• Radiation Oncology Journal
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• v.24 no.1
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• pp.11-20
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• 2006

Puroose: In order to find out whether stereotactic radiation therapy (RT) using CyberKnife (CK) could improve survival rate and lower acute toxicity compared to conventional RT. Materials and Methods: From April 2003 through April 2004, 19 patients with Eastern Cooperative Oncology Group (ECOG) performance status ${\leq}3$ and locally advanced pancreas cancer without distant metastasis, evaluated by CT or PET/CT, were included. We administered stereotactic RT consisting of either 33 Gy, 36 Gy or 39 Gy in 3 fractions to 6, 4 and 9 patients, respectively, in an effort to increase the radiation dose step by step, and analyzed the survival rate and gastrointestinal toxicities by the acute radiation morbidity criteria of Radiation Therapeutic Oncology Group (RTOG). Prognostic factors of age, sex, ECOG performance score, chemotherapy, bypass surgery, radiation dose, CA 19-9, planning target volume (PTV), and adjacent organ and vessel invasion on CT scan were evaluated by Log Rank test. Results: The median survival time was 11 months with 1-year survival rate of 36.8%. During follow-up period (range $3{\sim}20$ months, median 10 months), no significant gastrointestinal acute toxicity (RTOG grade 3) was observed. In univariate analysis, age, sex, ECOG performance score, chemotherapy, bypass surgery, radiation dose, CA 19-9 level, and adjacent organ and vessel invasion did not show any significant changes of survival rate, however, patients with PTV (80 cc showed more favorable survival rate than those with PTV>80 cc (p-value<0.05). In multivariate analysis, age younger than 65 years and PTV>80 cc showed better survival rate. Conclusion: In terms of survival, the efficacy of stereotactic radiation therapy using CK was found to be superior or similar to other recent studies achieved with conventional RT with intensive chemotherapy, high dose conformal RT, intraoperative RT (IORT), or intensity modulated RT (IMRT). Furthermore, severe toxicity was not observed. Short treatment time in relation to the short life expectancy gave patients more convenience and, finally, quality of life would be increased. Consequently, this could be regarded as an effective novel treatment modality for locally advanced, unresectable pancreas cancer. PTV would be a helpful prognostic factor for CK.

• Journal of Radiation Protection and Research
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• v.39 no.1
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• pp.1-6
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• 2014

A whole body counter (WBC) is used in nuclear power plants (NPP) to identify and measure internal radioactivity of workers who is likely to ingest or inhale radionuclides. WBC has several counting geometry, i.e. the thyroid, lung, whole body and gastrointestinal tract, considered with the location where radionuclides are deposited in the body. But only whole body geometry is used to detect internal radioactivity during whole body counting at NPPs. It is overestimated internal exposure dose because this measured values are indicated as the most conservative radioactivity values among the them of others geometry. In this study, experiments to measure radioactivity depending on the counting geometry of WBC were carried out using a WBC, a phantom, and standard radiation sources in order to improve overestimated internal exposure dose. Quantitative criteria, could be selected counting geometry according to ratio of count rates of the upper and lower detectors of the WBC, are provided through statistical analysis method.

• Tuberculosis and Respiratory Diseases
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• v.56 no.1
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• pp.40-50
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• 2004

Background : Radiation pneumonitis(RP) is the major serious complication of thoracic irradiation treatment. In this study, we attempted to retrospectively evaluate the long-term prognosis of patients who experienced acute RP and to identify factor that might allow prediction of RP. Methods : Of the 114 lung cancer patients who underwent thoracic radiotherapy between December 2000 and December 2002, We performed analysis using a database of 90 patients who were capable of being evaluated. Results : Of the 44 patients(48.9%) who experienced clinical RP in this study, the RP was mild in 33(36.6%) and severe in 11(12.3%). All of severe RP were treated with corticosteroids. The median starting corticosteroids dose was 34 mg(30~40) and median treatment duration was 68 days(8~97). The median survival time of the 11 patients who experienced severe RP was significantly poorer than the mild RP group. (p=0.046) The higher total radiation dose(${\geq}60Gy$) was significantly associated with developing in RP.(p=0.001) The incidence of RP did not correlate with any of the ECOG performance, pulmonary function test, age, cell type, history of smoking, radiotherapy combined with chemotherapy, once-daily radiotherapy dose fraction. Also, serum albumin level, uric acid level at onset of RP did not influence the risk of severe RP in our study. Conclusion : Only the higher total radiation dose(${\geq}60Gy$) was a significant risk factor predictive of RP. Also severe RP was an adverse prognostic factor.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.391-397
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• 2016

Stereotactic body radiotherapy is effective technic in radiotherapy for low stage lung cancer. But lung cancer is affected by respiratory so accurately concentrate high dose to the target is very difficult. In this study, evaluated the target volume according to how to take the image. And evaluated the dose by photoluminescence glass dosimeter according to how to contour the volume and respiratory range. As a result, evaluated the 4D CT volume was 10.4 cm3 which was closest value of real size target. And in dose case is internal target volume dose was 10.82, 16.88, 21.90 Gy when prescribed dose was 10, 15, 20 Gy and it was the highest dose. Respiratory gated radiotherapy dose was more higher than internal target volume. But it made little difference by respiratory range. Therefore, when moving cancer treatment, acquiring image by 4D CT, contouring internal target volume and respiratory gated radiotherapy technic would be the best way.

• Radiation Oncology Journal
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• v.30 no.4
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• pp.213-217
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• 2012

Purpose: To evaluate treatment outcome of patients with high risk locally advanced gastric cancer after postoperative chemoradiotherapy. Materials and Methods: Between May 2003 and May 2012, thirteen patients who underwent postoperative chemoradiotherapy for gastric cancer with resection margin involvement or adjacent structure invasion were retrospectively analyzed. Concurrent chemotherapy was administered in 10 patients. Median dose of radiation was 50.4 Gy (range, 45 to 55.8 Gy). Results: The median follow-up duration for surviving patients was 48 months (range, 5 to 108 months). The 5-year overall survival rate was 42% and the 5-year disease-free survival rate was 28%. Major pattern of failure was peritoneal seeding with 46%. Locoregional recurrence was reported in only one patient. Grade 2 or higher gastrointestinal toxicity occurred in 54% of the patients. However, there was only one patient with higher than grade 3 toxicity. Conclusion: Despite reported suggested role of adjuvant radiotherapy with combination chemotherapy in gastric cancer, only very small portion of the patients underwent the treatment. Results from this study show that postoperative chemoradiotherapy provided excellent locoregional control with acceptable and manageable treatment related toxicity in patients with high risk locally advanced gastric cancer. Thus, postoperative chemoradiotherapy may improve treatment result in terms of locoregional control in these high risk patients. However, as these findings are based on small series, validation with larger cohort is suggested.

• Journal of the Korean Society of Radiology
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• v.10 no.3
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• pp.181-186
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• 2016

Cardiac angiography(CA) or cardiac intervention(CI) is one of the major examination methods applied to the detection of cardiovascular diseases using X-rays. These CA and CI procedures require radiation exposure to patients and physicians. We evaluated the radiation dose to cardiac operator during the each case of CA and CI procedures. The number of patients is 113 patients in CA and 34 patients in CI. Mean fluoroscopy time, mean cine time, and mean total cumulative dose area product(DAP) in patients during CA and CI was 165.9 sec vs. 1200.0 sec, 30.31 sec vs 107.5 sec, and $37130.3mGy.cm^2$ vs $213312.6mGy.cm^2$, respectively. Mean dose of thyroid, over chest apron and under chest apron in operator during CA and CI was 15.84 uSv vs 89.81 uSv, 20.16 uSv vs 123.20 uSv, and 0.30 uSv vs 2.40 uSv, respectively. Mean effective dose of operator during CI was about 6 times greater than during CA. Also there was significant inter-relationship between fluoroscopy or cine time and effective dose in operator during CA and CI(p=0.001 and p=0.001, respectively).

• Journal of Radiation Protection and Research
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• v.38 no.4
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• pp.242-245
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• 2013

Monte Carlo method was applied to discriminate the external contamination on radiation workers in nuclear power plants for internal dose assessment generally used with a bed type scanning detector whole body counter. Korean voxel model with internal contamination was used to estimate the detection patterns of whole body scanning. Also, the BOMAB model with various external contamination was assumed to compare with detection of radionuclides inside the human body. From the comparison of detection efficiency between front and back side up, external contamination was easily distinguished.

• The Korean Journal of Nuclear Medicine
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• v.33 no.4
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• pp.422-429
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• 1999

Purpose: The measurement of radiation absorbed dose is useful to predict the response after I-131 labeled metaiodobenzylguanidine (MIBG) therapy and determine therapy dose in patients with unresectable or malignant pheochromocytoma. We estimated the absorbed dose in tumor tissue after high dose I-131 MIBG in a patient with pheochromocytoma using a gamma camera and Medical Internal Radiation Dose (MIRD) formula. Materials and Methods: A 64-year old female patient with pheochromocytoma who had multiple metastases of mediastinum, right kidney and periaortic lymph nodes, received 74 GBq (200 mCi) of I-131 MIBG. We obtained anterior and posterior images at 0.5, 16, 24, 64 and 145 hours after treatment. Two standard sources of 37 and 74 MBq of I-131 were imaged simultaneously. Cummulated I-131 MIBG uptake in tumor tissue was calculated after the correction of background activity, attenuation, system sensitivity and count loss at a high count rate. Results: The calculated absorbed radiation dose was 32-63 Gy/ 74 GBq, which was lower than the known dose for tumor remission (150-200 Gy). follow-up studies at 1 month showed minimally reduced tumor size on computed tomography, and mildly reduced I-131 MIBG uptake. Conclusion: We estimated radiation absorbed dose after therapeutic I-131 MIBG using a gamma camera and MIRD formula, which can be peformed in a clinical nuclear medicine laboratory. Our results suggest that the measurement of radiation absorbed dose in I-131 MIBG therapy is feasible as a routine clinical practice that can guide further treatment plan. The accuracy of dose measurement and correlation with clinical outcome should be evaluated further.

• Journal of Radiation Protection and Research
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• v.34 no.4
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• pp.184-189
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• 2009

In pressurized heavy water reactors, workers who enter radiation controlled areas must submit their urine samples to health physicists after radiation work; these samples are then used to monitor internal radiation exposure from tritium intake. This procedure assumes that the samples submitted represent tritium concentration inside the body at equilibrium. According to both technical reports from the International Commission on Radiological Protection and experimental results from Canadian nuclear utilities, tritium inside the body generally reaches equilibrium concentration after approximately 2-3 hours of intake. In practice, urine samples can be submitted either before the 2 hours mark or after several hours of radiation work because of the numerous tasks that workers must perform and their frequent entries during nuclear power plant maintenance. In this paper, tritium concentration in workers' urine samples was measured as a function of time submitted after radiation work. Based on the measurement results, changes in the tritium concentration inside the body and its effect on internal dose assessment were then analyzed. As a result, it was found that tritium concentration reaches equilibrium concentration before the 2 hours mark for most workers' urine samples.

• 전기의세계
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• v.23 no.5
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• pp.54-60
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• 1974

Proposals were mode on how to differentiate radiation effects in morphological phases of polyethylene and discussions were developed with the results obtained on a low density polyethylene, SOCAREX, specified by number average molecular weight; overbar Mn=5,400, density; 0.92, and degree of branch; 3.4/100 carbon atom, which was irradiated to Co$^{60}$ .gamma. ray at the dose rate of 0.5 Mrad/hr in ambient temperature under the pressure of 10$^{-5}$ Torr. or 1 atm. respectively. The effect to crystalline phase in possibly deduced from dose dependent variation of relative area between (110) and (200) peaks on X ray diffraction spectrum and that, the effects to amorphous phase can be understood through dose dependent relaxation behaviours of .betha. peak on internal friction characteristics of the specimen. The results obtained thus far indicate that, in crystalline phase, relative crystallinity shows a rather rapid decrease up to 20 Mrad with increasing dose, however, little change of crystallinity can be observed in the region between 20-200 Mrad, and degradation appears to be more predominant than crosslinking up to 60 Mrad. While in amorphous phase the indication also shows that degradation is only predominant up to 20 Mrad. Furthermore several correlations can be seen with amenable explanation between dose dependent behaviours observed in both phases.