• 대한방사선기술학회지:방사선기술과학
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• 제43권1호
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• pp.15-21
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• 2020

This study was purpose to evaluation of Modulation Transfer Function in Measurements by using the International electrotechnical commission standard(IEC 62220-1) which were edge device each angle by using edge method. In this study was Aero(Konica, Japan) image receptor which is a indirect Flat panel detector(FPD) was used. The size of matrix 1994 × 2430 (14"× 17" inch) which performed 12 bit processing and pixel pitch is 175 ㎛. The results of shown as MTF measurements at IEC standard. The amount of data seemed reasonable and at an MTF value of 0.1 the spatial frequencies were 2.56 cycles/mm at an angle of 2.4°. MTF value of 0.5 the spatial frequencies were 1.32 cycles/mm at an angle of 2.4°. This study were to evaluate MTF by setting each angle 2.0°~2.8° degrees the most effective optimal edge angle and to suggest the quantitative methods of measuring by using IEC.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.501-504
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• 2001

We used time-of-flight method to analyze transport properties of charge carrier which is produced by X-ray exposure. It is the research of charge transport and specific property of trap that is performed in direct digital x-ray image receptor. But the results shows us different measurement value of electron and charge drift mobility and it is difficult to precise analysis about charge transport properties and trap mechanism. We measured transit time and drift mobility of charge carriers using time-of-flight method to evaluate the correlation of a-Se thickness change and electric field. We made a testing glass with a-Se of 400 ${\mu}m$ thickness on coming glass using thermoevaporation method and built Au electrode with 300nm, $2{\varphi}$ on both sides of a-Se, As a result of this experiment, electron and hole transit time was each $229.17{\mu}s$ and $8.73{\mu}s$ at $10V/{\mu}m$ electric field and Drift mobility was each $0.00174 cm^{2}/V{\cdot}s$, $0.04584cm^{2}/V{\cdot}s$.

• 대한방사선기술학회지:방사선기술과학
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• 제43권5호
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• pp.353-357
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• 2020

IVR procedures are on the rise, and patient doses are on the rise. It is necessary to evaluate fluoroscopy dose in IVR procedure. Evaluate ESD on IVR equipment as a reference to DRL settings, I would like to present the direction of improvement in the ESD rate test criteria for fluoroscopy dose. The experimental method is measured with 6cc ionization chamber under the 20cm PMMA Phantom. Radiation is subject to abdominal procedure. The average dose rate of the incident surface was 21.6 ± 11.4 mGy/min. The highest dose equipment was 58.5 mGy/min, and there was no equipment exceeding the domestic standard of 100 mGy/min. However, there were five units above 50 mGy/min. To reduce fluoroscopy dose, it is recommended to reduce pulse rate, The dose increases as the image receptor ages. It is recommended to modify the domestic inspection criteria to 50 mGy/min.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.501-504
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• 2001

We used time-of-flight method to analyse transport properties of charge carrier which is produced by X-ray exposure. It is the research of charge transport and specific property of trap that is performed in direct digital x-ray image receptor. But the results shows us different measurement value of electron and charge drift mobility and it is difficult to precise analysis about charge transport properties and trap mechanism. We measured transit time and drift mobility of charge carriers using time-of-fight method to evaluate the correlation of a-Se thickness change and electric field. We made a testing glass with a-Se of 470 ${\mu}{\textrm}{m}$ thickness on corning glass using thermoevaporation method and built Au electrode with 300nm, 2$\phi$ on both sides of a-Se. As a result of this experiment, electron and hole transit time was each 229.17 $\mu$s and 8.737 $\mu$s at 10V/${\mu}{\textrm}{m}$ electric field and Drift mobility was each 0.00174 $\textrm{cm}^2$/V.s, 0.04584 $\textrm{cm}^2$/V.s.

• Animal cells and systems
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• 제15권2호
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• pp.95-106
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• 2011

The transient receptor potential vanilloid 4 (TRPV4) cation channel, a member of the TRP vanilloid subfamily, is expressed in a broad range of tissues. Nitric oxide (NO) as a gaseous signal mediator shows a variety of important biological effects. In many instances, NO has been shown to exhibit its activities via a protein S-nitrosylation mechanism in order to regulate its protein functions. With functional assays via site-directed mutagenesis, we demonstrate herein that NO induces the S-nitrosylation of TRPV4 $Ca^{2+}$ channel on the $Cys^{853}$ residue, and the S-nitrosylation of $Cys^{853}$ reduced its channel sensitivity to 4-${\alpha}$ phorbol 12,13-didecanoate and the interaction between TRPV4 and calmodulin. A patch clamp experiment and $Ca^{2+}$ image analysis show that the S-nitrosylation of $Cys^{853}$ modulates the TRPV4 channel as an inhibitor. Thus, our data suggest a novel regulatory mechanism of TRPV4 via NO-mediated S-nitrosylation on its $Cys^{853}$ residue.

• 대한방사선기술학회지:방사선기술과학
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• 제40권3호
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• pp.363-370
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• 2017

본 연구는 전하결합소자(charged coupled device; CCD), CR (computed radiography), 평판형검출기(flat panel detector; FPD) 등을 사용하는 다양한 디지털 방사선(digital radiography; DR) 시스템의 물리적 영상 특성의 평가를 실시한 것이다. 본 연구에서 적용된 영상 특성은 신호응답특성(system response), 해상력특성(modulation transfer function; MTF), 잡음특성(wiener spectrum; WS), 양자검출효율(detective quantum efficiency; DQE) 등이며 이를 통하여 DR 시스템의 성능을 비교하였다. CCD의 신호응답특성은 입사선량에 비례하여 증가하였으며, CR과 FPD는 입사선량의 증가에 대수적 비례 관계를 보이면서 증가하였다. MTF는 CR과 FPD는 유사한 경향을 나타내었지만 CCD는 떨어지는 값을 나타내었다. WS는 FPD가 가장 낮았고, CR, CCD 순으로 증가하였다. DQE는 FPD, CR, CCD의 순으로 나타났다. DR 시스템은 영상수용체의 종류에 따라 서로 다른 영상 특성이 나타났다. 의료영상 획득 시 DR 시스템을 올바르게 사용하려면 영상의 물리적 특성을 정확히 알고 사용하는 것이 중요하다.

• 한국방사선학회논문지
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• 제16권3호
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• pp.217-223
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• 2022

본 연구는 엑스선 흉부촬영에서 격자를 이용하여 촬영법과 Air Gap Technique을 이용한 촬영법에서 얻은 영상을 평가하기 위하여 대학병원 영상의학과에서 10년 이상 근무한 방사선사 선생님 5인에게 주관적 평가 ROC와 객관적 평가 SNR를 시행하였다. 분석한 결과는 Cronbach Alpha 값이 0.714로 유의하게 높았다. Air Gap Technique 촬영법에서 팬톰과 상수용체 간격을 20 cm 띄우고 관전압 100 kVp, 관전류와 촬영시간 8 mAs로 설정하고 촬영한 영상을 ROC 평가에서 18점, SNR 평가에서 6.149로 가장 높은 점수를 얻었다. 또한 격자를 이용하여 촬영법에서는 팬톰과 상수용체 간격을 15 cm 띄우고 관전압 110 kVp, 관전류와 촬영시간을 8 mAs에서 촬영 시 ROC 평가점수가 19점과 객관적평가인 신호대잡음비(SNR)가 6,622으로 가장 높은 점수를 받았다. 이에 격자를 이용하여 나타나는 격자의 cut-off 현상으로 인하여 재촬영뿐만 아니라 판독지연, 환자의 피폭선량 증가, 기계적 수명단축 등의 단점을 벗어나는 Air Gap Technique 촬영법을 활용한다면, 중환자실 및 응급환자를 위한 이동형 엑스선 촬영장비를 사용할 경우를 포함하여 흉부 촬영 시에 많은 도움이 되리라 사료된다.

• Imaging Science in Dentistry
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• 제43권3호
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• pp.179-184
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• 2013

Purpose: X-ray exposure should be clinically justified and each exposure should be expected to give patients benefits. Since dental radiographic examination is one of the most frequent radiological procedures, radiation hazard becomes an important public health concern. The purpose of this study was to investigate the attitude of Korean dentists about radiation safety and use of criteria for selecting the frequency and type of radiographic examinations. Materials and Methods: The study included 267 Korean dentists. Five questions related to radiation safety were asked of each of them. These questions were about factors associated with radiation protection of patients and operators including the use of radiographic selection criteria for intraoral radiographic procedures. Results: The frequency of prescription of routine radiographic examination (an example is a panoramic radiograph for screening process for occult disease) was 34.1%, while that of selective radiography was 64.0%. Dentists' discussion of radiation risk and benefit with patients was infrequent. More than half of the operators held the image receptor by themselves during intraoral radiographic examinations. Lead apron/thyroid collars for patient protection were used by fewer than 22% of dental offices. Rectangular collimation was utilized by fewer than 15% of dental offices. Conclusion: The majority of Korean dentists in the study did not practice radiation protection procedures which would be required to minimize exposure to unnecessary radiation for patients and dental professionals. Mandatory continuing professional education in radiation safety and development of Korean radiographic selection criteria is recommended.

• BMB Reports
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• 제40권2호
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• pp.212-217
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• 2007

The chicken oviduct is a dynamic organ that produces secretory proteins such as ovalbumin during the laying period. In this study, we identified oviduct-specific proteins in hens during the egg-laying period by proteomic analysis. Proteins extracted from the magnum of hens of different ages (5, 35, and 65 weeks) were analyzed by two-dimensional gel electrophoresis to compare the intensity of proteins among samples. Approximately 300 spots were detected on each gel. Based on the comparison of image gels, we found that the intensity of eight spots in 35-week magnums was increased at least by 2-fold compared with the others. Five of the eight spots were identified as calumenin, acidic ribosomal phosphoproteins (ARP), prohibitin, heart fatty acid-binding protein, and anterior gradient-2 (AGR-2). In particular, ARP and AGR-2 were highly expressed in 35- week magnums compared with 5- and 65-week magnums. In addition, the level of these proteins was consistent with their RNA levels. Expression of AGR-2 mRNA was detected in the mature magnum, whereas no signal was observed in premature tissue. Among various tissues, expression of AGR-2 mRNA was highest in the magnum, high in the isthmus, and five fold lower in muscle. It was undetectable in the liver and in other tissues (heart and kidney). However, the mRNA levels of other proteins were ubiquitous among tissues. In transcriptional activity of AGR-2, a 3.0 kb fragment of promoter region containing potential estrogen receptor binding sites had enhanced its activity strongly. In conclusion, these results suggest that AGR-2 has functional regulatory roles in the chicken oviduct during the egglaying period.

• Journal of Korean Neurosurgical Society
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• 제56권5호
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• pp.431-435
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• 2014

A fifty-year-old female non-smoker with no other specific medical history visited our institute. She complained of axial back pain with no other neurological deficit. Chest X-ray, chest computed tomography (CT) scan, CT-guided needle aspiration biopsy, whole-body positron emission tomography, spine CT and spine magnetic resonance image findings suggested NSCLC with epidermal growth factor receptor (EGFR) mutation, multiple brain metastases, and two isolated metastases to the T3 and L3 vertebral bodies. She underwent chemotherapy with gefitinib ($Iressa^{TM}$) for NSCLC and gamma knife surgery for multiple brain metastases. We performed a two-staged, total en bloc spondylectomy of the T3 and L3 vertebral bodies based on several good prognostic characteristics, such as the lack of metastases to the appendicular bone, good preoperative performance status, and being an excellent responder (Asian, never-smoker and adenocarcinoma histology) to EGFR inhibitors. Improved axial back pain after the surgery enabled her to walk with the aid of a thoracolumbosacral orthosis brace on the third postoperative day. Her Karnofsky performance status score (KPS) was 90 at the time of discharge and has been maintained to date 3 years after surgery. In selected NSCLC patients with good prognostic characteristics, we suggest that locally curative treatment such as total en bloc spondylectomy or radiosurgery should be emphasized to achieve longer term survival for the selected cases.