• Progress in Medical Physics
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• v.23 no.4
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• pp.219-228
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• 2012

The tangential breast intensity modulated radiotherapy (T-B IMRT) technique, which uses the same tangential fields as conventional 3-dimensional conformal radiotherapy (3D-CRT) plans with physical wedges, was analyzed in terms of the calculated dose distribution feature and dosimetric accuracy of beam delivery during treatment. T-B IMRT plans were prepared for 15 patients with breast cancer who were already treated with conventional 3D-CRT. The homogeneity of the dose distribution to the target volume was improved, and the dose delivered to the normal tissues and critical organs was reduced compared with that in 3D-CRT plans. Quality assurance (QA) plans with the appropriate phantoms were used to analyze the dosimetric accuracy of T-B IMRT. An ionization chamber placed at the hole of an acrylic cylindrical phantom was used for the point dose measurement, and the mean error from the calculated dose was $0.7{\pm}1.4%$. The accuracy of the dose distribution was verified with a 2D diode detector array, and the mean pass rate calculated from the gamma evaluation was $97.3{\pm}2.9%$. We confirmed the advantages of a T-B IMRT in the dose distribution and verified the dosimetric accuracy from the QA performance which should still be regarded as an important process even in the simple technique as T-B IMRT in order to maintain a good quality.

• Radiation Oncology Journal
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• v.4 no.2
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• pp.183-186
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• 1986

In brachytherapy of uterine cervical cancer using the high dose rate remote afterloading system, it is of prime importance to determine the position of the radiation sources and to estimate the irradiation time. However, calculation with manual method is so time consuming and laborious, that authors designed a software as an aid to intracavitary radiotherapy Planning using the personal computer to obtain the precision of treatment without being too complicated for routine use. Optimal source arrangement in combination with dose rate at each specific points and irradiation time can be easily determined using this software in several minutes.

• Progress in Medical Physics
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• v.9 no.4
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• pp.247-257
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• 1998

For effective radiotherapy, it should always be considered that calculation of different dose distribution in heterogenous tissue is important particularly on lung which has low density and large volume. To take precise dose distribution of 6MV X-ray in the thoracic cage, the authors had made a tissue equivalent phantom for thorax, measured dose distribution by thermoluminescent dosimeter and mm dosimeter, and derived methmetical equation coincided with provided theoretical formula. In comparision with isodose curve on case of homogeneous soft tissue, dose of heterogeneous lung tissue had been shown increase about 4% per cm depth on one and multiportal field, less than 15% difference on rotation field for esophagus, and around 20% difference on rotation field for lung according to the degree of rotation angle that must be corrected by dose compensation.

• Journal of radiological science and technology
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• v.27 no.4
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• pp.37-41
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• 2004

Purpose : Raise ability cultivation in presence at a sicked business by performance management estimation of device through measurement. Also Learn a technology that measure exact tube voltage, exposure time, output dose. And it is to grasp photofluorography X-ray generator existing circumstances using at hospital. Material & Method : Investigated Photofluorography X-ray generator(inside, outside each 10) of 10 university hospitals using tube voltage, exposure time, output dose measuring instrument. Result : Photofluorography device that tube voltage correctness is incongruent by examination PAE decision came out 3, and at exposure time correctness examination 2 incongruent, Also 3 that calculate coefficient of variation about exposure in repeatability examination of exposure were incongruent. Inappropriate photofluorography device is 5 outside hospital(mobile unit) and the thing in hospital was 3 in 3 kind of efficiency test. It appeared high that photofluorography device outside hospital is more incongruent than thing in hospital. Conclusion : May ready situation that can offer patient medical service of good quality by radiation exposure reduction, image quality administration, retake decrease etc. by keeping performance of Photofluorography device. Therefore, is considered that need on-time efficiency test.

• Proceedings of the KAIS Fall Conference
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• 2010.11b
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• pp.907-910
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• 2010

치과 진료시 파로라마 장치를 이용한 검사에서 유리선량계를 사용하여 피검자의 피폭선량을 측정하였다. 수정체의 피폭선량 영향을 평가하기 위하여 안경의 재질에 따라 수정체의 피폭선량을 측정하였다. 치아위치별 피폭선량 측정결과 82.4-2,340${\mu}Sv$ 선량분포로 나타나 최대 300% 이상의 피폭선량 차이를 보였다. 따라서 효과적이고 정확한 진단과 피폭선량 관리를 위해서는 장치제조시 예열시간 단축 과차폐등의 조치가 필요할 것으로 생각된다. 안경을 착용하였을 때 착용하지 않았을 때 비하여 수정체의 피폭선량이 안경의 재질에 따라서 1회 검사 시 20-75${\mu}Sv$ 증가되는 것으로 측정되었다. 그러므로 피폭 선량을 최소화하고 효율적인 검사를 위해 치과 파노라마 검사시 안경을 벗고 검사할 것을 권고 한다.

• Progress in Medical Physics
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• v.16 no.2
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• pp.77-81
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• 2005

To determine the appropriate method out of various available methods to measure build-up doses, the measurements and comparisons of depth doses of build-up region including the surface dose were executed using the Attix parallel-plate ionization chamber, the Markus chamber, a cylindrical ionization chamber, and a diode detector. Based on the measurements using the Attix chamber, discrepancies of the Markus chamber were within $2\%$ for the open field and increased up to $3.9\%$ in the case of photon beam containing the contaminant electrons. The measurements of an cylindrical ionization chamber and a diode detector accord with those of the Attix chamber within $1.5\%\;and\;1.0\%$ and after those detectors were completely immersed in the water phantom. The results suggest that the parallel-plate chamber is the best choice to measure depth doses in the build-up region containing the surface, however, using cylindrical ionization chamber or diode detector would be a reasonable choice if no special care is necessary for the exact surface dose.

• Journal of radiological science and technology
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• v.39 no.4
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• pp.607-614
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• 2016

The study investigates the necessity of 3 dimensional dose distribution evaluation instead of point dose and 2 dimensional dose distribution evaluation. Treatment plans were generated on the RANDO phantom to measure the precise dose distribution of the treatment site 0.5, 1, 1.5, 2, 2.5, 3 cm with the prescribed dose; 1,200 cGy, 5 fractions. Gamma analysis (3%/3 mm, 2%/2 mm) of dose distribution was evaluated with gafchromic EBT2 film and ArcCHECK phantom. The average error of absolute dose was measured at $0.76{\pm}0.59%$ and $1.37{\pm}0.76%$ in cheese phantom and ArcCHECK phantom respectively. The average passing ratio for 3%/3 mm were $97.72{\pm}0.02%$ and $99.26{\pm}0.01%$ in gafchromic EBT2 film and ArcCHECK phantom respectively. The average passing ratio for 2%/2 mm were $94.21{\pm}0.02%$ and $93.02{\pm}0.01%$ in gafchromic EBT2 film and ArcCHECK phantom respectively. There was a more accurate dose distribution of 3D volume phantom than cheese phantom in patients DQA using tomotherapy. Therefor it should be evaluated simultaneously 3 dimensional dose evaluation on target and peripheral area in rotational radiotherapy such as tomotherapy.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.115-120
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• 1997

영광3호기 방사선관리구역에 대한 중성자선량률을 정확히 평가하기 위하여 MCNP4A 전산코드를 이용, 방사선관리구역에서의 중성자 스펙트럼 계산을 수행하였다. 영광3호기에 대한 보다 정확하고 정밀한 3차원 몬테칼로 모델을 구축하기 위하여 핵연료집합체 구성요소 및 원자로심을 둘러싸고 있는 baffle, barrel,압력용기 등을 정확하게 묘사하였으며, 특히 방사선관리구역 주위의 구조물에 대해서도 3자원 MCNP 모델을 구축함으로써 원자로심부터 방사선관리구역까지 완전한 몬테칼로 모사(full-scope Monte Carlo simulation)를 이용한 계산을 수행하였다. 계산결과는 에너지 구간에 따른 중성자속 스펙트럼으로 나타내었으며 이 결과를 바탕으로 중성자속에 대한 선량률 환산인자를 고려하여 중성자선량률을 계산할 수 있다.

• The Journal of the Korea Contents Association
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• v.17 no.9
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• pp.292-299
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• 2017

Radiation protection aims to prevent a deterministic effect and minimize a stochastic effect. Overestimating a deterministic effect and a stochastic effect can result in an inaccurate assessment of the risks that will occur in the future, and thus accurate evaluation of the absorbed dose of these fundamental amounts is especially important. This study was intended to measure Kerma using PCXMC 2.0 based on Monte Carlo simulations and to assess the exact absorbed dose by comparing doses produced using multipurpose dosimeter and glass dosimeter. It has been decided to conduct experiments for skull, abdomen and pelvis, and Kerma measured PCXMC 2.0 based on Monte Carlo simulations. The absorbed dose was measured using muli purpose dosimeter and glass dosimeter. The results for the experiments conducted in skull, abdomen, pelvis show that the difference in dose appears great in the order of PCXMC 2.0, muli purpose dosimeter, and the glass dosimeter, and muli purpose dosimeter showed a value closer to that of Kerma. As a result, it has been found that the glass dosimeter was the most advantageous in measuring the actual absorbed dose.

• Progress in Medical Physics
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• v.15 no.2
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• pp.63-69
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• 2004

HDR brachytherapy administers a large dose of radiation in a short time compare with LDR, and its optimization for treatment is related to several complex factors, such as physical, radiation and optimization algorithms, so there is a need for these to be verified for accurate dose delivery. In our approach, a previous study concerning the phantom for dose verification has been modified, and a new pelvic phantom fabricated for the purpose of localization, including a structure enabling the use of a CT or MRI system. In addition, a comparison study was performed to verify an orthogonal method that is commonly used for brachytherapy localization by comparing target coordinates from a CT system. Since the developed phantom was designed to simulate the clinical setups of cervix cancer, it included an air-filled bladder and a rectum structure shaped sphere and cylinder An N-shaped localizer was used to obtain precision coordinates from both CT and films. Moreover, the IDL 5.5 software program for Windows was used to perform coordinates analysis based on an orthogonal algorithm. The film results showed differences within 1.0 mm of the selected target points compare with the CT coordinates. For these results, a Plato planning system (Nucletron, Netherlands) could be independently verified using this phantom and software. Furthermore, the new phantom and software will be efficient and powerful qualify assurance (QA) tools in the field of brachytherapy QA.