• 한국의학물리학회지:의학물리
• /
• 제35권1호
• /
• pp.1-9
• /
• 2024

Margin inclusion or exclusion remains the most critical and controversial aspect of stereotactic radiosurgery (SRS) for metastatic brain tumors. This review aimed to examine the available literature on the impact of margins in SRS of brain metastasis and to assess the response of some medical physicists on the use of these margins. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses method was used to review articles published in PubMed, Embase, and Science Direct databases from January 2012 to December 2022 using the following keywords: planning target volume, brain metastasis, margin, and stereotactic radiosurgery. A simple survey consisting of five questions was completed by ten medical physicists with experience in SRS treatment planning. The results were analyzed using IBM SPSS Statistics version 26.0. Of the 1,445 articles identified, only 38 articles were chosen. Of these, eight papers were deemed relevant to the focus of this review. These papers showed an increase in the risk of radionecrosis, whereas differences in local control were variable as the margin increased. In the survey, the response rate to whether or not to use margins in SRS, a critical question, was 50%. Margin addition increases the risk of radio necrosis. The local control rate varies among treatment modalities and cannot be generalized. From the survey, no consensus was reached regarding the use of these margins. This calls for further deliberations among professionals directly involved in SRS.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권17호
• /
• pp.7595-7597
• /
• 2015

Background: The aim of this study was to evaluate the effect of whole brain radiotherapy (WBRT) combined with streotactic radiosurgery versus stereotactic radiosurgery (SRS) alone for patients with brain metastases. Materials and Methods: This was a retrospective study that evaluated the results of 46 patients treated for brain metastases at Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital, Radiation Oncology Department, between January 2012 and January 2015. Twenty-four patients were treated with WBRT+SRS while 22 patients were treated with only SRS. Results: Time to local recurrence was 9.7 months in the WBRT+SRS arm and 8.3 months in SRS arm, the difference not being statistically significant (p=0.7). Local recurrence rate was higher in the SRS alone arm but again without significance (p=0,06). Conclusions: In selected patient group with limited number (one to four) of brain metastases SRS alone can be considered as a treatment option and WBRT may be omitted in the initial treatment.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권13호
• /
• pp.5279-5284
• /
• 2015

Background: The study analyzed the long term clinical outcomes of pituitary adenoma cases treated with the first Thailand installation of a dedicated Linac-based stereotactic radiation machine (X-Knife). Materials and Methods: A retrospective review of 115 consecutive pituitary adenoma patients treated with X-Knife at the Faculty of Medicine, Ramathibodi Hospital, Bangkok, Thailand from 1997 to 2003 was performed. Stereotactic radiosurgery (SRS) was selected for 21 patients (18%) including those with small tumors (${\leq}3cm$) located ${\geq}5mm$. from the optic apparatus, whereas the remaining 94 patients (82%) were treated with fractionated stereotactic radiotherapy (FSRT). Results: With a median follow-up time of 62 months (range, 21-179), the six-year progression free survival was 95% (93% for SRS and 95% for FSRT). The overall hormone normalization at 3 and 5 years was 20% and 30%, respectively, with average time required for normalization of approximately 16 months for SRS and 20 months for FSRT. The incidence of new hypopituitarism was 10% in the SRS group and 9% in the FSRT group. Four patients (5%) developed optic neuropathy (1 in the SRS group and 3 in the FSRT group). Conclusions: Linac-based SRS and FSRT achieved similar high local control rates with few complications in pituitary adenoma cases. However, further well designed, randomized comparative studies between SRS versus FSRT particularly focusing on hormone normalization rates are required.

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

• 한국의학물리학회지:의학물리
• /
• 제12권2호
• /
• pp.171-175
• /
• 2001

본 연구에서는 고정틀 정위방사선치료장비에 사용되는 치료계획시스템과 무고정틀 정위방사선치료시스템에 사용되는 치료계획시스템을 이용하여 intracranial 표적을 대상으로 치료계획을 수립하였다. 치료계획을 평가하기 위하여 RTOG-9005 규정서에서 정위방사선치료계획의 정도관리를 위하여 사용한 Planning Target Volume Coverage를 확인하고 Conformity Index(CI)와 Homogeneity Index(HI)를 구하였다. 이들 값으로부터 두 치료계획시스템에서 계산한 치료계획이 동일함을 알 수 있었다.

• Journal of Korean Neurosurgical Society
• /
• 제59권5호
• /
• pp.442-448
• /
• 2016

Objective : Increased expression of angiogenic factors, such as vascular endothelial growth factor (VEGF), is associated with the pathogenesis of cerebral cavernous malformations (CCMs). The purpose of this study was to investigate plasma levels of VEGF in normal subjects and in patients with CCM and to evaluate change in these levels following stereotactic radiosurgery (SRS). Methods : Peripheral venous blood was collected from 6 patients with CCM before SRS using Gamma Knife and at the 1 week, 1 month, 3month, and 6 month follow-up visits. Plasma VEGF levels were measured using commercially available enzyme-linked immunosorbent assay kits. Peripheral blood samples were obtained from 10 healthy volunteers as controls. Results : Mean plasma VEGF level of 41.9 pg/mL (range, 11.7-114.9 pg/mL) in patients with CCM at baseline was higher than that of the healthy controls (29.3 pg/mL, range, 9.2-64.3 pg/mL), without significant differences between CCM patients and controls (p=0.828). Plasma VEGF level following SRS dropped to 24.6 pg/mL after 1 week, and decreased to 18.5 pg/mL after 1 month, then increased to 24.3 pg/mL after 3 months, and 32.6 pg/mL after 6 months. Two patients suffering from rebleeding after SRS showed a higher level of VEGF at 6 months after SRS than their pretreatment level. Conclusion : Plasma VEGF levels in patients with CCM were elevated over controls at baseline, and decreased from baseline to 1 month after SRS and increased further for up to 6 months. Theses results indicated that anti-angiogenic effect of SRS might play a role in the treatment of CCMs.

• Journal of Korean Neurosurgical Society
• /
• 제61권5호
• /
• pp.633-639
• /
• 2018

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.

• 한국의학물리학회지:의학물리
• /
• 제9권1호
• /
• pp.1-9
• /
• 1998

정위적 방사선 수술과 신경외과적 수술분야 에서는 상호보완적인 영상정보를 얻기 위하여 컴퓨터 단층촬영 (CT), 자기공명영상 (MRI) 그리고 혈관조영촬영이 사용된다. 본 연구의 목적은 여러 영상장치와 다목적 QA(Quality Control) 팬톰을 이용하면서, 정위적 방사선수술 및 신경외과적 수술분 야에서 두경부내의 병소에 대한 모양, 크기, 위치를 정확하게 결정하기 위한 3 차원 정위 시스템을 개발하는 것이다. 목표물의 정확한 위치를 정의하기 위하여, Hitchcoke 정위 프레임과 컴퓨터 단층 촬영 (CT)/혈관 조영촬영용 위치측정 보조기구들을 3차원 공간상에 9개의 목표물을 가진 팬톰에 고정하였다. 컴퓨터 단층촬영과 혈관 조영촬영을 이용하여 얻은 기하학적 팬톰의 영상들을 이용하여, 목표물의 3차원 정위좌표를 얻기위한 알고리즘이 개발되었다. 개발된 알고리즘에 의해 계산된 목표물들의 위치는 팬톰의 절대 좌표와 비교 되었고, 각 CT 영상에서의 목표물들은 뇌혈관촬영 영상위에 상호 중첩될 수 있도록 개발 되었다. 512$\times$512 메트릭스와 2mm 슬라이스 두께를 가진 컴퓨터 단층촬영에 있어서는 1.02$\pm$0.17 mm의 평균거리오차를 보였고, 혈관 조영촬영인 경우에는 0.41$\pm$0.05mm 의 평균거리오차를 보였다. 목표물의 위치를 결정하는데 있어서 결과로 나온 정확도는 개발된 시스템이 정위적 방사선수술과 신경외과적수술을 위해 충분히 신뢰성이 있음을 확인해주었다.

• 한국의학물리학회:학술대회논문집
• /
• 한국의학물리학회 2005년도 제30회 춘계학술대회
• /
• pp.47-50
• /
• 2005

The aim of radiosurgery cures a patient to deliver the lower dose at the normal organ and the higher dose at the tumor. Therefore accuracy of the dose is required to gain effect of radiosurgery in surgical planning. In this paper, we developed the methods of target approximation for a fast treatment planning. Nominally, the stereotactic radiosurgery(SRS) using Linac and Gamma knife produces spherical dose distribution through circular collimators using multiple arcs and 201 holes on semi-spherical helmet by $^{60}Co$. We developed an automatic radiosurgical plan about spherical packing arrangement. To automatically plan the SRS, new planning methods based on cylinder and cube structure for target shaping was developed. This approach using heuristic and stochastic algorithm is a useful radiosurgical plan without restrictions in the various tumor shapes and the different modalities.

• Journal of Korean Neurosurgical Society
• /
• 제58권4호
• /
• pp.379-384
• /
• 2015

Objective : To investigate the risks and pattern of evolution of peritumoral brain edema (PTE) after stereotactic radiosurgery (SRS) for asymptomatic intracranial meningiomas. Methods : A retrospective study was conducted on 320 patients (median age 56 years, range 24-87 years) who underwent primary Gamma Knife radiosurgery for asymptomatic meningiomas between 1998 and 2012. The median tumor volume was 2.7 cc (range 0.2-10.5 cc) and the median follow-up was 48 months (range 24-168 months). Volumetric data sets for tumors and PTE on serial MRIs were analyzed. The edema index (EI) was defined as the ratio of the volume of PTE including tumor to the tumor volume, and the relative edema indices (rEIs) were calculated from serial EIs normalized against the baseline EI. Risk factors for PTE were analyzed using logistic regression. Results : Newly developed or increased PTE was noted in 49 patients (15.3%), among whom it was symptomatic in 28 patients (8.8%). Tumor volume larger than 4.2 cc (p<0.001), hemispheric tumor location (p=0.005), and pre-treatment PTE (p<0.001) were associated with an increased risk of PTE. rEI reached its maximum value at 11 months after SRS and decreased thereafter, and symptoms resolved within 24 months in most patients (85.7%). Conclusion : Caution should be exercised in decision-making on SRS for asymptomatic meningiomas of large volume (>4.2 cc), of hemispheric location, or with pre-treatment PTE. PTE usually develops within months, reaches its maximum degree until a year, and resolves within 2 years after SRS.