• Radiation Oncology Journal
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• v.19 no.4
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• pp.319-326
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• 2001

Purpose : Planning target volume (PTV) for tumors in abdomen or thorax includes enough margin for breathing-related movement of tumor volumes during treatment. Depending on the location of the tumor, the magnitude of PTV margin extends from 10 mm to 30 mm, which increases substantial volume of the irradiated normal tissue hence, resulting in increase of normal tissue complication probability (NTCP). We developed a simple and handy method which can reduce PTV margins in patients with liver tumors, respiratory motion reduction device (RRD). Materials and methods : For 10 liver cancer patients, the data of internal organ motion were obtained by examining the diaphragm motion under fluoroscope. It was tested for both supine and prone position. A RRD was made using MeV-Green and Styrofoam panels and then applied to the patients. By analyzing the diaphragm movement from patients with RRD, the magnitude of PTV margin was determined and dose volume histogram (DVH) was computed using AcQ-Plan, a treatment planning software. Dose to normal tissue between patients with RRD and without RRD was analyzed by comparing the fraction of the normal liver receiving to $50\%$ of the isocenter dose. DVH and NTCP for normal liver and adjacent organs were also evaluated. Results : When patients breathed freely, average movement of diaphragm was $12{\pm}1.9\;mm$ in prone position in contrast to $16{\pm}1.9\;mm$ in supine position. In prone position, difference in diaphragm movement with and without RRD was $3{\pm}0.9\;mm$ and 12 mm, respectively, showing that PTV margins could be reduced to as much as 9 mm. With RRD, volume of the irradiated normal liver reduced up to $22.7\%$ in DVH analysis. Conclusion : Internal organ motion due to breathing can be reduced using RRD, which is simple and easy to use in clinical setting. It can reduce the organ motion-related PTV margin, thereby decrease volume of the irradiated normal tissue.

• Radiation Oncology Journal
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• v.33 no.4
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• pp.320-327
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• 2015

Purpose: To investigate the treatment outcome and the toxicity of helical tomotherapy (HT) in patients with metastatic colorectal cancer (mCRC). Materials and Methods: We retrospectively reviewed 18 patients with 31 lesions from mCRC treated with HT between 2009 and 2013. The liver (9 lesions) and lymph nodes (9 lesions) were the most frequent sites. The planning target volume (PTV) ranged from 12 to 1,110 mL (median, 114 mL). The total doses ranged from 30 to 70 Gy in 10-30 fractions. When the ${\alpha}/{\beta}$ value for the tumor was assumed to be 10 Gy for the biologically equivalent dose (BED), the total doses ranged from 39 to $119Gy_{10}$ (median, $55Gy_{10}$). Nineteen lesions were treated with concurrent chemotherapy (CCRT). Results: With a median follow-up time of 16 months, the median overall survival for 18 patients was 33 months. Eight lesions (26%) achieved complete response. The 1- and 3-year local progression free survival (LPFS) rates for 31 lesions were 45% and 34%, respectively. On univariate analysis, significant parameters influencing LPFS rates were chemotherapy response before HT, aim of HT, CCRT, PTV, BED, and adjuvant chemotherapy. On multivariate analysis, $PTV{\leq}113mL$ and $BED>48Gy_{10}$ were associated with a statistically significant improvement in LFPS. During HT, four patients experienced grade 3 hematologic toxicities, each of whom had also received CCRT. Conclusion: The current study demonstrates the efficacy and tolerability of HT for mCRC. To define optimal RT dose according to tumor size of mCRC, further study should be needed.

• Radiation Oncology Journal
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• v.32 no.2
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• pp.77-83
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• 2014

Purpose: To determine the prognostic and predictive value of liver volume in colorectal cancer patients with unresectable liver metastases. Materials and Methods: Sixteen patients received whole liver radiotherapy (WLRT) between January 1997 and June 2013. A total dose of 21 Gy was delivered in 7 fractions. Results: The median survival time after WLRT was 9 weeks. In univariate analysis, performance status, serum albumin and total bilirubin level, liver volume and extrahepatic metastases were associated with survival. The mean liver volume was significantly different between subgroups with and without pain relief (3,097 and 4,739 mL, respectively; p = 0.002). Conclusion: A larger liver volume is a poor prognostic factor for survival and also a negative predictive factor for response to WLRT. If patients who are referred for WLRT have large liver volume, they should be informed of the poor prognosis and should be closely observed during and after WLRT.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1431-1438
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• 2022

In this study, natural radioactivity concentrations and dosimetric values of fly ash samples were evaluated for the landfill area of the coal-fired power plant (CFPP) complex at Binh Thuan, Vietnam. The average activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K were 93, 77, 92 and 938 Bq kg^-1, respectively. The average results for radon dose, indoor external, internal, and total effective dose equivalent (TEDE) were 5.27, 1.22, 0.16, and 6.65 mSv y^-1, respectively. The average emanation fraction for fly ash were 0.028. The excess lifetime cancer risks (ELCR) were recorded as 20.30×10^-3, 4.26×10^-3, 0.62×10^-3, and 25.61×10^-3 for radon, indoor, outdoor exposures, and total ELCR, respectively. The results indicated that the cover of shielding materials above the landfill area significantly decreased the gamma radiation from the ash and slag in the ascending order: Zeolite < PVC < Soil < Concrete. Total dose of all radionuclides in the landfill site reached its peak at 19.8 years. The obtained data are useful for evaluation of radiation safety when fly ash is used for building material as well as the radiation risk and the overload of the landfill area from operation of these plants for population and workers.

• The Korean Journal of Nuclear Medicine
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• v.26 no.1
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• pp.8-13
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• 1992

Low doses of ionizing radiation from external or internal sources cause heterogeneous distribution of energy deposition events in the exposed biological system. With the cell being the individual element of the tissue system, the fraction of cells hit, the dose received by the hit, and the biological response of the cell to the dose received eventually determine the effect in tissue. The hit cell may experience detriment, such as change in its DNA leading to a malignant transformation, or it may derive benefit in terms of an adaptive response such as a temporary improvement of DNA repair or temporary prevention of effects from intracellular radicals through enhanced radical detoxification. These responses are protective also to toxic substances that are generated during normal metabolism. Within a multicellular system, the probability of detriment must be weighed against the probability of benefit through adaptive responses with protection against various toxic agents including those produced by normal metabolism. Because irradiation can principally induce both, detriment and adaptive responses, one type of affected cells may not be simply summed up at the expense of cells with other types of effects, in assessing risk to tissue. An inventory of various types of effects in the blood forming system of mammals, even with large ranges of uncertainty, uncovers the possibility of benefit to the system from exposure to low doses of low LET radiation. This experimental approach may complement epidemiological data on individuals exposed to low doses of ionizing radiation and may lead to a more rational appraisal of risk.

• Progress in Medical Physics
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• v.3 no.2
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• pp.59-65
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• 1992

Carcimoma of the breast are first frequency malignancy in women in the world. third frequency in Korea. Radiation therapy in breast cancer were treated through opposed tangential fields with photon beam or electron beam. Density within the field and thickness to tumor are very importent factors determining dose distribution in radiation therapy of electron beam. Radiotherapy traetment planning using computed tomography in Breast cancer are able to ideal dose distribution. Authors concluded as following. 6MeV energy of electron beam propered below 1.5cm in chest wall's thickness or internal mammary lymphnode's depth. 9MeV energy of electron beam from 1.5cm to 2.0cm. 12 MeV energy of electron beam from 2.0cm to 2.5cm.

• Tuberculosis and Respiratory Diseases
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• v.40 no.4
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• pp.367-377
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• 1993

Background: The benefits of combination chemotherapy in unresectable non-small cell lung cancer remain uncertain. But, according to the recent reports, the response rates of cisplatin-based polychemotherapy regimens are higher than those of single agent. Also, the response rates of high-dose cisplatin group are higher than those of low-dose cisplatin group. In attemp to answer the question whether treatments, combination chemotherapy (high VPP) and combination chemotherapy with radiation therapy, improve survival in advanced non-small cell lung cancer, we begin to study. Method: Thirty-five patients above stage III, diagnosed histologically as non-small cell lung cancer, were enrolled. Among them, nineteen received a combination chemotherapy consisting of VP-16 & high-dose cisplatin (100 $mg/m^2$) and/or radiation therapy. The other group (16 subjects) received no therapy. To investigate the differences of survival and response rates between two groups and the side effects related to therapy, we reviewed patients' records. Results: 1) The overall objective response rate was 47%(9/19) with one complete remission. 2) In patients who received polychemotherapy and radiation therapy, the response rate was 60%(6/10) with one complete remission and survival rates of 3 months, 6 months and 12 months were 100%, 70% and 40%. 3) In patients who received polychemotherapy, the response rate was 33% (3/9) with no complete remission and survival rates of 3 months, 6 months and 12 months were 78%, 67% and 33%. 4) Overall, treated patients survived significantly longer (p<0.05) than non-treated patients (median survival 307 days versus 95 days). 5) Analysis of the various prognostic factors disclosed that good performance status, stage III and squamous cell type showed the good response rates. 6) The toxicities were nausea and/or vomiting (100%), alopecia (90%), anemia (79%), leukopenia (69%), thrombocytopenia (2%), increased creatinine (16%) and neurotoxicity (5%). Conclusion: According to above results, there are relatively good results that high VPP combination chemotherapy in advanced non-small cell lung cancer improves survival in the treated group than in the non-treated group. Thus, it is considerd that we select the patients with proper indications and treat them with effective chemotherpy and radiation therapy. But, because improvement related to high VPP ploychemotherapy is not marked in this study, it is necessary that we should investigate follow-up studies in many cases.

• Journal of Radiation Protection and Research
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• v.32 no.2
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• pp.45-50
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• 2007

In this study, uptake rates of internal organs and daily urinary excretion rates were measured to get more reliable estimation results for Korean. Radioactive iodine($^{131}I$) of $100{\mu}Ci$ was administered by ingestion to 28 adult males for the experiment and then the radioactivity in thyroid gland, liver, stomach, small intestine, kidneys, and urine was measured after time intervals of 2, 4, 6 and 24 hours. Uptake rates of each organ and daily urinary excretion rates were calculated on the basis of these experimental results. As a result, uptake rates of 19.70% for thyroid and daily urinary excretion rates of 71.12%, on the average, were indicated. The maximum of uptake rates and daily urinary excretion rates were recorded after 2 hours of administration of $^{131}I$, but those rates were decreased gradually later. It was also found that uptake rates were the highest in stomach, followed by the left kidney, liver, small intestine and right kidney except for thyroid gland. In this experiment, the calculated uptake change rate in thyroid gland after 24 hours of administration of $^{131}I$ was different from that of ICRP-54/67(30%) and ICRP-78(25%). Thus, it is necessary to apply more reliable approach, reflecting the characteristic of Korean physiology and to obtain the basic data of results using this approach for calculation of the internal adsorbed dose. In the future, this approach can be helpful for the internal dose assessment of radiation workers in a nuclear power plant or in a hospital.

• The Journal of Korean Society for Radiation Therapy
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• v.17 no.2
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• pp.113-124
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• 2005

Purpose : The using of endo-rectal balloon has proposed as optimal method that minimized the motion of prostate and the dose of rectum wall volume for treated prostate cancer patients, so we make the customized rectal balloon device. In this study, we analyzed the efficiency of the Self-customized rectal balloon in the aspects of its reproducibility. Materials and Methods : In 5 patients, for treatment planning, each patient was acquired CT slice images in state of with and without rectal balloon. Also they had CT scanning samely repeated third times in during radiation treatment (IMRT). In each case, we analyzed the deviation of rectal ballon position and verified the isodose distribution of rectum wall at closed prostate. Results : Using the rectal balloon, we minimized the planning target volume (PTV) by decreased the internal motion of prostate and overcome the dose limit of radiation therapy in prostate cancer by increased the gap between the rectum wall and high dose region. Conclusion : The using of rectal balloon, although, was reluctant to treat by patients. View a point of immobilization of prostate internal motion and dose escalation of GTV (gross tumor volume), its using consider large efficients for treated prostate cancer patients.

• Radiation Oncology Journal
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• v.12 no.2
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• pp.219-223
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• 1994

This paper describes the basic data measurements for total body irradiation with 6 Mv photon beam including compensators design. The technique uses bilateral opposing fields with tissue compensators for the head, neck, lungs, and legs from the hip to toes. In vivo dosimetry was carried out for determining absorbed dose at various regions in 7 patients using diode detectors(MULTIDOSE,k Model 9310, MULTIDATA Co., USA). As a results, the dose uniformity of${\pm}3.5{\%}$(generally, within${\pm}10{\%}$can be achieved with out total body irradiation technique.