• Journal of Korean Neurosurgical Society
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• 제51권1호
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• pp.1-7
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• 2012

Objective : The incidence and prevalence of spinal metastases are increasing, and although the role of radiation therapy in the treatment of metastatic tumors of the spine has been well established, the same cannot be said about the role of stereotactic radiosurgery. Herein, the authors present a systematic review regarding the value of spinal stereotactic radiosurgery in the management of spinal metastasis. Methods : A systematic literature search for stereotactic radiosurgery of spinal metastases was undertaken. Grades of Recommendation, Assessment, Development, and Education (GRADE) working group criteria was used to evaluate the qualities of study datasets. Results : Thirty-one studies met the study inclusion criteria. Twenty-three studies were of low quality, and 8 were of very low quality according to the GRADE criteria. Stereotactic radiosurgery was reported to be highly effective in reducing pain, regardless of prior treatment. The overall local control rate was approximately 90%. Additional asymptomatic lesions may be treated by stereotactic radiosurgery to avoid further irradiation of neural elements and further bone-marrow suppression. Stereotactic radiosurgery may be preferred in previously irradiated patients when considering the radiation tolerance of the spinal cord. Furthermore, residual tumors after surgery can be safely treated by stereotactic radiosurgery, which decreases the likelihood of repeat surgery and accompanying surgical morbidities. Encompassing one vertebral body above and below the involved vertebrae is unnecessary. Complications associated with stereotactic radiosurgery are generally self-limited and mild. Conclusion : In the management of spinal metastasis, stereotactic radiosurgery appears to provide high rates of tumor control, regardless of histologic diagnosis, and can be used in previously irradiated patients. However, the quality of literature available on the subject is not sufficient.

• Journal of Korean Neurosurgical Society
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• 제59권4호
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• pp.420-424
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• 2016

The spinal dural arteriovenous fistula (SDAVF) is rare, presenting with progressive, insidious symptoms, and inducing spinal cord ischemia and myelopathy, resulting in severe neurological deficits. If physicians have accurate and enough information about vascular anatomy and hemodynamics, they achieve the good results though the surgery or endovascular embolization. However, when selective spinal angiography is unsuccessful due to neurological deficits, surgery and endovascular embolization might be failed because of inadequate information. We describe a patient with a history of vasospasm during spinal angiography, who was successfully treated by spinal stereotactic radiosurgery using Novalis system.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.302-304
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• 2002

In linac-based stereotactic radiosurgery, assuring the quality of the planning and delivery of external photon beam requires accurate evaluation of beam parameters, usually including output factors, tissue-phantom ratio and off-axis ratios, and measurement of actual dose distributions from simulated treatment. We're going to test the use of calibrated radio chromic film (Gafchromic film; type MD-55, Nuclear associate) using a Lumiscan 75 digitizer to measure absolute dose and relative dose distributions for linac-based radiosurgery unit Relative dose distribution of a human-style spherical acryl phantom were measured using radiochromic film and calculated by treatment planning system. The absolute dose at the sphere center was measured by radiochromic film and micro chamber (Exradin A-14, 0.009cc). What we want to demonstrate in this work, the 'well selected' radiochromic films when external photon beam are used in linac-based stereotactic radiosurgery are very accurate detector for dosimetry.

• 한국의학물리학회지:의학물리
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• 제13권4호
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• pp.218-223
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• 2002

두개외 병소 즉, 척추 등에 발생한 종양 혹은 혈관기형 등의 병소에 대해 침습적 수술이 불가한 경우 정위적 방사선 수술이 임상에서 시도되고 있다. 본 연구는 실험적으로 팬텀에 대해 척추 정위 방사선수술을 시행하고 결과 분석을 통하여 두개외 수술 목표점에 대한 방사선수술 위치 정확도를 평가하고자 한다. 이 실험을 위하여 팬텀을 특별히 고안하였으며 수술실에서 방사선 수술 목표점의 위치는 광학적 추적 장치를 이용하여 결정하였고 3 mm 미세다엽시준기(mMLC; mcro Multi-Leaf Collimator)를 사용하여 시술하였다. 팬텀의 목표점에 대한 방사선수술 오차는 $\pm$1 mm 이내였으며 분할방사선 수술 경우도 $\pm$1 mm 이내였다. 결과적으로 광학적 위치추적 장치를 이용한 두개외 목표점의 방사선 수술은 매우 정확하고 유용한 방법으로 판단된다.

• 한국의학물리학회지:의학물리
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• 제31권3호
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• pp.63-70
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• 2020

Stereotactic radiosurgery is one of the most sophisticated forms of modern advanced radiation therapy. Unlike conventional fractionated radiotherapy, stereotactic radiosurgery uses a high dose of radiation with steep gradient precisely delivered to target lesions. Lars Leksell presented the principle of radiosurgery in 1951. Gamma Knife^® (GK) is the first radiosurgery device used in clinics, and the first patient was treated in the winter of 1967. The first GK unit had 179 cobalt 60 sources distributed on a hemispherical surface. A patient could move only in a single direction. Treatment planning was performed manually and took more than a day. The latest model, Gamma Knife^® Icon^TM, shares the same principle but has many new dazzling characteristics. In this article, first, a brief history of radiosurgery was described. Then, the physical properties of modern radiosurgery machines and physicists' endeavors to assure the quality of radiosurgery were described. Intrinsic characteristics of modern radiosurgery devices such as small fields, steep dose distribution producing sharp penumbra, and multi-directionality of the beam were reviewed together with the techniques to assess the accuracy of these devices. The reference conditions and principles of GK dosimetry given in the most recent international standard protocol, International Atomic Energy Agency TRS 483, were shortly reviewed, and several points needing careful revisions were highlighted. Understanding the principles and physics of radiosurgery will be helpful for modern medical physicists.

• Radiation Oncology Journal
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• 제7권1호
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• pp.101-112
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• 1989

The treatment planning and dosimetry of small fields for stereotactic radiosurgery with 10 MV x-ray isocentrically mounted linear accelerator is presented. Special consideration in this study was given to the variation of absorbed dose with field size, the central axis percent depth doses and the combined moving beam dose distribution. The collimator scatter correction factors of small fields $(1\times1\~3\times3cm^2)$ were measured with ion chamber at a target chamber distance of 300cm where the projected fields were larger than the polystyrene buildup caps and it was calibrated with the tissue equivalent solid state detectors of small size (TLD, PLD, ESR and semiconductors). The central axis percent depth doses for $1\timesl\;and\;3\times3cm^2$ fields could be derived with the same acuracy by interpolating between measured values for larger fields and calculated zero area data, and it was also calibrated with semiconductor detectors. The agreement between experimental and calculated data was found to be under $2\%$ within the fields. The three dimensional dose planning of stereotactic focusing irradiation on small size tumor regions was performed with dose planning computer system (Therac 2300) and was verified with film dosimetry. The more the number of strips and the wider the angle of arc rotation, the larger were the dose delivered on tumor and the less the dose to surrounding the normal tissues. The circular cone, we designed, improves the alignment, minimizes the penumbra of the beam and formats ball shape of treatment area without stellate patterns. These dosimetric techniques can provide adequate physics background for stereotactic radiosurgery with small radiation fields and 10MV x-ray beam.

• 한국의학물리학회지:의학물리
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• 제2권2호
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• pp.121-128
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• 1991

뇌정위적 방사선 수술 시 정확한 3차원적 선량분포에 대한 정보가 필요한다. 3차원적 치료계획은 최적선량분포를 얻기위한 것이며 환자 데이타, 선량분포, 방사선 조사 요소들에 대한 3차원적인 관계를 다루어야만 한다. 원형 조사면에 대한 single 조사면 선량 데이타와 3차원 선량 알고리듬을 이용하여 non-coplanar moving arcs 에 대한 3차원적 선량모델이 개발되었다. 뇌정위적 방사선 수술시 3차원 선량 알고리듬의 적용과 여러경우에 대한 응용에 대하여 논의되어진다.

• 대한방사선방어학회:학술대회논문집
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• 대한방사선방어학회 2011년도 추계 학술발표회 및 심포지엄
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• pp.206-207
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• 2011

• Journal of Korean Neurosurgical Society
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• 제46권4호
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• pp.360-364
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• 2009

Objective : Several treatment options have proven effective for metastatic brain tumors, including surgery and stereotactic radiosurgery. Tumors with cystic components, however, are difficult to treat using a single method. We retrospectively assessed the outcome and efficacy of gamma knife radiosurgery (GKRS) for cystic brain metastases after stereotactic aspiration of cystic components to decrease the tumor volume. Methods : The study population consisted of 24 patients (13 males, 11 females; mean age, 58.3 years) with cystic metastatic brain tumors treated from January 2002 to August 2008. Non-small cell lung cancer was the most common primary origin. After Leksell stereotactic frame was positioned on each patient, magnetic resonance images (MRI)-guided stereotactic cyst aspiration and GKRS were performed (mean prescription dose : 20.2 Gy). After treatment, patients were evaluated by MRI every 3 or 4 months. Results : After treatment, 13 patients (54.2%) demonstrated tumor control, 5 patients (20.8%) showed local tumor progression, and 6 patients (25.0%) showed remote progression. Mean follow-up duration was 13.1 months. During this period, 10 patients (41.7%) died, but only 1 patient (4.2%) died from brain metastases. The overall median survival after these procedures was 17.8 months. Conclusion : These results support the usefulness of GKRS after stereotactic cyst aspiration in patients with large cystic brain metastases. This method is especially effective for the patients whose general condition is very poor for general anesthesia and those with metastatic brain tumors located in eloquent areas.

• Radiation Oncology Journal
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• 제20권2호
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• pp.179-185
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• 2002

목적 : 본 교실에서 개발한 정위방사선수술 시스템의 정도관리를 위하여 다용도 팬톰을 제작하고 정위방사선수술 기법의 선량의 정확도를 확인하려 하였다. 대상 및 방법 : CL2100C 선형가속기에서 발생하는 6 MV 엑스선을 사용하여 정위적 방사선수술을 시행하였고 Farmer형 이온함, 0.125 cc 이온함, 다이오드 검출기 등을 정위 기준기구가 부착된 팬톰내에 설치한 후 선량을 측정하였다. 고정 빔, $20^{\circ}\~100^{\circ}$의 각도를 갖는 단일회전빔, 복합회전빔 등의 방사선조사 조건에서 측정기와 팬톰의 상대적 위치를 변화시키면서 측정하였다. 내경이 10, 20, 30, 40 mm인 원형의 3차 콜리메이터를 사용하였다. 결과 : 고정 빔, 단일 회전빔, 5개의 회전 빔으로 구성된 복합회전빔 등에서의 선량오차는 Farmer형 이온함으로 측정한 경우는 $0.5\%$ 이하, 0.125 cc 이온함의 경우에는 $0.5\%$, 다이오드 검출기인 경우에는 $2\%$ 이내였다. 결론 : 본 교실 개발 정위방사선수술 기법에 의한 방사선 조사선량의 정확도를 확인하였으며 이 자료는 향후 정위방사선수술 및 다분할 방사선치료의 정도관리에 유용한 기초자료로 활용될 것이다.