• Design & Manufacturing
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• v.14 no.4
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• pp.17-24
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• 2020

Products for heating indoors in low temperature and dry winter are largely divided into products using fossil fuels and products using electricity. The fossil fuels can warm the entire space by convection, but there is a high risk of fire and the frequent ventilation due to the increase in carbon monoxide and carbon dioxide. Heaters using electricity are mainly used because they are convenient to use and are cheap. However, these products can not efficiently warm the air because they use radiation energy. In other words, only the front part exposed to the heater is warm, and the rear part has no heating effect at all. Also, because it emits a large amount of light, fatigue of the eyes is very high. Another problem is that when using electric heaters, the room tends to be dry by high heat. Indoor humidity maintenance is a very important factor in the prevention and treatment of respiratory diseases. Especially, it is essential for health care for infants, bronchial organs and people with weak respiratory because humidity is low in winter. In this study, we conducted a study to develop a product that can improve heating efficiency while maintaining proper indoor humidity by combining heat energy and moisture particles. The concept of humidification and heating at the same time, moisture particles generated in the humidifier pass through the heater, include thermal energy, and the moisture particles with thermal energy are diffused into the space by forced convection, thereby warming the entire space. In addition, the heating time is shortened as the feeling temperature is increased with the high relative humidity, and this has the effect that the heating cost in winter is reduced.

• Journal of Radiation Protection and Research
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• v.49 no.1
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• pp.50-64
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• 2024

Background: The reference dose coefficients (DCs) of the International Commission on Radiological Protection (ICRP) have been widely used to estimate organ doses of individuals for risk assessments. This approach has been well accepted because individual anatomy data are usually unavailable, although dosimetric uncertainty exists due to the anatomical difference between the reference phantoms and the individuals. We attempted to quantify the individual variation of organ doses for photon external exposures by calculating and comparing organ DCs for 30 individuals against the ICRP reference DCs. Materials and Methods: We acquired computed tomography images from 30 patients in which eight organs (brain, breasts, liver, lungs, skeleton, skin, stomach, and urinary bladder) were segmented using the ImageJ software to create voxel phantoms. The phantoms were implemented into the Monte Carlo N-Particle 6 (MCNP6) code and then irradiated by broad parallel photon beams (10 keV to 10 MeV) at four directions (antero-posterior, postero-anterior, left-lateral, right-lateral) to calculate organ DCs. Results and Discussion: There was significant variation in organ doses due to the difference in anatomy among the individuals, especially in the kilovoltage region (e.g., <100 keV). For example, the red bone marrow doses at 0.01 MeV varied from 3 to 7 orders of the magnitude depending on the irradiation geometry. In contrast, in the megavoltage region (1-10 MeV), the individual variation of the organ doses was found to be negligibly small (differences <10%). It was also interesting to observe that the organ doses of the ICRP reference phantoms showed good agreement with the mean values of the organ doses among the patients in many cases. Conclusion: The results of this study would be informative to improve insights in individual-specific dosimetry. It should be extended to further studies in terms of many different aspects (e.g., other particles such as neutrons, other exposures such as internal exposures, and a larger number of individuals/patients) in the future.

• Radiation Oncology Journal
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• v.36 no.3
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• pp.241-247
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• 2018

Purpose: A hybrid-dynamic conformal arc therapy (HDCAT) technique consisting of a single half-rotated dynamic conformal arc beam and static field-in-field beams in two directions was designed and evaluated in terms of dosimetric benefits for radiotherapy of lung cancer. Materials and Methods: This planning study was performed in 20 lung cancer cases treated with the VERO system (BrainLAB AG, Feldkirchen, Germany). Dosimetric parameters of HDCAT plans were compared with those of three-dimensional conformal radiotherapy (3D-CRT) plans in terms of target volume coverage, dose conformity, and sparing of organs at risk. Results: HDCAT showed better dose conformity compared with 3D-CRT (conformity index: 0.74 ± 0.06 vs. 0.62 ± 0.06, p < 0.001). HDCAT significantly reduced the lung volume receiving more than 20 Gy (V₂₀: 21.4% ± 8.2% vs. 24.5% ± 8.8%, p < 0.001; V₃₀: 14.2% ± 6.1% vs. 15.1% ± 6.4%, p = 0.02; V₄₀: 8.8% ± 3.9% vs. 10.3% ± 4.5%, p < 0.001; and V₅₀: 5.7% ± 2.7% vs. 7.1% ± 3.2%, p < 0.001), V₄₀ and V₅₀ of the heart (V₄₀: 5.2 ± 3.9 Gy vs. 7.6 ± 5.5 Gy, p < 0.001; V₅₀: 1.8 ± 1.6 Gy vs. 3.1 ± 2.8 Gy, p = 0.001), and the maximum spinal cord dose (34.8 ± 9.4 Gy vs. 42.5 ± 7.8 Gy, p < 0.001) compared with 3D-CRT. Conclusions: HDCAT could achieve highly conformal target coverage and reduce the doses to critical organs such as the lung, heart, and spinal cord compared to 3D-CRT for the treatment of lung cancer patients.

• Journal of Convergence Society for SMB
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• v.4 no.1
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• pp.55-62
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• 2014

Wireless capsule endoscopy (WCE) was one of the most influential bio-medical electronic technologies to be developed at the beginning of the century. In comparison to traditional endoscopic diagnosis, this application is characterized as non-invasive and low-risk, thereby providing surgeons with a new alternative for inspecting the entire gastrointestinal (GI) track in a much more user friendly way. Apart from regular hardware upgrades, the frontier of WCE research basically lies in the miniaturization of the capsule and in active locomotion. In order to overcome the intrinsic drawback of current commercialized WCE products, which is that locomotion is generally a function of natural peristalsis, active locomotion is proposed as a series of strategies used to effectively navigate the device into different organs and conduct therapeutic functions within targeted human tissues. Reviews of several novel designs with respect to this aspect of research will be discussed in this article.

• Radiation Oncology Journal
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• v.37 no.2
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• pp.127-133
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• 2019

Purpose: The aim of this study was to identify volume changes and dose variations of rectum and bladder during radiation therapy in prostate cancer (PC) patients. Materials and Methods: We analyzed 20 patients with PC treated with helical tomotherapy. Daily image guidance was performed. We re-contoured the entire bladder and rectum including its contents as well as the organ walls on megavoltage computed tomography once a week. Dose variations were analyzed by means of Dmedian, Dmean, Dmax, V₁₀ to V₇₅, as well as the organs at risk (OAR) volume. Further, we investigated the correlation between volume changes and changes in Dmean of OAR. Results: During treatment, the rectal volume ranged from 62% to 223% of its initial volume, the bladder volume from 22% to 375%. The average Dmean ranged from 87% to 118% for the rectum and 58% to 160% for the bladder. The Pearson correlation coefficients between volume changes and corresponding changes in Dmean were -0.82 for the bladder and 0.52 for the rectum. The comparison of the dose wall histogram (DWH) and the dose volume histogram (DVH) showed that the DVH underestimates the percentage of the rectal and bladder volume exposed to the high dose region. Conclusion: Relevant variations in the volume of OAR and corresponding dose variations can be observed. For the bladder, an increase in the volume generally leads to lower doses; for the rectum, the correlation is weaker. Having demonstrated remarkable differences in the dose distribution of the DWH and the DVH, the use of DWHs should be considered.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.3
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• pp.1609-1614
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• 2013

Objective: To evaluate the effect of intravenous contrast on dose calculation in radiation treatment planning for oesophageal cancer. Methods: A total of 22 intravein-contrasted patients with oesophageal cancer were included. The Hounsfield unit (HU) value of the enhanced blood stream in thoracic great vessels and heart was overridden with 45 HU to simulate the non-contrast CT image, and 145 HU, 245 HU, 345 HU, and 445 HU to model the different contrast-enhanced scenarios. 1000 HU and -1000 HU were used to evaluate two non-physiologic extreme scenarios. Variation in dose distribution of the different scenarios was calculated to quantify the effect of contrast enhancement. Results: In the contrast-enhanced scenarios, the mean variation in dose for planning target volume (PTV) was less than 1.0%, and those for the total lung and spinal cord were less than 0.5%. When the HU value of the blood stream exceeded 245 the average variation exceeded 1.0% for the heart V40. In the non-physiologic extreme scenarios, the dose variation of PTV was less than 1.0%, while the dose calculations of the organs at risk were greater than 2.0%. Conclusions: The use of contrast agent does not significantly influence dose calculation of PTV, lung and spinal cord. However, it does have influence on dose accuracy for heart.

• Molecular & Cellular Toxicology
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• v.5 no.4
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• pp.317-322
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• 2009

Hepatic fibrosis is one of chronic liver diseases which spread in worldwide and it has high risk to turn advanced cirrhosis and hepatocellualr carcinoma. Brassica family has been produced for commercial purpose and in Korea Brassica rapa (Turnip) is cultivated in Ganghwa County, Gyeonggi-do Korea and used for making Kimchi. Recently pharmacological effects of turnip have been known; diabete mellitus modulation, alcohol oxidization, and fibrosis inhibition. In previous study we found antifibrogenic effect of turnip water extract and in this study we made turnip nanoparticle to promote turnip delivery into liver. At the same time we assessed the biological safety of turnip nanoparticle. Thioacetamide (TAA) induced hepatic nodular formation and fibrosis (mean of fibrosis score: 4). However, 1% turnip nanoparticle inhibited TAA-induced hepatic nodular formation and fibrosis (mean of fibrosis score: 2-3). Activities of serum enzymes (aspartic acid transaminase (AST), alanine transaminase (ALT), and total bilirubin (T-Bil)), complete blood count (CBC), and the appearance of organs were not different from control and 1% turnip nanoparticle treatment. Conclusively 1% turnip nanoparticle significantly reduced TAA-induced hepatic fibrosis and was safe in 7-weeks feeding.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7149-7152
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• 2014

A large number of epidemiological studies have demonstrated that obesity is a risk factor for several human cancers. Several animal studies using rodents with diet-induced or genetic obesity have also demonstrated that obesity can promote tumor development. However, the effects of obesity on the early stages of carcinogenesis, and especially on the spontaneous occurrence of somatic gene mutations, remain unclear. To investigate the effects of obesity on the rate of spontaneous gene mutations, we performed reporter gene mutation assays in liver, kidney, and colon, organs in which obesity appears to be associated with cancer development on the basis of epidemiological or animal studies, in mice with high fat diet (HFD)-induced obesity. Six-week-old male and female C57BL/6 gpt delta mice were fed HFD or standard diet (STD) for 13 or 26 weeks. At the end of the experiments, reporter gene mutation assays of liver, kidney, and colon were performed. Final body weights and serum leptin levels of male and female mice fed HFD for 13 or 26 weeks were significantly increased compared with corresponding STD-fed groups. Reporter gene mutation assays of liver, kidney, and colon revealed that there were no significant differences in gpt or $Spi^-$ mutant frequencies between STD- and HFD-fed mice in either the 13-week or 26-week groups. These results indicate that HFD treatment and consequent obesity does not appear to influence the spontaneous occurrence of somatic gene mutations.

• Journal of Trauma and Injury
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• v.20 no.2
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• pp.125-129
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• 2007

Purpose: The liver is one of the most commonly injured organs in abdominal trauma. Surgery has played a major role in treating traumatic liver injury. Recently, it was reported that conservative treatment could be the first-line management for hemodynamically stable patients without combined intraabdominal surgical problems. The aim of this study was to examine the prognostic factors in traumatic liver injury. Methods: The medical records of 41 patients who were treated for traumatic liver injury at Seoul National University Bundang Hospital from March 2003 to October 2007 were retrospectively reviewed. Results: Among the 41 patients, 34 cases (82.9%) were managed nonsurgically, and 7 cases (17.1%) were managed surgically. Out of the 5 (12.2%) mortalities, 2 were encountered in those who underwent surgery, and 3 were encountered in those who were treated nonsurgically. Univariate analysis showed that the initial systolic blood pressure, the initial hemoglobin level, and the grade of liver injury were significant prognostic factors for survival. Multivariate analysis indicated that initial low systolic blood pressure was the only independent risk factor. Conclusion: Patients with unstable vital signs initially have a poor prognosis. Aggressive management might be helpful for improving the survival rate in these patients.

• Journal of Radiation Protection and Research
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• v.43 no.2
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• pp.59-65
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• 2018

Background: We analyzed changes in the doses, structure volumes, and dose-volume histograms (DVHs) when data were transferred from one commercial treatment planning system (TPS) to another commercial TPS. Materials and Methods: A total of 22 volumetric modulated arc therapy (VMAT) plans for nasopharyngeal cancer were generated with the Eclipse system using 6-MV photon beams. The computed tomography (CT) images, dose distributions, and structure information, including the planning target volume (PTV) and organs at risk (OARs), were transferred from the Eclipse to the MRIdian system in digital imaging and communications in medicine (DICOM) format. Thereafter, DVHs of the OARs and PTVs were generated in the MRIdian system. The structure volumes, dose distributions, and DVHs were compared between the MRIdian and Eclipse systems. Results and Discussion: The dose differences between the two systems were negligible (average matching ratio for every voxel with a 0.1% dose difference criterion = $100.0{\pm}0.0%$). However, the structure volumes significantly differed between the MRIdian and Eclipse systems (volume differences of $743.21{\pm}461.91%$ for the optic chiasm and $8.98{\pm}1.98%$ for the PTV). Compared to the Eclipse system, the MRIdian system generally overestimated the structure volumes (all, p < 0.001). The DVHs that were plotted using the relative structure volumes exhibited small differences between the MRIdian and Eclipse systems. In contrast, the DVHs that were plotted using the absolute structure volumes showed large differences between the two TPSs. Conclusion: DVH interpretation between two TPSs should be performed using DVHs plotted with the absolute dose and absolute volume, rather than the relative values.