Is Real-Time Inverse Planning Optimizing Dose to the Normal Brain? A Prospective Comparative Trial in a Series of Brain Metastases Treated by Stereotactic Radiosurgery

2021 ◽  
pp. 1-8
Author(s):  
Yassine Beltaifa ◽  
Hussein Hamdi ◽  
Giorgio Spatola ◽  
Anne Balossier ◽  
Louise Merly ◽  
...  
Keyword(s):  
Brain Metastases ◽  
Real Time ◽  
Gamma Knife Radiosurgery ◽  
Comparative Trial ◽  
Conformity Index ◽  
Normal Brain ◽  
Brain Volumes ◽  
Inverse Treatment Planning ◽  
The Mean ◽  
Age Range

<b><i>Background:</i></b> Radiosurgery has demonstrated good safety and efficacy in the treatment of multiple brain metastases (BMs). However, multi-target dose planning can be challenging and time-consuming. A recently developed real-time inverse treatment planning (IP) by convex optimization has been demonstrated to produce high-quality treatment plans with good conformity and selectivity in single-target plans. We intended to test the capacity of this IP to rapidly generate efficient plans while optimizing the preservation of normal tissue in multiple BM. <b><i>Methods:</i></b> Seventy-nine patients (mean age 62.4, age range 22–85) with a total of 272 BMs were treated by Gamma Knife Radiosurgery. All subjects were treated using a forward planning (FP) technique by an expert neurosurgeon. The new Intuitive Plan was applied and able to automatically generate an alternative plan for each patient. All planning variables were collected from the IP to be compared with the corresponding measurements obtained from the FP. A paired sample <i>t</i> test was applied to compare the 2 plans for the following variables: brain volumes receiving 10 Gy (V10) (primary endpoint), and 12 Gy (V12), planning indices (selectivity, coverage, gradient, and Paddick Conformity Index [PCI]), beam-on time (BOT), and integral doses. Additionally, the noninferiority margin for each item was calculated, and the 2 plans were compared for noninferiority using a paired <i>t</i> test. <b><i>Results:</i></b> The mean age of patients was 62.4 years old (age range 22–85), with a sex ratio of 1.02. The average number of lesions per patient was 3.4 (range 1–12). The mean prescription dose was 21.46 Gy (range 14–24 Gy). Noninferiority of the IP was concluded for V10, V12, prescription isodose volume, BOT, PCI, and selectivity. The V10 (and V12) was significantly lower with the IP (<i>p</i> &#x3c; 0.001). These volumes were 8.69 cm<sup>3</sup> ± 11.39 and 5.47 cm<sup>3</sup> ± 7.03, respectively, for the FP and 7.57 cm<sup>3</sup> ± 9.44 and 4.78 cm<sup>3</sup> ± 5.86 for the IP. Only the coverage was significantly lower with the IP (−2.3%, <i>p</i> &#x3c; 0.001), but both selectivity (+17%) and PCI (+15%) were significantly higher with the IP than FP (<i>p</i> &#x3c; 0.001). <b><i>Conclusion:</i></b> This IP demonstrated its capacity to generate multi-target plans rapidly, with a dose to the brain (V10) and BOT noninferior to the one of a human expert planner. These results would benefit from confirmation in a larger prospective series.

Dosimetric comparison of fractionated radiosurgery plans using frameless Gamma Knife ICON and CyberKnife systems with linear accelerator–based radiosurgery plans for multiple large brain metastases

2020 ◽  
Vol 132 (5) ◽  
pp. 1473-1479 ◽  
Author(s):  
Eun Young Han ◽  
He Wang ◽  
Dershan Luo ◽  
Jing Li ◽  
Xin Wang
Keyword(s):  
Brain Metastases ◽  
Gamma Knife ◽  
Linear Accelerator ◽  
Treatment Time ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Normal Brain ◽  
Large Brain ◽  
The Mean

OBJECTIVEFor patients with multiple large brain metastases with at least 1 target volume larger than 10 cm3, multifractionated stereotactic radiosurgery (MF-SRS) has commonly been delivered with a linear accelerator (LINAC). Recent advances of Gamma Knife (GK) units with kilovolt cone-beam CT and CyberKnife (CK) units with multileaf collimators also make them attractive choices. The purpose of this study was to compare the dosimetry of MF-SRS plans deliverable on GK, CK, and LINAC and to discuss related clinical issues.METHODSTen patients with 2 or more large brain metastases who had been treated with MF-SRS on LINAC were identified. The median planning target volume was 18.31 cm3 (mean 21.31 cm3, range 3.42–49.97 cm3), and the median prescribed dose was 27.0 Gy (mean 26.7 Gy, range 21–30 Gy), administered in 3 to 5 fractions. Clinical LINAC treatment plans were generated using inverse planning with intensity modulation on a Pinnacle treatment planning system (version 9.10) for the Varian TrueBeam STx system. GK and CK planning were retrospectively performed using Leksell GammaPlan version 10.1 and Accuray Precision version 1.1.0.0 for the CK M6 system. Tumor coverage, Paddick conformity index (CI), gradient index (GI), and normal brain tissue receiving 4, 12, and 20 Gy were used to compare plan quality. Net beam-on time and approximate planning time were also collected for all cases.RESULTSPlans from all 3 modalities satisfied clinical requirements in target coverage and normal tissue sparing. The mean CI was comparable (0.79, 0.78, and 0.76) for the GK, CK, and LINAC plans. The mean GI was 3.1 for both the GK and the CK plans, whereas the mean GI of the LINAC plans was 4.1. The lower GI of the GK and CK plans would have resulted in significantly lower normal brain volumes receiving a medium or high dose. On average, GK and CK plans spared the normal brain volume receiving at least 12 Gy and 20 Gy by approximately 20% in comparison with the LINAC plans. However, the mean beam-on time of GK (∼ 64 minutes assuming a dose rate of 2.5 Gy/minute) plans was significantly longer than that of CK (∼ 31 minutes) or LINAC (∼ 4 minutes) plans.CONCLUSIONSAll 3 modalities are capable of treating multiple large brain lesions with MF-SRS. GK has the most flexible workflow and excellent dosimetry, but could be limited by the treatment time. CK has dosimetry comparable to that of GK with a consistent treatment time of approximately 30 minutes. LINAC has a much shorter treatment time, but residual rotational error could be a concern.

Gamma knife radiosurgery for intracranial metastatic melanoma: a 6-year experience

2002 ◽  
Vol 97 ◽  
pp. 494-498 ◽  
Author(s):  
Jorge Gonzalez-martinez ◽  
Laura Hernandez ◽  
Lucia Zamorano ◽  
Andrew Sloan ◽  
Kenneth Levin ◽  
...  
Keyword(s):  
Prognostic Factors ◽  
Brain Metastases ◽  
Metastatic Melanoma ◽  
Gamma Knife Radiosurgery ◽  
Tumor Control ◽  
Karnofsky Performance Scale ◽  
Content Type ◽  
Significant Difference ◽  
The Mean ◽  
Fine Print

Object. The purpose of this study was to evaluate retrospectively the effectiveness of stereotactic radiosurgery for intracranial metastatic melanoma and to identify prognostic factors related to tumor control and survival that might be helpful in determining appropriate therapy. Methods. Twenty-four patients with intracranial metastases (115 lesions) metastatic from melanoma underwent radiosurgery. In 14 patients (58.3%) whole-brain radiotherapy (WBRT) was performed, and in 12 (50%) chemotherapy was conducted before radiosurgery. The median tumor volume was 4 cm3 (range 1–15 cm3). The mean dose was 16.4 Gy (range 13–20 Gy) prescribed to the 50% isodose at the tumor margin. All cases were categorized according to the Recursive Partitioning Analysis classification for brain metastases. Univariate and multivariate analyses of survival were performed to determine significant prognostic factors affecting survival. The mean survival was 5.5 months after radiosurgery. The analyses revealed no difference in terms of survival between patients who underwent WBRT or chemotherapy and those who did not. A significant difference (p < 0.05) in mean survival was observed between patients receiving immunotherapy or those with a Karnofsky Performance Scale (KPS) score of greater than 90. Conclusions. The treatment with systemic immunotherapy and a KPS score greater than 90 were factors associated with a better prognosis. Radiosurgery for melanoma-related brain metastases appears to be an effective treatment associated with few complications.

Dosimetric Comparison of Intensity-Modulated Radiosurgery and Helical Tomotherapy for the Treatment of Multiple Intracranial Metastases

2009 ◽  
Vol 8 (5) ◽  
pp. 361-367 ◽  
Author(s):  
Lauren VanderSpek ◽  
Glenn Bauman ◽  
Jia-Zhu Wang ◽  
Slav Yartsev ◽  
Cynthia Ménard ◽  
...  
Keyword(s):  
At Risk ◽  
Helical Tomotherapy ◽  
Organs At Risk ◽  
Conformity Index ◽  
Normal Brain ◽  
Gradient Index ◽  
Integral Dose ◽  
Intensity Modulated ◽  
Intracranial Metastases ◽  
The Mean

The purpose of this study was to evaluate the dosimetry of single fraction, single-isocenter intensity-modulated radiosurgery (IMRS) plans for multiple intracranial metastases and to compare Helical Tomotherapy (HT). Ten treatment plans with 3–6 brain metastases treated with IMRS were re-planned with HT. The mean number of lesions was 5 and mean PTV 22 cm3. The prescribed dose was 16–20 Gy. The mean V100% was similar for IMRS and HT, and the mean conformity index was 1.4, mean Paddick confirmity index was 0.7, and mean MDPD was 1.1 for both. The mean gradient index was similar for both. The mean 50% isodose volume was 179.2 cm3 for IMRS and 277.0 cm3 for HT (p=0.01). The mean maximum doses to organs at risk were lower for IMRS except brainstem and right optic nerve. For brain, the integral dose was 5.1 and 6.8 Gy-kg (p<0.001) and mean dose 4.0 and 5.4 Gy (p<0.001) for IMRS and HT, respectively. The mean treatment times were 23 (IMRS) and 41 (HT) minutes. Conformity and homogeneity indices were equivalent and sparing of the organs at risk was clinically acceptable for both IMRS and HT. Though the gradient index was similar for IMRS and HT, the mean 50% isodose volume and integral dose to normal brain were lower for IMRS as was treatment time.

Clinical and Pathological Characteristics of Brain Metastasis Resected After Failed Radiosurgery

Neurosurgery ◽  
2010 ◽  
Vol 66 (1) ◽  
pp. 208-217 ◽  
Author(s):  
Jay Jagannathan ◽  
T. David Bourne ◽  
David Schlesinger ◽  
Chun-Po Yen ◽  
Mark E. Shaffrey ◽  
...  
Keyword(s):  
Brain Metastasis ◽  
Brain Metastases ◽  
Cell Carcinoma ◽  
Gamma Knife ◽  
Gamma Knife Radiosurgery ◽  
Proliferation Index ◽  
Time Interval ◽  
Cell Lung Carcinoma ◽  
Viable Tumor ◽  
The Mean

Abstract OBJECTIVE This study evaluates the tumor histopathology and clinical characteristics of patients who underwent resection of their brain metastasis after failed gamma knife radiosurgery. METHODS This study was a retrospective review from a prospective database. A total of 1200 brain metastases in 912 patients were treated by gamma knife radiosurgery during a 7-year period. Fifteen patients (1.6% of patients, 1.2% of all brain metastases) underwent resective surgery for either presumed tumor progression (6 patients) or worsening neurological symptoms associated with increased mass effect (9 patients). Radiographic imaging, radiosurgical and surgical treatment parameters, histopathological findings, and long-term outcomes were reviewed for all patients. RESULTS The mean age at the time of radiosurgery was 57 years (age range, 32–65 years). Initial pathological diagnoses included metastatic non–small cell lung carcinoma in 8 patients (53%), melanoma in 4 patients (27%), renal cell carcinoma in 2 patients (13%), and squamous cell carcinoma of the tongue in 1 patient (7%). The mean time interval between radiosurgery and surgical extirpation was 8.5 months (range, 3 weeks to 34 months). The mean treatment volume for the resected lesion at the time of radiosurgery was 4.4 cm3 (range, 0.6–8.4 cm3). The mean dose to the tumor margin was 21Gy (range, 18–24 Gy). In addition to the 15 tumors that were eventually resected, a total of 32 other metastases were treated synchronously, with a 78% control rate. The mean volume immediately before surgery for the 15 resected lesions was 7.5 cm3 (range, 3.8–10.2 cm3). Histological findings after radiosurgery varied from case to case and included viable tumor, necrotic tumor, vascular hyalinization, hemosiderin-laden macrophages, reactive gliosis in surrounding brain tissue, and an elevated MIB-1 proliferation index in cases with viable tumor. The mean survival for patients in whom viable tumor was identified (9.4 months) was significantly lower than that of patients in whom only necrosis was seen (15.1 months; Fisher's exact test, P &lt; 0.05). CONCLUSION Radiation necrosis and tumor radioresistance are the most common causes precipitating a need for surgical resection after radiosurgery in patients with brain metastasis.

scholarly journals RADI-33. DISTRIBUTED FRAMELESS GAMMA KNIFE RADIOSURGERY: A NEW TREATMENT PARADIGM FOR PATIENTS WITH BRAIN METASTASES

2019 ◽  
Vol 1 (Supplement_1) ◽  
pp. i28-i28
Author(s):  
Ankur Patel ◽  
Jameson Mendel ◽  
Aaron Plitt ◽  
Lucien Nedzi ◽  
Robert Timmerman ◽  
...  
Keyword(s):  
Brain Metastases ◽  
Gamma Knife ◽  
Treatment Time ◽  
Gamma Knife Radiosurgery ◽  
Median Number ◽  
Treatment Session ◽  
Normal Brain ◽  
Single Session ◽  
Treatment Paradigm ◽  
Number Of Treatment

Abstract INTRODUCTION: Stereotactic radiosurgery (SRS) has excellent efficacy for patients with limited intracranial disease. Its use in patients with &gt;10 brain metastases remains controversial. Nonetheless, cancer patients are living longer due to advancements in systemic therapeutics and avoiding the neurocognitive toxicities of whole brain radiation therapy is critical. Recent reports suggest that SRS may be effective in patients with ≥10 metastases. Treating large numbers of brain metastases in a single Gamma Knife radiosurgery (GKRS) treatment session poses several challenges. Treatment of metastases in close proximity to one another leads to an increased dose to normal brain, potentially increasing the risk of necrosis. Furthermore, single session treatment of multiple metastases may last several hours, causing significant patient discomfort. Here, we describe a novel treatment paradigm to address these issues: distributed frameless GKRS. Patients with ≥6 brain metastases undergo multi-session frameless GKRS with both temporal and spatial distribution over 2–5 sessions, decreasing treatment time per day and not treating adjacent metastases simultaneously. METHODS: We evaluated all patients with brain metastases who underwent distributed frameless SRS, using the Gamma Knife ICON, between January 2017 and November 2018. Fifty-one patients with 1097 unique lesions were included in this analysis. RESULTS: Mean patient age was 58.8 (range 29–89) years. Median follow-up was 4.1 (range: 0–20.4) months. The median number of metastases treated was 5 (range: 1–19) per treatment session and 11.5 (range: 3–82) per treatment course. The median number of treatment sessions per treatment course was 3 (range: 2–10). The median number of treatment courses, per patient, was 1 (range: 1–4). The median margin dose was 15 Gy. The median overall survival was 5.9 (range: 0.2–20.9) months. CONCLUSIONS: Distributed frameless Gamma Knife radiosurgery is technically feasible and should be considered in lieu of single session GKRS for patients with ≥6 brain metastases.

scholarly journals Biological implications of whole-brain radiotherapy versus stereotactic radiosurgery of multiple brain metastases

2014 ◽  
Vol 121 (Suppl_2) ◽  
pp. 60-68 ◽  
Author(s):  
Jinyu Xue ◽  
Gregory J. Kubicek ◽  
Jimm Grimm ◽  
Tamara LaCouture ◽  
Yan Chen ◽  
...  
Keyword(s):  
Brain Metastases ◽  
Stereotactic Radiosurgery ◽  
Whole Brain Radiotherapy ◽  
Biological Information ◽  
Normal Brain ◽  
Whole Brain ◽  
Multiple Brain Metastases ◽  
Brain Radiotherapy ◽  
Dose Volume ◽  
The Mean

ObjectThe efficacy and safety of treatment with whole-brain radiotherapy (WBRT) or with stereotactic radiosurgery (SRS) for multiple brain metastases (> 10) are topics of ongoing debate. This study presents detailed dosimetric and biological information to investigate the possible clinical outcomes of these 2 modalities.MethodsFive patients with multiple brain metastases (n = 11–23) underwent SRS. Whole-brain radiotherapy plans were retrospectively designed with the same MR image set and the same structure set for each patient, using the standard opposing lateral beams and fractionation (3 Gy × 10).Physical radiation doses and biologically effective doses (BEDs) in WBRT and SRS were calculated for each lesion target and for the normal brain tissues for comparison of the 2 modalities in the context of clinical efficacy and published toxicities.ResultsThe BEDs targeted to the tumor were higher in SRS than in WBRT by factors ranging from 2.4- to 3.0- fold for the mean dose and from 3.2- to 5.3-fold for the maximum dose. In the 5 patients, mean BEDs in SRS (calculated as percentages of BEDs in WBRT) were 1.3%–34.3% for normal brain tissue, 0.7%–31.6% for the brainstem, 0.5%–5.7% for the chiasm, 0.2%–5.7% for optic nerves, and 0.6%–18.1% for the hippocampus.ConclusionsThe dose-volume metrics presented in this study were essential to understanding the safety and efficacy of WBRT and SRS for multiple brain metastases. Whole-brain radiotherapy results in a higher incidence of radiation-related toxicities than SRS. Even in patients with > 10 brain metastases, the normal CNS tissues receive significantly lower doses in SRS. The mean normal brain dose in SRS correlated with the total volume of the lesions rather than with the number of lesions treated.

Survival and outcomes in patients with ≥ 25 cumulative brain metastases treated with stereotactic radiosurgery

2021 ◽  
pp. 1-11
Keyword(s):  
Brain Metastases ◽  
Stereotactic Radiosurgery ◽  
Gamma Knife ◽  
Radiation Effects ◽  
Univariate Analysis ◽  
Survival Rates ◽  
Gamma Knife Radiosurgery ◽  
Cumulative Number ◽  
Study Results ◽  
The Mean

OBJECTIVE In the era in which more patients with greater numbers of brain metastases (BMs) are being treated with stereotactic radiosurgery (SRS) alone, it is critical to understand how patient, tumor, and treatment factors affect functional status and overall survival (OS). The authors examined the survival outcomes and dosimetry to critical structures in patients treated with Gamma Knife radiosurgery (GKRS) for ≥ 25 metastases in a single session or cumulatively over the course of their disease. METHODS A retrospective analysis was conducted at a single institution. The institution’s prospective Gamma Knife (GK) SRS registry was queried to identify patients treated with GKRS for ≥ 25 cumulative BMs between June 2013 and April 2020. Ninety-five patients were identified, and their data were used for analysis. Treatment plans for dosimetric analysis were available for 89 patients. Patient, tumor, and treatment characteristics were identified, and outcomes and OS were evaluated. RESULTS The authors identified 1132 patients with BMs in their institutional registry. Ninety-five patients were treated for ≥ 25 cumulative metastases, resulting in a total of 3596 tumors treated during 373 separate treatment sessions. The median number of SRS sessions per patient was 3 (range 1–12 SRS sessions), with nearly all patients (n = 93, 98%) having > 1 session. On univariate analysis, factors affecting OS in a statistically significant manner included histology, tumor volume, tumor number, diagnosis-specific graded prognostic assessment (DS-GPA), brain metastasis velocity (BMV), and need for subsequent whole-brain radiation therapy (WBRT). The median of the mean WB dose was 4.07 Gy (range 1.39–10.15 Gy). In the top quartile for both the highest cumulative number and highest cumulative volume of treated metastases, the median of the mean WB dose was 6.14 Gy (range 4.02–10.15 Gy). Seventy-nine patients (83%) had all treated tumors controlled at last follow-up, reflecting the high and durable control rate. Corticosteroids for tumor- or treatment-related effects were prescribed in just over one-quarter of the patients. Of the patients with radiographically proven adverse radiation effects (AREs; 15%), 4 were symptomatic. Four patients required subsequent craniotomy for hemorrhage, progression, or AREs. CONCLUSIONS In selected patients with a large number of cumulative BMs, multiple courses of SRS are feasible and safe. Together with new systemic therapies, the study results demonstrate that the achieved survival rates compare favorably to those of larger contemporary cohorts, while avoiding WBRT in the majority of patients. Therefore, along with the findings of other series, this study supports SRS as a standard practice in selected patients with larger numbers of BMs.

scholarly journals Dosimetric characterization of hypofractionated Gamma Knife radiosurgery of large or complex brain tumors versus linear accelerator–based treatments

2016 ◽  
Vol 125 (Supplement_1) ◽  
pp. 97-103 ◽  
Author(s):  
Peng Dong ◽  
Angélica Pérez-Andújar ◽  
Dilini Pinnaduwage ◽  
Steve Braunstein ◽  
Philip Theodosopoulos ◽  
...  
Keyword(s):  
Brain Tumors ◽  
Gamma Knife ◽  
Linear Accelerator ◽  
Maximum Diameter ◽  
Conformity Index ◽  
Normal Brain ◽  
Gradient Index ◽  
Prescription Dose ◽  
The Mean ◽  
Prescription Isodose

OBJECTIVENoninvasive Gamma Knife (GK) platforms, such as the relocatable frame and on-board imaging, have enabled hypofractionated GK radiosurgery of large or complex brain lesions. This study aimed to characterize the dosimetric quality of such treatments against linear accelerator–based delivery systems that include the CyberKnife (CK) and volumetric modulated arc therapy (VMAT).METHODSTen patients treated with VMAT at the authors' institution for large brain tumors (> 3 cm in maximum diameter) were selected for the study. The median prescription dose was 25 Gy (range 20–30 Gy) in 5 fractions. The median planning target volume (PTV) was 9.57 cm3 (range 1.94–24.81 cm3). Treatment planning was performed using Eclipse External Beam Planning V11 for VMAT on the Varian TrueBeam system, Multiplan V4.5 for the CyberKnife VSI System, and Leksell GammaPlan V10.2 for the Gamma Knife Perfexion system. The percentage of the PTV receiving at least the prescription dose was normalized to be identical across all platforms for individual cases. The prescription isodose value for the PTV, conformity index, Paddick gradient index, mean and maximum doses for organs at risk, and normal brain dose at variable isodose volumes ranging from the 5-Gy isodose volume (V5) to the 15-Gy isodose volume (V15) were compared for all of the cases.RESULTSThe mean Paddick gradient index was 2.6 ± 0.2, 3.2 ± 0.5, and 4.3 ± 1.0 for GK, CK, and VMAT, respectively (p < 0.002). The mean V15 was 7.5 ± 3.7 cm3 (range 1.53–13.29 cm3), 9.8 ± 5.5 cm3 (range 2.07–18.45 cm3), and 16.1 ± 10.6 cm3 (range 3.58–36.53 cm3) for GK, CK, and VMAT, respectively (p ≤ 0.03, paired 2-tailed t-tests). However, the average conformity index was 1.18, 1.12, and 1.21 for GK, CK, and VMAT, respectively (p > 0.06). The average prescription isodose values were 52% (range 47%–69%), 60% (range 46%–68%), and 88% (range 70%–94%) for GK, CK, and VMAT, respectively, thus producing significant variations in dose hot spots among the 3 platforms. Furthermore, the mean V5 values for GK and CK were similar (p > 0.79) at 71.9 ± 36.2 cm3 and 73.3 ± 31.8 cm3, respectively, both of which were statistically lower (p < 0.01) than the mean V5 value of 124.6 ± 67.1 cm3 for VMAT.CONCLUSIONSSignificantly better near-target normal brain sparing was noted for hypofractionated GK radiosurgery versus linear accelerator–based treatments. Such a result supports the use of a large number of isocenters or confocal beams for the benefit of normal tissue sparing in hypofractionated brain radiosurgery.

Radiosurgery for dural carotid-cavernous sinus fistulas: Gamma Knife compared with XKnife radiosurgery

2010 ◽  
Vol 113 (Special_Supplement) ◽  
pp. 9-20 ◽  
Author(s):  
Hung-Chuan Pan ◽  
Ming-Hsi Sun ◽  
Jason Sheehan ◽  
Meei-Ling Sheu ◽  
Clayton Chi-Chang Chen ◽  
...  
Keyword(s):  
Clinical Improvement ◽  
Gamma Knife ◽  
Temporal Lobe ◽  
Treatment Modalities ◽  
Conformity Index ◽  
Index Number ◽  
The Mean ◽  
Instrument Accuracy ◽  
Group 1

Object In the modern era, stereotactic radiosurgery is an important part of the multidisciplinary and multimodality approach used to treat dural carotid-cavernous fistulas (DCCFs). Based on the ease of performance of techniques to fuse cerebral angiography studies with MR images or CT scans during the radiosurgical procedure, the Gamma Knife and XKnife are 2 of the most popular radiosurgical instruments for patients with DCCF. In this study, the authors compared the efficacy, neurological results, and complications associated with these 2 radiosurgical devices when used for DCCF. Methods Records for 41 patients with DCCF (15 treated using the XKnife and 26 with Gamma Knife surgery [GKS]) were retrieved from a radiosurgical database encompassing the period of September 2000 to August 2008. Among these patients, at least 2 consecutive MR imaging or MR angiography studies obtained after radiosurgery were available for determining radiological outcome of the fistula. All patients received regular follow-up to evaluate the neurological and ophthalmological function at an interval of 1–3 months. The symptomatology, obliteration rate, radiation dose, instrument accuracy, and adverse effects were determined for each group and compared between 2 groups. The data were analyzed using the Student t-test. Results The mean age of the patients was 63 ± 2.6 years, and the mean follow-up period was 63.1 ± 4.4 months (mean ± SD). Thirty-seven patients (90%) achieved an obliteration of the DCCF (93% in the XKnife cohort and 88% for the GKS cohort). In 34 of 40 patients (85%) with chemosis and proptosis of the eyes, these symptoms were resolved after treatment (4 had residual fistula and 2 had arterializations of sclera). All 5 patients with high intraocular pressure demonstrated clinical improvement. Ten (71%) of 14 patients with cranial nerve palsy demonstrated improvement following radiosurgery. Significant discrepancies of treatment modalities existed between the XKnife and GKS groups, such as radiation volume, conformity index, number of isocenters, instrument accuracy, peripheral isodose line, and maximum dosage. The XKnife delivered significantly higher radiation dosage to the lens, optic nerve, optic chiasm, bilateral temporal lobe, and brainstem. Few adverse events occurred, but included 1 patient with optic neuritis (GKS group), 1 intracranial hemorrhage (XKnife group), 1 brainstem edema (XKnife), and 3 temporal lobe radiation edemas (XKnife). Conclusions Radiosurgery affords a substantial chance of radiological and clinical improvement in patients with DCCFs. The Gamma Knife and XKnife demonstrated similar efficacy in the obliteration of DCCFs. However, a slightly higher incidence of complications occurred in the XKnife group.

Sign in / Sign up

Export Citation Format

Share Document