Na131I에 依한 汚染度 및 汚染除去의 實驗的 硏究

秋成實,朴昌潤 대한방사선방어학회 1984 방사선방어학회지 Vol.9 No.2

암상방사선물리학의 최신동향

추성실 대한의학협회 1978 대한의학협회지 Vol.21 No.6

연속 및 중복 운동조사에 의한 유암의 치료방식의 비교

추성실 대한영상의학회 1973 대한영상의학회지 Vol.9 No.2

The method of tangential rotation therapy for non-operated breast cancer has been developed in Yonsei Cancer Center. This method is in principle to avoid the disorder of the lung field by radiotherapy as well as possible and to make an adequate radiation dosage according to each treated region, including breast, axilla, supra or infraclavicullar fossa, and sternum. We have various irradiation methods conducted today, but this continuous and repeated tangential rotation therapy is extraordinarily superior to a traditional fixed tangential therapy. The advantages of this method are summarized as follows: 1) Simultaneous treatment with different doses is possible to the breast and the thorax including the sternum. 2) The radiation effect on the intrathoracic organs including lung and heart is almost absent. 3) It is easy to simultoneous irradiation in the large treated region. 4) The dose distribution of various types is possible by changing a rotation angle and an eccentric angl in accordance with irradiated region. 5) The irradiated fields are not overlapped and not so complicated as a fixed polytagential therapy. Therefor the continuous and repeated tangential rotation therapy is an adequate method for the non-operated breast cancer and may be sure of helping for radiation therapy.

심부백분선량의 경사보상

추성실 대한영상의학회 1973 대한영상의학회지 Vol.9 No.2

An accurate and simple compensating method of sloping field have been devised for effective dose planning. The experimental formula, induced with linear absorption coefficient and measured values, shown in formula (5), is applied accurately to sloping compensation of wide region depends on source skin distance, field size, absorption coefficient and angle of incidence. According to this method, the distance of shifting for the normal isodose curve,“h”, is varied by the distance of shifting between the normal and sloping surface,“d”, shown in Fig. 1. We need more simple compensating factor within the permitting error in clinical practice. It is possible to obtain the reasonable compensating factore by analysing the sloping field calculated by the experimental formula. The reasonable compensating factor by analysing the sloping field calculated by the experimental formula. The results of this analysis are shown in Figs. 3-5, comparing with the shift methods of $\frac{1}{2}$d. 2/3d and \ulcornerd. In radiation therapy it may be recommended to use“Compensating factor”indicated in Table 1 to correct for the sloping field.

고에너지 전자선의 경사조사로 인한 선량분포의 보상

추성실 대한영상의학회 1976 대한영상의학회지 Vol.12 No.1

Compensation of dose distribution of an electron beam for the oblique incidence is to shift the standard isodose curves according to the distance of the air space. The error of the corrected distribution from the measured one was more than 10% when the space was more than 2 cm in 8∼12 MeV electron beam. The electron beam diverged approximately in accordance with the inverse-square law when the scattering foil was assumed to be the virtual source. Correction of the air space shifting and the inverse square law resulted in an error less than 3%.

Disign and Thermal Distribution of Intra-hyperthermia Microwave Antennas for Utero-cervical Applicators

추성실,문성록,Chu, Sung-Sil,Moon, Sun-Rock The Korean Society for Radiation Oncology 1990 Radiation Oncology Journal Vol.8 No.1

자궁암치료에서 재발되거나 치료가 어려운 종양에 대하여 방사선과 온열요법을 병행함으로서 치료 성과를 다소 향상시킬 수 있었다. 더욱이 방사선 근접조사와 강내온열치료는 주위 건강조직의 피해를 줄이면서 종양에 집중손상을 줄 수 있었으며 강내방사선조사 기구를 공동으로 이용하므로서 시술이 간단하고 치료부위를 정확히 조준할 수 있었다. 그러나 강내조사용 안테나는 그 모양과 구성에 따라 온열 분포가 변하며 재래식 쌍극철심형 안테나는 끝부분 또는 연결부위의 가온이 급증하여 균등한 온열분포를 기대할 수 없었다. 저자들은 안테나의 길이를 마이크로파의 약수 즉 3, 6, 12 cm로 하여 공명이 잘 이루어지도록 하였으며 끝이 굵고 접촉 부위가 가느다란 꼬깔형 (conical) 안테나를 제작하여 사용한 결과 안테나 축에 따라 거의 일정하거나 약간 타원형의 온도분포를 이루었으며 가온 깊이도 $2\~3\;cm$로서 비교적 깊은 곳까지 가열할 수 있어 강내 치료효과를 향상시킬 수 있다고 생각된다. Intracavitary brachytherapy combined hypertermin for utero-conical cancer seems to be a promising method for salvage treatments in persistent tumors and inoperable or previously irradiated cervical recurrences. In order to heat the vaginal apex and uterus, powerfull conical antennas which are suitable for afterloading cervical applicator have been designed for use in conjuction with intracavitary radiation therapy. The antennas were constructed with conical conductive material to feed line and the effective lenght were designed proportional to microwave length, Power deposition profiles of 2450 MHz of conical antennas were studied in both phantom models and muscle tissue and compared to those of commonly used dipole antenna. Improvement of the heating pattern was found in both phantom and muscle tissue. The heating pattern produced by the conical antenna resembles an ellipsoid and then the temperature distribution in depth was extended to $2\~3\;cm$ from the effective antenna axis.

방사선 입체조형치료를 위한 동적쐐기여과판의 고안과 조직내 선량분포 특성

추성실 한국의학물리학회 1998 의학물리 Vol.9 No.2

쐐기형 선량분포는 임상에 많이 응용하고 있으며 고정쐐기여과판은 선질의 강화와 조사면 주위 의 산란선 증가, 등선량 각도의 불일치, 여과판의 장착 및 취급이 부정확하고 어려우며 입체조형 방사선 치료시 많은 조사면을 입체방향으로 중첩시킴으로서 발생되는 선량의 불균질을 방지하고 동적입체방사선조형치료(dynamic 3D conformal radiotherapy) 및 선량강도조절치료(intensity modulation radiotherapy)를 가능케 하는 동적쐐기여과판을 고안 제작한다. 동적쐐기여과판은 콜리메이터를 움직이면서 선량율을 변화시켜서 최적한 쐐기각의 등량곡선을 얻을 수 있도록 미분치료표(segmented treatment tables: STT) 유도하며 표준형의 STT를 컴퓨터에 입력시킨다. STT에 의하여 생성되는 동적쐐기여과판의 특성과 조직내 선량분포를 쐐기각, 조사변의 크기, 조사선량율둥 여러 조건하에서 측정 분석함으로서 방사선 감수성이 높은 장기 내의 종양과 저항성 이 강한 악성종양치료에 도움을 주며 전반적인 방사선치료 성과를 향상시키고자 한다. 연세암센터에서 가동되는 선형가속기 (Varian Clinac-2100C/D)를 이용하여 6MV 와 10MV 광자선과 쐐기각이 15$^{\circ}$, 30$^{\circ}$, 45$^{\circ}$, 60$^{\circ}$이고 정사각형 조사면의 한변이 4cm 부터 20cm 범위를 0.5cm 간격으로 콜리메이터를 움직이면서 선량 변동량을 표시하는 미분치료표 (STT)를 작성하였다. 쐐기투과선량인자 (wedge transmission factor) 는 표준 물팬텀내에 표준전리함을 장치하고 열린조사면과 미분치료표에 의한 쐐기조사면의 선량비료서 결정하였다. 쐐기여과판에 의한 조직내선량분포와 등량곡선 및 프로파일은 필름으로 측정하고 영상선량측정기로 작성하였다. 수식으로 유도한 미분치료표(segmented treatment tables: STT) 은 쐐기여과판의 쐐기각과 일치하였으며 쐐기투과선량인자는 쐬기각이 클수록 감소하였으며 조사변이 클수록 적어졌고 조사면 크기와의 관계는 비선형적이었다. 동적쐐기여과판에 의한 등량곡선의 쐐기 기울기는 고형여과판보다 더욱 일치된 경사각을 유지하였다. 심부선량백율은 열린조사면에 의한 것과 거의 비슷하였으며 고형쐐기여과판의 심부율보다 약간 줄어들었다. 동적쐐기여과판은 고형쐐기여과판보다 사용상, 선량측정 및 선량분포에 서 장점이 많으며 피부와 여과판사이의 길이가 길어서 침대에 부딪치는 일이 없고 피부의 산란선 오염이 감소되어 치료효과를 상승시킬 수 있다. 동적쐐기조사방법을 개발함으로서 지금까지 방사선 후유증과 종양의 불균일한 선량배열로 치료의 어려움이 있었던 분야를 개척할 수 있으며 동적입체 방사선조형치료 (dynamic 3D conformal radiotherapy) 및 선량강도조정치료 (intensity modulation radiotherapy)를 가능하게 함으로서 방사선치료성과를 향상시킬 수 있다. Wedge shaped isodoses are desired in a number of clinical situations. Hard wedge filters have provided nominal angled isodoses with dosimetric consequences of beam hardening, increased peripheral dosing, nonidealized gradients at deep depths along with the practical consequendes of filter handling and placement problems. Dynamic wedging uses a combination of a moving collimator and changing monitor dose to achieve angled isodoses. The segmented treatment tables(STT) that monitor unit setting by every distance of moving collimator, was induced by numerical formular. The characteristics of dynamic wedge by STT compared with real dosimetry. Methods and Materials : The accelerator CLINAC 2100C/D at Yonsei Cancer Center has two photon energies (6MV and 10MV), currently with dynamic wedge angles of 15$^{\circ}$, 30$^{\circ}$, 45$^{\circ}$ and 60$^{\circ}$. The segmented treatment tables(STT) that drive the collimator in concert with a changing monitor unit are unique for field sizes ranging from 4.0cm to 20.0cm in 0.5cm steps. Transmission wedge factors were measured for each STT with an standard ion chamber. Isodose profiles, isodose curves, percentage depth dose for dynamic wedge filters were measured with film dosimetry. Dynamic wedge angle by STT was well coincident with film dosimetry. Percent depth doses were found to be closer to open field but more shallow than hard wedge filter. The wedge transmission factor were decreased by increased the wedge angle and more higher than hard wedge filters. Dynamic wedging probided more consistent gradients across the field compared with hard wedge filters. Dynamic wedging has practical and dosimetric advantages over hard filters for rapid setup and keeping from table collisions. Dynamic wedge filters are positive replacement for hard filters and introduction of dynamic conformal radiotherapy and intensity modulation radiotherapy in a future.

코발트 60 점선원에 대한 자궁강내의 선량분포

추성실 대한영상의학회 1980 대한영상의학회지 Vol.16 No.1

According to the remarkable progress of high energy medical radioation apparatuses, the part of the teletheraphy using linear accelerator and telecobalt is now occupying almost the whole portion of cancer therapy in the field of radiation treatment. However, even in the present days, inserting sealed small source theraphy applied interstitially and intracavitry shows better results in some kinds of tumors just as the tumors of the tongue and those of the uterine cervix, especially, high dose rate sources are more effective for it. On the technic of these inserting theraphy, the dose calculations in the tumor are the most troublesome procedures to determine the therapy technic, and its technic must be doing under accurate dose distribution, dosimetry and localization. The high dose rate remotely controlled after loading apparatus, Toshibal RAL 303 , was installed in Yonsei Cancer Center in 1979. We applicated the computer technique to the dose computation and enabled to improve the accuracy of intracavitary irradiation for the cervix cancer. To obtain the exact localization of applications in the uterine cervix. We fabricated the simulating scaler and metallic o-ring contacting in tandem. Optimum standard arrangements of radiation sources were confirmed as 10 types, according to statistical evaluation of patients who had received brachtheraphy.

연령 확산 이론에 의한 전자선의 조직내 선량분포 평가

추성실 한국의학물리학회 1993 의학물리 Vol.4 No.1

고에너지 전자선은 방사선치료에서 중요한 역할을 담당하고 있으나 전하를 갖인 입자로서 인체조직과 상호작용이 복잡하여 조직내 전자선량분포를 정확히 표현하기에는 매우 어렵다. 전자선분포를 계산하는 데는 심부율과 평면분포율등 여러방법이 제시되고 있었으나 수학적 모형을 이용하는 것이 가장 신속하고 다양한 계산을 수행할수 있는 수단으로 알려져 왔으며 컴퓨터의 발달과 병행하여 실요화 되고 있다. 저자들은 연령확산방정식을 기초로한 수식적 모델을 도입하고 연세암센터에 설치된 선형가속기에서 측정된 전자선의 분포를 이용하여 실험식의 상수인자를 결정 삽입하므로서 조직내 어떤 깊이 어느 지점에서도 정확한 선량이 계산될 수 있는 실험식을 완성하였다. 사용자는 연령확산 실험식에서 전자선의 에너지와 조사면 그리고 선원간의 거리만 입력하면 조직내 전자선의 심부율과 등선량곡선을 정확히 예측할 수가 있고 고선량부위에서는 위축되고 저선량부위에서는 확산되는 등선량곡선의 모양을 정확히 기술할 수 있으며 컴퓨터에 의한 선량계획은 어떤 입상상태에서도 간단하고 신속하게 표시할 수 있었다. 전자선의 에너지 6-20MeV 에서 심부율의 정확도는 섬부율 50%이상일 때는 2% 이내이며 낮은 심부율 부위에서는 5%의 오차를 가졌고 조사면 6$\times$6$cm^2$에서 25$\times$25$cm^2$에 대한 심부율 오차는 3% 이내이며 확산오차는 3mm 이하로서 정확성이 비교적 높았다. Electron beams have found unique and complementary used in the treatment of cancer, but it's very difficult to delineate dose distribution, because of multi-collisions. Numerical solution is more usefull to describe electron distributed in tissue. A semi-empirical eqution is given for the dose at any point at various depths in water. This equation is a modificated model which was based on solutions of a general age diffusion equation. Parameters have been calulated from electron beams data with energies 6~18MeV form a LINAC for use in computerised dosimetry calculations. The depth doses and isodose curves are predicted as a function of the practical range, source skin distance and field size. Depth dose accuracy have been achieved 2% above 50% depth dose and 5% at lower doses, relative to maximum dose. Also, the shape of the isodose curves with the constrictions at higher dose and bulging ot lower values are accurately predicted. Computer calculated beams have been used to generate ever isodose distribution for certain clinical situations.

Enhanced Thermoelectric Transport Properties of n-type InSe by Sn doping

추성실,홍석원,김현식,김상일 대한금속·재료학회 2020 대한금속·재료학회지 Vol.58 No.5

Layered post transition metal chalcogenides such as SnSe, SnSe2, In2Se3, and In4Se3 have attracted attention as promising thermoelectric materials due to their intrinsically low lattice thermal conductivities. Recently, n-type indium selenide (InSe) based materials have also been suggested as good candidates for thermoelectric materials by optimizing their electrical properties, i.e., increasing carrier concentration. Here, we report enhancement of the thermoelectric properties of n-type InSe by Sn substitutional doping at the In site. A series of In1-xSnxSe for x = 0, 0.03, 0.05, 0.15 and 0.2 was examined. The carrier concentration and electrical conductivity increased due to the Sn substitution, since Sn behaves as a shallow electron donor in InSe, while the Seebeck coefficient decreased moderately. In addition, it was found that effective mass was increased by more than 10 times by Sn doping. As a result, the power factor was enhanced from 0.07 mW/ mK2 to 0.13 mW/mK2 at 800 K. The total thermal conductivity was unchanged despite Sn doping because the electrical contribution to the total thermal conductivity was very small. Consequently, Sn doping in InSe enhanced the dimensionless thermoelectric figure of merit zT from 0.04 to 0.14 at 800 K, mainly due to enhanced electrical properties.