A dosimetric comparison between Gamma Knife and CyberKnife treatment plans for trigeminal neuralgia

2010 ◽  
Vol 113 (Special_Supplement) ◽  
pp. 199-206 ◽  
Author(s):  
Martina Descovich ◽  
Penny K. Sneed ◽  
Nicholas M. Barbaro ◽  
Michael W. McDermott ◽  
Cynthia F. Chuang ◽  
...  
Keyword(s):  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Trigeminal Nerve ◽  
Dose Distribution ◽  
Treatment Time ◽  
Average Length ◽  
Cranial Nerves ◽  
Ct Cisternography ◽  
Treatment Plans ◽  
Gamma Knife Perfexion

Object The Leksell Gamma Knife and the Accuray CyberKnife systems have been used in the radiosurgical treatment of trigeminal neuralgia. The 2 techniques use different delivery methods and different treatment parameters. In the past, CyberKnife treatments have been associated with an increased incidence of treatment-related complications, such as facial numbness. The goal of this study was to develop a method for planning a CyberKnife treatment for trigeminal neuralgia that would reproduce the dosimetric characteristics of a Gamma Knife plan. A comparison between Gamma Knife and CyberKnife treatment plans obtained with this method is presented. Methods Five patients treated using the Gamma Knife Perfexion Unit were selected for this study. All patients underwent CT cisternography to accurately identify the position of the trigeminal nerve. The Gamma Knife plans used either one 4-mm-diameter collimator or two coincident 4-mm collimators (one open and one with sector blocking) placed at identical isocenter coordinates. A maximum local dose of 80 Gy was prescribed. Critical structures and representative isodose lines were outlined in GammaPlan and exported to the CyberKnife treatment planning platform. CyberKnife treatments were developed using the 5-mm-diameter cone and the trigeminal node set, which provides an effective collimation diameter of 4 mm at the isocenter. The 60-Gy isodose volume imported from GammaPlan was used as the target in the CyberKnife plans. The CyberKnife treatments were optimized to achieve target dose and critical structure sparing similar to the Gamma Knife plans. Isocentric and nonisocentric delivery techniques were investigated. Treatment plans were compared in terms of dosimetric characteristics, delivery, and planning efficiency. Results CyberKnife treatments using the 5-mm cone and the trigeminal node set can closely reproduce the dose distribution of Gamma Knife plans. CyberKnife isocentric and nonisocentric plans provide comparable results. The average length of the trigeminal nerve receiving a dose of 60 Gy was 4.5, 4.5, and 4.4 mm for Gamma Knife, nonisocentric CyberKnife, and isocentric CyberKnife, respectively. However, minimizing the dose to the critical structures was more difficult with the CyberKnife and required the use of tuning structures. In addition, the dose falloff away from the target was steeper in Gamma Knife plans, probably due to the larger number of beams (192 beams for Perfexion vs ~ 100 beams for CyberKnife). While the treatment time with the CyberKnife is generally shorter, the planning time is significantly longer. Conclusions CyberKnife radiosurgical parameters can be optimized to mimic the dose distribution of Gamma Knife plans. However, Gamma Knife plans result in superior sparing of critical structures (brainstem, temporal lobe, and cranial nerves VII and VIII) and in steeper dose falloff away from the target. The clinical significance of these effects is unknown.

Temporal disconnection between pain relief and trigeminal nerve microstructural changes after Gamma Knife radiosurgery for trigeminal neuralgia

2020 ◽  
Vol 133 (3) ◽  
pp. 727-735
Author(s):  
Peter Shih-Ping Hung ◽  
Sarasa Tohyama ◽  
Jia Y. Zhang ◽  
Mojgan Hodaie
Keyword(s):  
Pain Relief ◽  
Trigeminal Neuralgia ◽  
Pain Intensity ◽  
Gamma Knife ◽  
Trigeminal Nerve ◽  
Diffusion Tensor ◽  
Gamma Knife Radiosurgery ◽  
Time Points ◽  
Microstructural Effect

OBJECTIVEGamma Knife radiosurgery (GKRS) is a noninvasive surgical treatment option for patients with medically refractive classic trigeminal neuralgia (TN). The long-term microstructural consequences of radiosurgery and their association with pain relief remain unclear. To better understand this topic, the authors used diffusion tensor imaging (DTI) to characterize the effects of GKRS on trigeminal nerve microstructure over multiple posttreatment time points.METHODSNinety-two sets of 3-T anatomical and diffusion-weighted MR images from 55 patients with TN treated by GKRS were divided within 6-, 12-, and 24-month posttreatment time points into responder and nonresponder subgroups (≥ 75% and < 75% reduction in posttreatment pain intensity, respectively). Within each subgroup, posttreatment pain intensity was then assessed against pretreatment levels and followed by DTI metric analyses, contrasting treated and contralateral control nerves to identify specific biomarkers of successful pain relief.RESULTSGKRS resulted in successful pain relief that was accompanied by asynchronous reductions in fractional anisotropy (FA), which maximized 24 months after treatment. While GKRS responders demonstrated significantly reduced FA within the radiosurgery target 12 and 24 months posttreatment (p < 0.05 and p < 0.01, respectively), nonresponders had statistically indistinguishable DTI metrics between nerve types at each time point.CONCLUSIONSUltimately, this study serves as the first step toward an improved understanding of the long-term microstructural effect of radiosurgery on TN. Given that FA reductions remained specific to responders and were absent in nonresponders up to 24 months posttreatment, FA changes have the potential of serving as temporally consistent biomarkers of optimal pain relief following radiosurgical treatment for classic TN.

Targeting the cranial nerve: microradiosurgery for trigeminal neuralgia with CISS and 3D-Flash MR imaging sequences

2005 ◽  
Vol 102 ◽  
pp. 107-110 ◽  
Author(s):  
Vasilios A. Zerris ◽  
Georg C. Noren ◽  
William A. Shucart ◽  
Jeff Rogg ◽  
Gerhard M. Friehs
Keyword(s):  
Mr Imaging ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Trigeminal Nerve ◽  
Cranial Nerve ◽  
Fusion Imaging ◽  
Vascular Compression ◽  
Content Type ◽  
History Of ◽  
Fine Print

Object.The authors undertook a study to identify magnetic resonance (MR) imaging techniques that can be used reliably during gamma knife surgery (GKS) to identify the trigeminal nerve, surrounding vasculature, and areas of compression.Methods.Preoperative visualization of the trigeminal nerve and surrounding vasculature as well as targeting the area of vascular compression may increase the effectiveness of GKS for trigeminal neuralgia. During the past years our gamma knife centers have researched different MR imaging sequences with regard to their ability to visualize cranial nerves and vascular structures. Constructive interference in steady-state (CISS) fusion imaging with three-dimensional gradient echo sequences (3D-Flash) was found to be of greatest value in the authors' 25 most recent patients.In 24 (96%) out of the 25 patients, the fifth cranial nerve, surrounding vessels, and areas of compression could be reliably identified using CISS/3D-Flash. The MR images were acceptable despite patients' history of microvascular decompression, radiofrequency (RF) ablation, or concomitant disease. In one of 25 patients with a history of multiple RF lesions, the visualization was inadequate due to severe trigeminal nerve atrophy.Conclusions.The CISS/3D-Flash fusion imaging has become the preferred imaging method at the authors' institutions during GKS for trigeminal neuralgia. It affords the best visualization of the trigeminal nerve, surrounding vasculature, and the precise location of vascular compression.

scholarly journals Verification of dose distribution on the gamma knife perfexion radiosurgery using gafchromic EBT3 film: RANDO phantom study

2020 ◽  
Vol 1528 ◽  
pp. 012028
Author(s):  
I N Pranditayana ◽  
A R. Setiadi ◽  
M M Ramadhan ◽  
D Tandian ◽  
S A. Pawiro
Keyword(s):  
Gamma Knife ◽  
Dose Distribution ◽  
Phantom Study ◽  
Gamma Knife Perfexion

Gamma Knife radiosurgery for trigeminal neuralgia: the impact of magnetic resonance imaging–detected vascular impingement of the affected nerve

2010 ◽  
Vol 113 (1) ◽  
pp. 53-58 ◽  
Author(s):  
Jason P. Sheehan ◽  
Dibyendu Kumar Ray ◽  
Stephen Monteith ◽  
Chun Po Yen ◽  
James Lesnick ◽  
...  
Keyword(s):  
Pain Relief ◽  
Mr Imaging ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Trigeminal Nerve ◽  
Gamma Knife Radiosurgery ◽  
Vascular Compression ◽  
Pain Intensity Score ◽  
The Impact

Object Trigeminal neuralgia is believed to be related to vascular compression of the affected nerve. Radiosurgery has been shown to be reasonably effective for treatment of medically refractory trigeminal neuralgia. This study explores the rate of occurrence of MR imaging–demonstrated vascular impingement of the affected nerve and the extent to which vascular impingement affects pain relief in a population of trigeminal neuralgia patients undergoing Gamma Knife radiosurgery (GKRS). Methods The authors performed a retrospective analysis of 106 cases involving patients treated for typical trigeminal neuralgia using GKRS. Patients with or without single-vessel impingement on CISS MR imaging sequences and with no previous surgery were included in the study. Pain relief was assessed according to the Barrow Neurological Institute (BNI) pain intensity score at the last follow-up. Degree of impingement, nerve diameter preand post-impingement, isocenter placement, and dose to the point of maximum impingement were evaluated in relation to the improvement of BNI score. Results The overall median follow-up period was 31 months. Overall, a BNI pain score of 1 was achieved in 59.4% of patients at last follow-up. Vessel impingement was seen in 63 patients (59%). There was no significant difference in pain relief between those with and without vascular impingement following GKRS (p > 0.05). In those with vascular impingement on MR imaging, the median fraction of vessel impingement was 0.3 (range 0.04–0.59). The median dose to the site of maximum impingement was 42 Gy (range 2.9–79 Gy). Increased dose (p = 0.019) and closer proximity of the isocenter to the site of maximum vessel impingement (p = 0.012) correlated in a statistically significant fashion with improved BNI scores in those demonstrating vascular impingement on the GKRS planning MR imaging Conclusions Vascular impingement of the affected nerve was seen in the majority of patients with trigeminal neuralgia. Overall pain relief following GKRS was comparable in those with and without evidence of vascular compression on MR imaging. In subgroup analysis of those with MR imaging evidence of vessel impingement of the affected trigeminal nerve, pain relief correlated with a higher dose to the point of contact between the impinging vessel and the trigeminal nerve. Such a finding may point to vascular changes affording at least some degree of relief following GKRS for trigeminal neuralgia.

scholarly journals Early postsurgical diffusivity metrics for prognostication of long-term pain relief after Gamma Knife radiosurgery for trigeminal neuralgia

2019 ◽  
Vol 131 (2) ◽  
pp. 539-548 ◽  
Author(s):  
Sarasa Tohyama ◽  
Peter Shih-Ping Hung ◽  
Jidan Zhong ◽  
Mojgan Hodaie
Keyword(s):  
Pain Relief ◽  
Trigeminal Neuralgia ◽  
Fractional Anisotropy ◽  
Gamma Knife ◽  
Trigeminal Nerve ◽  
Gamma Knife Radiosurgery ◽  
Mean Diffusivity ◽  
Clinical Effectiveness ◽  
Radial Diffusivity

OBJECTIVEGamma Knife radiosurgery (GKRS) is an important treatment modality for trigeminal neuralgia (TN). Current longitudinal assessment after GKRS relies primarily on clinical diagnostic measures, which are highly limited in the prediction of long-term clinical benefit. An objective, noninvasive, predictive tool would be of great utility to advance the clinical management of patients. Using diffusion tensor imaging (DTI), the authors’ aim was to determine whether early (6 months post-GKRS) target diffusivity metrics can be used to prognosticate long-term pain relief in patients with TN.METHODSThirty-seven patients with TN treated with GKRS underwent 3T MRI scans at 6 months posttreatment. Diffusivity metrics of fractional anisotropy, axial diffusivity, radial diffusivity, and mean diffusivity were extracted bilaterally from the radiosurgical target of the affected trigeminal nerve and its contralateral, unaffected nerve. Early (6 months post-GKRS) diffusivity metrics were compared with long-term clinical outcome. Patients were identified as long-term responders if they achieved at least 75% reduction in preoperative pain for 12 months or longer following GKRS.RESULTSTrigeminal nerve diffusivity at 6 months post-GKRS was predictive of long-term clinical effectiveness, where long-term responders (n = 19) showed significantly lower fractional anisotropy at the radiosurgical target of their affected nerve compared to their contralateral, unaffected nerve and to nonresponders. Radial diffusivity and mean diffusivity, correlates of myelin alterations and inflammation, were also significantly higher in the affected nerve of long-term responders compared to their unaffected nerve. Nonresponders (n = 18) did not exhibit any characteristic diffusivity changes after GKRS.CONCLUSIONSThe authors demonstrate that early postsurgical target diffusivity metrics have a translational, clinical value and permit prediction of long-term pain relief in patients with TN treated with GKRS. Importantly, an association was found between the footprint of radiation and clinical effectiveness, where a sufficient level of microstructural change at the radiosurgical target is necessary for long-lasting pain relief. DTI can provide prognostic information that supplements clinical measures, and thus may better guide the postoperative assessment and clinical decision-making for patients with TN.

The clinical application of plugging patterns for the Leksell gamma knife

2002 ◽  
Vol 97 ◽  
pp. 579-581 ◽  
Author(s):  
Paul Vaughan ◽  
Anna Hampshire ◽  
Tracy Soanes ◽  
Andras Kemeny ◽  
Matthias Radatz ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Trigeminal Neuralgia ◽  
Stereotactic Radiosurgery ◽  
Radiation Field ◽  
Gamma Knife ◽  
Clinical Application ◽  
Trigeminal Nerve ◽  
Conformity Index ◽  
Content Type ◽  
Fine Print

Object. In this report the authors explore the use of standardized plugging templates in formulating stereotactic radiosurgery dose plans for the Leksell gamma knife. Methods. Unplugged gamma knife dose plans previously used in the treatment of patients with trigeminal neuralgia (TN) and vestibular schwannoma (VS) were studied. Standardized plugging templates were then superimposed on these plans, and their effects on the conformity index of tumors and the transposition of the radiation field from the brainstem to the cerebrospinal fluid spaces for the trigeminal cases were examined. Conclusions. The standardized plugging templates significantly increased the conformity indices in cases of VS plans and for TN. Plugging significantly reduced the brainstem exposure to radiation while at the same time not altering the length of the trigeminal nerve being treated. Standardized plugging templates may therefore be a useful tool in optimizing dose plans.

Gamma knife radiosurgery for trigeminal neuralgia: the dry-eye complication

2002 ◽  
Vol 97 ◽  
pp. 525-528 ◽  
Author(s):  
Shinji Matsuda ◽  
Toru Serizawa ◽  
Makato Sato ◽  
Junichi Ono
Keyword(s):  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Dry Eye ◽  
Trigeminal Nerve ◽  
Gamma Knife Radiosurgery ◽  
Ophthalmological Examination ◽  
Related Factors ◽  
Content Type ◽  
Fine Print

Object. The purpose of this paper is to report a unique complication of gamma knife radiosurgery (GKS) for trigeminal neuralgia (TN). The nature of this complication and its related factors are discussed. Methods. Forty-one medically refractory patients with TN were treated with GKS. All patients received 80 Gy to the proximal trigeminal nerve root, using a 4-mm collimator and a single isocenter. Follow up consisted of three monthly outpatient sessions after GKS. Improvement, recurrence, complications, and changes in magnetic resonance imaging were recorded. To evaluate the factors behind the complications, a subgroup of 33 patients was assessed in whom the follow-up duration was more than 9 months. The follow-up duration was 3 to 36 months (mean 13 months). The results were excellent in 20 patients, good in 11, and fair in seven. No patient had a poor result. Three patients suffered recurrences. Seven patients suffered complications 9 to 24 months after GKS. All seven patients complained of facial numbness and hypesthesia was recorded. Three of them also complained of “dry eye” with diminution or absence of corneal reflex but no other abnormalities of the cornea and conjunctiva were found on ophthalmological examination. In these three patients, hypesthesia of the first division of the trigeminal nerve area had been found before their “dry eye” symptoms appeared. The irradiated volume on the brainstem was significantly related to this complication. Conclusions. The dry eye symptom seems to be a special form of sensory disturbance. An overdose of radiation to the brainstem may play an important role in the manifestation of this complication.

Trigeminal Nerve-Blood Vessel Relationship as Revealed by High-resolution Magnetic Resonance Imaging and Its Effect on Pain Relief after Gamma Knife Radiosurgery for Trigeminal Neuralgia

Neurosurgery ◽  
2002 ◽  
Vol 50 (6) ◽  
pp. 1261-1267 ◽  
Author(s):  
Ronald Brisman ◽  
Alexander G. Khandji ◽  
Robertus B.M. Mooij
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
High Resolution ◽  
Pain Relief ◽  
Blood Vessel ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Trigeminal Nerve ◽  
Gamma Knife Radiosurgery ◽  
Resonance Imaging

Abstract OBJECTIVE Blood vessel (BV) compression of the trigeminal nerve (Cranial Nerve [CN] V) is a common cause of trigeminal neuralgia (TN). High-resolution magnetic resonance imaging scans obtained during gamma knife radiosurgery (GKRS) in patients with TN may be used to analyze the BV-CN V relationship. Follow-up data from a large series of patients treated with GKRS for TN were used to provide information regarding the BV-CN V relationship and pain relief. METHODS T1-weighted, axial 1-mm-thick volume acquisition magnetic resonance imaging scans were obtained through the area of CN V at its exit from the brainstem after injection of 15 ml of gadolinium. The BV-CN V relationship on the symptomatic side that was treated with GKRS was categorized into the following groups: Group 1 (no close relationship), Group 2 (BV close to CN V but not touching it), and Groups 3 and higher (BV-CN V contact). RESULTS A total of 181 symptomatic nerves were studied in 179 patients with TN who were treated with GKRS. In BV-CN V Groups 1, 2, and 3 and higher, respectively, were 43 sides (24%), 31 sides (17%), and 107 sides (59%). In 100 sides where there was no surgical procedure before GKRS, 50% or greater pain relief was more likely in those with BV-CN V contact (51 [88%] of 58 sides) than in those without BV-CN V (29 [69%] of 42 sides) (P = 0.024). BV-CN V contact was observed more often in men (55 [69%] of 80 sides) than in women (52 [52%] of 101 sides) (P = 0.023) and more often in patients who had unilateral TN (104 [62%] of 169 patients) rather than bilateral TN (2 [20%] of 10 patients) (P = 0.016). CONCLUSION In patients who have not undergone previous surgery for TN, BV-CN V contact revealed by high-resolution magnetic resonance imaging may indicate a particularly favorable response to GKRS.

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