• Journal of Radiation Protection and Research
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• v.20 no.4
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• pp.227-236
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• 1995

Using beam data and accurate 3D dose model, a study of the spatial dose distribution for various arcs was carried out. The dose dirstibution generated by the accurate dose model could be represented by a simple approximate analytic form which is convenient and very efficient for calculating dose distribution iteratively in the optimization procedure. We developed an empirical cylindrical dose model to compute dose for one full rotational arc or partial rotational arc. After a tedious search for fits to a collection of 200 points of accurate dose data, we found simple formular with 7 parameters search. As a consequence, the programs required approximately less than 1 second to compute dose for one single arc on a 20 by 20 matrix (400 points) using fast approximate dose model. In conclusion the fast approximate dose model give dose distributions similar to the accurate dose model, which makes this fast dose model an attractive alternative to the accurate 3D dose model.

• Progress in Medical Physics
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• v.5 no.1
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• pp.67-74
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• 1994

Dose distribution of point source represents an inverse square law as the distance, Difference of measurement value and calculation value according to moving distance of radiation source show very large error in dose calculation of Brachytherapy. Therefore, in RALS of high dose rate, dose calculation have an important effect in treatment of uterine cervix cancer and recurrent rate. In this paper, authors measured moving distance of radiation source carrying out RALS. And we measured Rectum dose compared with calculationdose.

• Progress in Medical Physics
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• v.4 no.1
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• pp.29-39
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• 1993

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.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.63-68
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• 1996

열형광 선량계(TLD)를 사용한 피부 선량평가는 베타선의 에너지를 구분함으로 정확히 평가된다. 이는 차폐체에 의한 감쇄효과를 이용하는 방법으로 본 논문에서는 7개의 두께가 다른 알루미늄 차폐체를 사용하였고, TLD로는 미국 Teledyne Isotopes사의 LiF$_{7}$ 선량계를 채택하였다. 비상 베타 선량계의 베타선에 대한 특성실험을 위해 한국 원자력연구소가 확보 하고 있는 PTB 표준선원인 $^{90}$ Sr/ $^{90}$ Y (E$_{max}$=2.27MeV, E$_{avg}$=0.8MeV), $^{204}$Tl(E$_{max}$=0.76MeV, E$_{avg}$=0.26MeV), $^{147}$ Pm (E$_{max}$= 0.225MeV, E$_{avg}$=0.06MeV)에 대한 조사를 하였다. 이런 결과로 비상 베타 선량계의 표준 베타선원에 대한 보정계수와 소자별 반응비를 구할 수 있었고, 이것을 이용하여 미지의 베타선원에 대하여 정확한 선량평가를 하기위한 알고리즘을 개발하였다.

• The Journal of Korean Society for Radiation Therapy
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• v.7 no.1
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• pp.32-44
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• 1995

I. 제 목 고에너지 X-선 소조사야의 선량분포 및 계측에 관한 연구 II. 연구의 목적 및 중요성 최근 수술이 어려운 뇌종양등에 대한 방사선수술법(Radiosurgery)이 관심의 대상이 되고 있다. 방사선수술법은 크게 나누어 200여개의 Co-60이 장착된 장치(Gamma Knife)를 이용하는 방법과, X-선치료기를 이용하는 방법은 몇개의 보조기구를 설치하면 가능한 매우 경제적인 방법이다. 따라서 Microtron을 이용한 방사선수술의 기초자료확보를 위하여 소조사야에 대한 선량과 선량분포의 측정 및 계산을 실시하였다. III. 연구의 내용 및 범위 Microtron으로부터 조사되는 6MV, 10MV, 21MV X-선의 지름 3cm이하 소조사야에 대한 정확한 선량 및 선량분포 자료를 확보하기 위해, 가. Microtron치료기와 보조장치등에 대한 정밀도 계측 및 평가 나. 보조 Collimator의 적당한 크기와 재료의 선택 및 설계, 제작. 다. 에너지와 조사야 크기 각각에 대한 여러측정장치(Ion chamber, Diode detector, TLD 및 Film등)를 이용한 선량 및 선량분포 측정. 라. 측정값들의 비교, 검토 및 측정된 자료에 의한 선량 및 선량분포의 계산을 수행했다. IV. 연구결과 및 활용에 대한 건의 본 연구에서 얻은 결과는 다음과 같다. 가. Microtron치료기와 보조장치등의 정확도의 허용 오차범위내에서 잘 일치하였다. 나. 보조 collimater adpator는 총 길이 24cm로 하였으며 재질로는 두랄미늄을 사용하였고, 보조 collimator는 low melting alloy를 사용하였으며 소조사야 크기의 정확도는 0.5mm이내에서 매우 잘 일치 하였다. 다. 방사선 수술법의 에너지 선택에 중요한 요소중의 하나인 penumbra는 6MV X-선에서 가장 적게 나타났으며 라. 소조사면에 대한 깊이-선량 백분율곡선은 모든 에너지에서 조사면이 작아질수록 표면으로 이동하는 경향을 보였다. 이상의 결과로부터 방사선 수술을 시행할 경우 수십억원에 이르는 장비의 도입이나 새로운 시설 없이 Microtron에서 조사되는 고에너지 X-선을 이용할 수 있을 것으로 사료된다. 또한 새로 구입한 측정기나 보조 Collimator를 이용하여 소조사야에 대한 선량측정기술을 습득함으로써 일반적인 소조사야의 방사선치료나 회전치료등에 활용할 수 있다.

• Journal of the Korean Society of Radiology
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• v.9 no.7
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• pp.449-457
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• 2015

In this study, to evaluate the usefulness of the treatment plan of tomotherapy and volumetric modulated arc therapy (VMAT) in the radiotherapy for prostate cancer, the absorbed dose, dose volume histogram (DVH), treatment efficiency, and the results of dose verification accuracy using MapCHECK2 were compared and analyzed. Of the prostate cancer patients who underwent tomotherapy treatment in the Radiologic Oncology of H University Hospital between July 2014 and December 2014, 12 patients were randomly selected. As a result of analyzing the absorbed dose and DVH, both radiologic treatment plans showed slight differences in the treatment of the cancer tissues and the bladder, but the difference was in the error range of -5% to +3%, and did not exceed the side effect guideline or the tolerance dose limit. VMAT showed higher treatment efficiency than tomotherapy with a 2.5 times shorter treatment time and a 10.3 times less monitor unit (MU). Both showed 95% or higher dose accuracy satisfying the standard. VMAT showed 2.3% higher efficiency than tomotherapy. In both tomotherapy and VMAT, appropriate doses were absorbed for cancer tissues, and did not exceed the tolerance dose for normal tissues showing no significant difference in dose distribution. However, considering the shorter treatment time, lower total MU, and better treatment efficiency and dose verification accuracy, VMAT may be more useful than tomotherapy in cancer treatments.

• Progress in Medical Physics
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• v.4 no.2
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• pp.19-25
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• 1993

Treatment planning of lung cancer with density corrected Computed tomography. Eighty-seven patients with lung cnacer who had radiation therapy in Yeungnam University Medical Center between, April 1 1990 and Aug. 30 1993 were retrospectively evaluated total tumor dose, dose distribution, field correction, and loading change, compared with contour or CT image planning and density corrected CT planning. In dose distribution, higher dose was calculated in compare with density corrected CT planning less than 5% difference were found in 45 patient(52%), 5-10% in 25 patients (29%), 10-15% in 15 patients (17%) and over 15% in 2 patients (2%). Correction of treatment field was performed in 18 patients (21%) and changing of dose loading was given in 15 patients (17%). In conclusion, we emphasize that density corrected CT planning is the very important factor which contribute to increase therapeutic gain by exact selection of target volume, target dose, normal tissue dose and dose of critical organ.

• Journal of The Korean Radiological Technologist Association
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• v.29 no.1
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• pp.6-11
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• 2003

목적 : 전신방사선조사(TBI)시 균등한 선량을 조사할 목적으로 사용되는 각 신체부위별 보상체(compensator) 두께의 결정은 열형광선량계(TLD)를 이용하여 표면선량(surface dose)을 측정하고, 심부선량(depth dose)으로 환산하는 방법을 주로 이용한다. 그러나 이와 같은 방법은 골(bone) 조직에 대한 선량감쇠(dose attenuation)의 영향이 고려되지 않아 신체중심부에서의 정확한 심부선량을 알 수가 없다. 이에 본 연구

• Journal of Radiation Protection and Research
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• v.40 no.4
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• pp.202-210
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• 2015

The low dose radiation is done for a long period, thus researchers have to know the exact dose distribution for the irradiated mouse. This research has been conducted in order to find out methods in transmitting an exact dose to mouse in a mouse irradiation experiment carried out using $^{137}Cs$ irradiation equipment installed in the DIRAMS (Dongnam Institution of Radiological & Medical Sciences) research center. We developed a single mouse housing cage and shelf with adjustable geometric factors such as distance and angle from collimator. The measurement of irradiated dose showed a maximal 42% difference of absorbed dose from the desired dose in the conventional irradiation system, whereas only 6% difference of the absorbed dose was measured in the self-developed mouse apartment system. In addition, multi mice housing showed much difference of the absorbed dose in between head and body, compared to single mouse housing in the conventional irradiation system. This research may allow further research about biological effect assessment for the low dose irradiation using the self-developed mouse apartment to provide more exact doses which it tries to transmit, and to have more reliability for the biological analysis results.

• Journal of radiological science and technology
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• v.30 no.1
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• pp.33-38
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• 2007

The propose of this study is a verification of the correct calculation of the dose around source and the prescription dose of Ir-192 source in the plato treatment planning system. The source and orthogonal coordinates for lateral direction and those for the anterior posterior direction were drawn on a A4 paper and then input into the system. The prescription dose was prescribed to two points with radius 1 cm in the direction of polar angle $90^{\circ} and $270^{\circ} from the center of the source. The doses of prescription point and dose points acquired from the treatment planning system were compared with those from manual calculation using the geometry function formalism derived by Paul King et al. In this analysis, the doses of prescription point were exactly consistent with each other and those of dose points were obtained within the error point of 1.85%. And the system of accuracy was evaluated within 2% of tolerance error. Therefore, this manual dose calculation used for the geometry function formalism is considered to be useful in clinics due to its convenience and high quality assurance.