1.Neutron Generation from a 24 MV Medical Linac.
Jeong Ok LEE ; Dong Hyeok JEONG ; Jeong Ku KANG
Korean Journal of Medical Physics 2005;16(2):97-103
The energy spectra and dose calculations were performed for secondary neutrons from a 24 MV LINAC using MCNPX code (V2, 4, 0). The energy spectra for neutrons and photons emitted from the LINAC head, and absorbed dose to water were calculated in water phantom. The absorbed doses calculated with Monte Carlo were 0.66~0.35 mGy/photon Gy at the surface to d=5 cm, and calculated with interaction data was 0.52 mGy/photon Gy at the depth of electron equilibrium in water. We have shown that this work can be applied to dose estimation of neutrons from high energy LINAC through the comparison of our results with other results.
Head
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Neutrons*
;
Photons
;
Water
2.Calibration and Radiation Survey of High Dose Rate Remote Afterloading System.
Jeong Ok LEE ; Jeong Ku KANG ; Sun Rock MOON
Journal of the Korean Society for Therapeutic Radiology 1995;13(1):101-112
High Dose Rate Remote Afterloading system was installed at Wonkwang Universi-ty Hospital in January 1994. In this report, the calibration of a Gammamed 12-i High Dose Rate Remote Afterloading system and the radiation survey around the facility after design and construct a shieding room are discussed. The radiation survey of the facility indicates that the use of ordinary concrete shielding of existing room will provide adequate shielding. Also, the methodologies for performing source calibra-tion are presented.
Calibration*
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Carboxymethylcellulose Sodium
3.Three-dimensional dose reconstruction-based pretreatment dosimetric verification in volumetric modulated arc therapy for prostate cancer
Yuri JEONG ; Jeong Geun OH ; Jeong Ku KANG ; Sun Rock MOON ; Kang Kyoo LEE
Radiation Oncology Journal 2020;38(1):60-67
Purpose:
We performed three-dimensional (3D) dose reconstruction-based pretreatment verification to evaluate gamma analysis acceptance criteria in volumetric modulated arc therapy (VMAT) for prostate cancer.
Materials and Methods:
Pretreatment verification for 28 VMAT plans for prostate cancer was performed using the COMPASS system with a dolphin detector. The 3D reconstructed dose distribution of the treatment planning system calculation (TC) was compared with that of COMPASS independent calculation (CC) and COMPASS reconstruction from the dolphin detector measurement (CR). Gamma results (gamma failure rate and average gamma value [GFR and γAvg]) and dose-volume histogram (DVH) deviations, 98%, 2% and mean dose-volume difference (DD98%, DD2% and DDmean), were evaluated. Gamma analyses were performed with two acceptance criteria, 2%/2 mm and 3%/3 mm.
Results:
The GFR in 2%/2 mm criteria were less than 8%, and those in 3%/3 mm criteria were less than 1% for all structures in comparisons between TC, CC, and CR. In the comparison between TC and CR, GFR and γAvg in 2%/2 mm criteria were significantly higher than those in 3%/3 mm criteria. The DVH deviations were within 2%, except for DDmean (%) for rectum and bladder.
Conclusions
The 3%/3 mm criteria were not strict enough to identify any discrepancies between planned and measured doses, and DVH deviations were less than 2% in most parameters. Therefore, gamma criteria of 2%/2 mm and DVH related parameters could be a useful tool for pretreatment verification for VMAT in prostate cancer.
4.Measurement and Monte Carlo Simulation of 6 MV X-rays for Small Radiation Fields.
Dong Hyeok JEONG ; Jeong Ok LEE ; Jeong Ku KANG ; Soo Kon KIM ; Seung Kon KIM ; Sun Rock MOON
The Journal of the Korean Society for Therapeutic Radiology and Oncology 1998;16(2):195-202
PURPOSE: In order to obtain basic data for treatment plan in radiosurgery, we measured small fields of 6 MV X-rays and compared the measured data with our Monte Carlo simulations for the small fields. MATERIALS AND METHODS: The small fields of 1.0, 2.0 and 3.0 cm in diameter were used in this study. Percentage depth dose (PDD) and beam profiles of those fields were measured and calculated. A small semiconductor detector, water phantoms, and a remote control system were used for the measurement. Monte Carlo simulations were performed using the EGS4 code with the input data prepared for the energy distribution of 6 MV X-rays, beam divergence, circular fields and the geometry of the water phantoms. RESULTS: In the case of PDD values, the calculated values were lower than the measured values for all fields and depths, with the differences being 0.3 to 5.7% at the depths of 2.0 to 20.0 cm and 0.0 to 8.9% at the surface regions. As a result of the analysis of beam profiles for all field sizes at a depth of 10cm in water phantom, the measured 90% dose widths were in good agreement with the calculated values, however, the calculated penumbra radii were 0.1 cm shorter than measured values. CONCLUSION: The measured PDDs and beam profiles agreement with the Monte Carlo calculations approximately. However, it is different when it comes to calculations in the area of phantom surface and penumbra because the Monte Carlo calculations were performed under the simplified geometries. Therefore, we have to study how to include the actual geometries and more precise data for the field area in Monte Carlo calculations. The Monte Carlo calculations will be used as a useful tool for the very complicated conditions in measurement and verification.
Radiosurgery
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Semiconductors
;
Water
5.An experience with a free vascularized myo-osteochondral rib graft for mandibular reconstruction.
Jong Ho LEE ; Ku Jong SEO ; Kwang PARK ; Moo Kang JUNG ; Gee Duk PARK ; Jung Jae JEONG
Journal of the Korean Association of Oral and Maxillofacial Surgeons 1993;19(2):115-124
No abstract available.
Mandibular Reconstruction*
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Ribs*
;
Transplants*
6.A Case of Myotonic Dystrophy with Prolonged Atrial Flutter.
Won Kwon KANG ; Dae Hoi KU ; Seung Hun SHIN ; Yeon Chae JEONG ; Eun Seok JEON ; Jong Hoon PARK
Korean Circulation Journal 1989;19(4):770-775
Myotonic dystrophy is a multisystemic disorder inherited as an autosomal dominant trait. The characteristic clinical features include the presence of myotonia, atrophy of the muscles of the face and the sternocleidomastoids and numerous nonmusclar manifestations such as cataracts, frontal baldness, gonadal dysfunctions and cardiac abnormalities. We experienced one case of myotonic dystrophy with prolonged atrial flutter in 30-year-old male who was admitted because of palpitation. We present this case with reviewing literatures.
Adult
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Alopecia
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Atrial Flutter*
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Atrophy
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Cataract
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Gonads
;
Humans
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Male
;
Muscles
;
Myotonia
;
Myotonic Dystrophy*
7.The clinical study to evaluate the safety and efficacy of D-chiro-inositol in patients with type 2 diabetes.
Bon Jeong KU ; Hyun Jin KIM ; Kang Seo PARK
Korean Journal of Medicine 2007;72(1):29-36
BACKGROUND: D-chiro-inositol (DCI) is a postreceptor signaling molecule of insulin action. Blood and urine levels of DCI were decreased in diabetic animals. Treatment of DCI improves insulin resistance and normalizes blood glucose level in diabetic animals. In diabetic patients, treatment of DCI has a effect of glucose control in some study but not in others. So we study to confirm the effect and to evaluate the safety of DCI by the use of pinitol, methyl derivates of DCI. METHODS: We performed a randomized, double-blind, placebo-controlled study in 82 patients with type 2 diabetes mellitus who visited the Eulji University Hospital from March 2005 to August 2005. We checked the change of HbA1c, FBS, and PP2 to evaluate pinitol effect of sugar control. And also we checked the effect of pinitol treatment to evaluate safety. RESULTS: We treated with either pinitol or placebo for 12 weeks in 66 patients and completed the study in 61 patients. There are no difference in the basal clinical or laboratory data between the pinotol and control groups. In the pinitol group there more decrease in the levels of HbA1c and in fasting blood glucose than in control group after 12 weeks study. When we performed subgroup analysis, in patients with a HbA1c level above 8% there was a more effectively respond to pinitol treatment. Than in less no significant side effects was occurred. There are no differences in side effects seen between the two groups. CONCLUSIONS: Treatment of pinitol was effective and safe in type 2 diabetic patients who received oral hypoglycemic agents. This is especially seen in patients with a high HbA1c level (>8%).
Animals
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Blood Glucose
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Diabetes Mellitus
;
Diabetes Mellitus, Type 2
;
Fasting
;
Glucose
;
Humans
;
Hypoglycemic Agents
;
Inositol
;
Insulin
;
Insulin Resistance
8.Is Completion Thyroidectomy Necessary in Patients with Papillary Thyroid Carcinoma who Underwent Lobectomy?
Il Ku KANG ; Kwangsoon KIM ; Ja Seong BAE ; Jeong Soo KIM
Korean Journal of Head and Neck Oncology 2021;37(2):25-31
Background/Objectives:
Although thyroid lobectomy recently is considered as sufficient for low-risk papillary thyroid carcinoma (PTC), completion thyroidectomy is required due to the insufficiency of the preoperative evaluation. The aim of this study was to investigate recurrence rate and disease free survival depending on the gross extrathyroidal extension (gETE) or the number of metastatic lymph node identified in patients with PTC.Materials & Methods: We assessed 3373 patients with PTC who underwent lobectomy at Seoul St. Mary’s Hospital (Seoul, Korea) between January 2009 and December 2014. Clinicopathological characteristics and long-term surgical outcomes were retrospectively analyzed through complete chart reviews. The mean follow-up duration was 97.1 ± 21.4 months.
Results:
The rate of recurrence was higher in gETE group (1.8% vs. 6.0%, p=0.004), leading to decreased disease free survival in Kaplan-Meier analysis (log-rank p<0.001). N1 group (n=1389) was analyzed into two groups whether the number of positive nodes is more than 5 or less. For the group of the more metastatic nodes, the recurrence rate higher compared to the other group (3.0% vs. 9.3%, p<0.001). DFS was longer in the group that had lesser metastatic nodes (log-rank p<0.001). However, in terms of N1 group over 1cm (n=492), No statistical difference was observed according to the number of positive lymph nodes (4.5% vs. 9.1%, p=0.092)
Conclusion
When it comes to node positive PTC, Despite the number of positive lymph nodes was over 5, follow-up with no further surgery can be an option.
9.Dose Calculation for the Buchler Remote Afterloading System.
Sun Rock MOON ; Soo Kon KIM ; Jeong Ok LEE ; Jeong Ku KANG ; Seung Kon KIM ; Weon Kuu CHUNG
Journal of the Korean Society for Therapeutic Radiology 1996;14(3):247-253
PURPOSE: The dose calculation program for the Buchler type remote afterloading system was developed. This program also can be used to calculate dose for various sealed sources. METHODS AND MATERIALS: We determined the source length and distribution by dividing the program disk to 72 points. The dose rate for the each program disk and source was calculated. The dose rate table for the xy coordinate was established. The dose rate for the interesting points of the patient were calculated by using this table. We also made isodose curve from this calculations. RESULTS: The storage size for the dose rate table were increased.But the calculation of the dose rate for the patient were carried out rapidly. So we could get real time calculation. CONCLUSION: By using this program, we could calculate the dose rate for the various oints of the patient quickly and accurately. This program will be useful for the treatment with various linear sources.
Brachytherapy
;
Humans
10.A Study on the Simulation and the measurement of 6 MeV Electron Beam.
Sung Ah LEE ; Jeong Ok LEE ; Sun Rock MOON ; Jong Jin WON ; Jeong Ku KANG ; Seung Kon KIM
Journal of the Korean Society for Therapeutic Radiology 1995;13(3):285-290
PURPOSE: We compared the calculated percent depth dose curves of 6 MeV electron beam to that of measured to evaluate the usefulness of Monte-Carlo simulation method in radiation physics. MATERIALS AND METHODS: The radiation dose values of 6 MeV electron beam using EGS4 code with one million histories in water were compared values that were measured form the depth dose curve of electron beam irradiated by medical accelerator ML6M. The central exis dose values were calculated according the changing field size, such as 5 X 5, 10 X 10, 15 X 15, 20 X 20 cm2. RESULTS: The value calculated showed a very similar shape to depth dose curve. The calculated and measured value of Dmax at 10 X 10cm2 cone is 15mm and 14mm respectively. The calculated value of the surface radiation dose rate is 65.52% and measured one is 76.94%. The surface radiation dose rate has vaied from 64.43% to 66.99. The calculated values of Dmax are in the range between 15mm and 18mm. The calculated value was fitted well with measured value around the Dmax area, excluding build up range and below the 90% depth dose area. CONCLUSION: This result suggested that the calculation of dose value can be replace the direct measurement of the dose for radiation therapy. Also, EGS4 may be a very convenient program to assess the effect of radiation dose using by personal computers.
Microcomputers
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Water