• Imaging Science in Dentistry
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• v.54 no.1
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• pp.93-104
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• 2024

Chronic nonbacterial osteomyelitis(CNO) is histologically characterized by nonspecific osteitis. This inflammatory disorder, which lacks an infectious origin, typically presents with chronic pain and swelling at the affected site that can persist for months or even years. However, it is rare for CNO to affect the mandible. A 10-year-old girl presented with a primary complaint of pain in her left mandible. She had no significant medical or dental history. On examination, swelling was visible on the left buccal side, and imaging revealed radiolucent bone deterioration within the left mandible. This case report presents the radiological changes observed over a 12-year follow-up period. Variations in radiopacity, radiolucency, and periosteal reactions were noted periodically. This case highlights the radiological characteristics and findings that are crucial for the diagnosis of CNO, a condition for which no clear diagnostic criteria are currently available.

• Imaging Science in Dentistry
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• v.31 no.3
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• pp.159-164
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• 2001

Purpose: To evaluate the osseous changes of TMJ in internal derangement and osteoarthritis patients using MRI. Materials and Methods: MR images of 111 TMJs in 64 patients were analyzed to evaluate the osseous changes, 111 TMJs were divided into 6 groups according to the radiologic Stages by Schellhas and Wilkes. On MR images, we evaluate the osseous changes of articular eminence and condylar head. Results: The most frequent Stage in internal derangement of TMJ was Stage I. And 28 joints (25.2%) revealed osteoarthritis with internal derangement. When osseous change of articular eminence and condylar head occur, flattening was the most common osseous change. Sclerosis was observed in all Stages and osteophytosis of condylar head was observed in Stage II (1.8%) and III (0.9%). Out of 28 joints with osteoarthritis, 6 joints (21.4%) showed joint effusion. Conclusion: MR image revealed abnormal configuration of disk, but the detection of minimal osseous change was subtle.

• The Journal of the Korean bone and joint tumor society
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• v.6 no.2
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• pp.61-68
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• 2000

Purpose : We examined the patients to evaluate the radiologic findings of solitary plasmacytoma of the bone. Materials and Methods : We retrospectively reviewed radiologic findings of 9 cases with solitary plasmacytoma of the bone (SPB) for recent 5 years, but 2 cases were not included this study due to an abnormal finding of bone marrow and another 2 cases were not included due to an abnormal manifestations of computed tomography (n=1) and MRI (n=1). Results : Among 5 cases, 4 cases had an osteolytic bone destruction and 1 case had an osteosclerotic bone destruction on the plain radiograph. Computed tomography and MRI showed more informations about trabeculated bone destruction and the soft-tissue extension of the lesion comparing to plain radiographs. The MRI finding of SPB in 4 cases showed a relatively high signal intensity on T1-weighted image and intermediate signal intensity on T2-weighted image, on which the signal intensity of the lesion is slightly higher than that of the muscle. One case had an extensive soft-tissue involvement and multiple necrosis, which presented iso to low signal intensity on T1-weighted image and high heterogeneous signal intensity on T2-weighted image. The Gadolinium-enhanced T1-weighted images of 5 cases showed diffusely strong enhancement of the lesion except on the necrosis areas. Conclusion : Computed tomography and MRI may present some characteristics of SPB and demonstrate another foci of plasma cell infiltrates, so these can be helpful for the diagnosis and treatment of SPB.

• Progress in Medical Physics
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• v.20 no.4
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• pp.191-198
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• 2009

In this study, we evaluated an edge detector for small-beam dosimetry. We measured the dose linearity, dose rate dependence, output factor, beam profiles, and percentage depth dose using an edge detector (Model 1118 Edge) for 6-MV photon beams at different field sizes and depths. The obtained values were compared with those obtained using a standard volume ionization chamber (CC13) and photon diode detector (PFD). The dose linearity results for the three detectors showed good agreement within 1%. The edge detector had the best linearity of ${\pm}0.08%$. The edge detector and PFD showed little dose rate dependency throughout the range of 100~600 MU/min, while CC13 showed a significant discrepancy of approximately -5% at 100 MU/min. The output factors of the three detectors showed good agreement within 1% for the tested field sizes. However, the output factor of CC13 compared to the other two detectors had a maximum difference of 21% for small field sizes (${\sim}4{\times}4\;cm^2$). When analyzing the 20~80% penumbra, the penumbra measured using CC13 was approximately two times wider than that using the edge detector for all field sizes. The width measured using PFD was approximately 30% wider for all field sizes. Compared to the edge detector, the 10~90% penumbras measured using the CC13 and PFD were approximately 55% and 19% wider, respectively. The full width at half maximum (FWHM) of the edge detector was close to the real field size, while the other two detectors measured values that were 8~10% greater for all field sizes. Percentage depth doses measured by the three detectors corresponded to each other for small beams. Based on the results, we consider the edge detector as an appropriate small-beam detector, while CC13 and PFD can lead to some errors when used for small beam fields under $4{\times}4\;cm^2$.

• The Journal of Korean Society for Radiation Therapy
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• v.17 no.2
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• pp.141-145
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• 2005

Purpose : It is known that the neutron is generally generated from the photon, its energy is larger than 10 MV. The neutron is leaked in the container inspection system installed at the customs though its energy is below 9 MV. It is needed that the spacial effect of the neutrons released from radiation treatment machine, linac, installed in the medical canter. Materials and Methods : The medical linear accelerator(Clinac 1800, varian, USA) was used in the experiment. Measuring neutron was used bubble detector(Bubble detector, BDPND type, BTI, Canada) which was created bubble by neutron. The bubble detector is located on the medical linear accelerator outskirt in three different distance, 30, 50, 120 cm and upper, lower four point from the iso-center. In addition, for effect on protect material we have measured eight points which are 50 cm distance from iso-center. The SAD(source-axis-distance), distance from photon source to iso-center, is adjusted to 100 cm and the field size is adjusted to $15{\times}15cm^2$. Irradiate 20 MU and calculate the dose rate in mrem/MU by measuring the number of bubble. Results : The neutron is more detected at 5 position in 30, 50 cm, 7 position in 120 cm and with wedge, and 2 position without mount. Conclusion : Though detection position is laid in the same distance in neutron measurement, the different value is shown in measuring results. Also, neutron dose is affected by the additional structure, the different value is obtained in each measurement positions. So, it is needed to measure and evaluate the neutron dose in the whole space considering the effect of the distance, angular distribution and additional structure.

• Journal of the Korean Society of Radiology
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• v.17 no.4
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• pp.607-614
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• 2023

Clear overlapping of the bilateral epicondyle and proper separation of the elbow joint are crucial for obtaining accurate lateral general radiographs of the elbow. However, due to the complex anatomical structure of the elbow, achieving optimal positioning is challenging, leading to the need for repeated x-ray examinations. Therefore, the purpose of this study was to investigate the angle of the forearm in patients where accurate lateral images of the elbow joint can't be obtained after vertical incidence using a styrofoam device during elbow joint lateral x-ray imaging. Twenty patients were enrolled in our study following the established protocol. First, a vertical x-ray at an angle of 0° between the forearm and the table was taken (control group). Here, if the lateral image of the elbow joint was deemed inadequate, the forearm angle was adjusted using custom-made styrofoam supports with 5° and 10° inclinations (experimental groups). For the evaluation method, two assessors utilized a 5-point Likert scale to assess the images. The reliability of the assessments was analyzed using Cronbach's alpha coefficient. As a result, patients with inadequate overlap of the bilateral epicondyle and separation of the elbow joint in the initial examination (control group) were able to obtain the best images when setting a 10° angle between the forearm and the table. The subjective evaluation was 1.6 ± 0.8 points at 0°, 2.7 ± 0.8 points at 5°, and 4.4 ± 1.3 points at 10°, respectively. The reliability analysis for the angles of 0°, 5°, and 10° yielded Cronbach's alpha values of 0.867, 0.697, and 0.922, respectively. In conclusion, when it is not possible to obtain accurate images using the conventional position and X-ray beam direction, it is considered that by initially acquiring images with an angle of 10° between the forearm and the table, and gradually decreasing the angle while obtaining images, it would be possible to achieve the optimal image while reducing the number of repeat examinations.

• Journal of radiological science and technology
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• v.30 no.4
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• pp.321-327
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• 2007

The purpose of this study to survey radiation workers' knowledge, attitude and behavior related to radiation safety management at medical institutions as an educational approach to radiation safety management and to accumulate materials in continuity of past data and, by doing so, to examine changes over time, to analyze long-term trends systematically and to derive ground data for establishing radiation safety control plans to prevent health disorders caused by radiation not only in radiation workers but also in ordinary people. For these purposes, a questionnaire survey was conducted with radiation workers at medical institutions throughout the country for around 40 days in 2001 and 2006. The results are summarized as follows. 1. The levels of knowledge, attitude and behavior related to radiation safety management were all higher in 2006 than in 2001. 2. Statistically significant correlations were observed between knowledge and attitude, between behavior and knowledge and between attitude and behavior in both 2001 and 2006. In particular, the correlation between attitude and behavior were higher in 2006 than in 2001, suggesting that radiation workers' attitude has been improved. 3. Factors affecting radiation workers' behavior related to radiation safety management were knowledge and attitude in both 2001 and 2006, and the effect of attitude was higher than that of knowledge.

• Progress in Medical Physics
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• v.18 no.3
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• pp.149-160
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• 2007

Recent advent of 64-multidetctor (MD) CT enables more coverage of Z-axis in the perfusion imaging. The purpose of this study was to evaluate the clinical usefulness of perfusion CT by using 64-MD CT in detecting the lesion in patients with acute stroke. The perfusion CT was performed by using 64-MD CT in 62 consecutive patients who were initially suspected to have subacute ischemic stroke symptoms during the period of recent 9 months. These patients had subacute stroke (n=62). CT scanning was conducted with Jog Mode which provided 16 imaging slices with 5 mm of slice thickness, and 8 cm of coverage in Z-axis. Scan interval was 1 seconds for each imaging slice and total 15 scans were repeated. After CT scanning, perfusion maps (CBV, CBF, MTT and TTP) were created at Extended Brilliance Workstation. The CBV and CBF maps showed that lesions were smaller images. While on the MTT and TTP map lesions were seen to be larger fifty-one were large than they appeared on these images. Two slices of perfusion maps obtained at the level of the basal ganglia were chosen to simulate conventional older perfusion CT with 8 cm of coverage in Z-axis. TTP and MTT maps may be clinically useful for evaluation of the penumbral zone in cases of aubacute cerebral ischemic stroke. The perfusion CT is useful in the assessment of acute stroke as an initial imaging modality.

• Journal of radiological science and technology
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• v.29 no.3
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• pp.147-155
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• 2006

The crystal structures of fully dehydrated $K_3Na_8H-A(R_1=0.0478,\;R_2=0.0458\;and\;a=12.257(1){\AA})$ have been studied by single-crystal x-ray diffraction methods in the cubic space group. Pm3m in order to understand the structure of the zeolite as a gas storage medium and the mechanisms based on the encapsulation and decapsulation processes of gas molecules. In the crystal structures of dehydrated $K_3Na_8H-A$, three $K^+$ ions per unit cell are located on the 8-oxygen ring(0.0, 0.4531, 0.4531) and eight $Na^+$ ions per unit cell are located near the centers of 6-oxygen rings. Each $K^+$ ions on the 8-ring is $2.87(2){\AA}$ and $2.79(1){\AA}$ away from two kinds of framework oxygen atoms. These values are more realistic than previously known values in $K_{12}Na-A$. The exact positions of $K^+$ ions are ca. $0.8{\AA}$ away from the centers of the 8-rings which are previously reported as the preferred location of $K^+$ ions. Because the zeolites frameworks are stabilized as the results, more effective controls of gas molecules at encapsulation, decapsulation, and storage are achieved. Additionally, the available storage volumes are also maximized and more volume of gases can be stored in the materials. Therefore, oxygen storage bottles in hospital can be minimized and portable oxygen bottles for patients in emergency can be developed by using the materials.

• Journal of radiological science and technology
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• v.24 no.1
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• pp.33-41
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• 2001

This study is to get preliminary data for an effectiveness evaluation of abdominal examination and improvement of it. Abnormal cases of abdominal ultrasonography are classified by sex, frequency, diagnosis and age. 4,924 examinees were included at a university hospital of health promotion center from January to December in 1999. The results are as follows. 1. According to the distribution of sex, there are more male patients(55.0%) than females patients(48.0%). For men, 40's showed the highest percentage among examinees. For women, 50's were the highest. 2. The reason that they visited the health promotion center was that 'they wanted to check their health status'. This answers were reported the highest(59.3%). 3. Patients that had abnormal cases of abdominal ultrasonography were 48.3%. Liver, kidney, gallbladder showed the highest percentage of abnormal cases in order of organs. Additionally, abnormal cases were discovered in liver cases. 4. According to the frequency of abnormal cases among examinees, the slight fatty liver were the highest regardless of sex. Men had the slight fatty liver, kidney simple cyst, liver calcification and liver simple cyst in order of abnormal cases. Women showed the slight fatty liver kidney simple cyst, kidney calcification, liver simple cyst, and blood vessel tumor in order of abnormal cases. 5. For the abnormal cases of liver by sex and age, the 50's reported the highest number of abnormal cases in men(299 patients). In addition, 60's had the highest of disease rata 47.8%. For women, 50's reported the highest number of abnormal cases(361 patients). Over 70's patients had the highest of disease rata 52.6%. For kidney, men and women showed the highest number of abnormal cases -62 vs 44 respectively. Over 70's patients had the highest percentage of disease rata-23.2% vs 14.0% respectively. For gallbladder, the number of abnormal cases were the most in men's 60's (31 patients) and in women's in the same age group (32patients). Disease showed the highest percentage in men's 60's(7.6%) and in women's 70's (14.0%). 6. According to malignant tumor, 17patients were liver cancer, 2patients stomach ca and 1pt kidney cancer. 7. The relationship between the malignant tumor and the examination motive was that 'they wanted to check their health status(41.0%)' and 'regular checkup (24.0%)'.