• Journal of Sensor Science and Technology
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• v.24 no.2
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• pp.96-100
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• 2015

In the present study, we developed a real-time radiation-monitoring sensor for an underwater radiation-monitoring system and evaluated its effectiveness using reference radiation sources. The monitoring sensor was designed and miniaturized using a silicon photomultiplier (SiPM) and a cerium-doped-gadolinium-aluminum-gallium-garnet (Ce:GAGG) scintillator, and an underwater wireless monitoring system was implemented by employing a remote Bluetooth communication module. An acrylic water tank and reference radiation sources ($^{137}Cs$, $^{90}Sr$) were used to evaluate the effectiveness of the monitoring sensor. The underwater monitoring sensor's detection response and efficiency for gamma rays and beta particles as well as the linearity of the response according to the gammaray intensity were verified through an evaluation. This evaluation is expected to contribute to the development of base technology for an underwater radiation-monitoring system.

• Radiation Oncology Journal
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• v.13 no.3
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• pp.233-241
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• 1995

Purpose : To analyse clinical outcome and prognostic factors according to treatment modality, this paper report our experience of retrospective study of patients with esophageal cancer Materials and Methods : One hundred and ten patients with primary esophageal cancer who were treated in Presbyterian Medical Center from May 1985 to December 1992. We analysed these patients retrospectively with median follow up time of 28 months, one hundred and four patients($95{\%}$) were followed up from 15 to 69 months. In methods, twenty-eight patients were treated with median radiation dose irradiated 54.3Gy only. Fifty-six patients were treated with combined chemoradiotherapy. Sixteen cases of these patients were treated with concurrent chemoradiation and the other patients(forty cases) were treated sequential chemoradiotherapy. In concurrent chemoradiotherapy group, patients received 5-FU continuous IV infusion for 4 days. Cisplatin IV bolus. and concurrent esophageal irradiation to 30 Gy. After that patients received 5-FU continuous IV, Cisplatin bolus injection and Mitomycin-C bolus IV, Bleomycin continuous IV, and irradiation to 20 Gy. In sequential chemoradiotherapy group, the chemotherapy consisted of 5-FU 1,000mg/$m^2$ administered as a continuous 24 hour intravenous infusion during five days and Cisplatin 80-100mg/$m^2$ bolus injected, or Bleomycin, Vinblastine, Cisplatin, Methotrexate were used of 1 or 2 cycles. After preoperative concurrentm chemoradiation twenty-six patients underwent radical esophagectomy. Results : Ninety-three patients could be examined for response assessment, By treatment modality, response rates were $85.1{\%}$ for radiation alone group and $86.3{\%}$ for combined chemoradiation group. But in operation group, after one cycle of concurrent chemoradiation treatment, response rate was $61.9{\%}$. The pathologic complete response were $15.4{\%}$ in operation group. Overall median survival was II months and actuarial 5-year survival rate was $8{\%}$. The median survival interval was 6 months for radiation alone group, 11 months for combined chemoradiation group and 19 months for operation group. And also median survival was 19 months for complete responder group that 8 months for noncomplete responder group. In univariative analysis, statistically significant prognostic factors were tumor size, clinical stage, tumor response, and operation. In multivariative analysis, significantly better survival was associated with clinical stage, tumor response, radiation dose, and operation. Conclusion : Compared with radiotherapy alone, combined multimodality may improve the median survival in patients with localized carcinoma of the esophagus and toxicity is acceptable.

• Radiation Oncology Journal
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• v.7 no.2
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• pp.227-233
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• 1989

From April 1986 to Dec 1988, fifty one patients with carcinoma of lung were treated by radiation therapy in Department of Therapeutic Radiology, Yeungnam University Hospital Of the 51 patients, $31(61\%)$ were squamous cell ca, $8(15.7\%)$ were small cell ca, and remained $4(7.9\%)$ were other cell types. Total radiation dose was average $64Gy (60\~75 Gy)$ for group A and 45Gy $(40\~59Gy)$ for group B. The mass regression and the response of airway obstruction to radiation therapy was established on the basis of follow up chest X-ray. The mass regression above $50\%$ of total volume was noted in 23 patients $(74.2\%)$ among 31 patients and the difference between two groups was not seen. In squamous cell ca, however, the mass regression rate (above $50\%$ of total volume) was $83.3\%$ (10/12) in group A compared to $50\%$ (3/6) in group B(p<0.05). The alleviation of airway obstruction was noted as follows. In group A, CR $42.9\%$, PR $35.7\%$, no response $21.4\%$ and in group B, CR $55.6\%,\;PR\;33.3\%$, no response $11.1\%$. But, in squamous cell ca, responsiveness is higher than group B. The study indicates that the importance of higher radiation dose in the management of primary tumor mass and airway obstruction caused by lung cancer especially squamous cell ca. So, meticulous treatment planning and multimodality combination therapy without increasing si.do elect or complication is recommended in management of inoperable bronchogenic carcinoma.

• Radiation Oncology Journal
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• v.17 no.2
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• pp.113-119
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• 1999

Purpose : To evaluate possible acute toxicity and early response of concurrent radiation therapy and low dose daily cisplatin as a radiosensitizer in patients with locally advanced uterine cervical carcinomas. Materials and Method : From December 1996 to January 1999, 38 previously untreated Patients with locally advanced squamous cell carcinoma of the uterine cervix (from stage IIB to stage IIIB) were treated at Inha University Hospital. All patients underwent standard pretreatment staging Procedures after the initial evaluation by gynecologists and radiation oncologists. Sixteen Patients with huge cervical mass (>4 cm) were submitted to the group treated with concurrent radiation therapy and low dose daily cisplatin while the remainder was treated with radiation therapy alone. Radiation therapy consisted of 4500 cGy external beam irradiation to whole pelvis (midline block after 3000 cGy), 900$\~$1000 cGy boost to involved parametrium, and high dose-rate intracavitary brachytherapy (a total dose of 3000$\~$3500 cGy/500 cGy per fraction to point A, twice per week). In the group treated with low dose cisplatin concurrently, 10 mg of daily intravenous cisplatin was given from the 1st day of radiation therapy to the 20th day of radiation therapy. Acute toxicity was measured according to expanded common toxicity criteria of the NCI (C) Clinical Trials. Early response data were analyzed at minimum 4 weeks' follow-up after completion of the treatment protocol. Results: Hematolgic toxici쇼 was more prominent in patients treated with radiation therapy and cisplatin. Six of 16 patients (37.5$\~$) treated with radiation therapy and cisplatin and one of 22 patients (4.5$\~$) treated with radiation therapy alone experienced grade 3 leukopenia. In Fisher's exact test, there was statistically significant difference between two groups regarding leukopenia (P=0.030). There was no apparent difference in the frequency of gastrointestinal and genitourinary toxicity between two groups (P=0.066). Three of 16 patients (18.7$\~$) treated with radiation therapy and cisplatin and two of 22 patients (9.1$\~$) treated with radiation therapy alone experienced more than 5 kg weight loss during the treatment. There was no statistically significant difference on weight loss between two groups (P=0.63). Two patients on each group were not evaluable for the early response because of incomplete treatment. The complete response rate at four weeks' follow-up was 80$\~$(16/20) for the radiation therapy alone group and 78$\~$ (11/14) for the radiation therapy and cisplatin group. There was no statistically significant difference in early response between two treatment groups (P=0.126). Conclusion : This study led to the conclusion that the hematologic toxicity from the treatment with concurrent radiation therapy and low dose daily cisplatin seems to be more prominent than that from the treatment of radiation therapy alone. There was no grade 4 hematologic toxicity or mortality in both groups. The hematologic toxicity in both treatment groups seems to be well managable modically. Since the risk factors were not balanced between two treatment groups, the direct comparison of early response of both groups was not possible. However, preliminary results regarding early response for patients with bulky cervical tumor mass treated with radiation therapy and low dose daily cisplatin was encouraging. Longer follow-up is necessary to evaluate the survival data. A phase III study is needed to evaluate the efficacy of concurrent daily low dose cisplatin with radiation therapy in bulky cervical cancer.

• Journal of Ecology and Environment
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• v.37 no.4
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• pp.195-200
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• 2014

The chances of accidental exposure are augmented as the application of ionizing radiation increases in various fields. Such accidental exposures may occur at nuclear power plants, laboratories, and hospitals. Cytogenetic assays have been used for estimating radiation dose in the situation of the accidents. The micronucleus assay has several advantages over the other cytogenetic methods as it is simple and fast. The present study aimed at investigation of the micronuclei frequencies in cytokinesis-block cells in human blood lymphocytes after ${\gamma}$-irradiation and at establishment of a standard dose response relationship. The samples of peripheral blood were obtained from 6 different donors aged between 24 and 30 years old. The bloods were irradiated in vitro with 0-5 Gy. A linear quadratic dose-response equation was obtained by scoring the micronuclei in binucleated cells; $y=27.87x^2+46.13x+2.08$ ($r^2=0.99$). Irradiation caused a significant decrease in the nuclear division index. Necrotic and apoptotic cells increased in number after irradiation in a dose-dependent manner. In conclusion, the conventional cytokinesis-block micronucleus assay has proven to be the great technique in biological dosimetry. Dose-response calibration curve derived from CMBN assay could be used to estimate the exposure dose during a radiological emergency.

• Radiation Oncology Journal
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• v.34 no.3
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• pp.230-238
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• 2016

Purpose: Hypoxia can impair the therapeutic efficacy of radiotherapy (RT). Therefore, a new strategy is necessary for enhancing the response to RT. In this study, we investigated whether the combination of nanoparticles and RT is effective in eliminating the radioresistance of hypoxic tumors. Materials and Methods: Gold nanoparticles (GNPs) consisting of a silica core with a gold shell were used. CT26 colon cancer mouse model was developed to study whether the combination of RT and GNPs reduced hypoxia-induced radioresistance. Hypoxia inducible $factor-1{\alpha}$ ($HIF-1{\alpha}$) was used as a hypoxia marker. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining were conducted to evaluate cell death. Results: Hypoxic tumor cells had an impaired response to RT. GNPs combined with RT enhanced anti-tumor effect in hypoxic tumor compared with RT alone. The combination of GNPs and RT decreased tumor cell viability compare to RT alone in vitro. Under hypoxia, tumors treated with GNPs + RT showed a higher response than that shown by tumors treated with RT alone. When a reactive oxygen species (ROS) scavenger was added, the enhanced antitumor effect of GNPs + RT was diminished. Conclusion: In the present study, hypoxic tumors treated with GNPs + RT showed favorable responses, which might be attributable to the ROS production induced by GNPs + RT. Taken together, GNPs combined with RT seems to be potential modality for enhancing the response to RT in hypoxic tumors.

• Radiation Oncology Journal
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• v.33 no.3
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• pp.179-187
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• 2015

Purpose: The purpose of this study was to investigate the predictable value of pretreatment $^{18}F$-fluorodeoxyglucose positron emission tomography-computed tomography ($^{18}F$-FDG PET-CT) in radiotherapy (RT) for patients with hepatocellular carcinoma (HCC) or portal vein tumor thrombosis (PVTT). Materials and Methods: We conducted a retrospective analysis of 36 stage I-IV HCC patients treated with RT. $^{18}F$-FDG PET-CT was performed before RT. Treatment target was determined HCC or PVTT lesions by treatment aim. They were irradiated at a median prescription dose of 50 Gy. The response was evaluated within 3 months after completion of RT using the Response Evaluation Criteria in Solid Tumors (RECIST). Response rate, overall survival (OS), and the pattern of failure (POF) were analyzed. Results: The response rate was 61.1%. The statistically significant prognostic factor affecting response in RT field was maximal standardized uptake value (maxSUV) only. The high SUV group (maxSUV ${\geq}5.1$) showed the better radiologic response than the low SUV group (maxSUV < 5.1). The median OS were 996.0 days in definitive group and 144.0 days in palliative group. Factors affecting OS were the %reduction of alpha-fetoprotein (AFP) level in the definitive group and Child-Pugh class in the palliative group. To predict the POF, maxSUV based on the cutoff value of 5.1 was the only significant factor in distant metastasis group. Conclusion: The results of this study suggest that the maxSUV of $^{18}F$-FDG PET-CT may be a prognostic factor for treatment outcome and the POF after RT. A %reduction of AFP level and Child-Pugh class could be used to predict OS in HCC.

• Radiation Oncology Journal
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• v.29 no.3
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• pp.174-180
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• 2011

Purpose: To evaluate the radiotherapy treatment outcome of patients in stage IE and IIE nasal natural killer/T-cell lymphoma. Materials and Methods: From August 1999 to August 2009, 46 patients with stage IE and IIE nasal natural killer/T-cell lymphoma were treated by definitive radiotherapy and chemotherapy. 33 patients were treated with chemotherapy followed by radiotherapy (CT + RT) and they received 50.4 Gy in 28 fractions. 13 patients were treated with concurrent chemoradiotherapy (CCRT) and they received 40 Gy in 20 fractions. Results: The median follow-up period was 4.6-137.6 months (median, 50.2 months) for all patients. The 4-year overall survival was 68.6% and 4-year disease free survival (DFS) was 61.9%. The 4-year locoregional recurrence free survival was 65.0%, and 4-year distant metastasis free survival (DMFS) was 66.2%. For patients treated with CT + RT, 15 patients (45.5%) achieved complete response after chemotherapy, and 13 patients (39.4%) achieved partial response. 13 patients (81.8%) achieved complete response after radiotherapy, and 6 patients (18.2%) achieved partial response. For patients treated with CCRT, 11 patients (84.6%) achieved complete response, and one patient (7.7%) achieved partial response. In univariate analysis, presence of cervical lymph node metastasis was only significant prognostic factor for DFS and DMFS. Conclusion: This study did not show satisfactory overall survival rate and disease free survival rate of definitive radiotherapy and chemotherapy for stage IE and IIE nasal natural killer/T-cell lymphoma. For patients with cervical lymph node metastasis, further investigation of new chemotherapy regimens is necessary to reduce the distant metastasis.

• Radiation Oncology Journal
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• v.17 no.4
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• pp.307-313
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• 1999

Purpose : To investigate the Presence of adaptive response by low dose radiation in murine tumors in relation to radiation induced apoptosis as well as related mechanism. Materials and Methods : Syngeneic murine tumors, OCa-I and HCa-l, were given 0.05 Gy pretreatment followed by therapeutic dose of 25 Gy radiation. Induction of apoptosis was analyzed for each treatment group. Regulating molecules of apoptosis, p53, Bcl-2, Bax, Bcl-X, were also analyzed by Western blotting. Results : In 0.05 Gy pretreatment group of OCa-I, 25 Gy-induced apoptosis per 1000 cells was 229, which was estimated at $30\%$ lower level than the expected (p<0.05). In contrast, this reduction in radiation induced apoptosis was not seen in HCa-l. In the expression of apoptosis regulating molecules, p53 increased in both tumors in response to radiation. Bcl-2 and Bax did not show significant change in both tumors however, the expression of Bcl-2 surpassed that of Bax in 0.05 Gy pretreatment group of OCa-l. Bcl-X was not expressed in OCa-l. In HCa-l, Bcl-X showed increased expression even with 0.05 Gy. Conclusion : Adaptive response by low dose radiation Is shown in one murine tumor, OCa-l, in relation to radiation induced apoptosis. Apoptosis regulating molecules including Bcl-2/Bax and Bcl-X, appear to related. This study shows an evidence that adaptive response is present, but not a generalized phenomenon in vivo.

• Radiation Oncology Journal
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• v.15 no.1
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• pp.65-69
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• 1997

Purpose : To obtain the actual dose distribution from measured data by doconvolution method using the measured ion chamber response function. Materials and Methods : The chamber response functions for 2 ionization chambers (diameter 5mm, 6.4mm) were measured. and dose Profiles were measured for $10{\times}20cm^2$ field size using two different detectors. The deconvolution of chamber response function from the measured data were performed for these Profiles. The same procedures were repeated for 4MV, 6MV and 1 SMV photon energies. Results : Different dose Profiles were obtained for the same field with the chambers which have the different response functions. Nearly the same results could be obtained with deconvolution for the profiles from various detectors. Conclusion : The effect of the chamber response function can be extracted by deconvolution method. Deconvolved dose profile using various ionization chambers gave better dose distributions. Technical improvements are needed for practical application.