• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.26 no.3
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• pp.133-138
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• 2020

As HMR (home meal replacement) food market grows rapidly, a new packaging with more HMR specialized functions is highly required to promote consumers' convenience. A susceptor is defined as a material generating heat by absorbing electromagnetic energy such typically as radiofrequency or microwave radiation. In microwave cooking, susceptors are made of conductive metal thin film deposited on paper or plastic sheet and have generally been used to help crispen or brown foods by converting microwave energy into heat. This mini review article deals with current status of microwave susceptor packaging including commercial products, technical theory, types of susceptor and a test method for heating performance.

• Journal of Digital Convergence
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• v.18 no.3
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• pp.267-273
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• 2020

To determine the biological effects of exercise on hippocampus in mice brain exposed to radiofrequency radiaton (RF), the expression of AMPKα, p-AMPKα, ERK1/2, p-ERK1/2, p38, and p-p38 protein in the mouse exposed to RF were investigated in the hippocampal tissues, Western blot method was used to compare the protein expression levels for each molecule. Significant increases in protein expression of individual and phosphorylated molecules were observed in the spontaneous exercise group, and the expression of these molecules was notably decreased in the RF exposure and spontaneous exercise group. This study shows that neuroplasticity can be increased by exercise in hippocampus that is responsible for memory, but memory and cognitive function may be affected by exposure to RF. We may expect clinically interesting results on dementia or Alzheimer disease if we proceed further investigation on the effect of RF.

• Radiation Oncology Journal
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• v.2 no.1
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• pp.11-20
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• 1984

The renewed interest in the use of hyperthermia in cancer therapy is bases on radiobiological and clinical evidence indicated that there may be a significant therapeutic advantage with the use of heat alone or combined with radiation or chemotherapy, There are many methods for generating heat for localized tumor as like radiofrequency, microwave, electromagnetic induction and ultrasound. But it is very difficult to be even thermal dose distribution and stable output of power and then the detection of temperature in tumor is difficult to be precise with thermocouples and semiconductor sensors. We designed the microwave heating generator, dipole antenna applicators and autometic temperature controlled thermocouples for localized hyperthermia on skin and in cavities. 1. The microwave generator with 120 W, 2,450MHz magnetron could be heating up to $40^{\circ}C\~50^{\circ}C\;for\;1\~2$ hours in living tissues. 2. The thermal dose distribution in tissue with microwave was described $42^{\circ}C\~44^{\circ}C$ with in 3 cm depth and $2\~6cm$ diameter area. 3. Skin surface heating applicator with spiral 3 times wave length antenna radiated high Power of microwave. 4, Intracavitary heating applicator with dipole antenna with autometic control temperature sensor kept up continuously constant temperature in tissue. 5. For constant thermal distribution, applied two steps power with 10W microwave after $17\~20W$ during first 10 minutes. 6. The cooling rate by blood flew in living tissue was rised as $10\%$ then meats.

• Physical Therapy Korea
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• v.22 no.2
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• pp.70-80
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• 2015

The spinal cord is highly complex, consisting of a specialized neural network that comprised both neuronal and non-neuronal cells. Any kind of injury and/or insult to the spinal cord leads to a series of damaging events resulting in motor and/or sensory deficits below the level of injury. As a result, muscle paralysis (or paresis) leading to muscle atrophy or shrinking of the muscle along with changes in muscle fiber type, and contractile properties have been observed. Traditionally, histology had been used as a gold standard to characterize spinal cord injury (SCI)-induced adaptation in spinal cord and skeletal muscle. However, histology measurements is invasive and cannot be used for longitudinal analysis. Therefore, the use of conventional magnetic resonance imaging (MRI) is promoted to be used as an alternative non-invasive method, which allows the repeated measurements over time and secures the safety against radiation by using radiofrequency pulse. Currently, many of pathological changes and adaptations occurring after SCI can be measured by MRI methods, specifically 3-dimensional MRI with the advanced diffusion tensor imaging technique. Both techniques have shown to be sensitive in measuring morphological and structural changes in skeletal muscle and the spinal cord.

• Clinical and Experimental Pediatrics
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• v.63 no.11
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• pp.422-428
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• 2020

In today's world, most children are exposed to various manmade electromagnetic fields (EMFs). EMFs are electromagnetic waves less than 300 GHz. A developing child's brain is vulnerable to electromagnetic radiation; thus, their caregivers' concerns about the health effects of EMFs are increasing. EMF exposure is divided into 2 categories: extremely low frequencies (ELFs; 3-3,000 Hz), involving high-voltage transmission lines and in-house wiring; and radiofrequencies (RFs; 30 kHz to 300 GHz), involving mobile phones, smart devices, base stations, WiFi, and 5G technologies. The biological effects of EMFs on humans include stimulation, thermal, and nonthermal, the latter of which is the least known. Among the various health issues related to EMFs, the most important issue is human carcinogenicity. According to the International Agency for Research on Cancer's (IARC's) evaluation of carcinogenic risks to humans, ELFs and RFs were evaluated as possible human carcinogens (Group 2B). However, the World Health Organization's (WHO's) view of EMFs remains undetermined. This article reviews the current knowledge of EMF exposure on humans, specifically children. EMF exposure sources, biological effects, current WHO and IARC opinions on carcinogenicity, and effects of EMF exposures on children will be discussed. As well-controlled EMF experiments in children are nearly impossible, scientific knowledge should be interpreted objectively. Precautionary approaches are recommended for children until the potential health effects of EMF are confirmed.

• Radiation Oncology Journal
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• v.14 no.2
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• pp.115-122
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• 1996

Purpose : To improve the treatment results of locally advanced nonsmall cell lung cancer (NSCLC) patients we treated those patients with regional hyperthermia combined with radiotherapy. And we conducted a retrospective analysis of the results. Material and Methods Thirty two nonsmall cell lung cancer Patients treated at the Department of Radiation Oncology, St. Mary's hospital, Catholic University Medical College were the base of this analysis. Fourteen patients of above them were treated with hyperthermia and radiotherapy of more than 3000 cGy in radiation dose. Radiofrequency capacitive hyperthermia was administered twice weekly immediately after radiotherapy. Total sessions of hyperthermia ranged from 3 to 13 times (mean 7.8). Eighteen patient received an external radiation therapy alone Median radiation dose was 5580 cGy (range, 3000-7000 cGy) in fraction of 180-300 cGy, 5 fractions per week. Results: The results of themoradiotherapy group (HTRT group) were compared with radiation alone group (RT group). There were no complete response (CR) and 12 Partial responses (PR) (CR rate $0\%$, response rate $85.7\%$) in HTRT group, whereas there were 2 CRs, 8 PRs and 8 no responses (CR rate $11.1\%$, response rate $55.6\%$) in RT group. There was significant differece in local response rate of the tumors between RT group and HTRT group (p < 0.05). Overall 2 rear survival rate and mean survival were $7.1\%$ and 10.5 months for HTRT group, and $0\%$ and 8.1 months for RT group. However, by the number of hyperthermia. in cases with more than or equal to 10 sessions of hyperthermia, there were significant improvement in 2 year year survival rate and mean survival ($40.0\%$ and 18.2 months) compared with those in cases with less than 10 sessions of hyperhtemia ($7.4\%$ and 7.4 months) (p < 0.05). Conclusion : Thermoradiotherapy in locally advanced NSCLC patients increased their response rate but not 2 year survival and mean survival, therefore thermoradiotherpy with enough number of hyperthermia is suggested that may be one of the effective palliative treatments of those patients. And in cases with more than 10 sessions of hyperthermia, there showed improved 2 year survival rate and mean survival But the number of the cases was small further study in this aspect is required.

• Radiation Oncology Journal
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• v.16 no.1
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• pp.27-33
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• 1998

Purpose : To improve the therapeutic results of postoperative recurrent disease and inoperable disease of stomach cancer, we used the thermoradiotherapy. We conducted a retrospective analysis of the results and compared the results of hyperthermia before radiotherapy and those of hyperthermia after radiotherapy Materials and Methods : From July 1994 to November 1996, we treated twenty patients with locally advanced stomach cancer and recurrent stomach cancer with thermoradiotherapy. We divided those patients into two groups : hyperthermia before radiotherapy group (PreRT group : 13 Patients) and hyperthermia after radiotherapy group (PostRT group : 7 patients). We performed radiation therapy with the total tumor dose of 3000-5040cGy in a traction of 180-300cGy and 5 fractions per week. Hyperthermia was performed with 8 MHz radiofrequency apparatus. PreRT group patients were treated daily for 30 minutes before the radiation therapy within the interval of ten minutes. And PostRT group patients were treated with 1-2 sessions Per week for 40-60 minutes after the radiation therapy within the interval of 10 minutes. Results : Overall response rate was $33.3\%$. This response rate appeared the same in both groups. Mean survival and 1 rear survival rate were 10.3 months and $16.5\%$. In PreRT group, mean survival and 1 year survival rate were 6.8 months and $9.0\%$, and in PostRT group, mean survival and 1 year survival rate were 7.7 months and $34\%$. There were no statistically significant difference between the prognostic factors and therapeutic results. Conclusion : The thermoradiotherapy was a safe treatment method in advanced and recurrent gastric cancer when compared with other treatment. Because the number of patients we treated was small and the follow up period was short. we were not able to draw any conclusions about the therapeutic efficacy of the sequence of radiation therapy and hyperthermia. Therefore, further clinical trials of thermoradiotherauy for stomach cancer appear to be warranted.

• Radiation Oncology Journal
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• v.7 no.2
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• pp.247-257
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• 1989

Thirty patients with nonresectable hepatocellular carcinoma (HCC) due to either locally advanced lesion or association with liver cirrhosis, treated with combined radiotherapy and hyperthermia between April 1988 and July 1988, at Dept. of Radiation Oncology, Yonsei university College of medicine, were analysed. External radiotherapy of a total dose of 3060cGy/3.5 wks was given. Hyperthermia was given twice a week with a total of 6 treatment sessions using 8MHz radiofrequency capacitive type heating device, i.e., Thermotron RF-8 and Cancermia. In all cases hyperthermia was given within 30 minutes after radiotherapy for 30~60min. Temperature was measured by inserting thermocouple into the tumor mass under the ultrasonographic guidance only for those who had not bleeding tendency. As a result, partial response (PR) was achieved in 12 patients (40%), and symptomatic improvement was observed in 22 patients (78.6%) among 28 patients who had suffered from abdominal pain. The most significant factor affecting the tumor response rate was the type of tumor (single massive: 10/14, 71.4%; diffuse infiltrative: 2/10, 20%; multinodular:0/6, 0%; p<0.005). There were not any significant side effects relating to combined treatment. The overall 1 year survival rate was 34%, with 50% in the PR group and 22% in the no response group (NR), respectively. Median survival was 6.5 months and longer for those of PR than of NR (11 mos. vs 5, p<0.05). In conclusion, combined radiotherapy and hyperthermia appeared to be effective in local control and symptomatic palliation of HCC. Further study including a larger number of the patients to confirm its effect in survival and detrimental side effect should be urged.

• Safety and Health at Work
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• v.14 no.1
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• pp.17-30
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• 2023

The human reproductive system can be affected by occupational exposure to many physical and chemical risk factors. This study was carried out to review the studies conducted on the issue of the pathophysiological effects of occupational physical and chemical risk factors on the reproductive system of females and males. In this systematic review, the databases such as "Google Scholar," "Pub-Med," "Scopus," and "Web of Science" were used. Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA 2020), the studies included in our study were published between 2000 and 2021. In order to extract the required data, all sections of the articles were reviewed. Out of 57 articles we reviewed, 34 articles were related to field studies and 23 articles to clinical studies. Among them, 43 studies dealt with the pathophysiological effects of chemical agents, six studies dealt with the pathophysiological effects of physical factors, and 8 studies dealt with the pathophysiological effects of physicochemical factors on the human reproductive system. Physical (noise, heat, and radiofrequency radiation) and chemical (such as carbamate and organophosphate pesticides, benzene, toluene, xylene, formaldehyde, NO2, CS2, manganese, lead, nickel, and n-hexane) risk factors had pathophysiological effects on the human reproductive system. The presence of these risk factors in the workplace caused damage to the human reproductive system. The rate of these negative pathophysiological effects can be reduced by performing appropriate managerial, technical, and engineering measures in work environments.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.85-87
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• 2004

We fabricated flexible thermoradiotherapy probes to alternated combination with Interstitial hyperthermia and Brachyradiotherapy thermoradiotherapy probe was coated by gold plate on polyethylene brachytherapy probe. When Agar phantom was heated 15 minute with 30 W radiofrequency power, temperature increased as 5oC for polyethylene probe and 20oC for gold coated polyethylene probe. We observed that the 1 cm square array would heat a volume with a 1.25 cm radius circular field cross section to therapeutic temperatures (90% relative SAR using Tm) and the 2 cm square array with a 1.75 cm radius rectangular field with central inhomogeneity. With 2 cm long electrode implants, we observed that the 1 cm square array would heat a 3 cm long sagittal section to therapeutic temperature (90% relative SAR using Tm). The histopathological changes associated with RF heating of normal canine brains have been correlated with thermal distributions. RF needle electrode heating was applied for 50 min to generate tissue temperatures of 43${\circ}$C. We obtained a quarter of the heated tissue material immediately after heating and sacrificed at intervals from 7${\sim}$30 days. The acute stage was demonstrated by liquefactive necrosis, pyknosis of neuronal element in the gray matter. Mild gliosis occurring around the necrosis was demonstrated in the last sacrificed (days30)canine brain.