Tolerance dose in gamma knife surgery of lesions extending to the anterior visual pathway

2005 ◽  
Vol 102 ◽  
pp. 230-233 ◽  
Author(s):  
Hiroyuki Kenai ◽  
Masanori Yamashita ◽  
Takaharu Nakamura ◽  
Tomoshige Asano ◽  
Michifumi Sainoh ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Visual Pathway ◽  
Visual Disturbance ◽  
Gamma Knife Surgery ◽  
Content Type ◽  
Tolerance Dose ◽  
The Mean ◽  
Fine Print ◽  
Delivered Dose

Object.The authors performed a retrospective analysis of the radiation dose to the anterior visual pathway (AVP) to assess its tolerance to gamma knife surgery.Methods.They examined five cases followed for more than 3 years. The AVP was treated with 10-Gy doses or higher.The mean maximum delivered dose to the AVP was 14 Gy. Ten gray or more was delivered to 25.5% of the ipsilateral AVP, 12 Gy or more to 12.5% of the ipsilateral AVP, and 14 Gy or more to 5.7% of the ipsilateral AVP. Although the mean follow-up period was 40.8 months (36–51 months), no cases of visual function deterioration developed.Conclusions.The tolerance dose of the AVP is considered to be less than 8 to 10 Gy; however, although the delivered dose to the AVP definitely exceeded the tolerance dose in all five cases, no visual disturbance has been identified. Longer follow up is required before any final conclusions may be drawn. Nonetheless, it is suggested that a visual disturbance may be avoided by using careful accurate dose planning even if the dose delivered to the AVP is higher than currently believed to be acceptable.

Tolerance dose in gamma knife surgery of lesions extending to the anterior visual pathway

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 230-233 ◽  
Author(s):  
Hiroyuki Kenai ◽  
Masanori Yamashita ◽  
Takaharu Nakamura ◽  
Tomoshige Asano ◽  
Michifumi Sainoh ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Visual Pathway ◽  
Visual Disturbance ◽  
Gamma Knife Surgery ◽  
Content Type ◽  
Tolerance Dose ◽  
The Mean ◽  
Fine Print ◽  
Delivered Dose

Object. The authors performed a retrospective analysis of the radiation dose to the anterior visual pathway (AVP) to assess its tolerance to gamma knife surgery. Methods. They examined five cases followed for more than 3 years. The AVP was treated with 10-Gy doses or higher. The mean maximum delivered dose to the AVP was 14 Gy. Ten gray or more was delivered to 25.5% of the ipsilateral AVP, 12 Gy or more to 12.5% of the ipsilateral AVP, and 14 Gy or more to 5.7% of the ipsilateral AVP. Although the mean follow-up period was 40.8 months (36–51 months), no cases of visual function deterioration developed. Conclusions. The tolerance dose of the AVP is considered to be less than 8 to 10 Gy; however, although the delivered dose to the AVP definitely exceeded the tolerance dose in all five cases, no visual disturbance has been identified. Longer follow up is required before any final conclusions may be drawn. Nonetheless, it is suggested that a visual disturbance may be avoided by using careful accurate dose planning even if the dose delivered to the AVP is higher than currently believed to be acceptable.

Gamma knife surgery for cavernous hemangiomas: an analysis of 125 patients

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 81-86 ◽  
Author(s):  
Kang-Du Liu ◽  
Wen-Yuh Chung ◽  
Hsiu-Mei Wu ◽  
Cheng-Ying Shiau ◽  
Ling-Wei Wang ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Gamma Knife Surgery ◽  
Content Type ◽  
Cavernous Hemangiomas ◽  
Rebleeding Rate ◽  
Radiation Induced ◽  
Bleeding Episodes ◽  
The Mean ◽  
Fine Print

Object. The authors sought to determine the value of gamma knife surgery (GKS) in the treatment of cavernous hemangiomas (CHs). Methods. Between 1993 and 2002, a total of 125 patients with symptomatic CHs were treated with GKS. Ninety-seven patients presented with bleeding and 45 of these had at least two bleeding episodes. Thirteen patients presented with seizures combined with hemorrhage, and 15 patients presented with seizures alone. The mean margin dose of radiation was 12.1 Gy and the mean follow-up time was 5.4 years. In the 112 patients who had bled the number of rebleeds after GKS was 32. These rebleeds were defined both clinically and based on magnetic resonance imaging for an annual rebleeding rate of 32 episodes/492 patient-years or 6.5%. Twenty-three of the 32 rebleeding episodes occurred within 2 years after GKS. Nine episodes occurred after 2 years; thus, the annual rebleeding rate after GKS was 10.3% for the first 2 years and 3.3% thereafter (p = 0.0038). In the 45 patients with at least two bleeding episodes before GKS, the rebleeding rate dropped from 29.2% (55 episodes/188 patient-years) before treatment to 5% (10 episodes/197 patient-years) after treatment (p < 0.0001). Among the 28 patients who presented with seizures, 15 (53%) had good outcomes (Engel Grades I and II). In this study of 125 patients, symptomatic radiation-induced complications developed in only three patients. Conclusions. Gamma knife surgery can effectively reduce the rebleeding rate after the first symptomatic hemorrhage in patients with CH. In addition, GKS may be useful in reducing the severity of seizures in patients with CH.

Volume reduction in meningiomas after gamma knife surgery

2005 ◽  
Vol 102 ◽  
pp. 189-194 ◽  
Author(s):  
Guenther C. Feigl ◽  
Otto Bundschuh ◽  
Alireza Gharabaghi ◽  
Madjid Samii ◽  
Gerhard A. Horstmann
Keyword(s):  
Gamma Knife ◽  
Tumor Volume ◽  
Gamma Knife Surgery ◽  
Volume Reduction ◽  
World Health ◽  
Tumor Control ◽  
Content Type ◽  
The Mean ◽  
Fine Print

Object.The purpose of this study was to evaluate the volume-reducing effects of gamma knife surgery (GKS) of meningiomas with and without previous surgical treatment.Methods.A group of 127 patients with a mean age of 57.1 years (range 9–81 years) with 142 meningiomas (128 World Health Organization Grade I and 14 Grade II) were included in this study. The management strategy reduces tumor volume with surgery when necessary (81 patients). Stereotactic GKS with a Gamma Knife model C was performed in all tumors of suitable size. Magnetic resonance imaging follow-up examinations with volumetric tumor analysis was performed 6 months after treatment and annually thereafter.The mean tumor volume was 5.9 cm3(range < 5 to > 40 cm3). The mean follow-up time after GKS was 29.3 months (range 11–61 months). The mean prescription dose was 13.8 Gy (range 10–18 Gy). A reduction in volume occurred in 117 (82.4%) of all tumors, and in 20 tumors (14.1%) growth ceased. The overall tumor control rate of 96.4%. The mean volume reduction achieved with GKS was more than 46.1%. Only five tumors (3.5%) showed a volume increase.Conclusions.Gamma knife surgery was effective in reducing meningioma volume at short-term follow up. Further studies are needed to examine the development of these findings over a longer period.

Gamma knife surgery for cavernous hemangiomas: an analysis of 125 patients

2005 ◽  
Vol 102 ◽  
pp. 81-86 ◽  
Author(s):  
Kang-Du Liu ◽  
Wen-Yuh Chung ◽  
Hsiu-Mei Wu ◽  
Cheng-Ying Shiau ◽  
Ling-Wei Wang ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Gamma Knife Surgery ◽  
Content Type ◽  
Cavernous Hemangiomas ◽  
Rebleeding Rate ◽  
Radiation Induced ◽  
Bleeding Episodes ◽  
The Mean ◽  
Fine Print

Object. The authors sought to determine the value of gamma knife surgery (GKS) in the treatment of cavernous hemangiomas (CHs). Methods. Between 1993 and 2002, a total of 125 patients with symptomatic CHs were treated with GKS. Ninety-seven patients presented with bleeding and 45 of these had at least two bleeding episodes. Thirteen patients presented with seizures combined with hemorrhage, and 15 patients presented with seizures alone. The mean margin dose of radiation was 12.1 Gy and the mean follow-up time was 5.4 years. In the 112 patients who had bled the number of rebleeds after GKS was 32. These rebleeds were defined both clinically and based on magnetic resonance imaging for an annual rebleeding rate of 32 episodes/492 patient-years or 6.5%. Twenty-three of the 32 rebleeding episodes occurred within 2 years after GKS. Nine episodes occurred after 2 years; thus, the annual rebleeding rate after GKS was 10.3% for the first 2 years and 3.3% thereafter (p = 0.0038). In the 45 patients with at least two bleeding episodes before GKS, the rebleeding rate dropped from 29.2% (55 episodes/188 patient-years) before treatment to 5% (10 episodes/197 patient-years) after treatment (p < 0.0001). Among the 28 patients who presented with seizures, 15 (53%) had good outcomes (Engel Grades I and II). In this study of 125 patients, symptomatic radiation-induced complications developed in only three patients. Conclusions. Gamma knife surgery can effectively reduce the rebleeding rate after the first symptomatic hemorrhage in patients with CH. In addition, GKS may be useful in reducing the severity of seizures in patients with CH.

Long-term outcomes in patients with vestibular schwannomas treated using gamma knife surgery: 10-year follow up

2005 ◽  
Vol 102 (1) ◽  
pp. 10-16 ◽  
Author(s):  
Toshinori Hasegawa ◽  
Yoshihisa Kida ◽  
Tatsuya Kobayashi ◽  
Masayuki Yoshimoto ◽  
Yoshimasa Mori ◽  
...  
Keyword(s):  
Effective Treatment ◽  
Gamma Knife ◽  
Gamma Knife Surgery ◽  
Vestibular Schwannomas ◽  
Long Term Outcomes ◽  
Content Type ◽  
The Mean ◽  
Fine Print

Object. Gamma knife surgery (GKS) has been a safe and effective treatment for vestibular schwannomas in both the short and long term, although less is known about long-term outcomes in the past 10 years. The aim of this study was to clarify long-term outcomes in patients with vestibular schwannomas treated using GKS based on techniques in place in the early 1990s. Methods. Eighty patients harboring a vestibular schwannoma (excluding neurofibromatosis Type 2) were treated using GKS between May 1991 and December 1993. Among these, 73 patients were assessed; seven were lost to follow up. The median duration of follow up was 135 months. The mean patient age at the time of GKS was 56 years old. The mean tumor volume was 6.3 cm3, and the mean maximal and marginal radiation doses applied to the tumor were 28.4 and 14.6 Gy, respectively. Follow-up magnetic resonance images were obtained in 71 patients. Forty-eight patients demonstrated partial tumor remission, 14 had tumors that remained stable, and nine demonstrated tumor enlargement or radiation-induced edema requiring resection. Patients with larger tumors did not fare as well as those with smaller lesions. The actuarial 10-year progression-free survival rate was 87% overall, and 93% in patients with tumor volumes less than 10 cm3. No patient experienced malignant transformation. Conclusions. Gamma knife surgery remained an effective treatment for vestibular schwannomas for longer than 10 years. Although treatment failures usually occurred within 3 years after GKS, it is necessary to continue follow up in patients to reveal delayed tumor recurrence.

Volume reduction in meningiomas after gamma knife surgery

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 189-194 ◽  
Author(s):  
Guenther C. Feigl ◽  
Otto Bundschuh ◽  
Alireza Gharabaghi ◽  
Madjid Samii ◽  
Gerhard A. Horstmann
Keyword(s):  
Gamma Knife ◽  
Tumor Volume ◽  
Gamma Knife Surgery ◽  
Volume Reduction ◽  
World Health ◽  
Tumor Control ◽  
Content Type ◽  
The Mean ◽  
Fine Print

Object. The purpose of this study was to evaluate the volume-reducing effects of gamma knife surgery (GKS) of meningiomas with and without previous surgical treatment. Methods. A group of 127 patients with a mean age of 57.1 years (range 9–81 years) with 142 meningiomas (128 World Health Organization Grade I and 14 Grade II) were included in this study. The management strategy reduces tumor volume with surgery when necessary (81 patients). Stereotactic GKS with a Gamma Knife model C was performed in all tumors of suitable size. Magnetic resonance imaging follow-up examinations with volumetric tumor analysis was performed 6 months after treatment and annually thereafter. The mean tumor volume was 5.9 cm3 (range < 5 to > 40 cm3). The mean follow-up time after GKS was 29.3 months (range 11–61 months). The mean prescription dose was 13.8 Gy (range 10–18 Gy). A reduction in volume occurred in 117 (82.4%) of all tumors, and in 20 tumors (14.1%) growth ceased. The overall tumor control rate of 96.4%. The mean volume reduction achieved with GKS was more than 46.1%. Only five tumors (3.5%) showed a volume increase. Conclusions. Gamma knife surgery was effective in reducing meningioma volume at short-term follow up. Further studies are needed to examine the development of these findings over a longer period.

Functional outcome after gamma knife surgery or microsurgery for vestibular schwannomas

2002 ◽  
Vol 97 (5) ◽  
pp. 1091-1100 ◽  
Author(s):  
Jean Régis ◽  
William Pellet ◽  
Christine Delsanti ◽  
Henry Dufour ◽  
Pierre Hughes Roche ◽  
...  
Keyword(s):  
Functional Outcome ◽  
Gamma Knife ◽  
Gamma Knife Surgery ◽  
Patient Questionnaire ◽  
Hearing Level ◽  
Content Type ◽  
Class 1 ◽  
The Mean ◽  
Fine Print

Object. Microsurgical excision is an established treatment for vestibular schwannoma (VS). In 1992 the authors used a patient questionnaire to evaluate the functional outcome and quality of life in a series of 224 consecutive patients. In addition, starting with gamma knife surgery (GKS) in 1992, the authors decided to use the same methodology to evaluate prospectively the results of this modality to compare the two alternatives. Methods. Among the 500 patients who were included prospectively, the authors only evaluated patients in whom GKS was the primary treatment for unilateral VS. Four years of follow up was available for the first 104 consecutive patients. Statistical analysis of the GKS and microsurgery populations has shown that only a comparison of Stage II and III (according to the Koos classification) was meaningful in terms of group size and preoperative risk factor distribution. Objective results and questionnaire answers from the first 97 consecutive patients were compared with the 110 patients in the microsurgery group who fulfilled the inclusion criteria. Questionnaire answers indicated that 100% of patients who underwent GKS compared with 63% of patients who underwent microsurgery had no new facial motor disturbance. Forty-nine percent of patients who underwent GKS (17% in the microsurgery study) had no ocular symptoms, and 91% of patients treated with GKS (61% in the microsurgery study) had no functional deterioration after treatment. The mean hospitalization stay was 3 days after GKS and 23 days after microsurgery. All the patients who underwent GKS who had been employed, except one, had kept the same professional activity (56% in the microsurgery study). The mean time away from work was 7 days for GKS (130 days in the microsurgery study). Among patients whose preoperative hearing level was Class 1 according to the Gardner and Robertson scale, 70% preserved functional hearing after GKS (Class 1 or 2) compared with only 37.5% in the microsurgery group. Conclusions. Functional side effects happen during the first 2 years after radiosurgery. Findings after 4 years of follow up indicated that GKS provided better functional outcomes than microsurgery in this patient series.

Gamma knife surgery for intracranial cavernous hemangioma

2005 ◽  
Vol 102 ◽  
pp. 102-106 ◽  
Author(s):  
Moo Seong Kim ◽  
Se Young Pyo ◽  
Young Gyun Jeong ◽  
Sun Il Lee ◽  
Yong Tae Jung ◽  
...  
Keyword(s):  
Basal Ganglia ◽  
Gamma Knife ◽  
Cavernous Hemangioma ◽  
Gamma Knife Surgery ◽  
Content Type ◽  
Presenting Symptoms ◽  
Cavernous Hemangiomas ◽  
The Mean ◽  
Fine Print

Object. The purpose of this study was to assess the benefits of radiosurgery for cavernous hemangioma. Methods. Sixty-five cavernous hemangiomas were treated with gamma knife surgery (GKS) between October 1994 and December 2002. Forty-two patients attended follow up. The mean patient age was 37.6 years (range 7–60 years). The lesions were located in the frontal lobe in 12 cases, deep in the parietal lobe in five, in the basal ganglia in five, in the temporal in three, in the cerebellum in three, in the pons/midbrain in six, and in multiple locations in eight cases. The presenting symptoms were seizure in 12, hemorrhage in 11, and other in 19. The maximum dose was 26.78 Gy, and the mean margin dose was 14.55 Gy. The mean follow-up period after radiosurgery was 29.6 months (range 5–93 months). The tumor decreased in size in 29 cases, was unchanged in 12, and increased in size in one. In the seizure group, seizures were controlled without anticonvulsant medication in nine cases (81.8%) after 31.3 months (range 12–80 months). After 93 months, one patient developed a cyst, which was resected. Rebleeding occurred in one case (2.3%). On T2-weighted imaging changes were seen in 11 cases (26.2%), in three (7.1%) of which neurological deterioration was correlated with imaging changes. In other cases these deficits were temporary. Conclusions. The authors found that GKS was an effective treatment modality for cavernous hemangiomas, especially for those located within the brainstem, basal ganglia, or deep portions of the brain. It can reduce seizure frequency significantly although this takes time. In the group receiving a marginal dose below 15 Gy the patients fared better than when the dose exceeded 15 Gy.

Gamma knife surgery for intracranial cavernous hemangioma

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 102-106 ◽  
Author(s):  
Moo Seong Kim ◽  
Se Young Pyo ◽  
Young Gyun Jeong ◽  
Sun Il Lee ◽  
Yong Tae Jung ◽  
...  
Keyword(s):  
Basal Ganglia ◽  
Gamma Knife ◽  
Cavernous Hemangioma ◽  
Gamma Knife Surgery ◽  
Content Type ◽  
Presenting Symptoms ◽  
Cavernous Hemangiomas ◽  
The Mean ◽  
Fine Print

Object. The purpose of this study was to assess the benefits of radiosurgery for cavernous hemangioma. Methods. Sixty-five cavernous hemangiomas were treated with gamma knife surgery (GKS) between October 1994 and December 2002. Forty-two patients attended follow up. The mean patient age was 37.6 years (range 7–60 years). The lesions were located in the frontal lobe in 12 cases, deep in the parietal lobe in five, in the basal ganglia in five, in the temporal in three, in the cerebellum in three, in the pons/midbrain in six, and in multiple locations in eight cases. The presenting symptoms were seizure in 12, hemorrhage in 11, and other in 19. The maximum dose was 26.78 Gy, and the mean margin dose was 14.55 Gy. The mean follow-up period after radiosurgery was 29.6 months (range 5–93 months). The tumor decreased in size in 29 cases, was unchanged in 12, and increased in size in one. In the seizure group, seizures were controlled without anticonvulsant medication in nine cases (81.8%) after 31.3 months (range 12–80 months). After 93 months, one patient developed a cyst, which was resected. Rebleeding occurred in one case (2.3%). On T2-weighted imaging changes were seen in 11 cases (26.2%), in three (7.1%) of which neurological deterioration was correlated with imaging changes. In other cases these deficits were temporary. Conclusions. The authors found that GKS was an effective treatment modality for cavernous hemangiomas, especially for those located within the brainstem, basal ganglia, or deep portions of the brain. It can reduce seizure frequency significantly although this takes time. In the group receiving a marginal dose below 15 Gy the patients fared better than when the dose exceeded 15 Gy.

Gamma knife surgery for vestibular schwannoma: 10-year experience of 195 cases

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 87-97 ◽  
Author(s):  
Wen-Yuh Chung ◽  
Kang-Du Liu ◽  
Cheng-Ying Shiau ◽  
Hsiu-Mei Wu ◽  
Ling-Wei Wang ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Gamma Knife ◽  
Vestibular Schwannoma ◽  
Tumor Volume ◽  
Radiation Effect ◽  
Gamma Knife Surgery ◽  
Homogeneous Distribution ◽  
Content Type ◽  
Fine Print

Object. The authors conducted a study to determine the optimal radiation dose for vestibular schwannoma (VS) and to examine the histopathology in cases of treatment failure for better understanding of the effects of irradiation. Methods. A retrospective study was performed of 195 patients with VS; there were 113 female and 82 male patients whose mean age was 51 years (range 11–82 years). Seventy-two patients (37%) had undergone partial or total excision of their tumor prior to gamma knife surgery (GKS). The mean tumor volume was 4.1 cm3 (range 0.04–23.1 cm3). Multiisocenter dose planning placed a prescription dose of 11 to 18.2 Gy on the 50 to 94% isodose located at the tumor margin. Clinical and magnetic resonance (MR) imaging follow-up evaluations were performed every 6 months. A loss of central enhancement was demonstrated on MR imaging in 69.5% of the patients. At the latest MR imaging assessment decreased or stable tumor volume was demonstrated in 93.6% of the patients. During a median follow-up period of 31 months resection was avoided in 96.8% of cases. Uncontrolled tumor swelling was noted in five patients at 3.5, 17, 24, 33, and 62 months after GKS, respectively. Twelve of 20 patients retained serviceable hearing. Two patients experienced a temporary facial palsy. Two patients developed a new trigeminal neuralgia. There was no treatment-related death. Histopathological examination of specimens in three cases (one at 62 months after GKS) revealed a long-lasting radiation effect on vessels inside the tumor. Conclusions. Radiosurgery had a long-term radiation effect on VSs for up to 5 years. A margin 12-Gy dose with homogeneous distribution is effective in preventing tumor progression, while posing no serious threat to normal cranial nerve function.

Sign in / Sign up

Export Citation Format

Share Document