• The Journal of Korean Society for Radiation Therapy
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• v.1 no.1
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• pp.70-78
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• 1985

The intrauterine irradiation is essential to achieve adequate tumor dose to centeral tumor mass in radio therapy for uterine malignancy. The complications of pelvic organ are known to be directly related to radiation dose and physical parameters. The comparison study of currently using 2 systems was undertaken. The simulation films and medical records of 135 patients who was treated with intrauterine irradiation at one of general hospitals in Busan and Seoul between Jan. 1983 and June 1983, were critically analized and physical parameters of low dose rate system and remote controlled high dose rate system were measured. The physical parameters include distances between lateral walls of vaginal fornices, longitudinal and lateral angles of tandem to the body axis, the distance from the external os of uterine cervix to the central axis of ovoids, the radiation dose ratio to rectum and bladder to reference point A. Followings were summary of study results: 1. In distances between lateral walls of vaginal fornices the low dose rate system showed wide distribution and relatively larger distances. In low dose rate system 5.0-5.9 cm was $55.89\%$ 6.0-6.9 cm: $23.53\%$, 4.0-4.9cm: $10.29\%$, 3.0-3.9cm: $10.29\%$, and in high dose rate system 5.0-5.9cm was $80.59\%$, 4.0-4.9cm: $17.91\%$, $6.0\~6.9\;cm:\;1.5\%$. 2. In lateral angulation of tandem to body axis, the low does system revealed mid position (the position along body axis) $64.7\%$, Lt. deviation $19.13\%$ and Rt. deviation $16.17\%$. However the high dose rate system revealed mid position $49.26\%$ Lt. deviation $40.29\%$ and Rt. deviation $10.45\%$. 3. In longitudinal angulation of tandem to body axis the mid position was $11.77\%$ and anterior angulation $88.23\%$ in low dose rate system but in high dose rate system the mid position was $1.56\%$ and anterior angulation $98.44\%$. 4. Down ward displacement of ovoids below external os was only $2.94\%$ in low dose rate system and $67.69\%$ in high dose rate system. 5. The radiation dose ration to rectum to reference point A was $102.70\%$ in high dose rate system and $70.09\%$ in low dose rate system. The dose ratio to bladder to reference point A was $78.14\%$ in high dose rate system and $75.32\%$ in low dose rate system.

• Radiation Oncology Journal
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• v.2 no.2
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• pp.261-270
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• 1984

The intrauterine irradiation is essential to achieve adequate tumor dose to central tumor mass of uterine malignancy in radiotherapy. The complications of pelvic organ are known to be directly related to radiation dose and physical parameters. The simulation radiation and medical records of 203 patients who were treated with intrauterine irradiation from Feb. 1983 to Oct. 1983, were critically analized. The physical parameters to include distances between lateral walls of vaginal fornices, longitudinal and lateral angles of tandem applicator to the body axis, the distance from the external os of uterine cervix to the central axis of ovoids were measured for low dose rate irradiation system and high dose rate remote control afterloading system. The radiation doses and dose distributions within cervical area including interesting points and bladder, rectum, according to sources arrangement and location of applicator, were estimated with personal computer. Followings were summary of study results ; 1. In distances between lateral walls of vaginal fornices, the low dose rate system showed as $4\~7cm$ width and high dose rate system showed as $5\~6cm$. 2. In horizontal angulation of tandem to body axis, the low dose rate system revealed mid position$64.6\%$, left deviation $19.2\%$and right deviation $16.2\%$. 3. In longitudinal angulation of tandem to body axis, the mid position was $11.8\%$ and anterior angulation $88.2\%$ in low dose rate system but in high dose rate system, anterior angulation was $98.5\%$. 4. Down ward displacement of ovoids below external os was only $3\%$ in low dose rate system and $66.7\%$ in high dose rate system. 5. In radiation source arrangement, the most activities of tandem and ovoid were 35 by 30 in low dose rate system but 50 by 40 in high dose rate system. 6. In low and high dose rate system, the total doses an4 TDF were 50, 70 Gy and 141, 123, including 40 Gy external irradiation. 7. The doses and TDF in interesting points Co, B, were 93, 47 Gy and 230, 73 in high dose rate system but in low doss rate system, 123, 52 Gy and 262, 75 respectively. 8. Doses and TDF in bladder and rectum were 70, 68 Gy and 124, 120 in low dose rate system, but in high dose rate system, 58, 64 Gy 98, 110 respectively, and then grades of injuries in bladder and rectum were 25, $30\%$ and 18, $23\%$ respectively.

• Journal of Radiation Protection and Research
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• v.38 no.4
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• pp.179-184
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• 2013

The biological effects of radiation are dependent on the dose rate and dose of radiation. In this study, effects of dose and dose rate using whole body radiation on plasma cytokines and blood count from male BALB/c mice were evaluated. We examined the blood and cytokine changes in mice exposed to a low (3.49m Gy $h^{-1}$) and high (2.6 Gy $min^{-1}$) dose rate of radiation at a total dose of 0.5 and 2 Gy, respectively. Blood from mice exposed to radiation were evaluated using cytokine assays and complete blood count. Peripheral lymphocytes and neutrophils decreased in a dose dependent manner following high dose rate radiation. The peripheral lymphocytes population remained unchanged following low dose rate radiation; however, the neutrophils population increased after radiation. The sera from these mice exhibited elevated levels of flt3 ligand and granulocyte-colony-stimulating factor (G-CSF), after high/low dose rate radiation. These results suggest that low-dose-rate radiation does not induce blood damage, which was unlike high-dose-rate radiation treatment; low-dose-rate radiation exposure activated the hematopoiesis through the increase of flt3 ligand and G-CSF.

• Progress in Medical Physics
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• v.1 no.1
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• pp.51-60
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• 1990

Dose distributions around Co- 60 moving source in high dose rate remote afterloading unit, Buchler 3K unit, were experimented with X-omat V films and calculations. In our experiments, film dosimetries have achieved to evaluated the axial dose distributions for source oscillations were 0, 3.5, 5.0 and 6.0 cm in periodically, In results, the dose distributions in axial of source movement showed apparently higher than in transverse direction caused by source locations, dwelling time and air gap in the applicator. In the calculations, the dose rate was derived by using the inverse square law, filteration corrections and Meisberger constant for scatter corrections as source movings. In our experiments and calculations, the average dose uncertainties were showed -2.1$\pm$1.9% in fixed sourdce, -2.9$\pm$1.8%, -7.4$\pm$6.1% and -6.7$\pm$4.6% at 3.5 cm, 5.0 cm and 6.0 cm source oscillations, but the calculations have showed very close to experimental dose rate within 4 cm distance from source.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.7
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• pp.1450-1455
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• 2009

Assumed that an IPTV camera system is to be used as an ad-hoc sensor for the surveillance and diagnostics of safety-critical equipments installed in the in-containment building of the nuclear power plant, an major problem is the presence of high dose-rate gamma irradiation fields inside the one. In order to uses an IPTV camera in such intense gamma radiation environment of the in-containment building, the radiation-weakened devices including a CCD imaging sensor, FPGA, ASIC and microprocessors are to be properly shielded from high dose-rate gamma radiation using the high-density material, lead or tungsten. But the passive elements such as mirror, lens and window, which are placed in the optical path of the CCD imaging sensor, are exposed to a high dose-rate gamma ray source directly. So, the gamma-ray irradiation characteristics of the passive elements, is needed to test. A CCD camera lens, made of glass material, have been gamma irradiated at the dose rate of 4.2 kGy/h during an hour up to a total dose of 4 kGy. The radiation induced color-center in the glass lens is observed. The degradation performance of the gamma irradiated lens is explained using an color component analysis.

• Radiation Oncology Journal
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• v.12 no.2
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• pp.243-252
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• 1994

The use of high dose rate remote afterloading system for the treatment of intraluminal lesions necessitates the need for a more accurate of dose distributions around the high intensity brachytherapy sources, doses are often prescribed to a distance of few centimeters from the linear source, and in this range the dose distribution is very difficult to assess. Accurated and optimized dose calculation with stable numerical algorithms by PC level computer was required to treatment intraluminal lesions by high dose rate brachytherapy system. The exposure rate from sources was calculated with Sievert integral and dose rate in tissue was calculated with Meisberger equation, An algorithm for generating a treatment plan with optimized dose distribution was developed for high dose rate intraluminal radiotherapy. The treatment volume becomes the locus of the constrained target surface points that is the specified radial distance from the source dwelling positions. The treatment target volume may be alternately outlined on an x-ray film of the implant dummy sources. The routine used a linear programming formulism to compute which dwell time at each position to irradiate the constrained dose rate at the target surface points while minimizing the total volume integrated dose to the patient. The exposure rate and the dose distribution to be confirmed the result of calculation with algorithm were measured with film dosimetry, TLD and small size ion chambers.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.958-967
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• 2023

This work studies the defect features in a dilute FeMnNi alloy by an Object Kinetic Monte Carlo (OKMC) model based on the "grey-alloy" method. The dose rate effect is studied at 573 K in a wide range of dose rates from 10^-8 to 10^-4 displacement per atom (dpa)/s and demonstrates that the density of defect clusters rises while the average size of defect clusters decreases with increasing dose rate. However, the dose-rate effect decreases with increasing irradiation dose. The model considered two realistic mechanisms for producing <100>-type self-interstitial atom (SIA) loops and gave reasonable production ratios compared with experimental results. Our simulation shows that the proportion of <100>-type SIA loops could change obviously with the dose rate, influencing hardening prediction for various dose rates irradiation. We also investigated ways to compensate for the dose rate effect. The simulation results verified that about a 100 K temperature shift at a high dose rate of 1×10^-4 dpa/s could produce similar irradiation microstructures to a lower dose rate of 1×10^-7 dpa/s irradiation, including matrix defects and deduced solute migration events. The work brings new insight into the OKMC modeling and the dose rate effect of the Fe-based alloys.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1185-1186
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• 2008

A nuclear explosion emits a transient radiation pulse like gamma rays. Gamma rays have a high energy and cause unexpected effects in semiconductor devices. These effects are mainly referred to dose-rate latcup and dose-rate upset. By transient radiation pulse in CMOS devices, dose-rate latchup is simulated in this paper.

• Journal of the Korean Society of Industry Convergence
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• v.15 no.3
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• pp.71-77
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• 2012

This study gives the optimal reaction conditions, reaction mechanisms, reaction rates leaded from the oxidation of phenol by electron beam accelerator and ozone used for recent water treatment. It gives the new possibility of water treatment process to effectively manage industrial sewage containing toxic organic compounds and biological refractory materials. The high decomposition of phenol was observed at the low dose rate, but at this low dose rate, the reaction time was lengthened. So we must find out the optimal dose rate to promote high oxidation of reactants. The reason why the TOC value of aqueous solution wasn't decreased at the low dose was that there were a lot of low molecular organic acids as an intermediates such as formic acid or glyoxalic acid. In order to use both electron beam accelerator and biological treatment for high concentration refractory organic compounds, biological treatment is needed when low molecular organic compounds exist abundantly in sewage. In this experiment, the condition of making a lot of organic acids is from 5 kGy into 20 kGy dose. Decomposition rate of phenol by electron beam accelerator was first order reaction up to 300ppm phenol solution on the basic of TOC value and also showed first order reaction by using both air and ozone as an oxidants.

• Korean Journal of Head & Neck Oncology
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• v.14 no.1
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• pp.61-69
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• 1998

Objectives: The response rate of the radioactive iodine(RI) therapy with low dose was variable. Only a few studies reported the response and complication rate with high dose. The goal of this study was to access the ablation and complication rate after high dose of RI therapy (more than 100mCi) and to evaluate the factors affect the results. Material and Methods: During a period of 12 years, 225 patients received high dose of RI from 100 to 200mCi depending on the RI uptake in the whole body after total thyroidectomy. 100mCi of RI was given to 123 patients for ablation who showed the uptake only in the thyroid bed. 150mCi was given to another 84 patients for ablation who had uptake confined to the neck. The other 21 patients took more than 200mCi of RI because the whole body scan showed distant metastasis. Among these patients, the ablation and the complication rate was investigated. Results: Elevated level of the serum thyroglobulin(Tg) decreased less than 5ng/ml after RI therapy in all patients except two in the first group. The second group showed reduction of the serum Tg in 93%. Eighteen of the 21 patients in the third group are still alive after RI therapy. There were no fatal complications after high dose RI therapy and most of the complications were minimal and transient. The complication rate was not related with the dose of RI, age, sex, DNA flowcytometry, serum thyroglobulin level and the extent of node dissection. Conclusion: We concluded that RI therapy with high dose was very effective for thyroid ablation after operation and it also showed excellent results with minimal complications for treatment of metastatic lesions.