Discrepancy of Intensity Modulation Radiation Therapy Dose Delivery due to the Dose-Dynamic Multi-Leaf Collimator Gravity Effect

이정우,정진범,이두현,박정훈,Bo-Young Choe,서태석,장홍석,Semie Hong,박병문,강민영,최경식,김유현 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.6

The aim of the present study was to investigate the multi-leaf collimator (MLC) gravity effect on intensity modulated radiation therapy (IMRT) dose-dynamic delivery at different gantry angles. The non-uniform fluence for IMRT was generated by means of dose-dynamic MLC (DMLC) performances, which were multiple static segments (MSS) or fully dynamic sliding window (SW) delivery methods at different gantry angles. SW delivery is quite similar to MSS with regard to MLC sliding pattern through the X1 to X2 jaw direction, except that it is irradiated during DMLC movement. To determine how the DMLC gravity aects the IMRT dose fluence, we mounted a two-dimensional ion chamber matrix (MatriXX, Scanditronix-Wellhofer, Schwarzenbruck, Germany) to a linear accelerator (CL 21EX, Varian, Palo Alto, CA, USA). Individual IMRT dose-dynamic segments were applied by using MSS and SW for 6-MV photon beams at five dierent gantry angles: 0℃ (neutral gravity), 45℃ (semi-along gravity), 90℃ (vertical-along gravity), 315℃ (semi-against gravity) and 270℃ (against gravity). To test the correlation of leaf speed and gravity, we delivered half monitor units (MUs) for planned doses for absolute dose comparison. Strict γ-index (dose difference: 2 %; distance to agreement: 2 mm) histograms were used for quantitative analyses of the discrepancy. The dose distribution by MSS under neutral gravity (gantry 0℃) with 137 MUs at a prescribed dose (45 cGy) point, which was in the low gradient area, was used as a reference for the other results. The γ-index histograms showed an increased tendency of the dose discrepancy toward the gravity-along direction rather than toward the gravity-against direction. The acceptable proportional ranges below 1 of the γ-index were 96.2 - 99.6 % (mean: 97.6 %), 92.6 - 93.5 % (mean: 93.0 %), 90.4 - 92.6 % (mean: 91.3 %), 94.6 - 98.0 % (mean: 96.4 %) and 92.9 - 96.8 % (mean: 95.0%) for neutral, semi-along, vertical-along, semi-against and vertical-against gravity of the positions of MLC segments, respectively. we noted that MSS deliveries were more stable than were the SW deliveries (unacceptable γ-index range 1.0 - 2.0: mean 3.6 % for MSS and 5.4 % for SW). For the dose measurement on the prescribed dose point, all measurements showed a good agreement within an average of 2 %. Our experiment conclusively demonstrated that the DMLC gravity affects the IMRT dose distribution. The effect may impact more severely in the gravity along direction and SW while the leaf speed is not in fluenced so much. The aim of the present study was to investigate the multi-leaf collimator (MLC) gravity effect on intensity modulated radiation therapy (IMRT) dose-dynamic delivery at different gantry angles. The non-uniform fluence for IMRT was generated by means of dose-dynamic MLC (DMLC) performances, which were multiple static segments (MSS) or fully dynamic sliding window (SW) delivery methods at different gantry angles. SW delivery is quite similar to MSS with regard to MLC sliding pattern through the X1 to X2 jaw direction, except that it is irradiated during DMLC movement. To determine how the DMLC gravity aects the IMRT dose fluence, we mounted a two-dimensional ion chamber matrix (MatriXX, Scanditronix-Wellhofer, Schwarzenbruck, Germany) to a linear accelerator (CL 21EX, Varian, Palo Alto, CA, USA). Individual IMRT dose-dynamic segments were applied by using MSS and SW for 6-MV photon beams at five dierent gantry angles: 0℃ (neutral gravity), 45℃ (semi-along gravity), 90℃ (vertical-along gravity), 315℃ (semi-against gravity) and 270℃ (against gravity). To test the correlation of leaf speed and gravity, we delivered half monitor units (MUs) for planned doses for absolute dose comparison. Strict γ-index (dose difference: 2 %; distance to agreement: 2 mm) histograms were used for quantitative analyses of the discrepancy. The dose distribution by MSS under neutral gravity (gantry 0℃) with 137 MUs at a prescribed dose (45 cGy) point, which was in the low gradient area, was used as a reference for the other results. The γ-index histograms showed an increased tendency of the dose discrepancy toward the gravity-along direction rather than toward the gravity-against direction. The acceptable proportional ranges below 1 of the γ-index were 96.2 - 99.6 % (mean: 97.6 %), 92.6 - 93.5 % (mean: 93.0 %), 90.4 - 92.6 % (mean: 91.3 %), 94.6 - 98.0 % (mean: 96.4 %) and 92.9 - 96.8 % (mean: 95.0%) for neutral, semi-along, vertical-along, semi-against and vertical-against gravity of the positions of MLC segments, respectively. we noted that MSS deliveries were more stable than were the SW deliveries (unacceptable γ-index range 1.0 - 2.0: mean 3.6 % for MSS and 5.4 % for SW). For the dose measurement on the prescribed dose point, all measurements showed a good agreement within an average of 2 %. Our experiment conclusively demonstrated that the DMLC gravity affects the IMRT dose distribution. The effect may impact more severely in the gravity along direction and SW while the leaf speed is not in fluenced so much.

Multiple Spinal Cord Recurrences of an Intracranial Ependymoma after 14 Years

Hong, Semie,Choe, Woo Jin,Moon, Chang Taek The Korean Neurosurgical Society 2013 Journal of Korean neurosurgical society Vol.54 No.6

Ependymoma can spread via cerebrospinal fluid, but late spinal recurrences of intracranial tumor are very rare. We describe a case of a 33-year-old male who presented with multiple, delayed, recurrent lesions in the spinal cord from an intracranial ependymoma. The patient underwent gross total resection and postoperative radiation therapy 14 years prior to visit for a low grade ependymoma in the 4th ventricle. The large thoraco-lumbar intradural-extramedullary spinal cord tumor was surgically removed and the pathologic diagnosis was an anaplastic ependymoma. An adjuvant whole-spine radiation therapy for residual spine lesions was performed. After completion of radiation therapy, a MRI showed a near complete response and the disease was stable for three years.

Outcome and Prognostic Factors of Childhood Diffuse Brainstem Glioma

Semie Hong,Il Han Kim,Kyu Chang Wang 대한암학회 2005 Cancer Research and Treatment Vol.37 No.2

Purpose: The outcome and prognostic factors of brainstem glioma were evaluated following radiotherapy methods.Materials and Methods: Between 1986 and 2001, 45 childhood patients with diffuse brainstem glioma were treated. There were 26 boys and 19 girls, with a median age of 7 years (range 3∼18). The histopathological diagnoses were confirmed in 13 patients, which revealed a low-grade glioma in four patients, and high-grade glioma in the other nine. Before 1993, radiation therapy using a regime of 1.8 to 2.0 Gy once a day was performed in 16 cases; thereafter, a regimes of 1.1 or 1.5 Gy twice a day was given in 15 and 14 cases, respectively. Nine patients were treated with adjuvant chemotherapy. The response to the treatment was evaluated by the MRI findings 4 weeks after radiotherapy.Results: After radiotherapy, the neurological deficit improved in 42 of the 45 patients (93%). The MRI responses were as follows; partial response 22/39 (56%), minimal to no response in 16/39 (41%) and tumor progression in 1/39 (3%). The median time to disease progression was 7 months, and the median survival was 12 months; the overall survival rate at 1 year was 41%. There was no significant prognostic factor for overall survival. The progression-free survival was influenced by the tumor histology (low grade vs. high grade, p=0.05) in those patients whose pathology was confirmed.Conclusion: The radiation therapy fractionation schedule did not influence the survival. Low grade histology was a possible favorable prognostic factor of progression-free survival in pediatric brainstem glioma patients.

Detection of <i>Cryptosporidium parvum</i> in Environmental Soil and Vegetables

Hong, Semie,Kim, Kyungjin,Yoon, Sejoung,Park, Woo-Yoon,Sim, Seobo,Yu, Jae-Ran The Korean Academy of Medical Sciences 2014 JOURNAL OF KOREAN MEDICAL SCIENCE Vol.29 No.10

초기 성문암 환자에서의 소분할 조사법을 이용한 방사선치료

우홍균(Hong Gyun Wu),홍세미(Semie Hong),신성수(Seong Soo Shin),박찬일(Charn Il Park) 대한방사선종양학회 2001 Radiation Oncology Journal Vol.19 No.4

목적: 초기 성문암의 방사선치료에 있어 소분할 치료(hygofractionated radiation therapy)의 용이성과 그 부작용의 정도를 파악하고자 하였다. 대상 및 방법: 1999년 2월부터 2000년 2월까지 서울대학교 병원 치료방사선과에 내원하여 조직학적으로 확진된 Ⅰ,Ⅱ 병기의 초기 성문암환자는 20명을 대상으로 전향적 연구를 진행하였다. 환자군의 성별분포는 18명이 남자, 2명이 여자였으며 연령의 중앙값은 59세였다. 병기의 분포는 T1aN0-16명, T1bN0-1명, T2n0 3명이었다. 18명의 환자는 후두미세수술을 통한 조직생검을 시행하였으며 2명의 환자는 레이저 절제술을 시행받았다. 모든 환자는 근치적 방사선치료를 2.5Gy의 분할조사선량으로 총 60 Gy의 방사선을 24회 분할하여 시행받았다. 치료 기간의 중앙값은 36일 이었다(범위31~45일). 결과: 방사선치료 기간 중 금성 반응으로 치료를 중단한 환자는 없었다. 주된 급성 부작용은 식도염과 애성이였으며 치료 후에는 호전되었다. RTOG grade 3의 식도염으로 인한 연하통을 보인 환자가 1례에서 있었고, 6례에서 grade 3의 애성을 보였다. 방사선치료에 대한 반응은 치료 종료 1개월 후에 판정하고 모든 환자에서 완전관해를 보였다. 20명의 환자 중 3명에서 재발이 관찰되었는데, 2례는 방사선치료 후 10개월과 13개월의 시점에서 국소재발이 관찰되었고, 1례 방사선치료 후 2개월의 시점에서 경부 림프절에서의 재발이 관찰되었고 4개월 후 원격전이가 관찰되었다. 결론: 소분할 방사선치료는 시행상의 큰 어려움 없이 진행되었으며 질병에 관해에 효과적인 것으로 나타났다. 하지만 방사선치료기간의 단축이 종양의 치료결과에 미치는 영향과 만성 부작용을 파악하기 위해서 보다 오랜 기간의 추적 관찰이 필요할 것으로 생각된다. Purpose: This study was performed for the evaluation of the feasibility and toxictiy of hypofractionated radiation therapy for early glottic cancer Methods and Materials: From February 1999 to February 2000, 20 patients with histologically confirmed Stage Ⅰ,Ⅱ glottic cancer were enrolled into this study. There were 18 males and 2 females, the median age of the patients was 59 years. The distribution of stage distribution was as follows; T1aN0-16 patients, T1bN0-1 patient, T2N0-3 patients. Eighteen patients underwent laryngomicroscopic biopsy only, and two patients underwent laser cordectomy. All patients received radical radiation therapy(2.5 Gy per fraction, 24 fractons, total 60 Gy). Median duration of teratment was 36days (range 31~45 days). Results: Radiation therapy were well tolerated. Most common acute reactions were odynophagia and hoarseness, and these reactions resolved after radiation therapy. There were one case of RTOG grade 3 odynophagia (5%), six cases of grade 3 hoarseness (30%). Response of radiation therapy was evaluated one month after completion of treatment. All patients revealed complete response. During follow up, total three cases of treatment failure were detected. two cases were local recurrence in 10 and 13 months of radiation therapy and one case was local recurrence and distant metastasis in 2 months of radiation therapy Conclusion: This hypofractionated radiation therapy schedule was feasible and effective for control of early glottic cancer. But longer follow up time would be required to assess the long0term disease control and the late complication by shortening radiation therapy duration.

Neoadjuvant Chemotherapy and Radiation Therapy in Advanced Stage Nasopharyngeal Carcinoma

홍세미(Semie Hong),우홍균(Hong-Gyun Wu),박찬일(Charn II Park) 대한방사선종양학회 1999 Radiation Oncology Journal Vol.17 No.4

목 적 : 국소적으로 진행된 비인두암환자에서 선행보조 항암화학요법의 실행 용이성과 부작용의 정도를 평가한다. 대상 및 방법 : 77명의 조직학적으로 비인두암으로 확진 되고 이전에 치료를 받은 적이 없는 진행된 병기의 비인두암 환자들이 1984년부터 1996년까지 서울대학교병원에서 선행보조 항암화학요법과 방사선치료를 시행받았다. 환자군의 병기분포는 다음과 같다. 1992년 AJCC 분류법에 따라 제 3 병기에 속하는 환자가 2명이었고 제 4병기에 속하는 환자가 75명이었다. 방사선치료 시행 전에 선행보조 항암화학요법으로 66명의 환자가 5-FU와 Cisplatin의 정맥내 투여를 시행 받았고, 11명의 환자가 5-FU와 Carboplatin의 정맥 내 투여를 시행 받았다. 생존환자의 중앙추적기간은 44개월이었다. 결 과 : 항암화학요법에의 반응율은 87%였다. 항암화학요법의 부작용은 심하지 않았다. 3명의 환자만이 3도의 부작용을 경험하였다. 1명은 백혈구 감소증을 보였고 2명은 오심과 구토의 부작용을 보였다. 방사선에 의한 점막염도 심하지 않았는데, 10명의 환자에서 2도의 점막염이 발생하였다. 5년 생존율과 5년 무병생존율은 각각 68%와 65%였다. 5년 무원격전이율은 82%였으며 5년 국소 치유율은 75%였다. 결 론 : 선행보조 항암화학요법이 진행된 병기의 비인두암 환자에 있어서 부작용을 크게 증가시키지 않으면서 효과적인 치료방법임을 알 수 있었다. Purpose : To assess the feasibility and the toxicity of the neoadjuvant chemotherapy on the treatment of patients with locoregionally advanced nasopharyngeal carcinoma. Methods and Materials : We analyzed 77 previouly untreated and histologically confirmed advanced stage nasopharyngeal carcinoma patients treated with neoadjuvant chemotherapy followed by radiation therapy at the Seoul National University Hospital between 1984 and 1996. The stage distribution was therapy at the Seoul National University Hospital between 1984 and 1996. The stage distribution was as follows : AJCC stage III-2, stage IV-75, Sixty-six patients received infusion of 5-FU (1000 mg/m2, on Day 1~5) and cisplatin (100 mg/m2, on Day 1), eleven patients received infusion of 5-FU (1000 mg/m2, on Day 1~5) and carboplatin (300 mg/m 2, on Day 1), as neoadjuvant chemotherapy prior to radiation therapy. The median follow-up for surviving patients was 44 months. Results : The overall chemotherapy response rates were 87%. The toxicities of chemotherapy were mild. Only 3 patients experienced Grade 3 toxicities (1 for cytopenia, 2 for nausea/vomiting). The degree of radiation induced mucositis was not severe, and then pati ents developed Grade 2 mucositis. The 5-year overall survival rates were 68% and the 5-year disease free survival rates were 65%. The 5-year overall survival rates were 68% and the 5-year disease free survival rates were 65%. The 5-year freedom from distant metastasis rates were 82% and 5-year locoregional control rates were 75%. Conclusion : This single institution experience suggests that neoadjuvant chemotherapy improves overall survival and disease free survival for patients with advanced stage nasopharyngeal carcinoma without increase of toxicity.

Cranial Irradiation in the Management of Childhood Leukemic Hyperleukocytosis

홍세미(Semie Hong),김일환(Il Han Kim) 대한방사선종양학회 2001 Radiation Oncology Journal Vol.19 No.2

목 적 :극심한 백혈구 증가증(105/mm3 이상)을 동반한 급성 백혈병은 뇌내 출혈로 인한 조기 급사의 위험이 높은 질환이다. 응급 전두개 방사선조사는 비교적 단순하게 이 문제에 대처할 수 있는 방법으로 본 저자들은 24명의 극심한 백혈구 증다증을 보인 환아에서의 전두개 방사선 치료의 경험을 보고하고자 한다. 대상 및 방법 : 1990년부터 1998년까지 40명의 극심한 백혈구 증가증을 보이는 급성 백혈병 환아가 응급 전두개 방사선조사를 위해 의뢰되었다. 이들중 24명의 환아의 초기 병록의 검색이 가능하였다. 환자군은 남아가 16명, 여아가 8명이었으며 연령 분포는 2세에서 13세(중앙값 9.5세) 였다. 초기의 백혈구 수치는 109,910/mm2 에서 501,111/ mm2의 범위에 있었다. 모든 환자에게 말초 혈액 도말 검사를 시행하였고 응급 전두개 방사선조사는 백혈구 수치가 105/mm2 이상이며, 말초 혈액에서 림프구모세포가 관찰된 환자들에게 시행되었다. 모든 환자는 염기성 전해질을 포함한 정맥 수액요법과 경구 allopurinol 복용의 처치를 받았다. 전두개 방사선 조사는 진단일로부터 시작되었으며 2Gy의 분할 조사선량으로 1회 시행받은 환아가 4명, 2회 시행받은 환아가 20명이었다. 결 과 :백혈구 수는 19명의 환아에게서 감소를 나타냈으며 방사선조사 후 뇌내 출혈은 관찰되지 않았다. 5례의 조기 사망이 있는데 4례는 대사적 합병증과 관련된 것이었고 1례는 방사선조사 전에 일어난 뇌내 출혈로 인한 사망으로 방사선조사 5시간 후에 사망하였다. 전두개 방사선조사 후에 즉각적인 부작용은 관찰 되지 않았다. 결 론 :이상의 결과에서 극심한 백혈구 증가증을 보이는 소아 백혈병 환자에게 응급 전두개 방사선조사는 안전하게 그리고 효과적으로 이용될 수 있을것이다. Purpose :Acute leukemia with hyperleukocytos is (more than 105/mm3) is at high risk of early sudden death, usually from intracerebral hemorrhage. Emergency cranial irradiation is a relatively s imple approach to solve this the problem. We summarized our experience of cranial irradiation in 24 leukemic children who presented with hyperleukocytos is . Methods and Materials : Between 1990 and 1998, 40 children with acute leukemia presenting with hyperleukocytos is were referred for emergency cranial irradiation. Among these patients , 24 children were evaluable. There were 16 boys and eight girls , their ages ranged from 2 to 13 years (median 9.5 years). The initial leukocyte counts ranged 109,910/mm3 to 501,000/mm3 . Peripheral blood smear was performed in all patients and noted the morphology of the blast. Introduction of emergency cranial irradiation was determined by the leukocyte counts (more than 100,000/mm) and the existence of the blast in peripheral blood smear. All patients were treated with intravenous hydration with alkaline fluid and oral allopurinol. Cranial irradiation started on the day of diagnos is . With 2 Gy in one fraction in 4 patients , 4 Gy in two fractions in 20 patients. Results : The WBC count had fallen in 19 patients (83%) and no intracerebral hemorrhage occurred after irradiation. There were five cases of early deaths . Four patients died of metabolic complications , and one patient with intracerebral hemorrhage. He died 5 hours after cranial irradiation. No patient had any immediate s ide effect from cranial irradiation. Conclusion :Our data suggest, that emergency cranial irradiation can be safely chosen and effective in childhood leukemic patients presenting with high leukocyte counts.

Comparison of New AJCC Staging System with Old AJCC Staging System in Nasopharyngeal Carcinoma

홍세비(Semie Hong),우홍균(Hong-Gyun Wu),박찬일(Charn Il Park) 대한방사선종양학회 2000 Radiation Oncology Journal Vol.18 No.4

목 적 :본 연구는 1997년에 개정된 비인강암에 대한 AJCC병기 분류법을 1992년의 분류법과 비교하여 새로운 병기분류법의 신뢰성을 평가하고자 시행되었다. 재료 및 방법 : 1983년부터 1996년까지 서울대학교 병원 치료방사선과에 방사선 치료를 위해 내원한 185명의 조직학적으로 확진되고 원격전이의 증거가 없는 비인강암 환자들을 대상으로 하였다. 이들 환자들에 대하여 의무 기록과 전산화 단층촬영, 자기공명영상을 검토하여 1992년 병기 분류법과 1997년 병기 분류법에 따라 병기를 분류하였고 각 병기 분류법에 따라 생존율을 산출하였다. 결 과 : 1992년 분류법과 1997년 분류법에 따른 5년 생존율은 병기 I에서 각각 100%; 병기 II에서는 100% 와 68.8%; 병기 III에서는 61.4% 와 63.8%; 병기 IV에서는 61.1% 와 63.2% 였다. 각각의 분류법으로 산출한 5년 생존율은 각각의 병기분류법 내에서 병기에 따라 유의한 차이를 보였으나 양 분류법 간에는 병기 II를 제외하고는 통계학적인 차이는 없었다. 결 론 :새로운 비인강암의 AJCC 병기분류법은 이전의 1992년 분류법과 비교하여 신뢰할 수 있을 것으로 생각되나 더 많은 환자를 대상으로 임상적 연구가 진행되어야 할 것으로 생각된다. Purpose :This study was designed to examine the reliability of the new version of the AJCC staging system (1997) of nasopharyngeal carcinoma in comparison with the AJCC staging system of 1992. Materials and Methods : Between 1983 and 1996, 185 patients with histologically proven nasopharyngeal carcinoma were treated with radiation therapy at the Department of Therapeutic Radiology Seoul National University Hospital. For these patients, AJCC staging system of 1992 was compared with the 1997 version, by reviewing hospital records, computed tomography (CT) and/or magnetic resonance imaging (MRI). Results :5-year overall survival rates according to the 1992 and 1997 AJCC staging systems were 100%, and 100% at stage I; 100%, and 68.8% at stage II; 61.4%, and 63.8% at stage III; 61.1%, and 63.2% at stage IV. 5-year overall survival rates of each classification showed significant differences between stages (p=0.0049 for the old version, p=0.01 for the new), but no significant difference was found between the staging systems except at stage II. Conclusion :The new AJCC staging system allows staging as reliably as the 1992 version, but the adequacy of the newly modified staging classification should be confirmed by further clinical examination.

해양생태계서비스 기반 공간관리 의사결정 지원 수단 개발

정세미(Semi Jeong),오예진(Yejin Oh),최희정(Hee-jung Choi),박재영(Jaeyoung Park),홍장원(Jangwon Hong),남정호(Jungho Nam) 한국해양환경·에너지학회 2018 한국해양환경·에너지학회 학술대회논문집 Vol.2018 No.11

복합형 회전익기의 덕티드팬 기동제어용 베인 공력특성 연구

김세미(Semi Kim),강동훈(Donghun Kang),홍슬기(Seulki Hong),최재호(Jaeho Choi),강인모(In-Mo Kang),유흥철(Heung-Cheol You) 한국항공우주학회 2019 한국항공우주학회 학술발표회 논문집 Vol.2019 No.11