Conventional quality control and evaluation of Leksell Icon Gamma Knife cone-beam CT / 中华放射医学与防护杂志

Objective:To analyze the conventional quality control result of Leksell Icon Gamma Knife cone-beam CT and evaluate long-term stability of cone-bem CT.Methods:QA TOOL Plus was used to verify the accuracy of cone-beam CT. The phantom Catphan 503 was scanned, and the image spatial resolution, contrast to noise ratio and homogeneity were analyzed.Results:The maximum deviation in image volume of cone-beam CT was 0.09-0.17 mm, which passed the accuracy test. At the scanning patterns with CT dose index of 2.5 and 6.3 mGy, the spatial resolution was very stable at 7 and 8 lp/cm respectively. The contrast noise ratio and uniformity meet the reference requirements.Conclusions:The conventional quality control results of Leksell Icon Gamma Knife cone-beam CT are stable in 12 months. In addition to referring to the manufacturer′s baseline value, the unified analysis and evaluation standard for Gamma Knife need to be further improved for the quality control of cone-beam CT.

Jugular foramen schwannoma: A rare tumor treated by stereotactic radiosurgery

Jugular foramen schwannomas (JFS) are rare benign tumors located in the jugular foramen. They can present with various symptoms depending on the extent of involvement of the tumor such as hearing loss, tinnitus, headache, and ataxia. Surgical resection has been considered as the primary treatment option for JFS. Stereotactic radiosurgery (SRS) offers an equally good treatment in patients with small and residual tumors after surgery with the advantage of being non-invasive with minimal complication rates. Herein, we present a rare case of JFS treated by SRS in our institution.

Gamma knife radiosurgery in pituitary adenomas. A single-center experience / Radiocirugía gamma knife en adenomas hipofisarios: experiencia en un centro

Abstract Stereotactic radiosurgery with gamma knife (GKS) is a treatment option for persistent or recurrent pituitary adenoma. The aim of our study was to report Argentine experience in GKS, assessing the efficacy and safety in our patients with pituitary adenomas. We performed a retrospective analysis of patients with pituitary adenomas treated with GKS between 2002 and 2017 in a single institution. Patient characteristics, biochemical remission rate (for functioning tumors), tumor control rate and adverse effects with GKS were inves tigated. The study cohort comprised 99 patients with a mean follow-up of 63 months: 51 somatotropinomas, 28 non-functioning adenomas, 15 corticotropinomas, 2 prolactinomas and 3 mixed pituitary tumors. The mean radiation dose was 30.6Gy for corticotropinomas, 29.3Gy for somatotropinomas and 19.6Gy for non-secreting adenomas. Global tumor control rate was 94.2%. Biochemical remission rate was 55.9%, being higher in acromegaly than in Cushing's disease (OR4.7, 95%Ci 2.1-10.4, p<0.0001). The mean time to remission was 29.5 months (range: 6-156). Hypopituitarism occurred in 26% of patients and those with Cushing's disease were more prone to develop new hormone deficiency after GKS (OR 2.93, 95%Ci 1.2-7.2, p = 0.019). This study shows argentine experience with the use of GKS in patients with pituitary adenomas, with similar results to those reported by centers with large radiosurgical experience. We achieved biochemical remission in more than 50% of patients and global tumor control in most of them. Hypopituitarism was the most frequent adverse effect, while others were infrequent.

Resumen La radiocirugía gamma-knife (GKS) constituye una alternativa de tratamiento en adenomas hipofisarios persis tentes o recurrentes. El objetivo de nuestro trabajo fue comunicar la experiencia argentina con GKS, evaluando eficacia y seguridad en nuestros pacientes con adenomas hipofisarios. Realizamos un análisis retrospectivo de pacientes con adenomas hipofisarios tratados con GKS entre 2002 y 2017. Se investigaron: características basales, tasa de remisión bioquímica, tasa de control tumoral y efectos adversos del GKS. Estudiamos 99 pa cientes adultos con un seguimiento medio de 63 meses: 51 somatotropinomas, 28 adenomas no funcionantes, 15 corticotropinomas, 2 prolactinomas y 3 tumores mixtos. La do sis media de radiación fue 30.6 Gy para cortico tropinomas, 29.3 Gy para somatotropinomas y 19.6 Gy para adenomas no secretores. La tasa global de control tumoral fue 94.2%. La tasa de remisión bioquímica fue 55.9%, si endo mayor en acromegalia que en enfermedad de Cushing (OR4.7, 95% Ci 2.1-10.4, p < 0.0001). El tiempo medio hasta la remisión fue 29.5 meses (rango: 6-156). Se produjo hipopituitarismo en el 26% de los pacientes. Aquellos con enfermedad de Cushing fueron más propensos a desarrollar nuevas deficiencias hormonales después del GKS (OR2.93, 95% Ci 1.2-7.2, p = 0.019). Este trabajo muestra la experiencia argentina con GKS en pacientes con adenomas hipofisarios, con resultados similares a los reportados por centros con amplia experiencia radioquirúrgica. Logramos remisión bioquímica en más del 50% de los pacientes y control tumoral global en la mayoría de ellos. El hipopituitarismo fue el efecto adverso más frecuente, mientras que otros fueron infrecuentes.

Comparación dosimétrica en radiocirugía intracraneal entre Cyberknife y un bisturí de rayos gamma y su puesta en marcha Centroamérica / Dosimetric comparison in intracranial radiosurgery between Cyberknife and a gamma knife and its implementation Central America

Introducción: La dupla Cyberknife y bisturí de rayos gamma (Infini) que se describe es la primera en Latinoamérica. Ambas máquinas han mostrado ser los mejores equipos para radiocirugía intracraneal. Se describe la experiencia inicial de Cyberknife en Centroamérica y su incorporación a un programa existente de bisturí de rayos gamma por vía de análisis comparativos dosimétricos. Material y método: En el año 2019 se realizaron planes comparativos y se trataron 180 pacientes con radiocirugía intracraneal con ambos sistemas tanto en patología tumoral, como vascular y funcional. Resultados: En el análisis dosimétrico comparativo en el gradiente de dosis de Infini mostró ser superior a Cyberknife en todos los casos. Para una esfera utilizando el colimador de 4 mm en Infini y de 5 mm en Cyberknife utilizando un plan isocéntrico con el -Trigeminal Path- el gradiente de dosis para Infini fue de 1.5 y para Cyberknife de 1.66. Para los casos de patología el gradiente de dosis media para Infini fue de 3 mm y para Cyberknife de 3.8 mm. Dando un puntaje de gradiente de dosis (Gradient Score Index) si Infini fuese de 100, Cyberknife obtuvo 87.3. Cyberknife mostró mejor conformalidad y cobertura (97% versus 96%) para todos los targets. Entre enero 2019 y enero 2020 se realizaron 180 radiocirugías, 60 con Cyberknife y 120 con Infini, 60 pacientes recibieron 146 sesiones con Cyberknife, radiocirugía fraccionada 39 (65%) y 21 (35%) en sesión única. Las dosis medias en tumores en dosis única fue 15 Gy (12.5 a 25 Gy) y en radiocirugía fraccionada 21 Gy (18 y 35). Ningún paciente ha experimentado toxicidad mayor a grado dos. Conclusiones: El bisturí de rayos gamma rotatorio reveló superioridad en gradiente de dosis con relación al Cyberknife. En su primer año Cyberknife ha mostrado ser una herramienta segura en el tratamiento de patología intracraneal. Más seguimiento clínico y radiológico es necesario para verificar su efectividad comparativa

Introduction: The match between Cyberknife and Infini here described in this article is the first in Latinamerica. Both machines have proven to be the best for intracranial radiosurgery, we describe our initial experience with Cyberknife in Central America and how it was incorporated in an existing gamma ray program by ways of dosimetry comparisons. Methods: During 2019 comparative plans were made and a total of 180 patients received intracranial radiosurgery with both technologies, patients were treated for tumors, vascular anomalies, and functional pathology. Results: Basic dosimetry analysis regarding dose gradient the Infini proved superior to Cyberknife in all plans. For a sphere using the 4 mm collimator in Infini and the 5 mm in Cyberknife along with an isocentric plan using the -Trigeminal Path- dose gradient was 1.5 for Infini and 1.66 for Cyberknife. For the pathology cases Infini was 3 mm and for Cyberknife 3.8 mm on mean. Giving a Gradient Score Index (GSI) if Infini would be 100, Cyberknife would be 87.3. Cyberknife showed better conformality and coverage for all pathology targets (97% versus 96%). From January 2019 to January 2020, 180 intracranial radiosurgeries were done, 60 with Cyberknife and 120 with Infini, 60 patients received 146 sessions with Cyberknife, fractionated scheme 39 (65%) and 21 (35%) single dose. The median dose for tumors was 15 Gy (12.5 a 25 Gy) for single session and 21 Gy (18 y 35) for fractionated scheme. No patient experienced a higher toxicity tan grade two. Conclusions: In its first year Cyberknife has shown to be safe in treating intracranial pathology. Infini had a better dose gradient than Cyberknife. Longer clinical and radiological follow-up is needed to verify its comparative effectiveness.

Metástasis sintomáticas en cerebro superiores a 8. 5 cm3 manejados con radiocirugía / Symptomatic brain metastases greater than 8.5 cm3 managed with radiosurgery

Introducción: Las recomendaciones en el manejo de metástasis superiores a 2 cm especialmente las sintomáticas sugieren cirugía como primera opción. En el presente artículo se discute el papel de radiocirugía como primer manejo de estos pacientes. Material y método: Se evaluaron 37 pacientes sintomáticos con lesiones metastásicas superiores a 8.5 cc tratados con radiocirugía entre el 2011 y el 2018. Resultados: La media de volumen fue de 12.5 cc (8.5-78.4), 9 (24%) pacientes fueron tratados utilizando LINAC, el volumen medio fue de 20 cc (9.2-70 cc). Los tratamientos con Gamma-Ray fueron administrados a 28 (76%) pacientes, 9 (32%) de ellos en protocolo de radiocirugía adaptativa, la dosis para todo el grupo fue de 13.8 Gy (7.5-18 Gy), con dosis media de 17.9 Gy, el volumen medio fue de 16.3 cc (8.5-78.4 cc) para gamma. El Karnofsky al inicio era de 60 (50-70) y de 80 (60-100) a los 30 días (P=0.0001). A los 30 días, 95% de las lesiones habían reducido su tamaño en un 74% (11-95%). La sobrevida media de la serie fue de 19 meses (4-34), el riesgo acumulado de muerte del SNC fue de 5.4%. Conclusiones: Radiocirugía en nuestra experiencia ha mostrado ser eficaz en el control de metástasis a cerebro de gran tamaño, reduciendo la necesidad de cirugí

Introduction: Current recommendations with regards to metastases larger than 2 cm specially in symptomatic patients suggest surgery as a first choice. We analyze the role of upfront radiosurgery as first line of treatment in such patients. Methods: 37 symptomatic patients that harbored tumors greater than 8.5 cc in volume were treated from 2011 to January 2018. Results: The median tumor volume was 12.5 cc (8.5-78.4), 9 (24%) patients were treated with LINAC with a volume of 20 cc (9.2-70 cc). The treatments with GammaRay were administrated to 28 (76%) patients, 9 (32%) of them with adaptive radiosurgery protocol, the prescription dose for the gamma group was 13.8 Gy (7.5-18Gy) mean dose of 17.9 Gy (13.2-23.3 Gy) with a mean volume of 16.3 cc (8.5-78.4 cc). Karnofsky score was 60 (50-70) the day of treatment and 80 (60-100) at 30 days (P=0.0001). At 30 days, 95% of the tumors had reduced in size in a 74% (11-95%) for those evaluated. Median survival was 19 months (4-34), with an accumulative risk of death from central nervous progression of 5.4%. Conclusions: Radiosurgery in our experience has shown to be effective in controlling large metastases, reducing the need for open surgery.

Gamma Knife Radiosurgery on the Trigeminal Root Entry Zone for Idiopathic Trigeminal Neuralgia: Results and a Review of the Literature

Frameless Fractionated Gamma Knife Radiosurgery with ICON™ for Large Metastatic Brain Tumors

BACKGROUND: Recently, a new generation of gamma knife radiosurgery (GKRS) equipped with a frameless immobilization system has encouraged the use of fractionated GKRS as an increasingly favorable treatment option. We investigated the preliminary outcome of efficacy and toxicity associated with frameless fractionated gamma knife radiosurgery (FF GKRS) for the treatment of large metastatic brain tumors. METHODS: Fifteen patients with 17 lesions were treated using FF GKRS and included in this study, because of the large tumor size of more than 10 cm3. FF GKRS was performed based on a thermoplastic mask system for 3 to 5 consecutive days. RESULTS: The mean duration of clinical follow-up was 12 months (range, 4–24), and the local control rate was 100%. Tumor volume decreased in 13 lesions (76.5%), and remained stable in 4 lesions (23.5%). One patient was classified as new lesion development because of the occurrence of leptomeningeal seeding regardless of the tumor volume change. Compared with the initial volume at the time of FF GKRS, tumor volume change at the last follow-up was 62.32% ± 29.80%. Cumulative survival rate at 12 months was 93.3% ± 6.4%. One patient died during the follow-up period because of the progression of the primary disease. No patient showed radiation necrosis on the follow-up images. CONCLUSION: Daily FF GKRS by gamma knife ICON™ revealed satisfactory tumor control rate and low morbidity, despite the short follow-up period. Further prospective studies and a longer follow-up of a large cohort of patients diagnosed with brain metastases are required to elucidate the effect of FF GKRS in brain metastases.

Gamma Knife Radiosurgery for ARUBA-Eligible Patients with Unruptured Brain Arteriovenous Malformations

BACKGROUND: A randomized trial of unruptured brain arteriovenous malformations (ARUBA) reported superior outcomes in conservative management compared to interventional treatment. There were numerous limitations to the study. This study aimed to investigate the efficacy of gamma knife radiosurgery (GKS) for patients with brain arteriovenous malformations (AVMs) by comparing its outcomes to those of the ARUBA study. METHODS: We retrospectively reviewed ARUBA-eligible patients treated with GKS from June 2002 to September 2017 and compared against those in the ARUBA study. AVM obliteration and hemorrhage rates, and clinical outcomes following GKS were also evaluated. RESULTS: The ARUBA-eligible cohort comprised 264 patients. The Spetzler-Martin grade was Grade I to II in 52.7% and III to IV in 47.3% of the patients. The mean AVM nidus volume, marginal dose, and follow-up period were 4.8 cm³, 20.8 Gy, and 55.5 months, respectively. AVM obliteration was achieved in 62.1%. The annual hemorrhage rate after GKS was 3.4%. A stroke or death occurred in 14.0%. The overall stroke or death rate of the ARUBA-eligible cohort was significantly lower than that of the interventional arm of the ARUBA study (P < 0.001) and did not significantly differ from that of the medical arm in the ARUBA study (P = 0.601). CONCLUSION: GKS was shown to achieve a favorable outcome with low procedure-related morbidity in majority of the ARUBA-eligible patients. The outcome after GKS in our patients was not inferior to that of medical care alone in the ARUBA study. It is suggested that GKS is rather superior to medical care considering the short follow-up duration of the ARUBA study.

Prognostic Analysis of EGFR-TKIs Combined with Gamma Knife in EGFR-mutant Lung Adenocarcinoma with Brain Metastasis / 中国肺癌杂志

BACKGROUND@#Advanced epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma had a high overall incidence of brain metastasis during the full course, and local brain radiotherapy combined with systemic targeted therapy may be a better strategy. This study aimed to identify the prognostic factors of EGFR-mutant brain-metastatic lung adenocarcinoma patients who received EGFR-tyrosine kinase inhibitors (EGFR-TKIs) in combination with gamma knife radiosurgery.@*METHODS@#Retrospective analysis of EGFR-mutant lung adenocarcinoma patients with brain metastases which developed at initial diagnosis or during EGFR-TKIs treatment period were performed. Intracranial progression free survival (PFS) was statistically analyzed between different subgroups to find out the prognostic factors including gender, age, smoking history, extracranial metastasis, EGFR mutation type, size and number of intracranial lesions, carcino-embryonic antigen (CEA) level, lung-molGPA score and so on.@*RESULTS@#A total of 74 EGFR-mutant brain-metastatic lung adenocarcinoma patients were enrolled in this study, with median intracranial PFS of 14.7 months. One-year intracranial-progression-free rate was 58.5%, and two-year rate was 22.2%. Univariate survival analysis showed that patients with lower CEA level at initial diagnosis (3)(15 months vs 12.6 months, P=0.041) were prone to have a superior intracranial PFS. Multivariate analysis showed that CEA≥10 ng/mL and intracranial lesion≥2 cm were the independent risk factors of intracranial PFS.@*CONCLUSIONS@#EGFR-TKIs in combination with gamma knife radiosurgery was an efficient treatment option to control the cranial tumor lesion. CEA≥10 μg/L at initial diagnosis and intracranial lesion≥2 cm were the risk factors of EGFR-mutant brain-metastatic lung adenocarcinoma patients receiving EGFR-TKIs in combination with gamma knife radiosurgery.

Gamma Knife Radiosurgery in Recurrent Trigeminal Neuralgia after Other Procedures / 고신대학교의과대학학술지

OBJECTIVES: Trigeminal neuralgia (TN) is undurable paroxysmal pain in the distribution of the fifth cranial nerve. Invasive treatment modalities for TN include microvascular decompression (MVD) and percutaneous procedures, such as, radiofrequency rhizotomy (RFR). Gamma Knife radiosurgery (GKRS) is a considerable option for patients with pain recurrence after an initial procedure. This study was undertaken to analyze the effects of gamma knife radiosurgery in recurrent TN after other procedures. METHODS: Eleven recurrent TN patients after other procedures underwent GKRS in our hospital from September 2004 to August 2016. Seven patients had previously undergone MVD alone, two underwent MVD with partial sensory rhizotomy (PSR), and two underwent RFR. Mean patient age was 60.5 years. We retrospectively analyzed patient's characteristics, clinical results, sites, and divisions of pain. Outcomes were evaluated using the Visual Analog Scales (VAS) score. RESULTS: Right sides were more prevalent than left sides (7:4). The most common distribution of pain was V1 + V2 division (n = 5) following V2 + V3 (n = 3), V2 (n = 2), and V1 + V2 + V3 (n = 1) division. Median GKRS dose was 80 Gy and the mean interval between the prior treatment and GKRS was 74.45 months. The final outcomes of subsequent GKRS were satisfactory in most cases, and at 12 months postoperatively ten patients (90.0%) had a VAS score of ≤ 3. CONCLUSIONS: In this study, the clinical result of GKRS was satisfactory. Invasive procedures, such as, MVD, RFR are initially effective in TN patients, but GKRS provides a safe and satisfactory treatment modality for those who recurred after prior invasive treatments.

Episodes of prolonged “trance-like state” in an infant with hypothalamic hamartoma

Hypothalamic hamartoma (HH) is one of the most common causes of central precocious puberty (CPP) in first few years of life. It can present with either seizures or CPP, although both manifestations coexist in the majority of the children. Gelastic seizures (GS), or laughing spells, are usually the first type of seizures seen in patients with HH. Although a wide variety of seizure types are known to occur in children with HH, GS are most common and consistent seizure type. The clinical presentation of HH may vary with the size and position of the mass, although large tumours typically present with both CPP and seizures. Although CPP can be managed with medical therapy, seizures can be very difficult to treat, even with multiple antiepileptic drugs. Noninvasive gamma knife surgery has been used with some success for the treatment of refractory epilepsy. We present a case of HH with very early onset seizures and CPP. The patient had an atypical form of seizures described by the parents as a "trance-like state" in which the patient had prolonged episodes of unresponsiveness lasting for hours with normal feedings during the episodes. GS occurred late in the course and were refractory to various combinations of antiepileptic drugs. A brain magnetic resonance imaging showed a large sessile HH (>20 mm). Later in the course of the disease, the patient experienced cognitive and behavioural problems. The patient underwent gamma knife surgery at nearly 5 years of age and experienced a modest response in seizure frequency. This case highlights the presentation of HH as a previously unreported seizure morphology described as a prolonged "trance-like state."

Effect of Gamma Knife Coupled with Conventional Chemotherapy on the Clinical Efficacy and Immune Function in Patients with Esophageal Carcinoma Complicated by Loco-Regional Lymph Node Metastasis / 中国医科大学学报

Objective To observe patients with esophageal squamous cell carcinoma [ESCC, without distant lymph node metastasis (LM) ], who had local LM after radiotherapy and therefore were treated with gamma knife combined with conventional chemotherapy (5-fluorouracil +cisplatin); to evaluate the clinical efficacy in these patients after treatment; and to record adverse reactions. Methods A total of 120 patients with ESCC who underwent radical radiotherapy (with local LM thereafter) without distant LM were randomly divided into control (n = 60; 55 completed the procedure successfully) and observation (n = 60; 50 completed the procedure successfully) groups. The control group was treated with gamma knife, whereas the observation group was given chemotherapy (5-fluorouracil and cisplatin) in addition to the basic gamma knife for 4 courses of treatment. The clinical efficacy of the two groups was compared at the end of treatment, followed by detection of immunological indicators (cellular and humoral immunity) and recording of adverse reactions. Results After treatment, the short-term clinical efficacy in the observation group was found to be better than that in the control group but held no statistical significance (P＞ 0.05). However, the long-term clinical efficacy was significantly enhanced in the observation group than in the control group (P ＜ 0.05). After treatment, the immunological indicators (cellular and humoral immunity) of the two groups were substantially improved post treatment (P ＜ 0.05), exhibiting remarkable enhancement in the observation group compared with the control group (P ＜0.05). Remission rate of the clinical symptoms did not vary significantly between the two groups after treatment (P＞ 0.05). Adverse reactions such as leukopenia, decreased platelet count, nausea, and vomiting were observed during the course of treatment for both the groups, lacking any significant difference (P＞ 0.05). Conclusion Gamma knife coupled with chemotherapy (5-fluorouracil + cisplatin) can improve the treatment efficiency in ESCC patients with local LM following radical radiotherapy.

The Effect of Pain Reduction during Headframe Fixation for Stereotactic Radiosurgery by the Preceded Local Anesthesia under the Needle Cap Guidance

BACKGROUND: Gamma knife radiosurgery (GKRS) has become a major alternative in the neurosurgical field. However, many patients complained of considerable discomfort during the fixation of rigid headframe. This study investigated whether our modified procedure could reduce fixation-related pain. METHODS: Sixty-six patients who underwent GKRS were enrolled in this study. Thirty-one patients (Group A) underwent the conventional subcutaneous infiltration technique, and 35 patients (Group B) did the modified procedure. In group A, the headframe was held in position by an assistant, and local anesthetics were injected subcutaneously using a 23-gauge spinal needle at pinning sites. Subsequently, pins were applied according to measurements based on spinal needle depth. In group B, with the frame held in position by an assistant, pin sites were marked with a surgical pen under the guidance of needle cap placed on the pin holes. The head frame was then removed, and local anesthetics were injected subcutaneously and periosteally at each marked pin site using a 26-gauge needle. The headframe was then repositioned 5 minutes after local infiltration, and pins were applied according to measurements based on spinal needle depth. To evaluate pain severity during procedures, visual analogue scale (VAS) scores were recorded during local infiltration and frame placement with pins. The pain scores of the two groups were analyzed statistically. RESULTS: Group B had a significantly lower VAS score during frame placement than group A (7.26 vs. 3.61; p<0.001), and mean VAS score at local infiltration was also significantly lower in group B (4.74 vs. 3.74; p=0.008). CONCLUSION: Patients in group B experienced significantly less pain than those in group A during pin placement. Pre-fixation time advanced local anesthesia might reduce pain during stereotactic procedures, and the use of a 26-gauge needle appeared in less pain during local infiltration.

The value of contrast?enhanced T1 mapping technique in differentiating recurrence and radiation necrosis of brain metastases after gamma knife treatment / 中华放射学杂志

Objective To explore the value of contrast?enhanced T1 mapping technique in differentiating between recurrence and radiation necrosis of brain metastases after gamma knife treatment. Methods From March 2016 to June 2017,56 patients with brain metastases treated by gamma knife and confirmed by pathology or follow?up in Shandong Provincial Hospital were prospectively collected. Routine MRI and contrast?enhanced T1 mapping sequence scan were performed. T1 value was obtained 5 mins (T1 5 min) and 60 mins (T1 60 min) after injection of contrast agent. The Differences betweenT1 60 min and T1 5 min (T1 differ) was calculated,and relative cerebral blood volume (rCBV) value was obtained. Patients were divided into radiation necrosis group and tumor recurrence group according to imaging follow?up results or pathological results. Two?sides unpaired t test was used to compare the differences in T1 5 min,T1 60 min,T1 differ and rCBV between the 2 groups. Pearson correlation analysis was used to evaluate the correlation between T1 differ and rCBV, and the receiving operating curve (ROC) was used to evaluate the diagnostic efficiency of MRI quantitative parameters,and Z test was used to compare the differences of area under curve (AUC) between T1 differ and rCBV values. Results Of the 56 patients,27 had tumor recurrence and 29 had radiation necrosis. The differences in T1 5 min,T1 60 min,T1 differ and rCBV between the 2 groups was statistically significant (P<0.05). T1 differ and rCBV values were significantly correlated, r=0.58, P<0.01. The differential diagnosis of AUC between radiation necrosis and tumor recurrence were 0.66,0.73,0.97 and 0.95 respectively in T1 5 min,T1 60 min, T1 differ and rCBV, and there was no significant differences between AUC in T1 differ and rCBV (P=0.274). Conclusion The contrast?enhanced T1 mapping image can be used for differential diagnosis between radiation necrosis and recurrence after gamma knife treatment of brain metastases. T1 differ value has high differential efficiency.

Effects of low dose of gamma knife irradiation on the expression of NMDA receptor subunits in the cortex and hippocampus of epileptic rats / 中国神经精神疾病杂志

Objective To investigate the effects of low dose of gamma knife irradiation on the expression of N-methyl-D-aspartate (NMDA) receptor subunits in cortex and hippocampus of epileptic rats. Methods The rats were randomly divided into 4 groups: control group, GK group, pentylenetetrazole (PTZ) group and GK+ PTZ group. The rats were injected intraperitoneally with PTZ to establish the epileptic models. Gamma knife irradiation was performed on bilateral frontal cortex of rats at a peripheral dose of 15Gy. After irradiation, the changes of the seizure and behaviors were observed and recorded. The rats were killed on the 12th week after irradiation, Immunohistochemstry and western blotting were used to detect the relative expression levels of NMDAR subunits (NR1, NR2A, and NR2B) in the cortex and hippocampus. Results There were no epileptic seizures in the control group and the GK group. Compared with the PTZ group, the epileptic seizures of rats in the GK+PTZ group were significantly reduced after low dose gamma knife irradiation (P<0.05). Compared with control group, the protein expression levels of NR1, NR2A and NR2B in the PTZ group increased significantly in the cortex and hippocampus, and so were the positive neurons and their average absorbance value (P<0.05). Compared with PTZ group, the protein expression levels of NR1, NR2A and NR2B of the GK+PTZ group decreased remarkably in the cortex and hippocampus (P<0.05). Protein expression levels of NR1, NR2A and NR2B were not significantly different between control group and GK group (P＞0.05). Conclusion Epileptic rats exhibited an increase in the protein expression levels of NR1, NR2A and NR2B in the cortex and hippocampus while low dose of gamma knife irradiation can decrease expression levels of NMDA receptor subunits in the cortex and hippocampus of epileptic rats, which might represent a possible mechanism underlying the therapeutic effects of gamma knife irradiation on epileptic seizure.

Repeat Stereotactic Radiosurgery for Recurred Metastatic Brain Tumors

OBJECTIVE: We investigated the outcomes of repeat stereotactic radiosurgery (SRS) for metastatic brain tumors that locally recurred despite previous SRS, focusing on the tumor control. METHODS: A total of 114 patients with 176 locally recurring metastatic brain tumors underwent repeat SRS after previous SRS. The mean age was 59.4 years (range, 33 to 85), and there were 68 male and 46 female patients. The primary cancer types were non-small cell lung cancer (n=67), small cell lung cancer (n=12), gastrointestinal tract cancer (n=15), breast cancer (n=10), and others (n=10). The number of patients with a single recurring metastasis was 95 (79.8%), and another 19 had multiple recurrences. At the time of the repeat SRS, the mean volume of the locally recurring tumors was 5.94 mL (range, 0.42 to 29.94). We prescribed a mean margin dose of 17.04 Gy (range, 12 to 24) to the isodose line at the tumor border primarily using a 50% isodose line. RESULTS: After the repeat SRS, we obtained clinical and magnetic resonance imaging follow-up data for 84 patients (73.7%) with a total of 108 tumors. The tumor control rate was 53.5% (58 of the 108), and the median and mean progression-free survival (PFS) periods were 246 and 383 days, respectively. The prognostic factors that were significantly related to better tumor control were prescription radiation dose of 16 Gy (p=0.000) and tumor volume less than both 4 mL (p=0.001) and 10 mL at the repeat SRS (p=0.008). The overall survival (OS) periods for all 114 patients after repeat SRS varied from 1 to 56 months, and median and mean OS periods were 229 and 404 days after the repeat SRS, respectively. The main cause of death was systemic problems including pulmonary dysfunction (n=58, 51%), and the identified direct or suspected brain-related death rate was around 20%. CONCLUSION: The tumor control following repeat SRS for locally recurring metastatic brain tumors after a previous SRS is relatively lower than that for primary SRS. However, both low tumor volume and high prescription radiation dose were significantly related to the tumor control following repeat SRS for these tumors after previous SRS, which is a general understanding of primary SRS for metastatic brain tumors.

Efficacy of Gamma Knife Radiosurgery for Recurrent High-Grade Gliomas with Limited Tumor Volume

OBJECTIVE: This study aims to determine whether gamma knife radiosurgery (GKR) improves survival in patients with recurrent highgrade gliomas. METHODS: Twenty nine patients with recurrent high-grade glioma underwent 38 GKR. The male-to-female ratio was 10 : 19, and the median age was 53.8 years (range, 20–75). GKR was performed in 11 cases of recurrent anaplastic oligodendrogliomas, five anaplastic astrocytomas, and 22 glioblastomas. The median prescription dose was 16 Gy (range, 10–24), and the median target volume was 7.0 mL (range, 1.1–15.7). Of the 29 patients, 13 (44.8%) received concurrent chemotherapy. We retrospectively analyzed the progression-free survival (PFS) and overall survival (OS) after GKR depending on the Eastern Cooperative Oncology Group (ECOG) performance status (PS), pathology, concurrent chemotherapy, radiation dose, and target tumor volume. RESULTS: Starting from when the patients underwent GKR, the median PFS and OS were 5.0 months (range, 1.1–28.1) and 13.0 months (range, 1.1–75.1), respectively. On univariate analysis, the median PFS was significantly long in patients with anaplastic oligodendroglioma, ECOG PS 1, and target tumor volume less than 10 mL (p < 0.05). Meanwhile, on multivariate analysis, patients with ECOG PS 1 and target tumor volume less than 10 mL showed improved PFS (p=0.043 and p=0.007, respectively). The median OS was significantly increased in patients with ECOG PS 1 and tumor volume less than 10 mL on univariate and multivariate analyses (p < 0.05). CONCLUSION: GKR could be an additional treatment option in recurrent high-grade glioma, particularly in patients with good PS and limited tumor volume.

Gamma Knife Radiosurgery for Cancer Metastasized to the Ocular Choroid

OBJECTIVE: Choroidal metastases (CMs) are the most common intraocular tumor. Management is mainly radiation therapy with goals of pain control and visual improvement. However, many radiation-related complications are reported. Since gamma knife radiosurgery (GKS) for CM was first reported in 1995, few cases have been reported. We report 7 cases of CMs treated with GKS. METHODS: From April 2011 to November 2014, 7 patients with CM underwent GKS. Their median age at treatment was 64 years (range, 51–71 years). Four males and three females were treated. Lung cancer was the most common primary pathology, followed by renal cell carcinoma and stomach cancer. Four patients had multiple cerebral lesions and were treated simultaneously for choroidal lesions. The median marginal dose of 20 Gy (range, 15–25 Gy) was administered at the 50% isodose line. RESULTS: Median follow-up period after GKS was 8 months (range, 2–38.3 months). Four patients expired due to underlying malignancy progression. Except for two patients who were not followed with magnetic resonance image after GKS, all patients showed size reduction in the treated lesions, but a new choroidal lesion appeared in one patient and one recurred. Six of seven patients reported subjectively improved visual symptoms. Visual acuity improved in 2 patients, and 2 were stable upon objective examination. One patient showed no improvement in visual acuity, but ocular pain was relieved; another patient showed improved vision and tumor remission, but visual deterioration recurred. CONCLUSION: GKS was shown to be safe and effective and should be considered for CM treatment.

Repeat Stereotactic Radiosurgery for Recurred Metastatic Brain Tumors

OBJECTIVE: We investigated the outcomes of repeat stereotactic radiosurgery (SRS) for metastatic brain tumors that locally recurred despite previous SRS, focusing on the tumor control.METHODS: A total of 114 patients with 176 locally recurring metastatic brain tumors underwent repeat SRS after previous SRS. The mean age was 59.4 years (range, 33 to 85), and there were 68 male and 46 female patients. The primary cancer types were non-small cell lung cancer (n=67), small cell lung cancer (n=12), gastrointestinal tract cancer (n=15), breast cancer (n=10), and others (n=10). The number of patients with a single recurring metastasis was 95 (79.8%), and another 19 had multiple recurrences. At the time of the repeat SRS, the mean volume of the locally recurring tumors was 5.94 mL (range, 0.42 to 29.94). We prescribed a mean margin dose of 17.04 Gy (range, 12 to 24) to the isodose line at the tumor border primarily using a 50% isodose line.RESULTS: After the repeat SRS, we obtained clinical and magnetic resonance imaging follow-up data for 84 patients (73.7%) with a total of 108 tumors. The tumor control rate was 53.5% (58 of the 108), and the median and mean progression-free survival (PFS) periods were 246 and 383 days, respectively. The prognostic factors that were significantly related to better tumor control were prescription radiation dose of 16 Gy (p=0.000) and tumor volume less than both 4 mL (p=0.001) and 10 mL at the repeat SRS (p=0.008). The overall survival (OS) periods for all 114 patients after repeat SRS varied from 1 to 56 months, and median and mean OS periods were 229 and 404 days after the repeat SRS, respectively. The main cause of death was systemic problems including pulmonary dysfunction (n=58, 51%), and the identified direct or suspected brain-related death rate was around 20%.CONCLUSION: The tumor control following repeat SRS for locally recurring metastatic brain tumors after a previous SRS is relatively lower than that for primary SRS. However, both low tumor volume and high prescription radiation dose were significantly related to the tumor control following repeat SRS for these tumors after previous SRS, which is a general understanding of primary SRS for metastatic brain tumors.

Efficacy of Gamma Knife Radiosurgery for Recurrent High-Grade Gliomas with Limited Tumor Volume

OBJECTIVE: This study aims to determine whether gamma knife radiosurgery (GKR) improves survival in patients with recurrent highgrade gliomas.METHODS: Twenty nine patients with recurrent high-grade glioma underwent 38 GKR. The male-to-female ratio was 10 : 19, and the median age was 53.8 years (range, 20–75). GKR was performed in 11 cases of recurrent anaplastic oligodendrogliomas, five anaplastic astrocytomas, and 22 glioblastomas. The median prescription dose was 16 Gy (range, 10–24), and the median target volume was 7.0 mL (range, 1.1–15.7). Of the 29 patients, 13 (44.8%) received concurrent chemotherapy. We retrospectively analyzed the progression-free survival (PFS) and overall survival (OS) after GKR depending on the Eastern Cooperative Oncology Group (ECOG) performance status (PS), pathology, concurrent chemotherapy, radiation dose, and target tumor volume.RESULTS: Starting from when the patients underwent GKR, the median PFS and OS were 5.0 months (range, 1.1–28.1) and 13.0 months (range, 1.1–75.1), respectively. On univariate analysis, the median PFS was significantly long in patients with anaplastic oligodendroglioma, ECOG PS 1, and target tumor volume less than 10 mL (p < 0.05). Meanwhile, on multivariate analysis, patients with ECOG PS 1 and target tumor volume less than 10 mL showed improved PFS (p=0.043 and p=0.007, respectively). The median OS was significantly increased in patients with ECOG PS 1 and tumor volume less than 10 mL on univariate and multivariate analyses (p < 0.05).CONCLUSION: GKR could be an additional treatment option in recurrent high-grade glioma, particularly in patients with good PS and limited tumor volume.