• 대한방사선기술학회지:방사선기술과학
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• 제41권6호
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• pp.533-538
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• 2018

As the use of digital radiographic system has been expanded, there are some concerns an increase about in patient of radiation dose. Therefore, International Electro-technical Commission (IEC) has been proposed a standard foe exposure index (EI). In this study, the EI was measured on human chest model using computed radiography (CR). Radiation quality used RQA5 of IEC62494-1. After acquiring the chest anterior posterior image (Chest AP) by using the phantom, the EI was obtained by applying the system response. In this study, we have analyzed the images with the detector size (Full filed ROI) and the optimized image (Fit filed ROI). The EI increased proportionally with radiation dose increase. Due to the discrete increase in pixel value, the EI showed an exponential increase. The discrete increase in noise equivalent quanta (NEQ) resulted in a discrete increase in the EI. The EI of the two images used in this study increased with increasing NEQ but showed different increments. For the measurement of the EI, IEC standards must be followed. The EI should be used as an index to evaluate the image quality for quality control of X-ray image rather than as an indicator of exposure dose. When calculating the EI, the system response should be applied depending on whether or not the grid is used. The size of the field should be obtained by including only the necessary parts.

• 대한방사선기술학회지:방사선기술과학
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• 제45권2호
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• pp.159-164
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• 2022

The study developed a radiation dose measurement program in the radiology laboratory to measure how much exposure the students are exposed to during the radiology class, to request for the improvement and the revision of the current Nuclear Safety Act. The experimental program is shown in the following figure, and experiments were conducted to determine the degree of radiation exposure in the control room with a lead gown at a distance of 1 m, 2 m, and 1 m, and in a control room with a radiographic lead glass wall. The duration of the experiment was 3 months from April to June, when radiation imaging practice classes were conducted, and 128 hours of imaging practice per month were conducted. In order to find out the dose of radiation dose during radiology imaging practice class, the experiment was carried out from April to June for 3 months, and according to the program, the results of exposure dose were 0.34 mSv at 1 m distance, 0.01 mSv at shielding of lead gown at 1 m distance, 0.16 mSv at 2 m distance, and 0.01 mSv at control room with radiation lead glass wall. The exposure dose from the test results was much below the annual general public limit dose of 1 mSv. The restriction on the operation of the radiation equipment in the practice of the students is a regulation that infringes the right of students to learn, and amendments or exemptions of Nuclear Safety Act should be enacted to ensure that it does not violate the fundamental right to learn for students in radiology.

• Journal of Periodontal and Implant Science
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• 제54권1호
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• pp.37-43
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• 2024

Purpose: The inflammatory response due to inflammatory cytokines, bacterial pathogens, and the altered lipoprotein metabolism in patients with periodontitis indicates that infection with periodontal anaerobic bacteria may influence atherogenesis in vitro and in vivo. We aimed to explore the effect of periodontitis concerning clinical and ultrasound markers of early atherosclerosis. Methods: In this case-control study, a total of 30 systemically healthy adults (15 with periodontitis and 15 without periodontitis) over 40 years of age were studied. Periodontitis was determined by measuring the clinical attachment level (CAL) and radiographic bone loss (RBL). Conventional cardiovascular risk factors, including body mass index, serum levels of total cholesterol (TCH), triglycerides (TG), and high-density and low-density lipoprotein (HDL and LDL, respectively) cholesterol were evaluated. Carotid artery intima-media thickness (IMT) was measured using ultrasonography. Results: The mean values of the CAL and carotid IMT were 5.02±0.9 mm and 0.084±0.01 cm vs. 1.6±0.61 mm and 0.072±0.02 cm in the periodontitis and healthy groups, respectively, reflecting statistically significant differences (P=0.001 and P=0.037, respectively). There were statistically significant differences in the serum levels of TCH, TG, and LDL between the 2 groups (P=0.017). The CAL and RBL were positively associated with carotid IMT and serum cholesterol levels, except for HDL, whereas tooth loss was not associated with any markers (P<0.05). Compared to the healthy group, participants with periodontitis exhibited 2.09 times higher odds (95% confidence interval, 1.22-3.59) of having subclinical atherosclerosis. Conclusions: The presence of periodontitis increased the risk of atherosclerosis.

• Clinics in Shoulder and Elbow
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• 제27권1호
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• pp.26-31
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• 2024

Background: The coracoacromial ligament (CAL) is frequently observed to be damaged during arthroscopy and it is unclear how demographic, anatomic, and radiographic factors are related to CAL degeneration in full-thickness rotator cuff tears. Methods: A prospective study was conducted of patients at a single institution undergoing shoulder arthroscopy for first-time, full-thickness rotator cuff tears. We evaluated preoperative anteroposterior radiographs to obtain critical shoulder angle, glenoid inclination, acromial index, acromiohumeral distance, lateral acromial angle, and acromial morphology. We documented CAL quality, rotator cuff tear size and pattern during arthroscopy. Multiple logistic regression was used to identify predictive factors for encountering severe CAL fraying during arthroscopy. Results: Shoulders had mild CAL degeneration in 58.1% of cases, whereas severe CAL degeneration was present in 41.9% of shoulders. Patients with severe CAL attrition were significantly older (62.0 years vs. 58.0 years, P=0.042). Shoulders with severe CAL attrition had large rotator cuff tears in 54.1% of cases (P<0.001), and tears involving the infraspinatus (63.2% vs. 29.6%, P=0.003). The severe degeneration group was more likely to have a larger critical shoulder angle measurement on preoperative radiographs than those in the mild attrition group (36.1°±3.6° [range, 30°-45°] vs. 34.1°±3.8° [range, 26°-45°], P=0.037). Conclusions: While the clinical impact of CAL degeneration remains uncertain, increased severity of CAL degeneration is associated with older age, larger rotator cuff tear size, presence of infraspinatus tearing, and increased preoperative critical shoulder angle. Level of evidence: III.

• Radiation Oncology Journal
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• 제14권1호
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• pp.77-85
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• 1996

목적 : 다엽콜리메이터를 이용하여 부정형의 치료부위를 편리하고 정확히 차폐하며 삼차원 입체조형치료를 원활히 수행하기 위하여 다엽콜리메이터의 차폐특성을 계측하고 치료계획을 위한 최적방법을 확정한다. 대상 및 방법 : 차폐폭이 1cm이고 길이가 15cm인 52개의 금속차폐엽들이 양방향 각각 26개로 구성되어 컴퓨터계획에 의거 여러모양의 차폐면을 구사할 수 있는 다엽콜리메이터(Multileaf collimator)를 대상으로 방사선 치료에 요구되는 고에너지 방사선의 출력선량율, 차폐 및 투과효과, 반음영, 조직내 선량분포등을 전리함측정기와 열형광측정기 및 필름 선량측정방법을 이용하여 계측하였다. 다엽콜리메이터의 계단식 반음영 측정은 고체팬텀과 비디오밀도측정기를 이용하여 실효반음영(Effective penumbra)과 일반적반음영(General penumbra)으로 구분 평가하였다. 결과 : 다엽콜리메이터의 출력선량율은 표준차폐조리개에 비교하여 출력 선량율이 $1-2\%$ 증가 되었으며 치료오차 이내로 평가되었다. 다엽콜리메이터의 방사선투라 선량율은 6-10MV X선에서 평균 $2\%$로 표준차폐조리개보다 컸지만 혼합차폐벽돌보다 적었다. 원형으로 형성된 차폐엽 끝면의 조사선량은 약 $20\%$증가 되었으며 엽과 엽사이의 선량은 6mm 폭의 $5\%$증가로 심부치료에 영향이 없었다. 다엽콜리메이터의 실효반음영($20-80\%$)은 약 6mm로서 혼합차폐벽돌과 거의 같았으나 중심선에서 벗어날수록 $2-3\%$증가되었다. 다엽콜리메이터에 의한 계단식 모양의 반음영은 6-10MV x-선에서 차폐면 경사각이 45도일 때 약 11mm로 가장 컸으며 방사선속에 평행히 절단된 차폐벽돌보다 약 5mm 더 증가되었다. 결론 : 다엽콜리메이터는 1cm폭의 차폐엽들로 구성되어 계단식 차폐면에 대한 반음영이 다소 증가되고 있지만 조직내부의 다문조사 경우 반음영이 완화되므로 부정형 조사면 차폐에 적당하며 방사선 입체조형치료를 수행할 수 있는 가장 적당한 차폐기구로 생각된다.

• Imaging Science in Dentistry
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• 제44권4호
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• pp.257-262
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• 2014

Purpose: This study was performed to evaluate the effect of changing the orientation of a reconstructed image on the accuracy of linear measurements using cone-beam computed tomography (CBCT). Materials and Methods: Forty-two titanium pins were inserted in seven dry sheep mandibles. The length of these pins was measured using a digital caliper with readability of 0.01 mm. Mandibles were radiographed using a CBCT device. When the CBCT images were reconstructed, the orientation of slices was adjusted to parallel (i.e., $0^{\circ}$), $+10^{\circ}$, $+12^{\circ}$, $-12^{\circ}$, and $-10^{\circ}$ with respect to the occlusal plane. The length of the pins was measured by three radiologists, and the accuracy of these measurements was reported using descriptive statistics and one-way analysis of variance (ANOVA); p<0.05 was considered statistically significant. Results: The differences in radiographic measurements ranged from -0.64 to +0.06 at the orientation of $-12^{\circ}$, -0.66 to -0.11 at $-10^{\circ}$, -0.51 to +0.19 at $0^{\circ}$, -0.64 to +0.08 at $+10^{\circ}$, and -0.64 to +0.1 at $+12^{\circ}$. The mean absolute values of the errors were greater at negative orientations than at the parallel position or at positive orientations. The observers underestimated most of the variables by 0.5-0.1 mm (83.6%). In the second set of observations, the reproducibility at all orientations was greater than 0.9. Conclusion: Changing the slice orientation in the range of $-12^{\circ}$ to $+12^{\circ}$ reduced the accuracy of linear measurements obtained using CBCT. However, the error value was smaller than 0.5 mm and was, therefore, clinically acceptable.

• 비파괴검사학회지
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• 제26권2호
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• pp.69-76
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• 2006

차세대 원자로로 부각되고 있는 고온가스로에서는 윈자로에서는 고온 안정성 및 핵분열생성물 차단 성능이 우수한 TRISO(tri-isotropic) 핵연료를 사용하고 있다. TRISO 핵연료 입자는 직경이 약 1mm인 구 형태로 입자의 중심에는 직경 0.5mm의 핵연료 커널(kernel)이 포함되며 커널 외곽을 코팅 층이 에워싸고 있다. 이 코팅 층은 완충(buffer) PyC(pyrolytic carbon)층, 내부 PyC층, SiC층, 그리고 외부 PyC층으로 구성되어 있다. 각 코팅 층의 두께는 수십-백${\mu}m$ 범위이고 사양으로 정해져 있으며, 본 연구에서는 각 코팅 층의 두께를 비파괴적으로 측정하기 위하여 마이크로포커스 X-선 발생장치와 고해상도 X-선 평판(flat panel) 검출기초 구성된 정밀한 X-선 래디오그래피 장치를 개발하였다. 개발된 마이크로 X-선 래디오그래피 장치를 이용하여 $UO_2$ 핵물질 $ZrO_2$를 커널로 사용한 모의 TRISO 핵연료 입사에 대한 투과 영상을 획득한 후 디지털 영상처리 기술을 이용하여 코팅 층 사이의 경계선이 구분 가능하도록 영상을 개선하고 디지털 영상처리 알고리듬을 개발하여 코팅 층의 두께를 파동으로 측정하였다.

• 대한디지털의료영상학회논문지
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• 제14권2호
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• pp.23-31
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• 2012

There are AEC mode and fix mode to exposure when the whole spine antero-posterior radiography is done by using DR equipment. This study compared the utility of fix mode to AEC mode, by evaluating organ dose and effective dose and by examining the quality of radiographic image. GE DEFINIUM 8000 and ART-200X Rando Phantom manufactured by Flukebiometical were used for this study. The Rando phantom was set in front of wall detector of X-rays equipment. AEC mode was set at 80kVp and Fix mode was set at 80kVp, 25mAs, 32mAs, 40mAs, and 50mAs. Whole spine AP image were aquired by combining C, T-L and L-S spine images obtained through 3 exposures. When obtaining C, T-L and L-S spine images, were checked for Air kerma (mGy) value calculated by UNFORS Xi meter attached at the phantom surface of center of radiation field. The effective and organ doses were compared by PCXMC program (PC-Based Monte Carlo Program). The quality of obtained radiographic image was evaluated visually by 3 radiologists using resolution chart. When the effective doses was calculated based on tissue weighting factor of ICRP-103, 1.278mSv was measured by AEC mode, and Fix mode measured 0.405mSv at 25mAs, 0.518mSv at 32mAs, 0.649mSv at 40mAs, and 0.810mSv at 50mAS. In addition, the organ dose measured with esposure at 25mAs by Fix mode was almost equivalent to the organ dose by AEC mode, at the esophagus, thyroid, oral mucosa, salivaly glands located at the cervical spine part, while the organ dose by Fix mode was in general lower than the organ dose by AEC mode at the other organs. When Fix mode at 32mAs, 40mAs, and 50mAs was compared to AEC mode for organ dose in 26 organs, AEC mode had higher measurement in 21 organs but not for than brain, trachea, thyroid, oral mucosa, and salivaly glands which are located at the cervical spine part. The image quality evaluated by resolution test chart was much higher with AEC mode than the quality with Fix mode at all exposure conditions. However, while the image quality of cervical spine exposured at 50mAs by Fix mode was lower than the quality of AEC mode, thoraco-lumbar spine and lumbo-sacral spine were calculated and the quality was similar to AEC mode. Scoliosis occurs mainly at thoraco-lumbar and lumbo-sacral spine, not at cervical spine. Compared to AEC mode, Using the appropriate protocol (80kVp, 50mAs) of fix mode for whole spine AP radiography was thought to be useful because the image quality of the thoraco-lumar and lumbo-sacral spine was similar on AEC mode, Also organ and effective doses can be decreased with Fix mode. Therefore, It is considered that fix mode can be used properly with AEC mode for whole spine AP radiography when considering patient's body posture.

• 한국방사선학회논문지
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• 제15권1호
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• pp.63-70
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• 2021

골밀도검사에서 측정값에 영향을 주는 요인 중 하나인 방사선 조영제는 진단 목적으로 사용되어 조직 등에 흡수되어 골밀도 측정값을 높이는 효과가 있어, 골밀도검사 시행 전에는 될 수 있으면 피하고 있다. 이러한 방사선 조영제와는 다른 물리적 특성과 작용기전을 갖는 MRI 조영제는 금속원소인 가돌리늄 기반으로 방사선 불투과성 특징을 가지고 있어 일반적으로 방사선을 이용한 검사 전에 MRI 검사를 선 시행하고 있다. 본 연구에서는 MRI 조영제가 이중에너지 X-선 흡수법을 이용한 골밀도검사에 미치는 영향을 알아보고자 하였다. 가돌리늄 기반의 MRI 조영제 2종을 아크릴 수조에 용량별로 주입하여 인체모형 척추 팬텀을 넣고, 각 주입량 종류별로 5회씩 총 30회 scan 하여 L1-L4 번까지의 골밀도와 T-score를 분석하였다. 측정된 2종의 조영제별 Total(L1-L4) 골밀도의 평균값은 가도테레이트 메글루민성분 0mL, 7.5mL, 15mL일때, 각각 0.952±0.052, 0.957±0.050, 0.956±0.05 g/㎠로 나타났으며, 가도부트롤성분 0mL, 5mL, 10mL일 때, 각각 0.953±0.001, 0.954±0.001, 0.945±0.001g/㎠로 모든 부위에서 통계적으로 유의한 차이는 없었다(p>0.05). Total (L1-L4) T-score의 평균값은 가도테레이트 메글루민성분은 0mL, 7.5mL, 15mL일 때, 각각 -0.46±0.05, -0.4±0, -0.42±0.04로 나타났으며, 가도부트롤성분 0mL, 5mL, 10mL일 때, 각각 -0.46±0.05, -0.46±0.05, 0.5±0.00으로 모든 부위에서 통계적으로 유의한 차이는 없었다(p>0.05). 본 실험에서는 MRI 조영제는 이중에너지 X-선 흡수법을 이용한 골밀도검사에 영향이 없는 것으로 나타났으나, 임상 대상이 아닌 제한적 조건의 인체 모형 팬텀을 사용하여 조영제의 배출시간에 영향을 주는 신장 기능, 신체 상태 등이 고려되지 못한 제한점이 있어 추후 추가적인 임상연구 진행이 필요할 것으로 사료된다.

• 대한치과의사협회지
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• 제47권10호
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• pp.669-676
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• 2009

Purpose : Anterior region is crucial area for esthetic implant restoration. However, the alveolar process undergoes atrophy after removal of teeth and creates unfavorable situation for implant installation. The knowledge of the thickness of alveolar bone is required to estimate and expect the bone resorption after extraction. The aim of this study is to measure facial, palatal and faciopalatal bone thickness on maxillary anterior teeth. Methods : Facial, palatal, and faciopalatal bone thickness were measured on the computed tomography (CT) images from 57 patients, using an image analyzer program (Ondemand$3D^{(R)}$, Cybermed, Seoul, Korea). Results : The thickness of facial bone in incisors, lateral incisors and canines were less than 1 mm. The thickness of facial bone increased from anterior to posterior region and the thickness of palatal bone increased from posterior to anterior region. Conclusion : The measurement can be used for planning implant surgery before extraction. CT has are clinically useful in the evaluation of thickness of alveolar bone.