• Journal of Korean Neurosurgical Society
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• 제45권5호
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• pp.275-283
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• 2009

Objective : We retrospectively analyzed survival, local control rate, and incidence of radiation toxicities after radiosurgery for recurrent metastatic brain lesions whose initial metastases were treated with whole-brain radiotherapy. Various radiotherapeutical indices were examined to suggest predictors of radiation-related neurological dysfunction. Methods : In 46 patients, total 100 of recurrent metastases (mean 2.2, ranged 1-10) were treated by CyberKnife radiosurgery at average dose of 23.1 Gy in 1 to 3 fractions. The median prior radiation dose was 32.7 Gy, the median time since radiation was 5.0 months, and the mean tumor volume was $12.4cm^3$. Side effects were expressed in terms of radiation therapy oncology group (RTOG) neurotoxicity criteria. Results : Mass reduction was observed in 30 patients (65%) on MRI. After the salvage treatment, one-year progression-free survival rate was 57% and median survival was 10 months. Age(<60 years) and tumor volume affected survival rate(p=0.03, each). Acute (${\leq}$1 month) toxicity was observed in 22% of patients, subacute and chronic (>6 months) toxicity occurred in 21 %, respectively. Less acute toxicity was observed with small tumors (<$10cm^3$. p=0.03), and less chronic toxicity occurred at lower cumulative doses (<100 Gy, p=0.004). "Radiation toxicity factor" (cumulative dose times tumor volume of <1,000 Gy${\times}cm^3$) was a significant predictor of both acute and chronic CNS toxicities. Conclusion: Salvage CyberKnife radiosurgery is effective for recurrent brain metastases in previously irradiated patients, but careful evaluation is advised in patients with large tumors and high cumulative radiation doses to avoid toxicity.

• 디지털융복합연구
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• 제13권1호
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• pp.331-339
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• 2015

사이버나이프치료에서 삽입된 금표지자의 삽입 개수 및 인식의 제한으로 인하여 3D DOF로 치료하는 경우 척추구조물 정렬을 가능하게 하는 Xsight spine tracking system으로 회전방향의 위치오차를 보정함으로서 표적위치오차를 개선하고, 치료방법의 대안을 제시하고자 한다. 실험결과 6D DOF에서 표적위치오차는 $0.214{\pm}0.058mm$, 종양내부에 삽입된 2개 금표지자를 이용한 3D DOF에서 $0.673{\pm}0.142mm$, 종양외부에 삽입된 2개 금표지자를 이용한 3D DOF에서 $1.126{\pm}0.253mm$, Xsight spine tracking system의 적용 한 3D DOF에서 $0.542{\pm}0.103mm$로 나타났다. 실험결과 척추 구조물로 회전방향에 대한 보정을 시행하였을 때 표적위치에 대한 정확성이 약 48% 향상되었다. 또한, 선량분포의 일치성도 약 3%가 향상되어 일치하는 것을 확인할 수 있었다. 따라서 척추구조물 정렬을 병용한 Xsight spine tracking system의 회전방향에 대한 보정은 유용한 것으로 평가 되었다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권7호
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• pp.3271-3276
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• 2016

Background: Intracranial nonvestibular schwannomas arising from various cranial nerves excluding CN VIII are uncommon. Recently, stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (SRT) have been widely reported as effective treatment modalities for nonvestibular schwannomas. The purpose of this study was to study the long term clinical outcome for nonvestibular schwannomas treated with both X-Knife and CyberKnife (CK) radiosurgery at one institution. Materials and Methods: From 2004 to 2013, fifty-two nonvestibular schwannoma patients were included in this study, 33 patients (63%) were treated with CK, and 19 (37%) were treated with X-Knife. The majority of the tumors were jugular foramen schwannomas (38%) and trigeminal schwannomas (27%). HSRT was given for 45 patients (86%), whereas CSRT was for 6 (12%) and SRS for 1 (2%). Results: The median pretreatment volume was $9.4cm^3$ (range, $0.57-52cm^3$). With the median follow up time of 36 months (range, 3-135), the 3 and 5 year progression free survival was 94 % and 88%, respectively. Tumor size was decreased in 13 (25%), stable in 29 (56%), and increased in 10 (19%). Among the latter, 3 (30%) required additional treatment because of neurologic deterioration. No patient was found to develop any new cranial nerve deficit after SRS/SRT. Conclusions: These data confirmed that SRS/SRT provide high tumor control rates with low complications. Large volume tumors and cystic expansion after radiation should be carefully followed up with neurological examination and MRI, because it may frequently cause neurological deterioration requiring further surgery.

• 대한방사선치료학회지
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• 제33권
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• pp.99-108
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• 2021

목 적: 사이버나이프를 이용한 정위적 부분유방방사선치료(Stereotactic Partial Breast Irradiation) 시 기존의 침습적인 위치표지자(Fiducial Marker) 삽입 방식이 아닌 비침습방식에 대한 유용성을 평가 하고자 한다. 대상 및 방법: 본 연구를 위한 영상 중심(Imaging Center)의 일치도는 2D모의치료기와 사이버나이프의 양사방향(Both oblique, 45 °, 315 °) 영상 획득 후 다이스 유사 계수를 통해 정량적으로 평가하였다. 표면위치표지자의 위치 재현성은 본원 프로토콜을 기반으로 ATOM Phantom 표면에 금 재질의 위치표지자 8개를 부착하고 2D모의치료와 치료계획, 사이버나이프 영상을 분석하여 평가 하였다. 결 과: 영상 중심의 일치도 평가결과는 양사방향(45 °, 315 °)에서 각각 0.87, 0.9 였다. 표면위치표지자의 재현성 평가 결과 좌측 유방은 수평수직방향 Superior/Inferior 0.3 mm, Left/Right -0.3 mm, Anterior/Posterior 0.4 mm, 회전 방향 Roll 0.3 °, Pitch 0.2 °, Yaw 0.4 ° 로 나타났다. 우측 유방은 수평수직방향 Superior/Inferior -0.1 mm, Left/Right -0.1 mm, Anterior/Posterior -0.1 mm 회전 방향 Roll 0.2 °, Pitch 0.1 °, Yaw 0.1 ° 로 나타났다. 결 론: 사이버나이프를 이용한 정위적 부분유방암방사선치료 시 표면위치표지자의 비침습 트로토콜을 기반으로 통증 및 감염 등의 예방과 전처치 시간을 줄이고 환자의 경제적 부담을 경감 할 수 있었으며, 영상 중심의 높은 일치도 및 위치표지자의 재현성을 바탕으로 치료에 유용할 것으로 사료된다.

• Radiation Oncology Journal
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• 제33권3호
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• pp.261-264
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• 2015

External beam radiotherapy can be used to treat cutaneous squamous cell carcinomas (SCC). Acute skin toxicity is the most common adverse event. In this case study we report on an elderly patient with nasal root cutaneous SCC treated with stereotactic technique using a dedicated linear accelerator (CyberKnife system). Grade 3 skin toxicity was observed but it was resolved after 6 weeks. The use of stereotactic radiotherapy permitted a clinical remission of SCC with good cosmetic results.

• Radiation Oncology Journal
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• 제31권4호
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• pp.260-266
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• 2013

A clear consensus has not been established regarding the best treatment for solitary bone metastasis. Here, we reviewed the medical records of patients with a controlled primary malignancy who had only solitary spine metastasis without metastasis to the extraspinal bone or viscera and underwent treatment between April 2007 and December 2012 with stereotactic body radiosurgery using CyberKnife, with a total dose of 24 Gy in three to four fractions. During that time, there were only four cases. This was effective in each case, and all the four patients had no local failure and remained alive at a median follow-up of 68 months (range, 64 to 80 months). Although our experience is limited, this study suggests that stereotactic body radiotherapy could be a feasible, safe, effective, and noninvasive alternative treatment for solitary spine metastasis in patients who are medically inoperable or unsuitable for surgery.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2015년도 추계학술발표대회
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• pp.1763-1764
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• 2015

사이버나이프 시스템은 독특한 형태의 정위적 방사선 치료를 수행하는 로봇 팔을 이용하는 방사선 수술 시스템으로 치료 중 환자의 호흡 등에 따른 신체의 움직임에도 1mm 이내의 오차 범위에서 정확하게 방사선을 조사해야하며, 여러 병소를 동시에 치료할 수 있다. 사이버나이프 시스템은 로봇 팔, 선형 가속기, 병소 위치 추적 장치, 방사선 조사 스케줄러와 같은 다양한 모듈들이 통합된 시스템으로, 이를 통합 제어하기 위한 주제어 시스템이 필요하다. 본 논문에서는 본 연구원에서 개발하고자 하는 사이버나이프 주제어 시스템의 설계에 관하여 기술한다.

• Radiation Oncology Journal
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• 제25권4호
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• pp.268-277
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• 2007

목적: 호흡에 의한 종양의 움직임은 사이버나이프를 이용한 정위적 방사선수술과 같은 정확한 치료에 있어 고려할 만한 방해 요인이다 이 연구에서는 사이버나이프를 이용한 방사선 수술의 Interplay현상을 보고자 팬텀을 움직이게 하고 또한 움직이지 않게 하여 선량 분포의 왜곡을 조사하였다. 대상 및 방법: 팬텀은 $2.5{\times}2.5{\times}5.0$ 인치의 4개의 직육면체로 구성된 폴리에틸렌과 2장의 Gafchromic 필름으로 구성되었다. 치료 계획은 20, 30, 40, 50 mm지름을 가진 구를 가상하여 사이버나이프 치료기를 이용하여 104개의 빔 방향과 single center mode의 치료 계획 하에 총 30 Gy를 조사하였다. 특별히 제작된 로봇은 팬텀을 좌우, 전후, 두미쪽으로 각각 5, 10, 20 mm 움직이도록 고안되었다. 필름의 optical density을 이용하여 정적인 상태의 팬텀과 로봇에 의해 움직일 때의 팬텀의 선량 분포를 구하였다. 결 과: 정적인 상태에서 종양을 모두 포함할 수 있는 최소의 등선량은 20 mm 종양의 경우 80%, 30 mm에 84%, 40 mm에 83%이며 50 mm 종양에 80%였다. 정적인 상태와 움직일 때의 팬텀 사이에서 발생한 선량 분포의 차이(gap)는 20 mm 종양에서 두미방향으로 각각 3.2, 3.3 cm이며 오른쪽 3.5 mm, 왼쪽 1.1 mm였다. 30 mm 종양의 경우는 각각 3.9, 4.2, 2.8과 0 mm였고 40 mm 종양은 각각 4.0, 4.8, 1.1, 0 mm였다. 50 mm 종양의 경우 각각 3.9, 3.9, 0.0 mm였다. 결 론: 20 mm의 적은 종양을 치료할 때 80%의 등선량이 계획되더라도 움직이는 실제 치료에 있어 종양 움직임을 보완하기 위하여 60% 등선량으로 처방할 필요가 있다. 이때 두 등선량 곡선의 차이는 5 mm정도이다. 또한 30, 40과 50 mm의 종양에서는 움직임을 보완하기 위하여 등선량 곡선을 70%정도로 처방할 필요가 있다. 이때의 차이도 약 5 mm 미만이다. 이는 사이버나이프를 이용한 방사선수술 시 움직임 그 차체 보다 여유폭을 적게 줄 수 있다는 의미이며 이는 일반 방사선치료와 다른 점이라 할 수 있다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권8호
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• pp.3561-3566
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• 2014

Background: Recurrent nasopharyngeal carcinoma (NPC) after previous radiotherapy is challenging. There is no standard approach for salvage treatment. Here we present toxicity and treatment results for recurrent NFC patients who underwent fractionated stereotactic radiotherapy (FSRT) as second line radiotherapy (RT). Materials and Methods: Between April 2009 and July 2012, 24 patients, with a male to female ratio of 3:1, were treated with CykerKnife$^{(R)}$ FSRT for recurrent NFC in our institution. Seven out of 24 patients had metastatic recurrent disease. Median age was 53 years (range, 20-70 years). Initial RT dose was 70Gy. The time period between initial RT and FSRT was a median of 33.2 months. The median prescription dose for FSRT was 30Gy (range, 24-30 Gy) in a median of 5 fractions (range, 4-6). Results: The median follow-up for all patients was 19.5 months (IQR: 12.2.-29.2 months). The locoregional control; progression free survival and overall survival (OS) rates for 1-, 2- and 3-year were 64%, 38%, 21%; 60%, 30%, 17% and 83%, 43%, 31%, respectively. Median OS for the entire cohort was 22 months (95% CI: 16.5-27.5). On multivariate analysis recurrent tumor stage was the only prognostic factor for OS (p=0.004). One patient exhibited grade III temporal lobe necrosis. One died because of grade IV mucositis and overlapping infection. Conclusions: The treatment of recurrent NPC is controversial. Fractionated stereotactic radiotherapy is promising. However, the published trials are heterogeneous with respect to the selection criteria and treatment details. Prospective studies with long term follow-up data are warranted.

• Radiation Oncology Journal
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• 제33권2호
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• pp.89-97
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• 2015

Purpose: To evaluate the treatment results in early stage non-small cell lung cancer patients who have undergone fiducial-less CyberKnife radiosurgery (CKRS). Materials and Methods: From June 2011 to November 2013, 58 patients underwent CKRS at Asan Medical Center for stage I lung cancer. After excluding 14 patients, we retrospectively reviewed the records of the remaining 44 patients. All analyses were performed using SPSS ver. 21. Results: The median age at diagnosis was 75 years. Most patients had inoperable primary lung cancer with a poor pulmonary function test with comorbidity or old age. The clinical stage was IA in 30 patients (68.2%), IB in 14 (31.8%). The mean tumor size was 2.6 cm (range, 1.2 to 4.8 cm), and the tumor was smaller than 2 cm in 12 patients (27.3%). The radiation dose given was 48-60 Gy in 3-4 fractions. In a median follow-up of 23.1 months, local recurrence occurred in three patients (2-year local recurrence-free survival rate, 90.4%) and distant metastasis occurred in 13 patients. All patients tolerated the radiosurgery well, only two patients developing grade 3 dyspnea. The most common complications were radiation-induced fibrosis and pneumonitis. Eight patients died due to cancer progression. Conclusion: The results showed that fiducial-less CKRS shows comparable local tumor control and survival rates to those of LINAC-based SABR or CKRS with a fiducial marker. Thus, fiducial-less CKRS using Xsight lung tracking system can be effectively and safely performed for patients with medically inoperable stage I non-small cell lung cancer without any risk of procedure-related complication.