정위적 방사선 수술에서 물팬텀을 이용한 목표점 및 전달 선량확인

강영남,이동준,권수일,권양,Kang, Young-Nam,Lee, Dong-Jun,Kwon, Soo-Il,Kwon, Yang 한국의학물리학회 1996 의학물리 Vol.7 No.2

It is important that the precise decision of the region and the accurate delivery of radiation dose required for treatment in the stereotactic radiosurgery. In this research, radiosurgery was carried with Leksell streotactic frame(LSF) which is especially developed water phantom to verify in experiment. Leksell Gamma Knife and LSF are used in radiosurgery is the spherical water phantom has the thickness of 2 mm, the radius of 160mm. The film for target localization and ionchamber for dose delivery was used in measurement instruments We compare the coordinate of target which is initialized by biplannar film with simple X-ray to the coordinate of film measured directly. The calculated dose by computer simulation and the measured dose by ionization chamber are compared. In this research, the target localization has the range ${\pm}$0.3mm for the acceptable error range and the absolute dose is :${\pm}$0.3mm for the acceptable error range. This research shows that the values measured by using the especially manufactured phantom are included the acceptable error range. Thus, this water phantom will be used continuously in the periodic quality assurance of Gamma Knife Unit and Leksell Stereotactic Frame.

디자인 패턴 기반 소프트웨어의 테스트 가능성 분석

강영남(Young Nam Kang),최은만(Eun Man Choi) 한국정보과학회 2004 한국정보과학회 학술발표논문집 Vol.31 No.1B

잘 설계된 모든 객체지향 구조들은 패턴들로 가득 차 있다는 점에서 볼 때, 디자인 패턴은 상당히 유용하다. 특히 정확성, 강건성, 유연성, 재사용성, 효율성 측면에서 볼 때, 디자인 패턴은 충분히 가치가 있다. 이 논문에서는 디자인 패턴을 사용한 소프트웨어에서 테스트 가능성은 어떻게 달라지는지를 분석하고 자 한다. 테스트 가능성을 측정하는 메트릭을 이용하여, 패턴이 적용된 소프트웨어와 적용되지 않은 소프트웨어에서의 메트릭을 분석한다. 측정된 값은 디자인 패턴을 사용하지 않은 소프트웨어에 비해, 사용한 소프트웨어에서 몇몇 메트릭이 낮은 값을 보였다. 이것은 디자인 패턴을 적용하는 것이 오류의 가능성이나 테스트 케이스의 수를 줄여 준다는 것을 의미한다. 또한 어떤 디자인 패턴이 적용되었는지를 알고 있을 때, 그 디자인 패턴에 맞는 테스트 케이스가 무엇인지 분석하였다.

동적 팬톰을 이용한 사이버나이프 호흡동기 추적장치의 위치 정확성 평가

서재혁,강영남,장지선,신헌주,정지영,최병옥,최일봉,이동준,권수일,임종수,Seo, Jae-Hyuk,Kang, Young-Nam,Jang, Ji-Sun,Shin, Hun-Joo,Jung, Ji-Young,Choi, Byong-Ock,Choi, Ihl-Bohng,Lee, Dong-Joon,Kwon, Soo-Il,Lim, Jong-Soo 한국의학물리학회 2009 의학물리 Vol.20 No.4

In this study, we evaluated accuracy and usefulness of CyberKnife Respiratory Tracking System ($Synchrony^{TM}$, Accuray, USA) about a moving during stereotactic radiosurgery. For this study, we used moving phantom that can move the target. We also used Respiratory Tracking System called Synchrony of the Cyberknife in order to track the moving target. For treatment planning of the moving target, we obtained an image using 4D-CT. To measure dose distribution and point dose at the moving target, ion chamber (0.62 cc) and gafchromic EBT film were used. We compared dose distribution (80% isodose line of prescription dose) of static target to that of moving target in order to evaluate the accuracy of Respiratory Tracking System. We also measured the point dose at the target. The mean difference of synchronization for TLS (target localization system) and Synchrony were $11.5{\pm}3.09\;mm$ for desynchronization and $0.14{\pm}0.08\;mm$ for synchronization. The mean difference between static target plan and moving target plan using 4D CT images was $0.18{\pm}0.06\;mm$. And, the accuracy of Respiratory Tracking System was less 1 mm. Estimation of usefulness in Respiratory Tracking System was $17.39{\pm}0.14\;mm$ for inactivity and $1.37{\pm}0.11\;mm$ for activity. The mean difference of absolute dose was $0.68{\pm}0.38%$ in static target and $1.31{\pm}0.81%$ in moving target. As a conclusion, when we treat about the moving target, we consider that it is important to use 4D-CT and the Respiratory Tracking System. In this study, we confirmed the accuracy and usefulness of Respiratory Tracking System in the Cyberknife.

소조사면에서의 불균질 물질 보정 계산의 평가

신헌주,강영남,장지선,서재혁,정지영,최병옥,최일봉,이동준,권수일,Shin, Hun-Joo,Kang, Young-Nam,Jang, Ji-Sun,Seo, Jae-Hyuk,Jung, Ji-Young,Choi, Byung-Ock,Choi, Ihl-Bohng,Lee, Dong-Joon,Kwon, Soo-Il 한국의학물리학회 2009 의학물리 Vol.20 No.4

In this study, we estimated inhomogeneity correction factor in small field. And, we evaluated accuracy of treatment planning and measurement data which applied inhomogeneity correction factor or not. We developed the Inhomogeneity Correction Phantom (ICP) for insertion of inhomogeneity materials. The inhomogeneity materials were 12 types in each different electron density. This phantom is able to adapt the EBT film and 0.125 cc ion chamber for measurement of dose distribution and point dose. We evaluated comparison of planning and measurement data using ICP. When we applied to inhomogeneity correction factor or not, the average difference was 1.63% and 10.05% in each plan and film measurement data. And, the average difference of dose distribution was 10.09% in each measurement film. And the average difference of point dose was 0.43% and 2.09% in each plan and measurement data. In conclusion, if we did not apply the inhomogeneity correction factor in small field, it shows more great difference in measurement data. The planning system using this study shows good result for correction of inhomogeneity materials. In radiosurgery using small field, we should be correct the inhomogeneity correction factor, more exactly.

전신방사선조사 프로그램 개발

최병옥,장지선,강영남,최일봉,신성균,Choi Byung Ock,Jang Ji Sun,Kang Young Nam,Choi Ihl Bohng,Shin Sung Kyun 한국의학물리학회 2005 의학물리 Vol.16 No.3

전신방사선조사(total body irradiation)는 크게 두 가지가 있는데 첫 번째는 전후 이문대향조사방법(anterior-posterlor total body irradiation)이고 두 번째는 좌우 이문대향조사방법(lateral total body irradiation)이다. 본 병원에서 시행 중인 방법은 환자의 좌우 이문대향조사방법으로서 환자의 측면에서 방사선이 조사되기 때문에 인체의 윤곽에 따른 방사선의 분포가 각 부분에 대해서 다르게 나타나게 된다. 전신 방사선 치료에서 보상체(Compensator)를 사용하여 몸 전체에 균일한 방사선 분포를 만들어내게 한다. 하지만 이런 보상체의 제작은 인체의 모든 부위에서의 수치, 각 부분의 깊이와 길이가 필요한데 특히 머리 부위와 다리 부위 수치에 대한 세밀한 고려가 중요시 되며 또한 조사되는 방사선량의 정확성이 요구된다. 본 연구에서는 기존에 수작업으로 각 부분을 계산하는 방법에서 방사선데이터 및 환자의 각 부분을 데이터화하여 윈도우 환경에서 사용이 용이한 전신방사선조사 계산 프로그램을 개발하였다. 개발된 프로그램은 보상체의 제작 및 방사선량을 계산할 수 있도록 하였다. 본 연구에서는 프로그램 개발을 위하여 IDL 6.0 (Intersys, USA)과 Visual C++ (Microsoft, USA)를 사용하였다. 전신방사선치료시 사용하는 각 에너지별 최대조직선량비(Tissue Maximum Ratio, TMR), 출력인수(output factor), 거 리 역제곱법 칙(Inverse square law), 빔 스포일 러(beam speller), 조사면(field size) 등의 인수를 데 이 터 베이스화함으로써 환자별 보상체의 자동화 제작 및 방사선량 계산을 할 수 있도록 하여 수작업으로 인해 발생할 수 있는 오차와 시간을 줄일 수 있었다. 개발된 전신방사선조사 프로그램을 활용하여 수작업으로 인한 오차를 줄이고 정확한 수치 및 데이터의 적용으로 전신방사선조사에 대한 치료계획을 최적화한다.

Megavoltage Cone-Beam CT 영상의 변환을 이용한 선량 계산의 정확성 향상

김민주,조웅,강영남,서태석,Kim, Min-Joo,Cho, Woong,Kang, Young-Nam,Suh, Tae-Suk 한국의학물리학회 2012 의학물리 Vol.23 No.1

The dose re-calculation process using Megavoltage cone-beam CT images is inevitable process to perform the Adaptive Radiation Therapy (ART). The purpose of this study is to improve dose re-calculation accuracy using MVCBCT images by applying intensity calibration method and three dimensional rigid body transform and filtering process. The three dimensional rigid body transform and Gaussian smoothing filtering process to MVCBCT Rando phantom images was applied to reduce image orientation error and the noise of the MVCBCT images. Then, to obtain the predefined modification level for intensity calibration, the cheese phantom images from kilo-voltage CT (kV CT), MVCBCT was acquired. From these cheese phantom images, the calibration table for MVCBCT images was defined from the relationship between Hounsfield Units (HUs) of kV CT and MVCBCT images at the same electron density plugs. The intensity of MVCBCT images from Rando phantom was calibrated using the predefined modification level as discussed above to have the intensity of the kV CT images to make the two images have the same intensity range as if they were obtained from the same modality. Finally, the dose calculation using kV CT, MVCBCT with/without intensity calibration was applied using radiation treatment planning system. As a result, the percentage difference of dose distributions between dose calculation based on kVCT and MVCBCT with intensity calibration was reduced comparing to the percentage difference of dose distribution between dose calculation based on kVCT and MVCBCT without intensity calibration. For head and neck, lung images, the percentage difference between kV CT and non-calibrated MVCBCT images was 1.08%, 2.44%, respectively. In summary, our method has quantitatively improved the accuracy of dose calculation and could be a useful solution to enhance the dose calculation accuracy using MVCBCT images.

Megavoltage Cone-beam CT 영상의 변환을 이용한 변환 영상 정합의 정확도 향상

김민주,장지나,박소현,김태호,강영남,서태석,Kim, Min-Joo,Chang, Ji-Na,Park, So-Hyun,Kim, Tae-Ho,Kang, Young-Nam,Suh, Tae-Suk 한국의학물리학회 2011 의학물리 Vol.22 No.1

To perform the Adaptive Radiation Therapy (ART), a high degree of deformable registration accuracy is essential. The purpose of this study is to identify whether the change of MV CBCT intensity can improve registration accuracy using predefined modification level and filtering process. To obtain modification level, the cheese phantom images was acquired from both kilovoltage CT (kV CT), megavoltage cone-beam CT (MV CBCT). From the cheese phantom images, the modification level of MV CBCT was defined from the relationship between Hounsfield Units (HUs) of kV CT and MV CBCT images. 'Gaussian smoothing filter' was added to reduce the noise of the MV CBCT images. The intensity of MV CBCT image was changed to the intensity of the kV CT image to make the two images have the same intensity range as if they were obtained from the same modality. The demon deformable registration which was efficient and easy to perform the deformable registration was applied. The deformable lung phantom which was intentionally created in the laboratory to imitate the changes of the breathing period was acquired from kV CT and MV CBCT. And then the deformable lung phantom images were applied to the proposed method. As a result of deformable image registration, the similarity of the correlation coefficient was used for a quantitative evaluation of the result was increased by 6.07% in the cheese phantom, and 18% in the deformable lung phantom. For the additional evaluation of the registration of the deformable lung phantom, the centric coordinates of the mark which was inserted into the inner part of the phantom were measured to calculate the vector difference. The vector differences from the result were 2.23, 1.39 mm with/without modification of intensity of MV CBCT images, respectively. In summary, our method has quantitatively improved the accuracy of deformable registration and could be a useful solution to improve the image registration accuracy. A further study was also suggested in this paper.

$T_2,\;T_3$ 하부직장암의 수술 전 방사선치료 효과

강기문,최병옥,장홍석,강영남,채규영,최일봉,Kang Ki Mun,Choi Byung Ock,Jang Hong Seok,Kang Young Nam,Chai Gyu Young,Choi Ihl Bohng 대한방사선종양학회 2002 대한방사선종양학회지 Vol.20 No.3

Purpose : Preoperative radiotherapy has been used to induce tumor regression and allow complete resection of rectal cancer with a sphincter preservation surgery. This study was performed to determine the effectiveness of preoperative radiotherapy for $T_2,\;T_3$ distal rectal carcinoma. Materials and Methods : From November 1995 to June 1997, fifteen patients with invasive distal rectal cancer were treated with preoperative radiotherapy followed by sphincter preservation surgery. Classification by preoperative T stage consisted of 7 $T_2$ and 8 $T_3$ tumors. Radiation therapy was delivered with 6 MV and 15 MV linear accelerator, at 1.8 Gy fractions for 5 days per week. Total radiation doses were 45 Gy to 50.4 Gy (median : 50.4 Gy). Sphincter preservation surgery was peformed $4\~6$ weeks after the completion of radiotherapy. Median follow-up was 22 months (range : $16\~37\;months$). Results : One patient $(6.7\%)$ had a complete pathologic response. Comparing the stage at the diagnostic workup with the pathologic stage, tumor downstaging of T stages occurred in 11 of 15 patients $(73.3\%)$ and $N_1$ stages occurred in 2 of 5 patients $(40\%)$. No patient developed progressive disease undergoing treatment. Two patients suffered local recurrence at 7 and 20 months, and one a distant metastasis at 30 months. No grade 3 or 4 toxicity was observed. Conclusion : Our experience suggests that preoperative radiotherapy followed by sphincter preservation surgery is well tolerated, and can significantly reduce the tumor burden for $T_2\;T_3$ distal rectal cancer.

1차 관해된 급성 골수성 백혈병에서 자가 조혈모세포 이식을 위한 Cytarabine, Melphalan, 전신 방사선치료의 효과

강기문(Ki Mun Kang),최병옥(Byung Ock Choi),채규영(Gyu Young Chai),강영남(Young Nam Kang),장홍석(Hong Sek Jang),김희제(Hee Jae Kim),민우성(Wo Sung Min),김춘추(Chun Choo Kim),최일봉(Ihl Bohng Choi) 대한방사선종양학회 2003 대한방사선종양학회지 Vol.21 No.3

목 적: 급성 골수성 백혈병에서 자가 조혈모 세포 이식은 무병생존율에 도움을 주며 1차 관해된 급성 골수성 백혈병에서 자가 조혈모세포 이식은 점차 늘어나고 있는 추세이다.본 연구는1차 관해된 급성 골수성 백혈병에서 자가 조혈모 세포이식을 위한 전처치요법으로 cytarabine,melphalan과 전신 방사선치료를 시행하여 그 효과를 알아보고자 하였다. 대상 및 방법 : 1995년 1월부터 1999년 12월까지 급성 골수성 백혈병으로 1차 관해 후 자가 조혈모세포 이식을 받은 29명을 대상으로 하였다. 환자의 중앙연령은 33세(16~ 47세)이 었다.자가 조혈모세포 이식을 위한 전처치 요법은 cytarabine (3.0 gm/m2 , 3일), melphalan (100 mg/m2 , 1일)과 전신 방사선치료를 시행하였다.전신 방사선치료는 6 MV 선형가속기를 이용하여 200 cGy를 1일2회씩 5회 분할 조사하여 총 조사선량은 1000 cGy이었다. 결 과: 추적 관찰기간은 3~ 58개월 이었으며 중앙값은 40개월이었다. 전체 환자의 4년 무병생존율은 69.0%이었으며 중앙생존기간은 41.5개월이었다. 4년 재발률은27.6%이었다.무병생존율과 재발률에 영 향 을 미 치는 인자 분석에서는 FAB 분류만 이유의 한 예후인자로 분석되었다(M3군 vs. M3를 제 외 한 군;p=0.048,p=0.043).대상 환자중 9명에서 사망하였으며 치료와 관련된 사망은 1명이었고 8명은 재발로 사망하였다. 결 론: 1차 관해된 급성 골수성 백혈병에서 자가 조혈모세포 이식을 위한 melphalan, cytarabine과 전신 방사선치료는 비교적 효과적인 전처치 요법이었다. Purpose: Current results of autologous stem cell transplantation (SCT) suggest that this procedure may prolong disease free survival in patients with acute myeloid leukemia (AML). Autologous SCT is increasingly used as treatment for AML in first remission. The aim of this study was to evaluate the outcome of autologous SCT for patients with AML in first remission treated by autologous SCT using cytarabine, melphalan and total body irradiation (TBI) as the conditioning regimen. Materials and Methods Between January 1995 and December 1999, 29 patients with AML in first remission underwent autologous SCT. The median a ge of patients was 33 years (range, 16 to 47). The conditioning regimen consisted of cytarabine (3.0 gm/m 2 for 3 days), melphalan (100 mg/m 2 for 1 day) and TBI (total 1000 cGy in five fractions over 3 days). Results The median follow up was 40 months with a range of 3 to 58 months. The 4-year cumulative probability of disease free survival was 69.0%, and median survival was 41.5 months. The 4-year relapserate was 27.6%. The factor influencing disease free survival and relapse rate was the French-American-British (FAB) c lassification (M 3 group vs. other groups; p=0.048, p=0.043). One patient died from treatment-related toxicity. Conclusion: Although the small number of patients does not allow us to draw any firm conclusion, our results were encouraging and suggest that the association of cytarabine, melphalan and TBI as a conditioning regimen for autologous SCT for AML in first remission appears to be safe and effective.

사이버나이프 출력인자 분석: 전리함, 다이오드 검출기 및 필름

장지선,신동오,최병옥,이태규,최일봉,김문찬,권수일,강영남,Jang Ji-Sun,Shin Dong-Oh,Choi Byung-Ock,Lee Tae-Kyu,Choi Ihl-Bohng,Kim Moon-Chan,Kwon Soo-Il,Kang Young-Nam 한국의학물리학회 2006 의학물리 Vol.17 No.1

The accuracy of the dosimetry in the Cyberknife system is accomplishing important role from all processes of the stereotactic radiosurgery. In this study, we estimated relative output factors for Cyberknife. All measurements were peformed by six different detectors: diode detector, X-Omat V film, Gafchromic EBT film, 0.015 cc, 0.125 cc and 0.6 cc ionization chamber The diode detector and three ionization chambers peformed using water phantom at 80 cm SSD and 1.5 cm depth. When the film measurements were peformed, the water phantom was replaced with a solidwater phantom. Each collimator normalized with respect to the output factor of the largest collimator (60 mm). For the collimators over than 30 mm, the output factors from the different detectors showed a good agreement within 0.5% except 0.6 cc ion chamber For the collimators less than 15 mm, there were substantial differences In the output factors among different detectors. That is, the value of output factor for the 5 mm collimator of a diode and Gafchromic film was each $0.656{\pm}0.009$ and $0.777{\pm}0.013$. In the ion chamber and diode detector, those difference were due to the presence of large dose gradients and lack of electronic equilibrium in narrow megavoltage x-ray beams Therefore, the Gafchromic EBT film were considered more accurate than the others detectors.