• The Korean Journal of Pain
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• 제27권2호
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• pp.162-167
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• 2014

Background: Although a physician may be the nearest to the radiation source during C-arm fluoroscope-guided interventions, the radiographer is also near the fluoroscope. We prospectively investigated the radiation exposure of radiographers relative to their location. Methods: The effective dose (ED) was measured with a digital dosimeter on the radiographers' left chest and the side of the table. We observed the location of the radiographers in each procedure related to the mobile support structure of the fluoroscope (Groups A, M and P). Data about age, height, weight, sex, exposure time, radiation absorbed dose (RAD), and the ED at the radiographer's chest and the side of the table was collected. Results: There were 51 cases for Group A, 116 cases for Group M and 144 cases for Group P. No significant differences were noted in the demographic data such as age, height, weight, and male to female ratio, and exposure time, RAD and ED at the side of the table. Group P had the lowest ED ($0.5{\pm}0.8{\mu}Sv$) of all the groups (Group A, $1.6{\pm}2.3{\mu}Sv$; Group M, $1.3{\pm}1.9{\mu}Sv$; P < 0.001). The ED ratio (ED on the radiographer's chest/ED at the side of the table) of Group A was the highest, and the ED radio of Group P was the lowest of all the groups (Group A, $12.2{\pm}21.5%$; Group M, $5.7{\pm}6.5%$; Group P, $2.5{\pm}6.7%$; P < 0.001). Conclusions: Radiographers can easily reduce their radiation exposure by changing their position. Two steps behind the mobile support structure can effectively decrease the exposure of radiographers by about 80%.

• Tuberculosis and Respiratory Diseases
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• 제78권3호
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• pp.161-167
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• 2015

Tuberculosis (TB) remains a major global health problem, and the incidence of TB cases has not significantly decreased over the past decade in Korea. The standard short course regimen is highly effective against TB, but requires multiple TB-specific drugs and a long treatment duration. Recent studies using late-generation fluoroquinolones and/or high-dose rifapentine-containing regimens to shorten the duration of TB treatment showed negative results. Extending the treatment duration may be considered in patients with cavitation on the initial chest radiograph and positivity in sputum culture at 2 months of treatment for preventing TB relapse. Current evidence does not support the use of fixed-dose combinations compared to separate drugs for the purpose of improving treatment outcomes. All patients receiving TB treatment should be monitored regularly for response to therapy, facilitation of treatment completion, and management of adverse drug reactions. Mild adverse effects can be managed with symptomatic therapy and changing the timing of the drug administration, but severe adverse effects require a discontinuation of the offending drugs.

• 대한방사선기술학회지:방사선기술과학
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• 제31권3호
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• pp.223-228
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• 2008

의학적으로 방사선을 사용 시 가장 중요한 점은 환자의 병을 진단 가능하되 피폭선량을 최소화시켜야 한다는 점이다. 진단용 X-선 중 장파장부분은 대부분 흡수에 관여하게 되어 환자의 피폭선량을 증가시키므로 불필요하다. 이러한 장파장영역을 제거하기 위한 방법으로 가장 효과적인 방법은 여과 판의 사용이다. 이에 부가여과가 없는 경우와 0.3mmCu filter 사용 시의 화질과 피부입사선량에 대해 실험을 해 보았다. ROC 신호용 지름 4mm, 두께 3mm의 아크릴 디스크를 chest phantom에 랜덤하게 위치시키면서 non filter 및 Cu filter시 각 각 20매씩 총 40매의 신호+잡음영상을 촬영하고, 또한 신호가 없는 영상(잡음만의 영상)을 각 각 20매씩 40매 촬영하여 총 80매의 영상을 준비한 후 5명의 방사선종사자가 판독 후 P(S/s), P(S/n) 구하여, ROC곡선을 그리고, 감도와 특이도 및 곡선하면적을 구해 평가하였다. 또한 AAPM(American Association of Physicists in Medicine by the American Institute of Physics)권고에 따른 ANSI chest phantom과 Contrast-detail phantom을 이용하여 non filter 또는 Cu filter사용 시 시각적으로 관찰 가능한 병소의 갯수를 파악하였으며, 또한 두 경우에서 피부입사선량을 측정하였다. 그 결과 Cu filter사용 시에 ROC곡선이 좌상방향에 위치하고, 감도, 곡선하면적 및 CD phantom 병소의 갯수에서 모두 좋은 결과를 나타내었다. 또한 피부입사선량은 감소가 되어 여러 측면에서 부가필터의 사용을 검토해 볼 필요가 있으리라 사료된다.

• Korean Journal of Radiology
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• 제22권6호
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• pp.983-993
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• 2021

Objective: To investigate the image quality of ultralow-dose CT (ULDCT) of the chest reconstructed using a cycle-consistent generative adversarial network (CycleGAN)-based deep learning method in the evaluation of pulmonary tuberculosis. Materials and Methods: Between June 2019 and November 2019, 103 patients (mean age, 40.8 ± 13.6 years; 61 men and 42 women) with pulmonary tuberculosis were prospectively enrolled to undergo standard-dose CT (120 kVp with automated exposure control), followed immediately by ULDCT (80 kVp and 10 mAs). The images of the two successive scans were used to train the CycleGAN framework for image-to-image translation. The denoising efficacy of the CycleGAN algorithm was compared with that of hybrid and model-based iterative reconstruction. Repeated-measures analysis of variance and Wilcoxon signed-rank test were performed to compare the objective measurements and the subjective image quality scores, respectively. Results: With the optimized CycleGAN denoising model, using the ULDCT images as input, the peak signal-to-noise ratio and structural similarity index improved by 2.0 dB and 0.21, respectively. The CycleGAN-generated denoised ULDCT images typically provided satisfactory image quality for optimal visibility of anatomic structures and pathological findings, with a lower level of image noise (mean ± standard deviation [SD], 19.5 ± 3.0 Hounsfield unit [HU]) than that of the hybrid (66.3 ± 10.5 HU, p < 0.001) and a similar noise level to model-based iterative reconstruction (19.6 ± 2.6 HU, p > 0.908). The CycleGAN-generated images showed the highest contrast-to-noise ratios for the pulmonary lesions, followed by the model-based and hybrid iterative reconstruction. The mean effective radiation dose of ULDCT was 0.12 mSv with a mean 93.9% reduction compared to standard-dose CT. Conclusion: The optimized CycleGAN technique may allow the synthesis of diagnostically acceptable images from ULDCT of the chest for the evaluation of pulmonary tuberculosis.

• 한국방사선학회논문지
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• 제13권2호
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• pp.291-296
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• 2019

현대의학에서 핵의학 검사는 암의 진단에 많이 이용된다. 방사선 작업종사자가 개봉 방사성동위원소를 사용할 때 방사선 피폭에 노출된다. 환자에게 방사성동위원소를 투여할 때 방사선 작업종사자가 받는 피폭선량을 감소시키는 방법을 연구하였다. 납 차폐소재를 이용하여 연당량 0.2 mmPb, $300mm{\times}500mm{\times}150mm$ 크기로 차폐기구를 제작하였다. 차폐기구의 사용 유무, 실린더를 차폐기구와 함께 사용하였을 때 3가지 실험방법으로 갑상선, 가슴, 생식선의 흡수선량을 나노닷으로 측정하였다. 생식선 위치에서 0.908 mGy가 측정되었고, 실린더와 제작한 차폐기구를 함께 사용하였을 때 20.8% 감소한 0.719 mGy로 가장 큰 피폭 저감이 나타났다. 방사선 작업종사자가 받는 1년 예상 유효선량은 1.223 mSv로 가슴부위가 가장 높았으며 실린더와 차폐기구를 함께 사용하였을 때 0.994 mSv로 감소하였다. 방사성동위원소를 환자에게 투여할 때 제작된 차폐기구만을 사용하여도 방사선 작업종사자의 피폭을 감소시킬 수 있음을 확인하였다.

• 한국방사선학회논문지
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• 제10권3호
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• pp.181-186
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• 2016

심장혈관 조영술과 심장혈관 중재술은 심장혈관 질환을 치료하는 안전하고 효율적인 시술이다. 그러나 시술이 이루어지는 동안 환자와 시술자의 방사선 피폭에 대해서는 주의가 필요하다. 본 연구의 대상으로는 2015년 9월부터 2016년 1월 사이에 강원도 소재 한 대학병원의 심혈관센터에서 시행된 147명의 심장혈관 조영술(CA)과 심장혈관 중재술(CI)을 시행한 환자를 대상으로 시술자의 피폭선량을 평가하였다. CA만을 시행한 경우 시술자의 유효선량은 최소 0.39 uSv, 최대 30.6 uSv를 나타냈고 평균 유효선량은 4.11 uSv를 나타냈다. CI를 시행한 경우 유효선량은 최소 1.618 uSv, 최대 202.805 uSv를 나타냈고 평균 유효선량은 34.41 uSv를 나타냈다. 본 연구의 결과에서 갑상선 위치에서 측정된 선량을 머리가 받은 선량으로 대체할 경우 PCI에서 평균 받는 선량을 연평균 1000건의 시술을 시행한다고 할 경우 90 mSv/year 에 해당한다. 이를 2년 누적할 경우 눈의 제한선량인 150 mSv를 초과하는 수치이다. 심장혈관 중재적 시술은 의료 방사선의 피폭에 있어 CT 다음으로 큰 부분을 차지하고 있다. 따라서 시술이 시행되는 동안 환자와 시술자의 방사선 방어가 적절히 이루어질 수 있도록 하여야 하며 검사의 최적화와 정당성을 확보하여 안전한 검사가 될 수 있도록 해야 한다. 이를 위해 시술자에게는 적절한 교육이 이루어져야 하고 시술 중에는 개인방어 장비를 착용하여야 하며 모니터링을 통해 환자와 시술자의 피폭선량을 줄이는 노력이 필요하다.

• 한국산학기술학회논문지
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• 제11권11호
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• pp.4411-4417
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• 2010

64채널 MDCT(multidetector computed tomography)와 128채널 DSCT(dual source computed tomography)를 이용한 관상동맥 전산화단층촬영 시 유효선량과 획득한 영상의 질을 평가함으로서 임상에서의 유용성을 평가하고자 하였다. 피폭선량은 선량길이곱(dose length product: DLP)에 흉부 조직의 가중치(0.017)을 곱하여 유효선량(mSv)으로 계산하였으며, 영상 평가는 심장촬영검사 후 영상의학과 전문의가 5점 Likert 척도(5점 최상)로 평가하였다. DLP 값은 64 채널 MDCT에서는 $851{\sim}1277\;mGy{\cdot}cm$ (평균 유효선량: 17.23mSv), 128 채널 DSCT에서는 $82{\sim}110\;mGy{\cdot}cm$ (평균 유효선량: 1.58mSv)로 각각 분포하였다. 영상 평가점수는 64 채널 MDCT에서 $3.31{\pm}0.62$(4점 이상 34명), 128channel DSCT에서 $4.05{\pm}0.46$(4점 이상 96명)으로 각각 나타났다. 유효선량은 64채널 MDCT에 비해 128채널 DSCT가 1/10 이상 감소함을 알 수 있었다. 영상 평가점수는 통계적으로 유의한 차이를 보였으며 4점 이상 점수의 빈도는 128채널 DSCT에서 2.8배 높게 나타났다. 결론적으로 관상동맥 전산화단층촬영검사에서는 128채널 DSCT가 64채널 MDCT에 비해 환자가 받는 유효선량은 감소하고 영상 평가점수는 높게 나타나 임상에서 보다 유용할 것으로 판단된다.

• Korean Journal of Radiology
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• 제25권9호
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• pp.833-842
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• 2024

Objective: To assess the effect of a new lung enhancement filter combined with deep learning image reconstruction (DLIR) algorithm on image quality and ground-glass nodule (GGN) sharpness compared to hybrid iterative reconstruction or DLIR alone. Materials and Methods: Five artificial spherical GGNs with various densities (-250, -350, -450, -550, and -630 Hounsfield units) and 10 mm in diameter were placed in a thorax anthropomorphic phantom. Four scans at four different radiation dose levels were performed using a 256-slice CT (Revolution Apex CT, GE Healthcare). Each scan was reconstructed using three different reconstruction algorithms: adaptive statistical iterative reconstruction-V at a level of 50% (AR50), Truefidelity (TF), which is a DLIR method, and TF with a lung enhancement filter (TF + Lu). Thus, 12 sets of reconstructed images were obtained and analyzed. Image noise, signal-to-noise ratio, and contrast-to-noise ratio were compared among the three reconstruction algorithms. Nodule sharpness was compared among the three reconstruction algorithms using the full-width at half-maximum value. Furthermore, subjective image quality analysis was performed. Results: AR50 demonstrated the highest level of noise, which was decreased by using TF + Lu and TF alone (P = 0.001). TF + Lu significantly improved nodule sharpness at all radiation doses compared to TF alone (P = 0.001). The nodule sharpness of TF + Lu was similar to that of AR50. Using TF alone resulted in the lowest nodule sharpness. Conclusion: Adding a lung enhancement filter to DLIR (TF + Lu) significantly improved the nodule sharpness compared to DLIR alone (TF). TF + Lu can be an effective reconstruction technique to enhance image quality and GGN evaluation in ultralow-dose chest CT scans.

• The Korean Journal of Pain
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• 제26권2호
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• pp.148-153
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• 2013

Background: C-arm fluoroscope has been widely used to promote more effective pain management; however, unwanted radiation exposure for operators is inevitable. We prospectively investigated the differences in radiation exposure related to collimation in Medial Branch Block (MBB). Methods: This study was a randomized controlled trial of 62 MBBs at L3, 4 and 5. After the patient was laid in the prone position on the operating table, MBB was conducted and only AP projections of the fluoroscope were used. Based on a concealed random number table, MBB was performed with (collimation group) and without (control group) collimation. The data on the patient's age, height, gender, laterality (right/left), radiation absorbed dose (RAD), exposure time, distance from the center of the field to the operator, and effective dose (ED) at the side of the table and at the operator's chest were collected. The brightness of the fluoroscopic image was evaluated with histogram in Photoshop. Results: There were no significant differences in age, height, weight, male to female ratio, laterality, time, distance and brightness of fluoroscopic image. The area of the fluoroscopic image with collimation was 67% of the conventional image. The RAD ($29.9{\pm}13.0$, P = 0.001) and the ED at the left chest of the operators ($0.53{\pm}0.71$, P = 0.042) and beside the table ($5.69{\pm}4.6$, P = 0.025) in collimation group were lower than that of the control group ($44.6{\pm}19.0$, $0.97{\pm}0.92$, and $9.53{\pm}8.16$), resepectively. Conclusions: Collimation reduced radiation exposure and maintained the image quality. Therefore, the proper use of collimation will be beneficial to both patients and operators.

• Tuberculosis and Respiratory Diseases
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• 제84권2호
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• pp.134-139
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• 2021

Background: Intrapleural urokinase is one of the most widely used fibrinolytic agents in the treatment of complicated parapneumonic effusion (CPPE). However, little research has been performed on the optimal urokinase dosage. The aim of this study was to evaluate the treatment efficacy of half dose urokinase compared with conventional dose urokinase. Methods: We retrospectively enrolled 92 patients with CPPE or empyema who underwent intrapleural urokinase treatment at two tertiary hospitals. Patients received antibiotics, chest tube drainage, and other treatments as part of routine care. The primary outcome was the treatment success rate in the half dose urokinase group (50,000 IU daily for maximal 6 days) and the conventional dose urokinase group (100,000 IU daily). Treatment success was defined as clinical and radiological improvements without surgical treatment or re-admission within one month. Results: Forty-four patients received half dose urokinase, whereas 48 patients were treated with conventional dose urokinase. Both groups were relatively well matched at baseline, excluding higher serum white blood cell count and higher empyema prevalence in the half dose urokinase group. The treatment success rate was not different between the two groups (p=0.048). There were no differences in the rate of in-hospital death and surgical treatment, hospitalization duration, and indwelling catheter duration. In the multivariate analysis, urokinase dose was not a predictor of treatment success. Conclusion: Half dose intrapleural urokinase is equally effective conventional dose urokinase in treating patients with CPPE or empyema.