Effect Of Gamma Knife Surgery Research Articles

The evaluation of effect of gamma knife on cavernous sinus hemangioma through computed tomography

Objective: Using Computed Tomography (CT) to evaluate the treatment effect of gamma knife surgery in the treatment of Cavernous Sinus Hemangioma (CSHs). Method: This article retrospectively analysed 31 patients with CSHs who were confirmed clinically and pathologically from Oct 2013 to Apr 2015 in Imaging Center of Xian Central Hospital. Using CT scan images to observe the changes of patient’s clinical symptoms and tumour size before and after gamma knife treatment. The various data were statistically analysed. Further analysis of the influence of tumour lesion size, location and therapeutic dose on the therapeutic effect. Results: With CT scan, the location of tumour lesion and calcification for CHSs patients can be clearly be seen. After treatment with gamma knife, the diameter of tumour reduced from 3.57 ± 0.46 cm to 2.93 ± 0.56 cm, with significant reduction (P<0.05). From the change of Gross Tumour Volume (GTV) of these patients, 0 cases is complete remission, 22 cases are partial remission, 8 cases are stable and 1 case is progressive. The effective rate of gamma knife is 10.97%, and the stable rate is 96.77%. Furthermore, after treatment with gamma knife, 20 patient’s headache symptoms have been improved, 13 patient’s diplopia symptom have been improved, 5 patient’s tinnitus symptom have been alleviated, 18 patient’s eyelid ptosis symptom have been improved, 21 patient’s facial numbness symptom have been improved. Additionally, the location of tumour lesion is one factor that influences the treatment effect (P<0.05). Conclusions: Gamma knife treatment could improve nerve function and other symptoms in patients with CHSs, and has a good therapeutic effects and important value.

Pituitary insufficiency as a side effect after radiosurgery for pituitary adenomas: the role of the hypothalamus

Object Causes of pituitary insufficiencies as a side effect of Gamma Knife surgery (GKS) following irradiation of the hypothalamopituitary axis are still under debate. In an investigation of pituitary insufficiencies after GKS, the authors' main focus is on what role can be attributed to the hypothalamus with regard to endocrinological changes in hypothalamopituitary function following GKS. Methods A total of 108 patients consecutively treated between April 1992 and July 2003 were included in this retrospective study. All patients had undergone either transsphenoidal or transcranial surgery prior to GKS. The spot dosimetry method was used to determine doses delivered to structures of the hypothalamopituitary axis. For statistical analyses, endocrine insufficiency and deterioration in pituitary function were defined as a decrease in hormonal blood levels below the normal range for 1 or more anterior pituitary lobe hormones. Additionally, an analysis of the rate of patients requiring hormone replacement therapy after GKS due to new endocrinopathies was performed. Results Complete patient records of 61 male and 47 female patients with a mean age of 51.9 years (range 9.1–81.2 years) were available for our investigation. The overall tumor control rate was 97% and the endocrinological cure rate was 61.2%. Mean treatment doses in patients with and without new endocrine insufficiencies (shown as with/without insufficiencies and followed by probability values) were as follows: 1.3/0.8 Gy to the hypothalamus (p = 0.2); 2.2/1.6 Gy to the median eminence (p = 0.1); 6.5/4.1 Gy to the pituitary stalk (p = 0.004); and 12.4/9.5 Gy to the pituitary gland (p = 0.05). The median overall duration of follow-up after GKS was 6.7 years, with 84 patients (77.7%) whose follow-up was longer than 12 months. The median follow-up time after GKS in patients who developed a new pituitary dysfunction was 79.5 months (6.6 years, SD 3.8 years), and the median follow-up time in patients with no new insufficiencies was 78.4 months (6.5 years, SD 4 years). Conclusions Gamma Knife surgery is a safe and effective treatment for patients with residual and recurrent pituitary adenomas. The rate of pituitary insufficiencies after GKS is still lower than that after conventional radiotherapy. Very low radiation doses are directed to the hypothalamus, and thus this structure does not play a major role in the development of pituitary insufficiencies after GKS. The results of this study show that patients in whom the pituitary stalk and pituitary gland receive a high mean point dose are more likely to develop pituitary insufficiencies after GKS than those who receive a lower dose.

Effect of gamma knife surgery on treatment of craniopharyngiomas

Objective To evaluate the adaption,effectiveness,dose,complication of the treatment for cranio pharygiomas with gamma knife surgery.Methods Gamma knife surgery was performed in 41 patients.Patients with mixed solid and cystic tumors were treated with stereotaxic aspiration while six cases were treated with divergence surgery prior to gamma knife therapy.The central dose ranges from 17.1 ～40 Gy(29.6Gy in average).The patients were treated at 30%～50% equal dose curve with 6 ～14Gy of tumormargin dose(9.5Gy in average).The exposure dose of the optic nerve and optic tract is less than 10Gy.Results Of twenty-nine patients who were followed up from 6 to 100 months,sixteen had disappeared or decreased tumor,six had unchanged,two was performed craniotomy one year or three years after gamma knife surgery,and the remaining five were dead one year to three years.The tumor control rate was 75.9%(22/29).Conclusion The treatment of stereotaxic radiation with single and high dose is sensitive to most of the solid craniopharyngioma,and the treatment of stereotaxic resection combined with gamma knife surgery may be feasible for the recurrent mixed solid and cystic craniopharyngioma. Key words: Craniopharygioma; Gamma knife; Cadiosurgery

Clinical analysis of Gamma Knife surgery for trigeminal schwannomas

The authors sought to assess the clinical effect of Gamma Knife surgery (GKS) for trigeminal schwannomas. Between December 1994 and December 2003, 69 patients with trigeminal schwannomas underwent GKS, and 58 patients were followed up and reviewed at the Beijing Neurosurgical Institute. The mean target volume was 4.6 cm3. The mean peripheral dose was 13.1 Gy, and the mean central dose was 28.3 Gy. The mean radiological follow-up period was 42.5 months. Radiological follow-up demonstrated near-complete disappearance of the tumors in four patients (6.9%), in 34 patients (58.6%) a reduction was seen, in 16 patients (27.6%) no change was observed, and in four patients (6.9%) an enlargement was revealed. The overall tumor control rate was 93.1%. Improvement of presenting neurological symptoms was observed in 28 patients (48.3%), stabilization of presenting neurological symptoms was observed in 23 patients (39.6%), continued progression of presenting neurological symptoms was observed in seven patients (12.1%), and transient cranial nerve dysfunction was observed in six patients (10.4%). Among 13 patients with secondary trigeminal neuralgia, 10 patients had significant improvement or disappearance of trigeminal neuralgia after GKS. Gamma Knife surgery provides an effective and safe primary and/or adjunct treatment for patients with small- to moderate-sized trigeminal schwannomas, with a low risk of iatrogenic cranial neuropathy and great improvement of clinical symptoms.

Integration of gamma knife surgery in the management of cerebral metastases from melanoma

The aim of this study was to investigate the effect of gamma knife surgery on the local control of cerebral metastases from melanoma and to assess survival. In 29 patients, 105 of 178 cerebral metastases were treated with gamma knife surgery. Only five patients had metastases confined to the brain. Of the 96 metastases with magnetic resonance imaging follow-up, 61.5% regressed by more than 50% of the pretreatment volume, 25% regressing by more than 90% and 13.5% completely. The median survival from gamma knife surgery was 5.7 months (longest survival, 38 months). In multivariate analyses, a larger number of lesions requiring treatment (P < 0.001), recursive partitioning analysis class (P = 0.009) and a long time interval from initial melanoma diagnosis to detection of cerebral metastases (P = 0.001) influenced survival. It can be concluded that gamma knife surgery is a useful adjunct in the management of cerebral metastases from melanoma and has a significant impact on local control. Its greatest potential may be achieved in conjunction with systemic chemotherapy, especially in the presence of extracerebral metastases.

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

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 surgery for atypical meningiomas

Complete resection is the optimal treatment for atypical meningiomas (AMs) but its feasibility depends on the tumor site. The object of this study was to assess the effect of gamma knife surgery (GKS) on AM. In 15 patients 21 AMs were treated by GKS. Four patients had residual lesions and 10 patients had recurrent tumors after one or more microsurgical interventions. Three patients were treated twice with GKS because of tumor tissue outside the treatment volume, either at the margin or at a distant location. The median clinical and neuroimaging follow-up period was 35 months (range 21-67 months). Ten tumors shrank 6 to 12 months after GKS, 10 remained stable, and one grew. Between 18 and 36 months after GKS, four patients had a distant recurrence, and two had a margin recurrence. In one of these cases, an additional local recurrence was demonstrated 1 year later, and the patient underwent standard radiotherapy. No patient suffered persistent adverse effects after radiosurgery. After early tumor shrinkage, high recurrence rates were demonstrated both at the treatment margin and at distant locations in cases treated for AM. There was only one recurrence within the GKS radiation field. For small- and medium-sized AMs GKS may be a safe adjunct to other treatment modalities.

Gamma knife surgery for atypical meningiomas

Object. Complete resection is the optimal treatment for atypical meningiomas (AMs) but its feasibility depends on the tumor site. The object of this study was to assess the effect of gamma knife surgery (GKS) on AM. Methods. In 15 patients 21 AMs were treated by GKS. Four patients had residual lesions and 10 patients had recurrent tumors after one or more microsurgical interventions. Three patients were treated twice with GKS because of tumor tissue outside the treatment volume, either at the margin or at a distant location. The median clinical and neuroimaging follow-up period was 35 months (range 21–67 months). Ten tumors shrank 6 to 12 months after GKS, 10 remained stable, and one grew. Between 18 and 36 months after GKS, four patients had a distant recurrence, and two had a margin recurrence. In one of these cases, an additional local recurrence was demonstrated 1 year later, and the patient underwent standard radiotherapy. No patient suffered persistent adverse effects after radiosurgery. Conclusions. After early tumor shrinkage, high recurrence rates were demonstrated both at the treatment margin and at distant locations in cases treated for AM. There was only one recurrence within the GKS radiation field. For small- and medium-sized AMs GKS may be a safe adjunct to other treatment modalities.

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

An animal model has been developed to study the effect of gamma knife surgery(GKS) on cerebral function. 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. 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).

Neuropsychological change following gamma knife surgery in patients with left temporal lobe epilepsy: a review of three cases

Gamma knife surgery (GKS) is a radiation procedure recently used in the treatment of temporal lobe epilepsy (TLE). Preliminary studies have shown significant seizure reductions in patients 8–26 months postprocedure; however, little is known about the effect of GKS on cognitive functioning in TLE. We report neuropsychological data on three patients with left TLE and MRI evidence of hippocampal sclerosis who underwent GKS. Two models for assessing cognitive change, reliable change indices and regression-based norms for change, were used to measure preoperative versus 13- to 27-month postoperative cognitive change. Results revealed a significantly long delayed verbal memory decline on one measure following GKS. No patient declined on measures of IQ, visual memory, or language. Radiation-induced edema was present at the time of testing in all three patients, which may have affected verbal memory performance. While preliminary, these data suggest that GKS offers a less invasive option to anterior temporal lobectomy, but may produce neuropsychological changes similar to those produced by left anterior temperol lobectomy up to 2 years post-GKS treatment.

Effect of Gamma Knife Surgery on the Risk of Rupture Prior to AVM Obliteration

The incidence for hemorrhage in non-obliterated arteriovenous malformations (AVM) during the first two years following Gamma Knife (GK) surgery was compared to the calculated incidence in untreated patients. There was a decrease in the incidence of hemorrhage as compared to the natural course. This difference was statistically significant. The actual number of hemorrhages during the first two years was 49 in a series of 1604 patients. Additionally, 41 hemorrhages occurred beyond the two years following treatment over the entire follow up time span of up to 24 years. For the first two years the calculated incidence was roughly two times higher than the observed incidence. This impact on the natural history was detectable already within six months after the treatment for the malformations totally covered with at least 25 Gy. The relation between a high minimum and a high average dose on the one hand and a lower risk for hemorrhage on the other hand was statistically significant. Low treatment doses and high age correlated to a higher risk. Neither hemorrhage prior to treatment nor time interval between presenting hemorrhage and treatment seemed to influence the risk for post treatment hemorrhage. The risk for permanent neurological deficit or death due to AVM rupture during the latency period between the time of treatment and total nidus obliteration was less than 0.5% for small AVM and 2-4% for large ones during the first two years. Of the 24 patients with sequelae following AVM rupture after treatment 14 died and 10 remained with neurological deficit of different degrees. However, all survivors were self sufficient.