• Radiation Oncology Journal
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• v.33 no.3
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• pp.233-241
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• 2015

Purpose: To compare volumetric modulated arc therapy of RapidArc with robotic stereotactic body radiation therapy (SBRT) of CyberKnife in the planning and delivery of SBRT for hepatocellular carcinoma (HCC) treatment by analyzing dosimetric parameters. Materials and Methods: Two radiation treatment plans were generated for 29 HCC patients, one using Eclipse for the RapidArc plan and the other using Multiplan for the CyberKnife plan. The prescription dose was 60 Gy in 3 fractions. The dosimetric parameters of planning target volume (PTV) coverage and normal tissue sparing in the RapidArc and the CyberKnife plans were analyzed. Results: The conformity index was $1.05{\pm}0.02$ for the CyberKnife plan, and $1.13{\pm}0.10$ for the RapidArc plan. The homogeneity index was $1.23{\pm}0.01$ for the CyberKnife plan, and $1.10{\pm}0.03$ for the RapidArc plan. For the normal liver, there were significant differences between the two plans in the low-dose regions of $V_1$ and $V_3$. The normalized volumes of $V_{60}$ for the normal liver in the RapidArc plan were drastically increased when the mean dose of the PTVs in RapidArc plan is equivalent to the mean dose of the PTVs in the CyberKnife plan. Conclusion: CyberKnife plans show greater dose conformity, especially in small-sized tumors, while RapidArc plans show good dosimetric distribution of low dose sparing in the normal liver and body.

• Radiation Oncology Journal
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• v.13 no.1
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• pp.87-94
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• 1995

Since March 1992, total 200 patients who visited our hospital as functional or organic lesions of central nervous system were treated by gamma knife stereotactic radiosurgery for 27 months. Thirty-nine patients of total cases was diagnosed as cerebral arteriovenous malformation. The rate of magnification on X-ray film was reduced by cutting fixation adaptor from 1.0 to below 1.45 times. In order to treat the deep- and lateral-seated cerebral arteriovenous malformation, we slightly modified the angiographic indicator, the commercial Leksell system, by cutting each inner sides about 5mm, We performed the more distinction of the scales by adapting 0.5mm or 1mm copper filter to angiographic indicator. The center point of indicator(X=100mm, Y=100mm, Z=100mm) is corrected by adjusting scales of X-, Y-, Z-axis to each inner 100 and outer 100 point within 1-2mm by repeated exposure of X-ray on films in trial-and-errors. We have developed the 'GKANGIO' programed as the Fortran-77 in Microvax - 3100, which can save treatment planning time and perform accurate pretreatment planning using the theoretical target metrix center. The theoretical description of the simplified method is presented for the reduction of experimental and numerical errors in treatment planning of radiosurgery.

• Progress in Medical Physics
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• v.10 no.2
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• pp.89-94
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• 1999

We developed a sterotactic radiosurgery system which is comprised of 1) collimators with small circular aperture, 2) an angiographic target localizer, 3) a target localizer used for alignment of planned target position with isocenter of treatment machine, and 4) a treatment planning system named LinaPel. In this study, we performed a series of treatment simulations to specify and analyze geometrical errors contained our in-house radiosurgery system. As results, 1) using Geometrical Phantom(Radionics,USA), the accuracy of target localization by LinaPel was determined as Avg. =(equation omitted) the accuracy of mechanical isocenter was found out to be 0.6 $\pm$ 0.2 mm, 3) the positional difference of target localization which determined by CT and angiography was 0.8 mm, and their size difference was 1.5 mm, and 4) the positional error during whole treatment was found out to be 0.9 $\pm$ 0.3 mm. With these results, we concluded that our in-house radiosurgery system can be used clinically. However, these range of accuracies need periodical quality assurance strongly.

• Journal of Korean Neurosurgical Society
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• v.58 no.4
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• pp.373-378
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• 2015

Objective : To determine the advantages of parietal approach compared to Kocher's point approach for spontaneous, oval-shaped intracerebral hemorrhage (ICH) with expansion to the parietal region. Methods : We divided patients into two groups : group A had burr holes in the parietal bone and group B had burr holes at Kocher's point. The hematoma volume, Glasgow coma scale (GCS) score, and modified Barthel Index (mBI) score were calculated. At discharge, we evaluated the patients' Glasgow outcome scale (GOS) score, modified Rankin Scale (mRS) score, motor grade, and hospitalization duration. We evaluated the patients' mBI scores and motor grades at 6 months after surgery. Results : The hematoma volume in group A was significantly less than that in group B on postoperative days 1, 3, 5, 7, 14, and 21. Group A had significantly higher GCS scores than did group B on postoperative days 1 and 3. Group A had higher mBI scores postoperatively than did group B, but the scores were not significantly different. No differences were observed for the GOS score, mRS score, motor grade at discharge, or duration of hospitalization. The mBI score of group A at 6 months after surgery was significantly higher, and more patients in group A showed muscle strength improvement. Conclusion : In oval-shaped ICH with expansion to the parietal region, the parietal approach is considered to improve the clinical symptoms at the acute phase by removing the hematoma more effectively in the early stages. The parietal approach might help promote the long-term recovery of motor power.

• Journal of Korean Neurosurgical Society
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• v.58 no.3
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• pp.205-210
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• 2015

Objective : This study was aimed at optimizing the treatment of non-small-cell lung cancer (NSCLC) patients who are candidates for stereotactic radiosurgery (SRS) for brain metastases and harbor activating epithelial growth factor receptor (EGFR) mutations. Methods : We retrospectively reviewed the medical records from 2005 to 2010 of NSCLC patients with brain metastases harboring an activating EGFR mutation. Patients who received a combination therapy of SRS and EGFR-tyrosine kinase inhibitor (TKI) for brain metastases and those who received SRS without EGFR-TKI were compared. The primary endpoint was progression-free survival (PFS) of the brain metastases. Results : Thirty-one patients were eligible for enrolment in this study (SRS with TKI, 18; SRS without TKI, 13). Twenty-two patients (71.0%) were women and the median overall age was 56.0 years. PFS of brain lesions was not significantly prolonged in SRS with TKI treatment group than in SRS without TKI group (17.0 months vs. 9.0 months, p=0.45). Local tumor control rate was 83.3% in the combination therapy group, and 61.5% in the SRS monotherapy group (p=0.23). There were no severe adverse events related with treatment in both groups. Conclusions : Therapeutic outcome of concurrent SRS and TKI treatment was not superior to SRS monotherapy, however, there was no additive adverse events related with combined treatment.

• Journal of Korean Neurosurgical Society
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• v.57 no.2
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• pp.77-81
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• 2015

Objective : The purpose of this study was to investigate changes in the plasma level of vascular endothelial growth factor (VEGF) after Gamma Knife radiosurgery (GKRS) for the treatment of meningioma. Methods : Fourteen patients with meningiomas had peripheral venous blood collected at the time of GKRS and at 1 week, 1 month, 3 month and 6 month visits. Plasma VEGF levels were measured using commercially available enzyme-linked immunosorbent assay. For controls, peripheral blood samples were obtained from 20 healthy volunteers. Results : The mean plasma VEGF level (29.6 pg/mL) in patients with meningiomas before GKRS was significantly lower than that of the control group (62.4 pg/mL, p=0.019). At 1 week after GKRS, the mean plasma VEGF levels decreased to 23.4 pg/mL, and dropped to 13.9 pg/mL at 1 month, 14.8 pg/mL at 3 months, then increased to 27.7 pg/mL at 6 months. Two patients (14.3%) with peritumoral edema (PTE) showed a level of VEGF 6 months after GKRS higher than their preradiosurgical level. There was no significant association found in an analysis of correlation between PTE and tumor size, marginal dose, age, and sex. Conclusion : Our study is first in demonstrating changes of plasma VEGF after stereotactic radiosurgery (SRS) for meningioma. This study may provide a stimulus for more work related to whether measurement of plasma level has a correlation with tumor response after SRS for meningioma.

• Journal of Korean Neurosurgical Society
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• v.63 no.3
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• pp.380-385
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• 2020

Objective : A consensus regarding the ideal regimen for urokinase (UK) thrombolysis subsequent to stereotactic spontaneous intracerebral hemorrhage aspiration has yet to be established. The purpose of this study is to evaluate the efficacy of UK thrombolysis relative to when the regimen is changed. Methods : Venous blood from 30 heathy volunteers was obtained for this in-vitro study. Various concentrations of UK solution were added to microcentrifuge tubes containing the clotted blood. The efficacy of UK thrombolysis was identified by checking the weight of lysed hematoma following various time intervals with different concentrations of UK solution. Group one, the "3×4" group involved four administrations every 3 hours over 12 hours, and group two, the "6×2" group involved two administrations every 6 hours over 12 hours. Results : More hematoma was lysed in the 3×4 group than the 6×2 group across all concentration levels (however, the differences were only significant between groups at the 500 and 1000 IU concentration levels, p<0.05). There were no significant differences of lysed hematoma among the various UK solution concentrations within groups. Conclusion : This study suggests that frequent administrations of UK thrombolysis may result in a greater degree of lysed hematoma in comparison to a higher concentration of UK.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7401-7407
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• 2013

Aim: To compare survival outcomes after whole brain radiation therapy (WBRT), stereotactic radiosurgery (SRS), and WBRT plus SRS combination therapy in Korea, by performing a quantitative systematic review. Materials and Methods: We searched 10 electronic databases for reports on Korean patients treated with WBRT or SRS for brain metastases published prior to July 2010. Independent reviewers screened all articles and extracted the data. When a Kaplan-Meier survival curve was available, median survival time and standard errors were calculated. Summary estimates for the outcomes in each study were calculated using the inverse variance random-effects method. Results: Among a total of 2,761 studies, 20 studies with Korean patients (n=1,053) were identified. A combination of 12 studies (n=566) with WBRT outcomes showed a median survival time of 6.0 months (95%CI: 5.9-6.2), an overall survival rate of 5.6% (95%CI: 1-24), and a 6-month survival rate of 46.5% (95%CI: 37.2-56.1). For nine studies (n=412) on SRS, the median survival was 7.9 months (95%CI: 5.1-10.8), and the 6-month survival rate was 63.1% (95%CI: 49.8-74.8). In six studies (n=75) using WBRT plus SRS, the median survival was 10.7 months (95%CI: 4.7-16.6), and the overall and 6-month survival rates were 16.8% (95%CI: 6.2-38.2) and 85.7% (95%CI: 28.3-96.9), respectively. Conclusions: WBRT plus SRS showed better 1-year survival outcome than of WBRT alone for Korean patients with metastatic brain tumors. However, the results of this analysis have to be interpreted cautiously, because the risk factors of patients were not adjusted in the included studies.

• Journal of Korean Neurosurgical Society
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• v.42 no.4
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• pp.286-292
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• 2007

Objective : Gamma Knife Stereotactic Radiosurgery (GK SRS) has become an important treatment modality for vestibular schwannomas. We evaluated the tumor control rate, patterns of tumor volume change and preservation of hearing following low-dose radiation for vestibular schwannomas in a homogeneous cohort group in which the mean marginal dose was 12 Gy. Methods : A total of 59 patients were enrolled in this study. All enrolled patients were followed-up for at least 5 years and the radiation dose was 11-13 Gy. Regular MRI, audiometry and clinical evaluations were done and tumor volumes were obtained from MRI using the OSIRIS program. Results : The tumor control rate was 97%. We were able to classify the patterns of change in tumor volume into three categories. Transient increases in tumor volume were detected in 29% of the patients and the maximum transient increase in tumor volume was identified at 6 to 30 months after GK SRS. The transient increases in tumor volume ranged from 121% to 188%. Hearing was preserved in 4 of the 12 patients who had serviceable hearing prior to treatment. There were no other complications associated with GK SRS. Conclusion : Low-dose GK SRS was an effective and safe mode of treatment for vestibular schwannomas in comparison to the previously used high-dose GK SRS. Transient increases in tumor volume can be identified during the follow-up period after low-dose GK SRS for vestibular schwannomas. Physicians should be aware that these increases are not always indicative of treatment failure and that close observation is required following treatments. Unfortunately, a satisfactory hearing preservation rate was not achieved by reducing the radiation dose. It is thought that hearing preservation is a more sophisticated problem and further research is required.

• Journal of Korean Neurosurgical Society
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• v.40 no.3
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• pp.154-158
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• 2006

Objective : We treated 10 pediatric diffuse intrinsic brain stem glioma[BSG] patients with Novalis system [linac based radiotherapy unit, Germany] and examined the efficacy of the Fractionated Stereotactic Radiotherapy[FSRT]. Methods : A retrospective review was conducted on 10 pediatric diffuse intrinsic BSG patients who were treated with FSRT between May, 2001 and August, 2004. The mean age of the patient group was 7.7 years old. Male to female ratio was 4 to 1. The mean dose of FSRT was 38.7Gy, mean fractionated dose was 2.6Gy, mean fractionation size was 16.6, and target volume was $42.78cm^3$. The mean follow up period was 14 months. Results : Four weeks after completion of FSRT, improvements on neurological status and Karnofsky performance scale[KPS] score were recorded in 9/10 (90%] patients and magnetic resonance imaging[MRI] showed decrease in target tumor volume in 8 pediatric patients. The median survival period was 13.5 months after FSRT and treatment toxicity was mild. Conclusion : It is difficult for surgeons to choose surgical treatment for diffuse intrinsic BSG due to its dangerous anatomical structures. FSRT made it possible to control the tumor volume to improve neurological symptoms with minimal complications. We expect that FSRT is a feasible treatment modality for pediatric diffuse intrinsic BSG with tolerable toxicities.