• Journal of Chest Surgery
• /
• v.40 no.11
• /
• pp.786-788
• /
• 2007

Primary malignant fibrous histiocytoma of the lung is extremely rare, A 12-year-old child was admitted to the hospital due to an incidentally detected lung mass. A $2.5{\times}2.5 cm$ sized mass located in the right lower lobe was seen on the chest X-ray, the chest computed tomogram and the positron emission tomogram. We resected the mass through a right lateral thoracotomy and the mass was revealed to be a malignant spindle cell neoplasm on the frozen section diagnosis. So, we performed lobectomy of the right lower lobe with systemic dissection of the mediastinal lymph nodes; the final histopathological diagnosis of the mass was malignant fibrous histiocytoma. The patient was discharged on postoperative day 7 and adjuvant chemotherapy was not applied.

• Progress in Medical Physics
• /
• v.20 no.4
• /
• pp.290-297
• /
• 2009

In case of radiation treatment using small field high-energy photon beams, an accurate dosimetry is a challenging task because of dosimetrically unfavorable phenomena such as dramatic changes of the dose at the field boundaries, dis-equilibrium of the electrons, and non-uniformity between the detector and the phantom materials. In this study, the absorbed dose in the phantom was measured by using an ion chamber and a diode detector widely used in clinics. $GAFCHROMIC^{(R)}$ EBT films composed of water equivalent materials was also evaluated as a small field detector and compared with ionchamber and diode detectors. The output factors at 10 cm depth of a solid phantom located 100 cm from the 6 MV linear accelerator (Varian, 6 EX) source were measured for 6 field sizes ($5{\times}5\;cm^2$, $2{\times}2\;cm^2$, $1.5{\times}1.5\;cm^2$, $1{\times}1\;cm^2$, $0.7{\times}0.7\;cm^2$ and $0.5{\times}0.5\;cm^2$). As a result, from $5{\times}5\;cm^2$ to $1.5{\times}1.5\;cm^2$ field sizes, absorbed doses from three detectors were accurately identified within 1%. Wheres, the ion chamber underestimated dose compared to other detectors in the field sizes less than $1{\times}1\;cm^2$. In order to correct the observed underestimation, a convolution method was employed to eliminate the volume averaging effect of an ion chamber. Finally, in $1{\times}1\;cm^2$ field the absorbed dose with a diode detector was about 3% higher than that with the EBT film while the dose with the ion chamber after volume correction was 1% lower. For $0.5{\times}0.5\;cm^2$ field, the dose with the diode detector was 1% larger than that with the EBT film while dose with volume corrected ionization chamber was 7% lower. In conclusion, the possibility of $GAFCHROMIC^{(R)}$ EBT film as an small field dosimeter was tested and further investigation will be proceed using Monte Calro simulation.

• The Journal of Korean Society for Radiation Therapy
• /
• v.29 no.1
• /
• pp.77-84
• /
• 2017

Purpose: To evaluate the image quality improvement and dosimetric effects on virtual monochromatic images of a Dual Source-Dual Energy CT(DS-DECT) for radiotherapy planning. Materials and Methods: Dual energy(80/Sn 140 kVp) and single energy(120 kVp) scans were obtained with dual source CT scanner. Virtual monochromatic images were reconstructed at 40-140 keV for the catphan phantom study. The solid water-equivalent phantom for dosimetry performs an analytical calculation, which is implemented in TPS, of a 10 MV, $10{\times}10cm^2$ photon beam incident into the solid phantom with the existence of stainless steel. The dose profiles along the central axis at depths were discussed. The dosimetric consequences in computed treatment plans were evaluated based on polychromatic images at 120 kVp. Results: The magnitude of differences was large at lower monochromatic energy levels. The measurements at over 70 keV shows stable HU for polystyrene, acrylic. For CT to ED conversion curve, the shape of the curve at 120 kVp was close to that at 80 keV. 105 keV virtual monochromatic images were more successful than other energies at reducing streak artifacts, which some residual artifacts remained in the corrected image. The dose-calculation variations in radiotherapy treatment planning do not exceed ${\pm}0.7%$. Conclusion: Radiation doses with dual energy CT imaging can be lower than those with single energy CT imaging. The virtual monochromatic images were useful for the revision of CT number, which can be improved for target coverage and electron densities distribution.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.8 no.1
• /
• pp.191-197
• /
• 2013

Conventional CT and MRI scans produce cross-section slices of body that are viewed sequentially by radiologists who must imagine or extrapolate from these views what the 3 dimensional anatomy should be. By using sophisticated algorithm and high performance computing, these cross-sections may be rendered as direct 3D representations of human anatomy. The 2D medical image analysis forced to use time-consuming, subjective, error-prone manual techniques, such as slice tracing and region painting, for extracting regions of interest. To overcome the drawbacks of 2D medical image analysis, combining with medical image processing, 3D visualization is essential for extracting anatomical structures and making measurements. We used the gray-level thresholding, region growing, contour following, deformable model to segment human organ and used the feature vectors from texture analysis to detect harmful cancer. We used the perspective projection and marching cube algorithm to render the surface from volumetric MR and CT image data. The 3D visualization of human anatomy and segmented human organ provides valuable benefits for radiation treatment planning, surgical planning, surgery simulation, image guided surgery and interventional imaging applications.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.7 no.4
• /
• pp.937-944
• /
• 2012

Smoking in adolescence can cause other health risks such as drinking and abusing drugs. Besides, it goes on adulthood so it can threaten their health all days. This study want to know the relationship between smoking and internet addiction in mid- and highschool students in Korea. It conducted for 38,409 middle school students and 36,657 highschool student in Korea. Smoking and internet addiction was investigated by chi-squared test and the relation between them was done by a Logistic Regression Analysis. The statistical significance is under 0.05. The percentage of smoking is 34.2% in male student and 19.7% in female student. The percentage of internet addiction is 17.6% in male student and 11.4% in female student and it is higher in students who smoked by 1.06 times for male student and 1.62 times for female student. This result shows that smoking which is non-healthy habit is related with internet addiction significantly. Smoking can cause high stress and this stress is shown to be developed in internet addiction. In conclusion, smoking and internet addiction in adolescence are bad habits and they are affect each other. Therefore we have to consider a measure by looking as smoking, stress and internet addiction are complex health risks rather than trying to prevent and treat them individually.

• Journal of the Korean Society of Radiology
• /
• v.17 no.1
• /
• pp.31-36
• /
• 2023

Among imaging and treatment devices for small animals, positron emission tomography(PET) causes a change in spatial resolution within a field of view. This is a phenomenon caused by using a small gantry and a thin and long scintillation pixel, and detectors that measure the interaction depth are being developed and researched to solve this problem. In this study, a detector that measures the interaction depth was designed using several scintillator blocks and light guides with different reflector patterns. The scintillator block composed of 4 × 4 arrays of 3 mm × 3 mm × 5 mm scintillation pixels formed four layers, and a light guide was inserted in each layer to configure the entire detector. In order to check whether the interaction depth was measured, a gamma ray interaction was generated at the center of all scintillation pixels to acquire data and then reconstructed into a flood image. The reflector patterns of the light guides inserted between the layers were all different, so the positions of the scintillation pixels for each layer were formed in different locations. It is considered that even spatial resolution can be achieved over all regions of the field of view if all positions of the scintillation pixels thus formed are separated and used for image reconstruction.

• The Journal of the Korea Contents Association
• /
• v.22 no.2
• /
• pp.794-802
• /
• 2022

This retrospective study was to investigate the characteristics of unplanned readmission and factors affecting readmission within 30 days of discharge in patients who underwent heart valve surgery through electronic medical records. The participants were 423 unplanned re-hospitalization within 30 days after heart valve surgery at a tertiary hospital in Seoul from January 2018 to August 2019. A total of 48 patients (11.3%) were unplanned readmissions, and the most common causes were atrial fibrillation in 13 cases (27.1%) and pain at the surgical site in 13 cases (27.1%). Other causes were: 10 cases (20.8%) of warfarin inappropriate treatment concentration, 7 cases of general weakness (14.6%), 5 cases of hypotension (10.4%), 4 cases of pericardial effusion (8.3%), 3 cases of surgical wound infection (6.3%), 3 cases of hemorrhage (6.3%), 3 cases of high fever (6.3%), and 1 case of cerebral infarction (2.1%). Variables influencing readmission were history of cancer (OR = 2.60, 95% CI 1.13-6.03, p = .025) and the patients who went to a home rather than a hospital after discharge (OR = 2.91, 95% CI 1.33-6.36, p = .008), as a type of valve surgery, mitral valve valvuloplasty had a higher readmission rate than aortic valve replacement (OR = 1.21, 95% CI 1.21-4.98, p = .012). In order to reduce unplanned readmissions, an tailored education program is needed to enable patients and caregivers to manage their comorbid chronic diseases before discharge and assess risk factors for readmission in advance.

• Journal of dental hygiene science
• /
• v.6 no.4
• /
• pp.303-307
• /
• 2006

The objective of this study was to evaluate the effects of the topical application of fluoride by iontophoresis on the fluoride concentration in the dental enamel. Eighty-eight healthy teeth were extracted from orthodontic patients and divided into three experimental groups at 0.2 mA and 0.5 mA current and a control group. Each experimental group was further divided into three subgroups according to the application time (1, 3, and 5 min). Five to six teeth were assigned to each subgroup. Inotophoresis was performed using a 2% sodium fluoride solution and each tooth was sliced into a $3{\times}3mm$ specimen on enamel. The fluoride concentration in the enamel was measured using X-ray photoelectron spectroscopy. It was used to estimate the atomic ratio of fluoride on the enamel surface on selected samples. The specimen was observed via scanning electron microscopy as well. This finding was confirmed by the result that the fluoride ratios estimated by x-ray photoelectron spectroscopy was 2.71%, 2.87% and 3.80% after fluoride iontophoresis had been performed using a 2% sodium fluoride solution at 0.5 mA for 1, 3 and 5 min, respectively. In comparison, the fluoride ratio was 0.49% in the control group. As the current became higher and the time lapsed, the formation of irregular particles was strengthened on the enamel surface. Afterwards, the enamel surface was dissolved and new matrix was formed on the enamel. Fluorapatite was observed on the enamel after fluoride iontophoresis was performed at 0.5 mA for 5 min. The fluoride concentration tended to increase with increasing duration of iontophoresis. The study findings indicated that under proper conditions, fluoride iontophoresis has a positive effect in increasing the fluoride concentration in dental enamel.

• Journal of radiological science and technology
• /
• v.35 no.2
• /
• pp.157-164
• /
• 2012

The purpose of this study is to analyze the dose distribution when wedge filter is used in the various tissue electron density materials. The dose distribution was assessed that the enhanced dynamic wedge filter and physical wedge filter were used in the solid water phantom, cork phantom, and air cavity. The film dosimetry was suitable simple to measure 2D dose distribution. Therefore, the radiochromic films (Gafchromic EBT2, ISP, NJ, USA) were selected to measure and to analyze the dose distributions. A linear accelerator using 6 MV photon were irradiated to field size of $10{\times}10cm^2$ with 400 MUs. The dose distributions of EBT2 films were analyzed the in-field area and penumbra regions by using dose analysis program. In the dose distributions of wedge field, the dose from a physical wedge was higher than that from a dynamic wedge at the same electron density materials. A dose distributions of wedge type in the solid water phantom and the cork phantom were in agreements with 2%. However, the dose distribution in air cavity showed the large difference with those in the solid water phantom or cork phantom dose distributions. Dose distribution of wedge field in air cavity was not shown the wedge effect. The penumbra width, out of the field of thick and thin, was observed larger from 1 cm to 2 cm at the thick end. The penumbra of physical wedge filter was much larger average 6% than the dynamic wedge filter. If the physical wedge filter is used, the dose was increased to effect the scatter that interacted with photon and physical wedge. In the case of difference in electron like the soft tissue, lung, and air, the transmission, absorption, and scattering were changed in the medium at high energy photon. Therefore, the treatment at the difference electron density should be inhomogeneity correction in treatment planning system.

• Journal of Chest Surgery
• /
• v.31 no.9
• /
• pp.884-892
• /
• 1998

Background: The gastroepiploic artery is not only an alternative graft but also may be considered an important primary graft for coronary revascularization. However, the long-term patency of the gastroepiploic arterial graft is yet to be determined and the incidence of perioperative spasm and long-term patency of a coronary graft may be affected by the properties of the graft response to certain vasoactive substances. The reactivity of the gastroepiploic artery to vasoactive substances has not been studied extensively and the results of the studies are contradictory. Material and Method: This study was designed to test the reactivity of human gastroepiploic artery to four constrictors and four relaxants. The middle sections of the human gastroepiploic arteries were collected from the patients undergoing gastrectomy and the arterial rings with intact endothelium were suspended in organ baths for isometric tension recording. Result: Epinephrine, norepinephrine, and potassium chloride induced the maximum constriction to higher forces (7.0$\pm$1.1g, 6.6$\pm$0.9g, and 6.5$\pm$1.1g) than 5-hydroxytryptamine did (3.8$\pm$1.7g, p<0.05). Nitroprusside and histamine induced almost full relaxation in the gastroepiploic arteries preconstricted with norepinephrine. There was no significant difference between two relaxants regarding maximum relaxation force. Acetylcholine induced the maximum relaxation to weaker force when compared with nitroprusside and histamine (p<0.05), and isoproterenol was the weakest of the relaxants (p<0.05 compared with acetylcholine). Conclusion: The gastroepiploic artery has a strong capacity of endothelium-dependent relaxation which could have an important influence on long-term patency. The gastroepiploic artery exhibits a potent contractility to catecholamines and the enhanced contractility may facilitate vasospasm in the presence of high circulating levels of catecholamines. Nitroprusside, a potent relaxant in gastroepiploic artery, might be beneficial for the treatment of gastroepiploic arterial graft spasm. The gastroepiploic arterial graft with intact endothelium may respond weakly to beta-adrenoceptor agonist and 5-hydroxytryptamine.