scholarly journals Stereotactic radiosurgery in patients with glomus jugulare tumors

2004 ◽  
Vol 17 (2) ◽  
pp. 63-67 ◽  
Author(s):  
Bruce E. Pollock
Keyword(s):  
Hearing Loss ◽  
Vocal Cord ◽  
Gamma Knife ◽  
Cranial Nerve ◽  
Vocal Cord Paralysis ◽  
Gamma Knife Surgery ◽  
Glomus Jugulare ◽  
The Mean ◽  
Primary Management

Object Microsurgical removal of glomus jugulare tumors is frequently associated with injury of the lower cranial nerves. To decrease the morbidity associated with tumor management in these patients, gamma knife surgery (GKS) was performed as an alternative to resection. Methods Between 1990 and 2003, 42 patients underwent GKS as the primary management (19 patients) or for recurrent glomus jugulare tumors (23 patients). Facial weakness and deafness were more common in patients with recurrent tumors than in those in whom primary GKS was performed (48% compared with 11%, p = 0.02). The mean tumor volume was 13.2 cm3; the mean tumor margin dose was 14.9 Gy. The mean follow-up period for the 39 patients in whom evaluation was possible was 44 months (range 6–149 months). After GKS, 12 tumors (31%) decreased in size, 26 (67%) were unchanged, and one (2%) grew. The patient whose tumor grew underwent repeated GKS. Progression-free survival after GKS was 100% at 3 and 7 years, and 75% at 10 years. Six patients (15%) experienced new deficits (hearing loss alone in three, facial numbness and hearing loss in one, vocal cord paralysis and hearing loss in one, and temporary imbalance and/or vertigo in one). In 26 patients in whom hearing could be tested before GKS, hearing preservation was achieved in 86 and 81% at 1 and 4 years posttreatment, respectively. No patient suffered a new lower cranial nerve deficit after one GKS session; the patient in whom repeated GKS was performed experienced a new vocal cord paralysis 1 year after his second procedure. Conclusions Gamma knife surgery provided tumor control with a low risk of new cranial nerve injury in early follow-up review. This procedure can be safely used as a primary management tool in patients with glomus jugulare tumors that do not have significant cervical extension, or in patients with recurrent tumors in this location.

Gamma Knife surgery for Cushing's disease

2007 ◽  
Vol 106 (6) ◽  
pp. 980-987 ◽  
Author(s):  
Jay Jagannathan ◽  
Jason P. Sheehan ◽  
Nader Pouratian ◽  
Edward R. Laws ◽  
Ladislau Steiner ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Cushing’S Disease ◽  
Pituitary Adenomas ◽  
Cranial Nerve ◽  
Gamma Knife Surgery ◽  
Cushing's Disease ◽  
Free Cortisol ◽  
Radiation Induced ◽  
The Mean

Object In this study the authors address the efficacy and safety of Gamma Knife surgery (GKS) in patients with adrenocorticotropic hormone–secreting pituitary adenomas. Methods A review of data collected from a prospective GKS database between January 1990 and March 2005 was performed in patients with Cushing's disease. All but one patient underwent resection for a pituitary tumor, without achieving remission. Successful endocrine outcome after GKS was defined as a normal 24-hour urinary free cortisol (UFC) concentration posttreatment after a minimum of 1 year of follow up. Patient records were also evaluated for changes in tumor volume, development of new hormone deficiencies, visual acuity, cranial nerve neuropathies, and radiation-induced imaging changes. Ninety evaluable patients had undergone GKS, with a mean endocrine follow-up duration of 45 months (range 12–132 months). The mean dose to the tumor margin was 23 Gy (median 25 Gy). Normal 24-hour UFC levels were achieved in 49 patients (54%), with an average time of 13 months after treatment (range 2–67 months). In the 49 patients in whom a tumor was visible on the planning magnetic resonance (MR) image, a decrease in tumor size occurred in 39 (80%), in seven patients there was no change in size, and tumor growth occurred in three patients. Ten patients (20%) experienced a relapse of Cushing's disease after initial remission; the mean time to recurrence was 27 months (range 6–60 months). Seven of these patients underwent repeated GKS, with three patients achieving a second remission. New hormone deficiencies developed in 20 patients (22%), with hypothyroidism being the most common endocrinopathy after GKS. Five patients experienced new visual deficits or third, fourth, or sixth cranial nerve deficits; two of these patients had undergone prior conventional fractionated radiation therapy, and four of them had received previous GKS. Radiation-induced changes were observed on MR images in three patients; one had symptoms attributable to these changes. Conclusions Gamma Knife surgery is an effective treatment for persistent Cushing's disease. Adenomas with cavernous sinus invasion that are not amenable to resection are treatable with the Gamma Knife. A second GKS treatment appears to increase the risk of cranial nerve damage. These results demonstrate the value of combining two neurosurgical treatment modalities—microsurgical resection and GKS—in the management of pituitary adenomas.

Gamma Knife surgery for parasellar meningiomas: long-term results including complications, predictive factors, and progression-free survival

2011 ◽  
Vol 114 (6) ◽  
pp. 1571-1577 ◽  
Author(s):  
Brian J. Williams ◽  
Chun Po Yen ◽  
Robert M. Starke ◽  
Bhuvaneswara Basina ◽  
James Nguyen ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Cranial Nerve ◽  
Tumor Volume ◽  
Progression Free Survival ◽  
Gamma Knife Surgery ◽  
Tumor Control ◽  
Free Survival ◽  
Factors Associated ◽  
The Mean

Object Stereotactic radiosurgery serves as an important primary and adjuvant treatment option for patients with many types of intracranial meningiomas. This is particularly true for patients with parasellar meningiomas. In this study, the authors evaluated the outcomes of Gamma Knife surgery (GKS) used to treat parasellar meningiomas. Methods The study is a retrospective review of the outcomes in 138 patients with meningiomas treated at the University of Virginia from 1989 to 2006; all patients had a minimum follow-up of 24 months. There were 31 men and 107 women whose mean age was 54 years (range 19–85 years). Eighty-four patients had previously undergone resection. The mean pre-GKS tumor volume was 7.5 ml (range 0.2–54.8 ml). Clinical and radiographic evaluations were performed, and factors related to favorable outcomes in each case were assessed. Results The mean follow-up duration was 84 months (median 75.5 months, range 24–216 months). In 118 patients (86%), the tumor volume was unchanged or had decreased at last follow-up. Kaplan-Meier analysis demonstrated radiographic progression-free survival at 5 and 10 years to be 95.4% and 69%, respectively. Fourteen patients (10%) developed new cranial nerve palsies following GKS. Factors associated with tumor control included younger age, a higher isodose, and smaller tumor volume. A longer follow-up duration was associated with either a decrease or increase in tumor volume. Fourteen patients (10%) experienced new or worsening cranial nerve deficits after treatment. Factors associated with this occurrence were larger pretreatment tumor volume, lower peripheral radiation dose, lower maximum dose, tumor progression, and longer follow-up. Conclusions Gamma Knife surgery offers an acceptable rate of tumor control for parasellar meningiomas and accomplishes this with a low incidence of neurological deficits. Radiological control after radiosurgery is more likely in those patients with a smaller tumor volume and a higher prescription dose.

Gamma Knife surgery for invasive pituitary macroadenoma

2006 ◽  
Vol 105 (Supplement) ◽  
pp. 26-30 ◽  
Author(s):  
Mooseong Kim ◽  
Sunghwa Paeng ◽  
Seyoung Pyo ◽  
Yeonggyun Jeong ◽  
Sunil Lee ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Cavernous Sinus ◽  
Pituitary Adenomas ◽  
Gamma Knife Surgery ◽  
Tumor Control ◽  
Pituitary Macroadenoma ◽  
Female Ratio ◽  
Fractionated Radiotherapy ◽  
The Mean

ObjectPituitary adenomas have been treated using a variety of modalities including resection, medication, fractionated radiotherapy, and stereotactic radiosurgery. The policy has been that all adenomas should first be treated with resection to reduce the volume of the tumor. The authors' study was conducted to determine the efficacy of using Gamma Knife surgery (GKS) for pituitary adenomas invading the cavernous sinus.MethodsOf 397 patients with pituitary tumors who underwent GKS between October 1994 and October 2005, 68 patients had pituitary macroadenomas invading the cavernous sinus. Sixty-seven cases were available for follow up. The mean age of the patients in these cases was 42.8 years (range 14–73 years). The male/female ratio was 0.8:1. The mean adenoma volume was 9.3 cm3. A total of 24 patients had undergone craniotomies and resection, and 11 patients had undergone transsphenoidal surgery prior to GKS. The mean follow-up period was 32.8 months. Tumor control was defined as a decrease or no change in tumor volume after GKS. Endocrinological improvement was defined as a decline in hormone levels to below 50% of the pre-GKS level.Tumor control was achieved in 95.5% of the cases. Endocrinological improvement was achieved in 68% of 25 patients. One patient suffered hypopituitarism after GKS.Conclusions Gamma Knife surgery is a safe and effective treatment for invasive pituitary macroadenoma with few complications.

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.

P14.67 Long-term results of gamma knife radiosurgery for treatment of intracranial glomus jugulare tumors

2021 ◽  
Vol 23 (Supplement_2) ◽  
pp. ii50-ii51
Author(s):  
R M Emad Eldin ◽  
K M Abdel Karim ◽  
A M N El-Shehaby ◽  
W A Reda ◽  
A M Nabeel ◽  
...  
Keyword(s):  
Clinical Improvement ◽  
Gamma Knife ◽  
Tumor Volume ◽  
Gamma Knife Radiosurgery ◽  
Long Term Results ◽  
Glomus Jugulare ◽  
The Mean ◽  
Mean Time

Abstract BACKGROUND Glomus Jugulare tumors are benign but locally aggressive ones that represent a therapeutic challenge. Previous studies about the use of Gamma Knife Radiosurgery (GRS) in those tumors have documented good results that needed larger number of patients and longer follow up periods to be confirmed. MATERIAL AND METHODS Between August 2001 and December 2017, 70 patients with glomus jugulare tumors were treated at the Gamma Knife Center, Cairo. They were 46 females and 24 males. The mean age was 48 years (16–71 years). Nineteen of these patients were previously operated, 5 were partially embolized, 3 underwent embolization and subsequent surgery and 43 had gamma knife as their primary treatment. Volume-staged gamma knife radiosurgery was used in 10 patients and single-session in 60 patients, with a total of 86 sessions. The mean target volume was 12.7 cm3 (range 0.2 to 34.5 cm3). The mean tumor volume was 15.5 cm3 (range 0.2 to 105 cm3). The mean prescription dose was 14.5 Gy (range 12 to 18 Gy). RESULTS The mean follow up period was 60 months (range 18 to 206 months), and by the time of the data analysis, two of the patients were dead (66 and 24 months after GK treatment). The tumor control was 98.6% (69/70). Thirty-two tumors became smaller and 37 were unchanged. The symptoms improved in 36 patients, were stable in 32 patients, and worsened in 2 patients who developed a transient facial palsy and worsened hearing. Symptomatic improvement began before any reduction in tumor volume could be detected, where the mean time to clinical improvement was 7 months whereas the mean time to tumor shrinkage was 18 months. CONCLUSION This study about the long term follow up of the GKR for the intracranial glomus jugulare tumors confirmed that this is a highly effective and safe treatment. This data shows that the clinical improvement is not correlated with the radiological volume reduction.

Gamma Knife surgery for trigeminal schwannoma

2007 ◽  
Vol 106 (5) ◽  
pp. 839-845 ◽  
Author(s):  
Jason Sheehan ◽  
Chun Po Yen ◽  
Yasser Arkha ◽  
David Schlesinger ◽  
Ladislau Steiner
Keyword(s):  
Gamma Knife ◽  
Gamma Knife Surgery ◽  
Long Term Results ◽  
University Of Virginia ◽  
Trigeminal Schwannoma ◽  
The Mean ◽  
The University ◽  
Lost To Follow Up

Object Trigeminal schwannomas are rare intracranial tumors. In the past, resection and radiation therapy were the mainstays of their treatment. More recently, neurosurgeons have begun to use radiosurgery in the treatment of trigeminal schwannomas because of its successful use in the treatment of vestibular schwannomas. In this article the authors evaluate the radiological and clinical outcomes in a series of patients in whom Gamma Knife surgery (GKS) was used to treat trigeminal schwannomas. Methods Twenty-six patients with trigeminal schwannomas underwent GKS at the University of Virginia Lars Lek-sell Gamma Knife Center between 1989 and 2005. Five of these patients had neurofibromatosis and one patient was lost to follow up. The median tumor volume was 3.96 cm3, and the mean follow-up period was 48.5 months. The median prescription radiation dose was 15 Gy, and the median prescription isodose configuration was 50%. There was clinical improvement in 18 patients (72%), a stable lesion in four patients (16%), and worsening of the disease in three patients (12%). On imaging, the schwannomas shrank in 12 patients (48%), remained stable in 10 patients (40%), and increased in size in three patients (12%). These results were comparable for primary and adjuvant GKSs. No tumor growth following GKS was observed in the patients with neurofibromatosis. Conclusions Gamma Knife surgery affords a favorable risk-to-benefit profile for patients harboring trigeminal schwannomas. Larger studies with open-ended follow-up review will be necessary to determine the long-term results and complications of GKS in the treatment of trigeminal schwannomas.

Hearing preservation in patients with vestibular schwannoma treated with Gamma Knife surgery

2013 ◽  
Vol 118 (3) ◽  
pp. 571-578 ◽  
Author(s):  
Andrew M. Baschnagel ◽  
Peter Y. Chen ◽  
Dennis Bojrab ◽  
Daniel Pieper ◽  
Jack Kartush ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Gamma Knife ◽  
Vestibular Schwannoma ◽  
Hearing Preservation ◽  
Gamma Knife Surgery ◽  
Speech Discrimination ◽  
Before And After ◽  
Nerve Dysfunction ◽  
Preservation Rate

Object Hearing loss after Gamma Knife surgery (GKS) in patients with vestibular schwannoma has been associated with radiation dose to the cochlea. The purpose of this study was to evaluate serviceable hearing preservation in patients with VS who were treated with GKS and to determine if serviceable hearing loss can be correlated with the dose to the cochlea. Methods Forty patients with vestibular schwannoma with serviceable hearing were treated using GKS with a median marginal dose of 12.5 Gy (range 12.5–13 Gy) to the 50% isodose volume. Audiometry was performed prospectively before and after GKS at 1, 3, and 6 months, and then every 6 months thereafter. Hearing preservation was based on pure tone average (PTA) and speech discrimination (SD). Serviceable hearing was defined as PTA less than 50 dB and SD greater than 50%. Results The median cochlear maximum and mean doses were 6.9 Gy (range 1.6–16 Gy) and 2.7 Gy (range 0.7–5.0 Gy), respectively. With a median audiological follow-up of 35 months (range 6–58 months), the 1-, 2-, and 3-year actuarial rates of maintaining serviceable hearing were 93%, 77%, and 74%, respectively. No patient who received a mean cochlear dose less than 2 Gy experienced serviceable hearing loss (p = 0.035). Patients who received a mean cochlear dose less than 3 Gy had a 2-year hearing preservation rate of 91% compared with 59% in those who received a mean cochlear dose of 3 Gy or greater (p = 0.029). Those who had more than 25% of their cochlea receiving 3 Gy or greater had a higher rate of hearing loss (p = 0.030). There was no statistically significant correlation between serviceable hearing loss and age, tumor size, pre-GKS PTA, pre-GKS SD, pre-GKS Gardner-Robertson class, maximum cochlear dose, or the percentage of cochlear volume receiving 5 Gy. On multivariate analysis there was a trend toward significance for serviceable hearing loss with a mean cochlear dose of 3 Gy or greater (p = 0.074). Local control was 100% at 24 months. No patient developed facial or trigeminal nerve dysfunction. Conclusions With a median mean cochlear dose of 2.7 Gy, the majority of patients with serviceable hearing retained serviceable hearing 3 years after GKS. A mean cochlear dose less than 3 Gy was associated with higher serviceable hearing preservation.

Tumor shrinkage of vestibular schwannomas after Gamma Knife surgery: results after more than 5 years of follow-up

2010 ◽  
Vol 113 (Special_Supplement) ◽  
pp. 122-127 ◽  
Author(s):  
Osamu Nagano ◽  
Toru Serizawa ◽  
Yoshinori Higuchi ◽  
Shinji Matsuda ◽  
Makoto R.T. Sato ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Volume Expansion ◽  
Tumor Volume ◽  
Gamma Knife Surgery ◽  
Vestibular Schwannomas ◽  
Mr Images ◽  
Volume Changes ◽  
Cardiovascular Center ◽  
The Mean

Object The authors prospectively analyzed volume changes in vestibular schwannomas (VSs) after Gamma Knife surgery (GKS). Methods Among 104 VSs treated by GKS at the Chiba Cardiovascular Center between 1998 and 2004, 87 consecutively treated unilateral VSs observed on follow-up MR imaging for at least 5 years were analyzed. These lesions were harbored by 31 men and 56 women, with a mean age of 58.6 years (range 29–80 years). The Gd-enhanced volume of each lesion was measured serially every 3 months during the 1st year and every 6 months thereafter using GammaPlan or SurgiPlan. The frequency and degree of volume shrinkage were documented and possible prognostic factors were analyzed. Results The mean tumor volume at GKS was 2.5 cm3 (range 0.1–13.2 cm3). The lesions were irradiated by directing a mean dose of 12.0 Gy (range 10.5–13.0 Gy) to the tumor margin, which was located at the mean 52.2% isodose line (range 50%–67% isodose line). The mean follow-up period was 7.5 years (range 5.0–11.1 years). Peak tumor volume expansion was most frequently observed at 8.6 months after GKS and averaged 58% (range 0%–613%). Five years after GKS, the mean reduction in tumor volume was 31%, and 9 tumors still remained larger than their initial volumes. Tumors that homogeneously enhanced on MR images displayed less shrinkage than other tumors. Conclusions Most VSs exhibit shrinkage 5 years after GKS. The mean volume reduction in this series was 31%. These results indicate that careful serial follow-up is necessary for patients who harbor tumors that display homogeneous enhancement on MR images and patients whose tumors continue to expand in size after GKS.

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.

Gamma Knife surgery used as primary and repeated treatment for idiopathic trigeminal neuralgia

2008 ◽  
Vol 109 (Supplement) ◽  
pp. 179-184 ◽  
Author(s):  
Chuan-Fu Huang ◽  
Hsien-Tang Tu ◽  
Wen-Shan Liu ◽  
Shyh-Ying Chiou ◽  
Long-Yau Lin
Keyword(s):  
Pain Relief ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Gamma Knife Surgery ◽  
Repeated Treatment ◽  
Maximal Dose ◽  
Idiopathic Trigeminal Neuralgia ◽  
Facial Numbness ◽  
The Mean

Object The purpose of this study was to assess the outcome of idiopathic trigeminal neuralgia (TN) treated with Gamma Knife surgery (GKS) as a primary and repeated treatment modality with a mean follow-up of 5.7 years. Methods Between July 1999 and September 2005, a total of 89 patients with idiopathic TN underwent GKS as a primary treatment. The entry zone of the TN was targeted with a 4-mm collimator and treated with a maximal dose of 60–90 Gy (mean 79 Gy). The dose to the pontine margin was always kept < 15 Gy. Twenty patients received repeated GKS for recurrent or residual pain with a maximal dose of 40–76 Gy (mean 52 Gy). For the second procedure, the target was positioned at the same location as the first treatment. Results The mean follow-up period was 68 months (range 32–104 months). Sixty-nine (77.5%) of the 89 patients experienced a favorable response, as follows: 50 (56%) had excellent, 12 (13.5%) had good, and 7 (7.8%) had fair outcomes. The mean time to pain relief was 1.1 months (range 2 days–6 months). No significant correlation, but more likely a tendency, was found between the dose and pain relief (p = 0.08). Also, no correlation was noted for facial numbness (p = 0.77). The mean follow-up period after repeated GKS was 60 months (range 32–87 months). Outcomes after repeated GKS were excellent in 11 patients (55%) and good in 1 (5%). Seven patients experienced facial numbness. No correlation was found between the additive dose and pain relief (p = 0.24) or facial numbness (p = 0.15). Final outcomes of primary and repeated GKS were excellent in 61 (68.5%), good in 13 (14.6%), and fair in 7 (7.9%). In total, 91% of the patients were successfully treated with this method. There was no statistical significance for efficacy between primary and repeated GKS (p = 0.65), but there was a significant difference for facial numbness (p = 0.007). Conclusions Gamma Knife surgery established durable pain relief when used as a primary and repeated surgery. Treatment was successful for a total of 91% of patients at a mean follow-up of 5.7 years, but facial numbness was also relatively higher.

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