• Journal of the Korean Physical Society
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• v.73 no.9
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• pp.1377-1384
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• 2018

Accurate measurement of the absorbed dose and the effective dose is required in dental panoramic radiography involving relatively low energy with a rotational X-ray tube system using long exposures. To determine the effectiveness of measuring the irradiation by using passive dosimetry, we compared the entrance skin doses by using a radiophotoluminescent glass dosimeter (RPL) and an optically stimulated luminescence detector (OSL) in a phantom model consisting of nine and 31 transverse sections. The parameters of the panoramic device were set to 80 kV, 4 mA, and 12 s in the standard program mode. The X-ray spectrum was applied in the same manner as the panoramic dose by using the SpekCalc Software. The results indicated a mass attenuation coefficient of $0.008226cm^2/g$, and an effective energy of 34 keV. The equivalent dose between the RPL and the OSL was calculated based on a product of the absorbed doses. The density of the aluminum attenuators was $2.699g/cm^3$. During the panoramic examination, tissue absorption doses with regard to the RPL were a surface dose of $75.33{\mu}Gy$ and a depth dose of $71.77{\mu}Gy$, those with regard to the OSL were surface dose of $9.2{\mu}Gy$ a depth dose of $70.39{\mu}Gy$ and a mean dose of $74.79{\mu}Gy$. The effective dose based on the International Commission on Radiological Protection Publication 103 tissue weighting factor for the RPL were $0.742{\mu}Sv$, $8.9{\mu}Sv$, $2.96{\mu}Sv$ and those for the OSL were $0.754{\mu}Sv$, $9.05{\mu}Sv$, and $3.018{\mu}Sv$ in the parotid and sublingual glands, orbit, and thyroid gland, respectively. The RPL was more effective than the OSL for measuring the absorbed radiation dose in low-energy systems with a rotational X-ray tube.

• Journal of radiological science and technology
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• v.44 no.3
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• pp.195-203
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• 2021

Although intra oral dental x-ray is a lower dose than other radiological examinations, pediatric patients are known to have a higher risk of radiation damage than adults. For this reason, pediatric dental x-ray requires management of dose evaluation and imaging conditions during the examination. In this study, the dose calculation program ALARA-Dental(child/adult) was used to evaluate the organ dose and effective dose exposed to each examination site during intra oral imaging of children during dental radiographic examination, and dose analysis according to the imaging conditions was performed. As a result, the highest organ dose distribution was shown at 0.044 ~ 0.097 mGy in all are as of the mucous membrane of oral cavity except for the maxillary incisors and canines. Also, in the case of the thyroid gland, the maxillary canine and maxillary premolar examination showed 0.027 and 0.020 mGy, respectively, and the dose distribution was 15.4% to 70.0% higher than that of the mandibular examination. As for the effective dose calculated during intra oral imaging, the maxillary anterior and canine examinations showed the highest effective doses of 0.005 and 0.004 mSv, respectively, and the maxillary area examination showed a higher dose distribution on average than the mandible.

• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.481-487
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• 2023

In this study, we analyzed the incidence of side effects of photoneutron dose according to the number of beams during intensity-modulated radiotherapy of prostate cancer using 15 MV. The radiation treatment plan design for intensity-modulated radiation therapy for prostate cancer was established with a prescription dose of 220 cGy per dose and a total of 7260 cGy for 33 treatments. The linear accelerator used in the experiment is Varian's True Beam STx (Varian, USA). Photoneutron dose was generated by using 15 MV energy in the planning target volume (PTV). The treatment plan was designed with IMRT 5, 7, and 9 portals using the Eclipse System (Varian Ver 10.0, USA). An optically stimulated luminescence albedo neutron dosimeter (Landauer Inc., USA) was used to measure photoneutron dose. IMRT 5 portals, 1.7 per 1,000, 7 portals, 1.8 per 1,000, 9 portals, 2.0 per 1,000 were calculated as the probability of experiencing side effects on the thyroid gland due to photoneutron dose. This study studies the risk of secondary radiation exposure dose that can occur during intensity-modulated radiation therapy, and it is considered that it will be used as useful data in relation to stochastic effects in the future.

• Progress in Medical Physics
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• v.12 no.2
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• pp.103-112
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• 2001

Purpose: The purpose of this study was to investigate the current status of performing nuclear medicine quality control in korea and to test selected protocols of quality control of nuclear medicine counting system and gamma camera. Materials and Methods: Fifty three hospitals were included to investigate the current status of nuclear medicine quality control in korea. The precision of dose calibrator and thyroid uptake system was measured with Tc-99m 35.52 MBq for 2 minuets and Tc-99m 5.14 MBq for 10 sec every one minute, respectively. The sensitivity of CeraSPECT$^{TM}$ with low energy high resolution parallel hole collimator was measured using two cylindrical phantoms with 15 cm in diameter and 12 cm and 30 cm in heights containing Tc-99m. The correction factor for sensitivity of CeraSPECT$^{TM}$ was calculated using phantom data. The system planar sensitivity, uniformity, count rate and spatial resolution were measured for Varicam gamma camera with low energy high resolution parallel hole collimator using 140 keV centered 20% energy window, 256$\times$256 or 512$\times$512 matrix sizes. Results: The quality control of dose calibrator and well counter were showed poor performance status. On the other hand, The quality control of gamma camera and other systems were showed relatively good performance status. The results of precision of dose calibrator and thyroid uptake system was $\pm$1.4%(<$\pm$5%) and chi^2=29.7(>16.92), respectively. It showed that the sensitivity of CeraSPECT$^{TM}$ was higher in center slices compared with the edge slices. After correction of nonuniform sensitivities for patient data, it showed better results compare with prior to correction. System planar sensitivity of Varicam gamma camera was 4.39 CPM/MBq. The observed count rate at 20% loss was 102,407 counts/sec (head 1), 113,427 counts/sec (head 2), when input count rate was 81,926 counts/sec (head 1), 90,741 counts/sec (head 2). The spatial resolution without scatter medium were 8.16 mm of FWHM and 14.85 mm of FWTM. The spatial resolution with scatter medium were 8.87 mm of FWHM and 18.87 mm of FWTM. Conclusion: It is necessary to understand the importance of quality control and to perform quality control of nuclear medicine devices.vices.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.2
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• pp.437-445
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• 1995

The purpose of this study was to evaluate the equivalent and effective dose, and estimate radiation risk to the critical organs of head and neck region from the use of adult and child mode in panoramic radiography. The results were as follows. 1. The salivary glands showed the highest equivalent and effective dose in adult and child mode. the equivalent and effective dose in adult mode were 837μSv and 20.93μSv, those in child mode were 462μSv and 11.54μSv, respectively. 2. Total effective doses to the critical head and neck organs were estimated 34.21μSv in adult mode, 20.14μSv in child mode. From these datas, the probabilities of stochastic effect from adult and child mode were 2.50x10/sup -6/ and 1.47x10/sup -6/. 3. The other remainder showed the greatest risk of fatal cancer. The risk estimate were 4.5 and 2.7 fatal malignancies in adult and child mode from million panoramic examinations. The bone marrow and thyroid gland showed about 0.1 fatal cancer in adult and child mode from these examinations.

• The Korea Journal of Herbology
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• v.30 no.4
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• pp.109-119
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• 2015

Objectives : The aim of this study was to evaluate the effect of aqueous extracts of Mume Fructus(MF) on the 6-n-propyl-2-thiouracil(PTU)-induced rat hypothyroidism.Methods : Aqueous extracts of MF(yield = 19.38%) were administered, once per day for 42 days from 2 weeks before starting of PTU treatment as an oral dose of 300 and 150 ㎎/㎏(body weight), and hypothyroidism was induced by daily subcutaneous treatment of PTU 10 ㎎/㎏ for 28 days. The changes in the body weight, thyroid gland weights, liver weight, serum levels of thyroid hormone-thyroid stimulating hormone(TSH), tri-iodothyronine(T₃) and thyroxine(T₄), total cholesterol, low density lipoprotein(LDL), high density lipoprotein(HDL) and triglyceride (TG), aspartate aminotransferase(AST), alanine aminotransferase(ALT), liver antioxidant defense system-lipid peroxidation, H₂O₂, superoxide dismutase(SOD) and catalase(CAT) were examined with histopathology of thyroid glands and liver.Results : Results were compared with LevoT₄0.5 ㎎/㎏ treated rats. MF extracts recovered from the decreases in the body weight, liver weight, T₃and T₄, TG, liver CAT activities as results of PTU treatment. And MF extracts recovered from the increases of thyroid gland weights, TSH, HDL contents, liver H₂O₂, AST as results of PTU treatment. In addition, these PTU-induced histopathological changes in thyroid glands and liver related to hypothyroidism were dramatically decreased by treatment of both different dosages of MF extract, respectively.Conclusions : According to the above results, it is suggested that MF extracts have advantageous effects on the thyroid hormone productions with beneficial effects on the hypothyroidism related liver injuries mediated by the modulation on the antioxidant system.

• Korean Journal of Head & Neck Oncology
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• v.36 no.2
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• pp.9-15
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• 2020

Background/Objectives: To analyze the clinical characteristics of differentiated thyroid cancer (DTC) in children and adolescents. Materials & Methods: Medical records of 31 DTC cases that were diagnosed and treated at Korea Cancer Center Hospital between 2002 and 2018 were retrospectively reviewed. Results: Most cases were papillary carcinoma (n=26), with female predominance (n=25). Median age was 16.4 years (range, 11.9-18.6 years). Extrathyroidal extension was present in 24 cases. Twenty cases had tumor involvement at cervical lymph nodes and three had lung metastasis. Twenty-two patients received radioactive iodide treatment with a median cumulative dose of 300 mCi (range, 100-920 mCi). During a median follow-up of 68.2 months (range, 2.3-191.4 months), serum thyroglobulin level was elevated in 15 patients. Among them, two cases had remnant thyroid tissue, 4 had recurrence at cervical lymph nodes, and the remaining 9 did not have any detectable lesion. All were alive, and 5-year event-free survival (EFS) was 45.2±10.1%. Age £15 years, tumor size, lymph node status (N1b), and distant metastasis had negative effects on EFS. On multivariate analysis, age and tumor size had prognostic significance. Conclusion: For DTC of children and adolescents (£18 years old), age ≤15 years and tumor size were prognostic factor. Therefore, patients in this age group need meticulous follow-up. Further studies are necessary to answer the potential influence of age on the incidence and behavior of DTC.

• Korean Journal of Head & Neck Oncology
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• v.16 no.2
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• pp.182-186
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• 2000

The reduction of the postoperative wound pain has been a concern in recent surgery, especially in various types of minimally-invasive surgeries. This study was performed to evaluate the postoperative analgesic effect of the preincisional local anesthesia with the mixture of ketorolac(Tarasyn) and bupivacaine to the surgical site in minimally-invasive thyroid surgeries. Of 491 patients who were scheduled for minimally-invasive thyroid surgeries between October 1999 and July 2000, 244 were randomly assigned to receive a mixture of ketorolac tromethamine 15mg(0.5ml) and 0.25% bupivacaine 3ml via surgical site infiltration 3 minutes prior to the skin incision. The outcomes of these patients were compared to those of the 247 controls. Total number of patients in need of post-operative analgesic requirements(n=39, 16.0%), total dose of postoperative analgesics used($19.6{\pm}8.4mg$ of ketorolac) and Visual Analogue Pain Score(VAS, $2.6{\pm}1.2$) of the preincisional local anesthesia group were significantly lower than those of the control group(p<0.05). The mean postoperative hospital stay was $1.6{\pm}0.4$ days for the preincisional local anesthesia group versus $1.9{\pm}0.7$ days for the control group. The preincisional local infiltration of ketorolac and bupivacaine in the minimally invasive thyroidectomies reduces postoperative wound pain thus would be more beneficial to the patients.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7271-7275
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• 2014

Background: The aim of the present study was to evaluate the presentation, clinical course and outcome between children and young adults with differentiated thyroid cancer (DTC) treated in our hospital. Materials and Methods: The medical records of 145 patients with DTC who underwent surgery followed by radioiodine and thyroid hormone (TSH) suppression were retrospectively reviewed. The follow up was between January 2006 and June 2012. These patients consisted of 38 children (age${\leq}18y$) and 107 young adult patients (age${\leq}30y$). The clinical characteristics and outcome were analyzed and compared, and the progression-free survival (PFS) was evaluated using the Kaplan-Meier method. Results: At initial diagnosis, a greater degree of extra thyroidal extension was found in children than adults patients (p<0.001). However, there was no significant difference between the two groups with regard to the tumor size and the presence of lymph node or distant metastasis (p=0.172, p=0.050 and p=0.068, respectively). The extent of surgery and the cumulative or mean dose of radioiodine were similar in both groups. During the follow up, the overall survival rate was 100% for both groups, and the PFS rate was similar in children and in young adults group (log rank test, ${\chi}^2$=0.126, p=0.723). Conclusions: In comparison to the young adult patients, DTC in children presents with more aggressive behavior, but outcomes are similar between the two groups after the intensive management of surgery followed by radioiodine and TSH suppression therapy.

• Journal of radiological science and technology
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• v.4 no.1
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• pp.55-62
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• 1981

This study was conducted, during the period of 20-30th, July in 1981, to survey measurement methods in thyroid uptake rate test in Seoul city. The results were summarized as follows: 1. For the great part of nuclear medcine department, a mount of radioiodine($^{131}I$) administrated to the patients was $50-100{\mu}Ci$ in thyroid uptake rate test. 2. Distribution of scintillation, counter with crystal size of $1\frac{1}{2}inch$ was 43%, 3inch(22%), 2.5inch(14%) and $2\frac{1}{2}inch$ was 7% in RAI uptake rate test. 3. When RAI uptake rate test was performed, distribution of collimator in use was flat field type collimator(78%) in general and cylindrical type collimator was 22%. 4. High voltage applied to the P-M tube was $900{\sim}1000V$(50%) and most units provided $3{\sim}15%$ of the window range for the $^{131}I$ peak $\gamma-ray$ energy. 5. Distribution on the use of neck phantom for measurements standard solution was 57% and distribution of b filter in use for room background counts and extrathyroidal tissue was 43% and 50%. 6. The distance between the counter and the source was 25cm(58%) in measuring radioactivity of standard solution, thyroid tissue and background radioactivity count. 7. The early uptake measurements(2, 4, 6 hours) are done after administration of the radioiodine dose and also 24-hour and 48-hour uptake measurements are done in routine test.