽  
Cushing’S Disease ◽  
Tumor Size ◽  
Transsphenoidal Surgery ◽  
Gamma Knife Radiosurgery ◽  
Magnetic Resonance Images ◽  
Cushing's Disease ◽  
Content Type ◽  
Fine Print

Object. Although transsphenoidal surgery has become the standard of care for Cushing's disease, it is often unsuccessful in normalizing cortisol production. In this study the authors investigate the safety and efficacy of gamma knife radiosurgery (GKRS) for Cushing's disease after failed transsphenoidal surgery.Methods. The records of all patients who underwent GKRS at the authors' institution after unsuccessful transsphenoidal surgery for Cushing's disease were retrospectively reviewed. Successful treatment was considered a normal or below-normal 24-hour urinary free cortisol (UFC) level. Records were also evaluated for relapse, new-onset endocrine deficiencies, interval change in tumor size, and visual complications.Forty-three patients underwent 44 gamma knife procedures with follow up ranging from 18 to 113 months (mean 39.1, median 44 months). Normal 24-hour UFC levels were achieved in 27 patients (63%) at an average time from treatment of 12.1 months (range 3–48 months). Three patients had a recurrence of Cushing's disease at 19, 37, and 38 months, respectively, after radiosurgery. New endocrine deficiencies were noted in seven patients (16%). Follow-up magnetic resonance images obtained in 33 patients revealed a decrease in tumor size in 24, no change in nine, and an increase in size in none of the patients. One patient developed a quadrantanopsia 14 months after radiosurgery despite having received a dose of only 0.7 Gy to the optic tract.Conclusions. Gamma knife radiosurgery appears to be safe and effective for the treatment of Cushing's disease refractory to pituitary surgery. Delayed recurrences and new hormone deficiencies may occur, indicating the necessity for regular long-term follow up.

Gamma knife surgery for idiopathic trigeminal neuralgia performed using a far-anterior cisternal target and a high dose of radiation

2004 ◽  
Vol 100 (4) ◽  
pp. 597-605 ◽  
Author(s):  
Nicolas Massager ◽  
José Lorenzoni ◽  
Daniel Devriendt ◽  
Françoise Desmedt ◽  
Jacques Brotchi ◽  
...  
Keyword(s):  
Prognostic Factors ◽  
Pain Relief ◽  
Radiation Dose ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Pain Control ◽  
High Dose ◽  
Content Type ◽  
Idiopathic Trigeminal Neuralgia ◽  
Fine Print

Object. Gamma knife surgery (GKS) has emerged as a suitable treatment of pharmacologically resistant idiopathic trigeminal neuralgia. The optimal radiation dose and target for this therapy, however, remain to be defined. The authors analyzed the results of GKS in which a high dose of radiation and a distal target was used, to determine the best parameters for this treatment. Methods. The authors evaluated results in 47 patients who were treated with this approach. All patients underwent clinical and magnetic resonance imaging examinations at 6 weeks, 6 months, and 1 year post-GKS. Fifteen potential prognostic factors associated with favorable pain control were studied. The mean follow-up period was 16 months (range 6–42 months). The initial pain relief was excellent (100% pain control) in 32 patients, good (90–99% pain control) in seven patients, fair (50–89% pain control) in three patients, and poor (< 50% pain control) in five patients. The actuarial curve of pain relief displayed a 59% rate of excellent pain control and a 71% excellent or good pain control at 42 months after radiosurgery. Radiosurgery-induced facial numbness was bothersome for two patients and mild for 18 patients. Three prognostic factors were found to be statistically significant factors for successful pain relief: a shorter distance between the target and the brainstem, a higher radiation dose delivered to the brainstem, and the development of a facial sensory disturbance after radiosurgery. Conclusions. To optimize pain control and minimize complications of this therapy, we recommend that the nerve be targeted at a distance of 5 to 8 mm from the brainstem.

Intraparenchymal schwannoma of the medulla oblongata

2003 ◽  
Vol 98 (3) ◽  
pp. 621-624 ◽  
Author(s):  
Jiangkai Lin ◽  
Hua Feng ◽  
Fei Li ◽  
Bingmei Zhao ◽  
Qiaonan Guo
Keyword(s):  
Magnetic Resonance ◽  
Gamma Knife ◽  
Medulla Oblongata ◽  
Magnetic Resonance Images ◽  
Gamma Knife Surgery ◽  
Content Type ◽  
Suboccipital Craniectomy ◽  
Benign Schwannoma ◽  
Surrounding Parenchyma ◽  
Fine Print

✓ A 48-year-old man presented with a rare intraparenchymal schwannoma of the medulla oblongata. After he underwent gamma knife surgery, the patient's condition deteriorated and the mass, which at the time was thought to be a glioma, became larger on magnetic resonance images. The mass was resected through a suboccipital craniectomy via the transcerebellomedullary fissure approach. The tumor, which was moderately firm but distinct from the surrounding parenchyma, was removed totally. Postoperative histological and immunohistochemical examinations confirmed the diagnosis of a benign schwannoma. Brainstem schwannomas can be cured by microneurosurgery. It is important to distinguish these tumors from glioma. The main theories on the cause(s) of this lesion are briefly reviewed.

Gamma knife radiosurgery for thalamotomy in parkinsonian tremor: a five-year experience

1998 ◽  
Vol 88 (6) ◽  
pp. 1044-1049 ◽  
Author(s):  
Christopher M. Duma ◽  
Deane B. Jacques ◽  
Oleg V. Kopyov ◽  
Rufus J. Mark ◽  
Brian Copcutt ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Dose Response ◽  
Dose Group ◽  
Low Dose ◽  
Gamma Knife Radiosurgery ◽  
High Dose ◽  
Anatomical Landmarks ◽  
Content Type ◽  
Parkinsonian Tremor ◽  
Fine Print

Object. Certain patients, for example, elderly high-risk surgical patients, may be unfit for radiofrequency thalamotomy to treat parkinsonian tremor. Some patients, when given the opportunity, may choose to avoid an invasive surgical procedure. The authors retrospectively reviewed their experience using gamma knife radiosurgery for thalamotomies in this patient subpopulation: 1) to determine the efficacy of the procedure; 2) to see if there is a dose—response relationship; 3) to review radiological findings of radiosurgical lesioning; and 4) to assess the risks of complications. Methods. Radiosurgical nucleus ventralis intermedius thalamotomy using the gamma knife unit was performed to make 38 lesions in 24 men and 10 women (median age 73 years, range 58–87 years) over a 5-year period. A median radiation dose of 130 Gy (range 100–165 Gy) was delivered to 38 nuclei (four patients underwent bilateral thalamotomy) using a single 4-mm collimator following classic anatomical landmarks. Twenty-nine lesions were made in the left nucleus ventralis intermedius thalamus for right-sided tremor. Patients were followed for a median of 28 months (range 6–58 months). Independent neurological evaluation of tremor based on the change in the Unified Parkinson's Disease Rating Scale tremor score was correlated with subjective patient evaluation. Comparison was made between a subgroup of patients in whom “low-dose” lesions were made (range 110–135 Gy, mean 120 Gy) and those in whom “high-dose” lesions were made (range 140–165 Gy, mean 160 Gy) for purposes of dose—response information. Four thalamotomies (10.5%) failed, four (10.5%) produced mild improvement, 11 (29%) produced good improvement, and 10 (26%) produced excellent relief of tremor. In nine thalamotomies (24%) the tremor was eliminated completely. The median time to onset of improvement was 2 months (range 1 week–8 months). Concordance between an independent neurologist's evaluation and that of the patient was statistically significant (p < 0.001). Two patients who underwent unilateral thalamotomy experienced bilateral improvement in their tremor. There were no neurological complications. There was better tremor reduction in the high-dose group than in the low-dose group (p < 0.04). Conclusions. Although less effective than other stereotactic techniques, gamma knife radiosurgery for thalamotomy offers tremor control with minimal risk to patients unsuited for open surgery.

Usefulness of postischemic thrombolysis with or without neuroprotection in a focal embolic model of cerebral ischemia

2000 ◽  
Vol 92 (5) ◽  
pp. 841-847 ◽  
Author(s):  
Yi Yang ◽  
Qui Li ◽  
Hero Miyashita ◽  
Wendy Howlett ◽  
Muzaffar Siddiqui ◽  
...  
Keyword(s):  
Cerebral Hemorrhage ◽  
Time Course ◽  
Low Dose ◽  
Infarct Volume ◽  
Treated Group ◽  
High Dose ◽  
Content Type ◽  
Increased Risk ◽  
Dose Combination ◽  
Fine Print

Object. Recent studies have shown that the use of thrombolysis in the setting of acute stroke is associated with an increased risk of cerebral hemorrhage. The time of onset of symptoms to initiation of medication and the dose levels of the thrombolytic agents are important determinants for the risk of cerebral hemorrhage. The authors evaluated the time course of thrombolysis-related hemorrhages in experimental settings and tested whether the addition of neuroprotective medication augments the efficacy of thrombolysis and reduces the incidence of hemorrhages.Methods. Male Wistar rats were subjected to right middle cerebral artery embolization with an autologous thrombus and were then randomly assigned to one of the following groups: Group 1, saline-treated (2 hours after ischemic insult) animals as controls; Groups 2 to 4, high-dose urokinase (5000 U/kg) at 2, 3, and 6 hours after the insult; Group 5, low-dose urokinase (2500 U/kg) at 2 hours after the insult; Group 6, 20 mg/kg topiramate (TPM) at 2 hours after the insult; Group 7, a combination of 20 mg/kg TPM at 2 hours and low-dose urokinase (2500 U/kg) at 6 hours after the insult; and Group 8, 20 mg/kg TPM (20 mg/kg) at 2 hours and high-dose urokinase (5000 U/kg) at 2 hours after the insult. Neurological behavior and the infarct volume in the brain were assessed following cerebral embolism and the various treatments.All animals in the single therapy and low-dose combination groups survived surgery. Three of eight animals treated with high-dose urokinase alone at 6 hours and three of six animals in the combined high-dose urokinase and TPM group developed fatal intracerebral hemorrhages. There was a significantly better neurological outcome at 24 hours in the animals treated with either medication compared with controls. The volume of the infarct in the saline-treated group was 54.2 ± 9%. The use of TPM at 2 hours led to a decrease in the infarct to 20.1 ± 11.2% (p < 0.01). Treatment with urokinase at 6 hours after the occlusion showed a trend toward protection; the infarct volume was 31.9 ± 14.1% (p < 0.05). The addition of TPM to low- or high-dose urokinase achieved better neuroprotection (8.2 ± 6% and 11.9 ± 10.7%, respectively; both p < 0.01).Conclusions. In this study the authors show that the volume of the infarct can be significantly decreased with 2 to 6-hour delayed intraarterial thrombolysis with urokinase and that the efficacy of thrombolysis may be enhanced by combining neuroprotective agents like TPM. It is also shown that low-dose combination therapy may decrease the likelihood of cerebral hemorrhage.

Fluorescence-guided resection of glioblastoma multiforme by using high-dose fluorescein sodium

2003 ◽  
Vol 99 (3) ◽  
pp. 597-603 ◽  
Author(s):  
Jun Shinoda ◽  
Hirohito Yano ◽  
Shin-Ichi Yoshimura ◽  
Ayumi Okumura ◽  
Yasuhiko Kaku ◽  
...  
Keyword(s):  
Glioblastoma Multiforme ◽  
Tumor Cells ◽  
Surgical Procedure ◽  
Tumor Resection ◽  
Magnetic Resonance Images ◽  
High Dose ◽  
Fluorescein Sodium ◽  
Content Type ◽  
Endothelial Proliferation ◽  
Fine Print

✓ The authors have recently performed a fluorescence-guided tumor resection procedure by using high-dose fluorescein sodium without any special surgical microscopes for the intraoperative visualization of glioblastoma multiforme (GBM), and they report on the actual procedure and clinicopathological findings. Thirty-two patients with GBMs underwent tumor resection during which this fluorescence-guided procedure was used. Fluorescein sodium (20 mg/kg) was intravenously injected after dural opening at the craniotomy site. The tumor was stained almost homogeneously yellow and the color was intense enough to be readily perceived for resection. The center of the solid lesion was stained a deep yellow and surrounded by a transition zone that was faintly stained. The colored lesion was clearly distinguishable from the unstained zone outside the GBM, particularly in the white matter. Both the deeply and faintly stained regions included endothelial proliferation and dense tumor cells. In the unstained region, less dense tumor cells were consistently revealed; however, no endothelial proliferation could be seen. Grosstotal resection (GTR) was successful in 84.4% of the patients who received an injection of fluorescein sodium, which accounted for 100% of those in whom all the visible yellow color (both the deeply and faintly stained regions) was judged to have been resected during operation. Gross-total resection was performed in 100% of the patients who underwent the fluorescence-guided procedure and assigned to Stage I, a GBM stage in which, as a therapeutic policy, the tumor should be resected as radically as possible. The GTR rates in patients who received fluorescein sodium were significantly higher than those in patients who did not (73 patients with GBMs who underwent tumor resection without the fluorescence-guided procedure). Although the extent of surgery was revealed to be one of the significant and independent prognostic factors for GBM, the fluorescein sodium—guided resection procedure was not a significant or independent prognostic factor in this series. This surgical procedure does not require any special surgical microscopic equipment and is simple, safe, useful, readily accomplished, and universally available for resection of GBMs. Its efficacy simplifies the surgical procedure of navigating the stained lesion from the unstained area to achieve GTR of GBMs, which can be demonstrated on magnetic resonance images.

Gamma knife radiosurgery as a single treatment modality for large cerebral arteriovenous malformations

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 113-119 ◽  
Author(s):  
D. Hung-Chi Pan ◽  
Wan-Yuo Guo ◽  
Wen-Yuh Chung ◽  
Cheng-Ying Shiau ◽  
Yue-Cune Chang ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Arteriovenous Malformations ◽  
Radiation Treatment ◽  
Gamma Knife Radiosurgery ◽  
Consecutive Series ◽  
Content Type ◽  
Obliteration Rate ◽  
Complete Obliteration ◽  
Fine Print

Object. A consecutive series of 240 patients with arteriovenous malformations (AVMs) treated by gamma knife radiosurgery (GKS) between March 1993 and March 1999 was evaluated to assess the efficacy and safety of radiosurgery for cerebral AVMs larger than 10 cm3 in volume. Methods. Seventy-six patients (32%) had AVM nidus volumes of more than 10 cm3. During radiosurgery, targeting and delineation of AVM nidi were based on integrated stereotactic magnetic resonance (MR) imaging and x-ray angiography. The radiation treatment was performed using multiple small isocenters to improve conformity of the treatment volume. The mean dose inside the nidus was kept between 20 Gy and 24 Gy. The margin dose ranged between 15 to 18 Gy placed at the 55 to 60% isodose centers. Follow up ranged from 12 to 73 months. There was complete obliteration in 24 patients with an AVM volume of more than 10 cm3 and in 91 patients with an AVM volume of less than 10 cm3. The latency for complete obliteration in larger-volume AVMs was significantly longer. In Kaplan—Meier analysis, the complete obliteration rate in 40 months was 77% in AVMs with volumes between 10 to 15 cm3, as compared with 25% for AVMs with a volume of more than 15 cm3. In the latter, the obliteration rate had increased to 58% at 50 months. The follow-up MR images revealed that large-volume AVMs had higher incidences of postradiosurgical edema, petechiae, and hemorrhage. The bleeding rate before cure was 9.2% (seven of 76) for AVMs with a volume exceeding 10 cm3, and 1.8% (three of 164) for AVMs with a volume less than 10 cm3. Although focal edema was more frequently found in large AVMs, most of the cases were reversible. Permanent neurological complications were found in 3.9% (three of 76) of the patients with an AVM volume of more than 10 cm3, 3.8% (three of 80) of those with AVM volume of 3 to 10 cm3, and 2.4% (two of 84) of those with an AVM volume less than 3 cm3. These differences in complications rate were not significant. Conclusions. Recent improvement of radiosurgery in conjunction with stereotactic MR targeting and multiplanar dose planning has permitted the treatment of larger AVMs. It is suggested that gamma knife radiosurgery is effective for treating AVMs as large as 30 cm3 in volume with an acceptable risk.

Factors related to complete occlusion of arteriovenous malformations after gamma knife radiosurgery

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 96-101 ◽  
Author(s):  
Jong Hee Chang ◽  
Jin Woo Chang ◽  
Yong Gou Park ◽  
Sang Sup Chung
Keyword(s):  
Gamma Knife ◽  
Arteriovenous Malformations ◽  
Gamma Knife Radiosurgery ◽  
Maximum Diameter ◽  
Content Type ◽  
Complete Occlusion ◽  
Factors Associated ◽  
Martin Grade ◽  
Fine Print

Object. The authors sought to evaluate the effects of gamma knife radiosurgery (GKS) on cerebral arteriovenous malformations (AVMs) and the factors associated with complete occlusion. Methods. A total of 301 radiosurgical procedures for 277 cerebral AVMs were performed between December 1988 and December 1999. Two hundred seventy-eight lesions in 254 patients who were treated with GKS from May 1992 to December 1999 were analyzed. Several clinical and radiological parameters were evaluated. Conclusions. The total obliteration rate for the cases with an adequate radiological follow up of more than 2 years was 78.9%. In multivariate analysis, maximum diameter, angiographically delineated shape of the AVM nidus, and the number of draining veins significantly influenced the result of radiosurgery. In addition, margin radiation dose, Spetzler—Martin grade, and the flow pattern of the AVM nidus also had some influence on the outcome. In addition to the size, topography, and radiosurgical parameters of AVMs, it would seem to be necessary to consider the angioarchitectural and hemodynamic aspects to select proper candidates for radiosurgery.

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