MOSFET 선량계 특성분석을 위한 팬톰 개발 및 특성 비교

정진범,이정우,김연래,이두현,최경식,김재성,김인아,홍세미,서태석,Chung, Jin-Beom,Lee, Jeong-Woo,Kim, Yon-Lae,Lee, Doo-Hyun,Choi, Kyoung-Sik,Kim, Jae-Sung,Kim, In-Ah,Hong, Se-Mie,Suh, Tae-Suk 한국의학물리학회 2007 의학물리 Vol.18 No.1

본 연구는 MOSFET (Metal Oxide Semiconductors Fleid Effect Transistors) 선량계의 교정과 특성분석을 위해서, 자체 팬톰을 개발하고 이 팬톰을 적용하여 표준감도와 고감도 두 종류의 MOSFET선량계의 특성을 비교 평가하는 것이다. 본 연구에서 개발한 팬톰은 직경 10cm의 반구형 모양인 팬톰과 1cm 두께 $30{\times}30cm^2$의 평판형의 팬톰으로 아크릴로 제작되었다. 평판형 팬톰은 MOSFET 선량계의 교정과 선량재현성, 선량직선성, 선량률 의존성을 측정하는데 사용하였으며 반구형 팬톰은 빔 입사각도 및 선량계 방향에 대한 MOSFET 선량계 특성을 분석하기 위해서 사용하였다. 모든 측정과정은 선형가속기(CL21EX, Varian, USA)의 6 MV 광자선, SSD 100cm, 조사면 $10{\times}10 cm^2$에서 수행하였다 선량계 교정과 선량재현성 평가에 사용된 5개의 표준감도와 고감도 MOSFET 선량계에 각각 200 cGy로 5번 반복 조사하여 $1.09{\pm}0.01{\sim}1.12{\pm}0.02,\;2.81{\pm}0.03{\sim}2.85{\pm}0.04mV/cGy$. 범위의 평균 교정계수가 결정되었고 선론쌔현성은 두 선량계 모두 2%이내로 거의 동일하였다. $5{\sim}600\;cGy$ 범위에서의 선량직선성은 두 MOSFET 선량계 모두 결정계수 $R^2=0.997$, 0.999인 좋은 선량직선성을 나타내었다. 200 cGy로 $100{\sim}600\;MU/min$ 범위의 선량률 의존성도 1%이내로 두 선량계가 동일하게 나타났다. 그러나 빔 입사각도와 선량계 방향의 의존성 평가에서, 표준감도와 고감도 MOSFET선량계는 평균적으로 빔 입사각도에 대해 13%, 10%의 변동폭과 ${\pm}4.4%$와 ${\pm}2.1%$의 표준편차가 있었으며, 선량계 방향에 대해 5%, 2%의 변동폭, ${\pm}2.1%$와 ${\pm}1.5%$의 표준편차로 두 선량계 간 현저한 차이를 나타났다 그러므로 여러 방향의 치료빔을 사용하는 방사선 치료의 선량검증을 위해서는 빔 입사각도와 선량계 방향의 의존성이 적은 고감도 MOSFET 선량계를 사용하는 것이 표준감도 WOSFET 선량계를 사용하는 것보다는 더 정확한 선량검증을 수행할 수 있을 것으로 사료된다. This study is to develope a phantom for MOSFET (Metal Oxide Semiconductors Field Effect Transistors) dosimetry and compare the dosimetric properties of standard MOSFET and microMOSFET with the phantom. In this study, the developed phantom have two shape: one is the shape of semi-sphere with 10cm diameters and the other one is the flat slab of $30{\times}30cm$with 1 cm thickness. The slab phantom was used for calibration and characterization measurements of reproducibility, linearity and dose rate dependency. The semi-sphere phantom was used for angular and directional dependence on the types of MOSFETs. The measurements were conducted under $10{\times}10cm^2$ fields at 100cm SSD with 6MV photon of Clinac (21EX, Varian, USA). For calibration and reproducibility, five standard MOSFETS and microMOSFETs were repeatedly Irradiated by 200cGy five times. The average calibration factor was a range of $1.09{\pm}0.01{\sim}1.12{\pm}0.02mV/cGy$ for standard MOSFETS and $2.81{\pm}0.03{\sim}2.85{\pm}0.04 mV/cGy$ for microMOSFETs. The response of reproducibility in the two types of MOSFETS was found to be maximum 2% variation. Dose linearity was evaluated In the range of 5 to 600 cGy and showed good linear response with $R^2$ value of 0.997 and 0.999. The dose rate dependence of standard MOSFET and microMOSFET was within 1% for 200 cGy from 100 to 500MU/min. For linearity, reproducibility and calibration factor, two types of MOSFETS showed similar results. On the other hand, the standard MOSFET and microMOSFET were found to be remarkable difference in angular and directional dependence. The measured angular dependence of standard MOSFET and microMOSFET was also found to be the variation of 13%, 10% and standard deviation of ${\pm}4.4%,\;{\pm}2.1%$. The directional dependence was found to be the variation of 5%, 2% and standard deviation of ${\pm}2.1%,\;{\pm}1.5%$. Therefore, dose verification of radiation therapy used multidirectional X-ray beam treatments allows for better the use of microMOSFET which has a reduced angular and directional dependence than that of standard MOSFET.

Dosimetric Characteristics of Standard and Micro MOSFET Dosimeters as In-vivo Dosimeter for Clinical Electron Beam

정진범,Jeong-Woo Lee,서태석,이동현,최보영,김연실,김재성,김인아,최경식,Sung-Joon Ye 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.6

The metal oxide semiconductor field effect transistor (MOSFET) dosimeters have recently become commercially available. The purpose of this study was to investigate the fundamental dosimetric characteristics of MOSFET dosimeters for clinical electron beams and to compare standard MOSFET and micro MOSFET dosimeters. In this study, five identical standard MOSFET (TN-502-RD) and micro MOSFET (TN-502-RDM) dosimeters were used for measurements. All measurements, with the exception of angular dependence, were performed in a slab-shaped PMMA phantom. For determining the angular dependence of MOSFET dosimeters, a cylindrically shaped PMMA phantom was used. Both MOSFET dosimeters showed excellent linearity against doses measured in the dose range of 50-600 cGy for a electron beam of 9 MeV. The reproducibility of all MOSFETs, excepted one standard MOSFET, was less than ±2 %. The dose-rate dependence of the two types MOSFET was within ±3 %. However, for the angular dependence, standard and micro MOSFETs show remarkable differences relative to gantry angles. This study shows the dosimetric characteristic of standard and micro MOSFET dosimeters for clinical electron beams. Both MOSFET dosimeters are suitable for dosimetry of electron beams in the energy range of 6 − 20 MeV. However, the dose verification of radiation therapy using multidirectional electron beam treatments allows for better use of micro MOSFETs which have a reduced directional dependence compared to standard MOSFETs.

AR 코어를 이용한 모션 그래픽 가상 카메라 구현에 관한 연구

정진범,이재수,이승현 한국컴퓨터정보학회 2022 韓國컴퓨터情報學會論文誌 Vol.27 No.8

In this study, to reduce the time and cost disadvantages of the traditional motion graphic production method in order to realize the movement of a virtual camera identical to that of the real camera, motion graphics virtualization using AR Core-based mobile device real-time tracking data A method for creating a camera is proposed. The proposed method is a method that simplifies the tracking operation in the video file stored after shooting, and simultaneously proceeds with shooting on an AR Core-based mobile device to determine whether or not tracking is successful in the shooting stage. As a result of the experiment, there was no difference in the motion graphic result image compared to the conventional method, but the time of 6 minutes and 10 seconds was consumed based on the 300frame image, whereas the proposed method has very high time efficiency because this step can be omitted. At a time when interest in image production using virtual augmented reality and various studies are underway, this study will be utilized in virtual camera creation and match moving. 본 연구는 실제 카메라의 움직임과 동일한 가상 카메라의 움직임을 구현하기 위해 전통적인 모션그래픽 제작 방법이 가지고 있는 소요시간과 비용에 대한 단점을 줄이기 위해 AR Core 기반의모바일 디바이스 실시간 트래킹 데이터를 이용하여 모션그래픽 가상카메라를 생성하는 방법을 제안했다. 제안하는 방법은 촬영 이후 저장된 비디오 파일에서의 트래킹 작업을 간소화하고, 촬영단계에서 트래킹 성공 유무를 판단하기 위해 AR Core 기반 모바일 디바이스에서 촬영과 동시에진행하는 방법이다. 실험결과 전통적인 방법과 비교하였을 때 모션그래픽 결과 이미지의 차이는없었으나 300프레임(frame) 영상 기준 6분 10초의 시간이 소모된 반면에 제안한 방법은 이 단계를생략할 수 있어 매우 높은 시간적 효율성을 갖는다. 현재 가상 증강 현실을 이용한 영상제작에 대한 관심과 다양한 연구가 진행되고 있는 시점에서본 연구는 가상 카메라 생성과 매치 무빙 등에서 활용될 있을 것이다.

계보학적 비판으로서의 계몽의 변증법 읽기

정진범 한국철학회 2019 철학 Vol.- No.141

Dialectic of Enlightenment is usually understood as an immanent critique. In contrast, this article attempts to show that it can be better understood by reading it as a genealogical critique. For this purpose, the relationship between two forms of critiques is first examined: Both are not completely different, and the immanent critique already has the genealogical elements in itself. Furthermore, Nietzsche’s genealogical idea is to be introduced in order to make the method of inquiry more precise. Under this aspect, Dialectic of Enlightenment can be analysed in three questions: Where does the enlightenment come from? What are the criteria for the critique of Enlightenment? And, how do both questions relate to each other? In this study, the complex structure of discourse will be reconstructed, and finally the normativity of the critique can also be explained. 흔히 계몽의 변증법 은 내재적 비판의 관점에서 이해되어 왔다. 그러나 본 논문은 이 저작이 계보학적 비판으로 해석될 때 더 잘 이해될 수 있음을 입증하고자 한다. 이를 위해 본 논문은 우선 내재적 비판과 계보학적 비판의 관계를 규명할 것이다. 두 비판 형식은 완전히 이질적인 것이 아니며, 내재적 비판에 계보학적 단초가 이미 들어 있다는 점이 밝혀질 것이다. 더 나아가 본 논문은 계보학적 비판을 보다 엄밀히 규정하기 위하여 니체의 방법론을 도입할 것이다. 이에 따라 계몽의 변증법 은 세 가지 물음 하에서 분석될 것이다. 계 몽은 어디에서 유래했는가 하는 물음, 계몽은 어떤 척도에 의해 비판되는가 하 는 물음, 그리고 유래와 정당성 물음이 어떻게 결합되고 있는가 하는 물음이 그것이다. 이러한 탐구를 통하여 계몽 비판의 복잡한 담론 구조가 재구성될 것이며, 이로써 이 비판의 규범성이 해명될 수 있을 것이다.

Comparison of Anisotropic Analytic Algorithm Plan and Acuros XB Plan for Lung Stereotactic Ablative Radiotherapy Using Flattening Filter-Free Beams

정진범,엄근용,김인아,김재성,이정우,홍세미,김연래,박병문,강상원,서태석,Chung, Jin-Beom,Eom, Keun-Yong,Kim, In-Ah,Kim, Jae-Sung,Lee, Jeong-Woo,Hong, Semie,Kim, Yon-Lae,Park, Byung-Moon,Kang, Sang-Won,Suh, Tae-Suk Korean Society of Medical Physics 2014 의학물리 Vol.25 No.4

이 연구는 비편평화여과기(flattening filter-free, FFF) 빔을 이용한 폐 정위절제방사선치료(stereotactic ablative radiotherapy, SABR)에 대하여 서로 다른 선량계산 알고리즘의 선량적 효과를 조사하였다. SABR를 받은 10명의 폐암 환자를 대상으로하여 평가하였다. 모든 치료계획은 Eclipse 치료계획시스템의 Acuros XB (AXB) 알고리즘을 이용하여 수립되었다. 다른 선량계산 알고리즘과 비교를 위하여, 추가적으로 anisotropic analytic algorithm (AAA) 알고리즘을 적용한 치료계획을 재 수립하였다. 두 알고리즘 평가를 위해서, 치료표적과 손상위험장기의 선량체적히스토그램(dose-volume histogrim, DVH)를 분석하였다. 그리고 기술적 인자로써 계산시간과 총 MU 값을 평가하였다. DVH 비교분석을 통해, PTV의 최대선량은 AXB이 AAA 보다 5.2% 높았으며 최소선량은 4.4% 낮게 나타났다. PTV의 $V_{105%}$에서 7.06%까지 큰 차이를 나타났다. 폐의 최대선량은 AXB 치료계획에서 약간 크게 나타났다. 동측성 폐에 5, 10과 20 Gy 선량이 조사되는 체적은 AAA 보다 AXB에서 더 크게 나타났으나 대측성 폐에 대해서는 거의 비슷하게 나타났다. 척수와 심장에서 최대선량의 차이도 크지 않았다. 계산시간의 경우, AXB가 AAA보다 13.7% 정도 소요시간이 적었고 MU 값은 AXB에서 3.47% 더 많았다. 이 연구의 결과들은 회전조절치료 기법을 포함하여 FFF 빔이 적용된 폐 SABR 치료계획에서 AXB 알고리즘은 선량계산의 정확성과 계산시간의 감소의 장점을 제공할 수 있을 것이다. This study investigated the dosimetric effects of different dose calculation algorithm for lung stereotactic ablative radiotherapy (SABR) using flattening filter-free (FFF) beams. A total of 10 patients with lung cancer who were treated with SABR were evaluated. All treatment plans were created using an Acuros XB (AXB) of an Eclipse treatment planning system. An additional plans for comparison of different alagorithm recalcuated with anisotropic analytic algorithm (AAA) algorithm. To address both algorithms, the cumulative dose-volume histogram (DVH) was analyzed for the planning target volume (PTV) and organs at risk (OARs). Technical parameters, such as the computation times and total monitor units (MUs), were also evaluated. A comparison analysis of DVHs from these plans revealed the PTV for AXB estimated a higher maximum dose (5.2%) and lower minimum dose (4.2%) than that of the AAA. The highest dose difference observed 7.06% for the PTV $V_{105%}$. The maximum dose to the lung was also slightly larger in the AXB plans. The percentate volumes of the ipsilateral lung ($V_5$, $V_{10}$, $V_{20}$) receiving 5, 10, and 20 Gy were also larger in AXB plans than for AAA plans. However, these parameters were comparable between both AAA and AXB plans for the contralateral lung. The differences of the maximum dose for the spinal cord and heart were also small. The computation time of AXB plans was 13.7% shorter than that of AAA plans. The average MUs were 3.47% larger for AXB plans than for AAA plans. The results of this study suggest that AXB algorithm can provide advantages such as accurate dose calculations and reduced computation time in lung SABR plan using FFF beams, especially for volumetric modulated arc therapy technique.

실러의 유희충동(Spieltrieb): 미적 주체와 정치적 주체의 사이에서

정진범 철학연구회 2022 哲學硏究 Vol.- No.138

This study aims to investigate the political-philosophical implications of Schiller’s theory of aesthetic freedom focusing on the concept of play drive. It is assumed that Schiller’s “Letters on the Aesthetic Education of Man” is a propaedeutic to the political subject by means of aesthetics, because he has expanded the basic aesthetic concepts beyond the subjective-aesthetic boundary to the anthropological and political level. First, Schiller’s own understanding of play and drive, and the concept of play drive will be examined. It becomes clear that the play drive is Schiller’s own expression of aesthetic freedom. And after the meaning of the concept of play drive for the subject theory has been derived, the political-philosophical character of Schiller’s aesthetics should be explained from it. Schiller’s play drive is the third drive produced from the balance between the two human natures of sensibility and reason, or the balancing act itself, and is only activated in aesthetic experience. In reality, humans are dominated by the overwhelming dominance of one of the two natures, but in aesthetic experience this dominance is temporarily dissolved. The play drive refers to the state in whice the dual nature of human beings can be developed according to their own logic while being free from each other, and it refers to the state in which human beings are freed from the drives that have dominated them. Therefore, the aesthetic subject in the play drive has a decentralized and desubjectivated character. Although the aesthetic subject cannot practically intervene in real politics in a direct sense, it is prepared for it in an indirect sense. This is because it is liberated from domination through aesthetic experience and practices the faculties power of relationship rather than domination. In this sence, the freedom of the aesthetic subject is a potential resistance to the existing order that dominates reality. However, this reading does not claim that aesthetics by Schiller is instrumentalized for politics. Politics is also a means to realize aesthetic idea of human totality. Aesthetics and politics point to and demand each other, but are still heterogeneous.

세기변조방사선치료를 위한 환자맞춤형 정도관리의 통계적 분석

정진범 한국의료QA학회 2008 가을학술대회 Vol.2008 No.3

호흡에 의한 내부 움직임의 영향이 있는 장기에서의 실험적 선량 측정

정진범,정원균,서태석,김연래 한국방사성폐기물학회 2004 한국방사성폐기물학회 학술논문요약집 Vol.2 No.2

[테오도어 아도르노 사망 50주기 (1903~1969)] 유예된 혁명, 철학의 시간

정진범 대우재단 2019 지식의 지평 Vol.- No.27

The Effect of Photon Energy on the Intensity-modulated Radiation Therapy Plan for Prostate Cancer: a Planning Study

정진범,김재성,김인아,Jeong-Woo Lee,조웅,서태석 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.1

In this study, the effect of the beam energy on the intensity modulated radiation therapy (IMRT) plan for prostate cancer was studied for competing IMRT plans optimized for delivery with either 6- or 15-MV photons. This retrospective planning study included 10 patients treated for localized prostate cancer at the Seoul National University Bundang Hospital. A dose of 66 Gy was prescribed in 33 daily fractions of 2 Gy. For inverse IMRT treatment planning, we used a 7-coplanar non-opposed beam arrangement at 0, 50, 100, 150, 210, 260, and 310 degree angles. To ensure that differences among the plans were due only to energy selection, the beam arrangement, number of beam, and dose constraints were kept constant for all plans. The dose volume histograms (DVHs) for the 6- and 15-MV plans were compared for the planning target volume (PTV) and for organs at risk (OAR), such as the rectum, bladder and both femoral heads. The conformal index was defined as the ratio of the 95% isodose volume divided by the PTV volume enclosed by the 95% isodose line, because we selected the 95% isodose line as our reference. Doses received by the 95% and 5% volume of the PTV were less than or equal to 1% for 6-MV compared to the 15-MV IMRT plan for 10 patients. Percentage of doses received by the 10% volume of the bladder and rectum were less than or equal to 1%. Percentage of doses received by the 30 and 50% volume of bladder and rectum were 1 ∼ 2% higher for 6-MV photons. Also, percentage of dose received by the 10% and 50% volume of the right and the left femur heads were 4 ∼ 5% higher for 6-MV photons. The mean homogeneity index for the 6-MV and 15-MV photon plans was 1.06. The mean conformity index of 95% was 1.04 ± 0.01 and 1.12 ± 0.02 for 6-MV and 15-MV, respectively, but this difference was not statistically significant. The mean monitor unit was 812 ± 40 and 716 ± 33 for the 6-MV and the 15-MV photon plans, respectively. The 6-MV photon plan delivers 13.4% more MU than the 15-MV plan. The-15 MV dose distributions and DVHs of the PTV generated by the clinical treatment planning calculations were as good as, or slightly better than, those generated for 6-MV photons. The organs at risk, such as the rectum, bladder, and femoral head were also similar, with the DVH curve for the 6-MV plan being slightly higher near the low-dose region, but lower near the high-dose region. Therefore, we recommend the use of 15-MV photons for IMRT of prostate cancer to achieve better in target coverage, in addition, the integrated dose can be reduce by using IMRT with 15 MV photons.