레이저 투과 선량에 따른 황색포도상구균의 광역학적 비활성화

구본열(Bon-Yeoul Koo),김지원(Ji-Won Kim) 대한방사선과학회(구 대한방사선기술학회) 2022 방사선기술과학 Vol.45 No.2

Staphylococcus aureus is a major pathogen that causes clinical infections in humans and can also cause massively colonized in lesion skin, particularly in atopic dermatitis patients. This study investigated the effects of photodynamic inactivation with radachlorin and diode laser irradiation on the viability of S. aureus in vitro and assessed the effects of the dose of laser transmission. In the PDI group, 5 μL of S. aureus suspension and 5 μL of radachlorin were inoculated in a 55 mm petri dish (63.6 cm2). The samples were placed in a 37° incubator for 30 min and then irradiated with light (660 nm diode laser). After laser irradiation, the cells were stored for 24 h at 37° in an incubator with 5% CO2, and the number of colonies was counted. All CFU/mL of S. aureus were reduced by diode laser in the presence of radachlorin, with a killing rate of 87.9% at an energy dose of 9 J/cm2. This study contribute to treat colonized with S. aureus in atopic dermatitis patients and wound infections by providing information on the optimal dose of laser transmission using PDI to eliminate S. aureus.

이동형 방사선 차폐장치의 성능평가에 관한 연구

구본열(Koo Bon-Yeoul),한상현(Han Sang-Hyun) 대한방사선과학회(구 대한방사선기술학회) 2018 방사선기술과학 Vol.41 No.4

When using a mobile X-ray unit, primary radiation creates medical images and secondary radiation scatters in many directions, which reduces image quality and causes exposure to patients, care givers and medical personnel. The purpose of this study was to develop a radiation shielding system for effectively shielding secondary radiation and evaluate its effectiveness. Using a mobile X-ray unit, spatial dose according to presence of human equivalent phantom and spatial dose using the developed shielding device were measured, and the phantom at 80 cm equidistance from center of X-ray was compared with spatial dose according to use of a shield. Measurements were taken at intervals of 10 cm every 30° from the head direction(-90°) to the body direction(+90°). In the spatial dose measurement with and without the phantom, when the human equivalent Phantom was used, the spatial dose was increased by 40% in all directions from 40 cm to 100 cm from the central X-ray, and about 88% of the space dose was reduced when using the developed shields with the phantom. The equidistance dose at 80 cm from the central X-ray was increased by 39% from 5.1±0.26 μ Gy to 7.1±0.15 μGy when the human equivalent phantom was used, and when phantom was used and shielding was used, the spatial dose was reduced by about 90% from 7.1±0.15 μGy to 0.7±0.07 μGy. The spatial dose of natural radiation was measured to be about 0.2±0.04 μGy when using the developed shielding with Phantom at a distance of 1 m or more. It is expected that by using the developed shielding system, it will be possible to effectively reduce secondary radiation dose received in all directions and to ensure safe imaging.

이동형 X선 발생장치의 2차 방사선 차폐를 위한 선속조절기 개발 연구

구본열(Koo Bon-Yeoul),김가중(Kim Gha-Jung) 대한방사선과학회(구 대한방사선기술학회) 2018 방사선기술과학 Vol.41 No.5

Mobile X-ray generators are used not in the radiation area but in open space, which causes the exposure of secondary radiation to the healthcare professionals, patients, guardians, etc., regardless of their intentions. This study aimed to investigate the shielding effect of the developed radiation restrictor to block the secondary radiation scattered during the use of mobile X-ray generator. Upon setting the condition of mobile X-ray generator with chest AP, spatial doses were measured by the existence of human equivalent phantom and radiation restrictor, and measured by the existences of phantom and radiation restrictor at the same length of 100 cm. Measurements were taken at intervals of 10cm every 30° from -90° (head direction) to +90° (body direction). Upon the study results, spatial doses in all direction were increased by 45% on average when using phantom in the same condition, however, they were decreased by 64% on average when using the developed radiation restrictor. The dose at 100 cm from the center of X-ray was 3.0±0.08 μGy without phantom and was increased by 40% with 4.2±0.08 μGy after phantom usage. The dose when using phantom and the developed radiation restrictor was 1.4±0.08 μGy, which was decreased by 66% compared to the case without using them. Therefore, it is considered the scattered radiation can be shielded at 100-150 cm, the regulation of the distance between beds, effectively with the developed radiation restrictor when using mobile X-ray generators, which can lower the radiation exposure to the people nearby including healthcare professionals and patients

엑스선 촬영 시 보조도구 재료로써 탄소 섬유 강화 플라스틱의 유용성

문준호(Joon-Ho Moon),구본열(Bon-Yeoul Koo) 대한방사선과학회(구 대한방사선기술학회) 2023 방사선기술과학 Vol.46 No.3

텅스텐 차폐체의 감마선 투과선량 측정

한상현(Sang-Hyun Han),구본열(Bon-Yeoul Koo) 한국산학기술학회 2018 한국산학기술학회논문지 Vol.19 No.9

본 연구는 Apron의 재질로 이용되고 있는 텅스텐 차폐체를 핵의학과에서 사용하는 선원의 종류와 차폐체의 두께, 선원부터 검출기 사이의 거리를 변화시켜 차폐체에 투과시킨 후 투과선량과 차폐율을 알아보고자 하였다. 실험을 위해서 선원과 차폐체와 검출기를 일직선으로 배치하고 높이 100 ㎝ 지점에서 Inspector로 측정하였다. 그 결과 텅스텐에 차폐효과가 가장 높은 선원은 <SUP>201</SUP>Tl 선원으로 측정되었고, <SUP>123</SUP>I 선원이 <SUP>99m</SUP>Tc 선원보다 차폐효과가 높게 나타났다. 실험에 사용한 선원과 검출기 사이의 거리는 멀어질수록 투과선량은 작아졌고, 텅스텐 차폐체의 두께는 두꺼울수록 차폐율은 높게 측정되었다. 하지만 <SUP>13</SUP>1I와 <SUP>18</SUP>F 선원에서는 0.25 ㎜Pb의 차폐체를 사용했을 경우 차폐체가 없을 경우 보다 차폐율이 감소하는 것을 확인하였다. 따라서 <SUP>13</SUP>1I와 <SUP>18</SUP>F 선원을 사용할 경우에는 방사선 차폐효과가 높은 텅스텐일지라도 선원의 종류에 따른 특성과 차폐체의 두께를 고려하여 사용하길 권장하고, 실험 결과를 참고하여 사용한다면 피폭 저 감화방안에 도움을 줄 수 있을 것으로 생각된다. This study was conducted to investigate the penetration dose and shielding rates of tungsten shields used in apron material by changing the type of source used in the nuclear medicine department, thickness of shielding material and distance between the source and detector. For the experiment, the source, shield, and detector were arranged in a straight line and measured with an inspector at a height of 100 ㎝. The highest shielding effect of tungsten was measured for <SUP>201</SUP>Tl, while <SUP>123</SUP>I showed a higher shielding effect than <SUP>99m</SUP>Tc. For the sources used in the experiment, the penetration dose decreased with distance and the shielding rate was measured with thicker thickness. However, the shielding rate of <SUP>13</SUP>1I and <SUP>18</SUP>F sources was found to be lower than when there was no shielding at 0.25 ㎜Pb shield. Therefore, even if the radiation shielding effect of tungsten is high, considering the characteristics according to the type of source and the thickness of the shielding material, it may be helpful to reduce the exposure.

다이오드 레이저를 이용한 칸디다 알비칸스에 대한 항균 광역학 요법

김지원(Kim Ji-Won),구본열(Koo Bon-Yeoul) 대한방사선과학회(구 대한방사선기술학회) 2021 방사선기술과학 Vol.44 No.2

This study aimed to explore whether photodynamic therapy using Radachlorin and diode laser is an effective inhibitor of Candida albicans. Suspensions of Candida albicans were obtained, inoculated in petri dishes with Radachlorin, and incubated for 30 min. Then, the laser light of a diode laser was irradiated at at energy densities of 3 J/cm2 , 5 J/cm2 , 7 J/cm2 . As a result, Candida albicans showed a killing rate of 91.5% at an energy density of 7 J/cm2 . This study found that photodynamic therapy using a Radachlorin and diode laser was effective for the inhibition of Candida albicans.

3D 프린팅을 이용한 손 엑스선 검사 보조도구의 유용성

김지원(Ji-Won Kim),구본열(Bon-Yeoul Koo) 대한방사선과학회(구 대한방사선기술학회) 2023 방사선기술과학 Vol.46 No.6

As an auxiliary tool for fixing the patient's posture when taking an X-ray, sponges with high radiolucencies are laminated in various thicknesses. This study aimed to evaluate the usefulness of an auxiliary tool for hand oblique projection X-ray by manufacturing it with a uniform thickness by 3D printing and comparing it with existing sponge tools. In the auxiliary tool, radiolucency was measured at the stairs where each finger was located, and pixel information values were compared in the digital imaging and communications in medicine(DICOM) image. Contrast to noise ratio(CNR) and signal to noise ratio(SNR) were compared by shooting the hand phantom and the auxiliary tool together. As the thickness of the sponge tool increased, radiolucency decreased by 15.52% and pixel information value increased by 20.61%. The transmittance of the 3D printing tool increased by 0.82%, and the pixel information value differed by 5.66%. CNR and SNR increased by 20.03% and 22.42% in 3D printing compared to existing sponge tools. while taking hand oblique projection, maintaining the thickness of the auxiliary tool uniformly through 3D printing maintains high radiolucency and minimal impact on medical images, and increases CNR and SNR, making it useful as an auxiliary tool for taking hand oblique projection.