• Radiation Oncology Journal
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• v.11 no.1
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• pp.35-42
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• 1993

The dose response of the number of micronuclei in cytokinesis-blocked (CB) lymphocytes after in vitro irradiation with $\gamma$-rays and neutrons in the 5 dose ranges was studied for a heterogeneous population of 4 donors. One thousand binucleated cells were systematically scored for micronuclei. Measurements performed after irradiation showed a dose-dependent increase in micronuclei (MN) frequency in each of the donors studied. The dose-response curves were analyzed by a linear-quadratic model, frequencies per 1000 CB cells were ($0.31{\pm}0.049$)D+($0.0022{\pm}0.0002)D^2+(13.19{\pm}1.854) (r^2=1.000,\;X^2=0.7074,\;p=0.95$) following $\gamma$ irradiation, and ($0.99{\pm}0.528$)\;D+(0.0093{\pm}0.0047)\;D^2+(13.31{\pm}7.309)\;(r^2=0.996,\;X^2=7.6834,\;p=0.11) following neutrons irradiation (D is irradiation dose in cGy). The relative biological effectiveness (RBE) of neutrons compared with $\gamma$-rays was estimated by best fitting linear-quadratic model. In the micronuclei frequency between 0.05 and 0.8 per cell, the RBE of neutrons was $2.37{\pm}0.17$. Since the MN assay is simple and rapid, it may be a good tool for evaluating the $\gamma$-ray and neutron response.

• The korean journal of orthodontics
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• v.41 no.4
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• pp.255-267
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• 2011

Objective: The purpose of this study was to confirm the reliability of a cone beam computed tomography (CBCT)-generated panoramic view based on a CBCT 3D image and to find the most helpful 2D panoramic image compared with CBCT 3D image when examining the mesiodistal tooth axis. Methods: A test model was constructed according to cephalometric norms. The test model was repeatedly repositioned for CBCT and panoramic radiographic imaging. Panoramic radiographs were acquired at each of the following 3 occlusal plane positions: $-5^{\circ}$, $0^{\circ}$, and $+5^{\circ}$. Measurements of mesiodistal tooth axis in CBCT 3D image, CBCT-generated panoramic view, and panoramic radiographs were compared. Results: Compared with the CBCT-generated panoramic view, CBCT 3D image showed significant difference in the mesiodistal tooth axis in the premolars and no significant difference in the mesiodistal tooth axis in the incisors and canines. Mesiodistal tooth axis on the CBCT-generated panoramic view was significantly different from that on panoramic radiographs. Conclusions: CBCT-generated panoramic view can be a useful tool for evaluating mesiodistal tooth axis.

• Journal of the Korean Society of Radiology
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• v.16 no.7
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• pp.995-1006
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• 2022

The purpose of this study was to investigate the current status of practical course operation in a non-face-to-face online environment, learning effects, and students' experiences and perceptions for radiology major students using a survey. The questionnaire consisted of a total of 34 items in 5 areas: general characteristics of subjects, current learning participation in non-face-to-face environments, learning satisfaction, learning outcomes, improvement and requirements. For the analysis of the questionnaire responses, frequency analysis was performed on the response frequency, ratio, and scale for each item. Based on the general characteristics of the survey respondents, cross-analysis was performed using the chi-square test for participation in non-face-to-face learning, learning performance, and learning satisfaction. implemented. Improvements and requirements were qualitatively analyzed for the repetition frequency of words with the same meaning. Through the results of analyzing the responses of a total of 397 questionnaires, the direction of design and development of practical classes in a non-face-to-face environment in the future and basic information and implications for efficient operation were confirmed. Based on this, it is necessary to continue to think and make efforts for the efficient operation of non-face-to-face practice classes in the post-corona era.

• Radiation Oncology Journal
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• v.25 no.3
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• pp.185-191
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• 2007

Purpose: This study was performed to investigate the effects of immune cell activation and the antitumor effect for the combination of treatment with X-irradiation and E/eutherococcus senticosus Maxim Root (ESMR) on mouse tumor cells. Materials and Methods: ESMR (250g) was extracted with 80% methanol, concentrated under decompression and lyophilized. To determine whether ESMR is able to activate the immune cells or not, the proliferation of splenocytes in vitro and the number of B cells and T cells in splenic lymphocytes in ESMR-pretreated mice were evaluated. X-irradiation was given to the mouse fibrosarcoma tumor cells (FSa II) by 250 kv X-irradiation machine. The cytotoxicity of ESMR was evaluated from its ability to reduce the clonogenecity of FSa II cells. In X-irradiation alone group, each 2, 4, 6 and 8 Gy was given to FSa II cells. In X-irradiation with ESMR group, 0.2 mg/ml of ESMR was exposed to FSa II cells for 1 hour before X-irradiation. Results: The proliferation of cultured mouse splenocytes and thymocytes were enhanced by the addition of ESMR in vitro. The number of B cells and T cells in mouse splenic lymphocytes was significantly increased in ESMR pretreated mice in vivo. In FSa II cells that received a combination of 0.2 mg/ml of ESMR with X-irradiation exposure, the survival fraction with a dose of 2, 4 and 6 Gy was $0.39{\pm}0.005$, $0.22{\pm}0.005$ and $0.06{\pm}0.007$, respectively. For FSa II cells treated with X-irradiation alone, the survival fraction with a dose of 2, 4 and 6 Gy was $0.76{\pm}0.02$, $0.47{\pm}0.008$ and $0.37{\pm}0.01$. The difference in the survival fraction of the mouse FSa II cells treated with and without ESMR was statistically significant (p<0.05). Conclusion: Treatment with ESMR increased cell viability of mouse splenocytes in vitro and especially the subpopulation of B cells and T cells in splenocytes in ESMR-pretreated mice. However, treatment with ESMR did not increase the level of Th and Tc subpopulations in the thymocytes. Treatment with the combination of ESMR and X-irradiation was more cytotoxic to mouse tumor cells than treatment with X-irradiation alone; this finding was statistically significant.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.543-552
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• 2000

The purposes of this study were to evaluate the reproducibility of posteroanterior(PA) cephalograms obtained by two methods, the Head Posture Aligner(HPA) method in natural head posture and the conventional method(operator-guided method), and to compare the vertical rotational differences of the head Posture between lateral and PA cephalograms according to the method. The sample was consisted of 30 adults. At first day, a PA cephalogram and a lateral cephalogram were obtained from each subject by two methods to investigate the difference of vertical rotational posture between lateral and PA cephalograms. Two weeks later, another PA cephalogram was obtained using each method to evaluate the reproducibility of head posture. Five height measurements and nine width measurements were used in the paired t-test to compare the reproducibility of the PA cephalometric measurements between two methods. The differences of vertical rotational posture between lateral and PA cephalograms were calculated from a computer program and compared according to the method used, and following results were obtained. 1. Height measurements obtained by operator-guided method showed significant differences according to the time interval and revealed low reproducibility. 2. Height measurements obtained by HPA method did not show significant differences according to the time interval and presented high reproducibility. 3. In the comparison of width measurement, two methods did not show distinct differences in reproducibility. 4. The difference of vertical rotational posture between lateral and PA cephalograms showed $0.8^{\circ}$ in the HPA method, more less than $2.5^{\circ}$ in the operator-guided method. The results of the present study suggest that the HPA may be helpful in the PA cephalometric radiography in terms of reproducibility.

• Journal of the Korean Society of Radiology
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• v.10 no.3
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• pp.145-152
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• 2016

This study, targeting a cancer patient undergoing radiation treatment, conducted this research with the aim of looking into the relevance between family support belonging to a patient's primary environment, social support consisting of medical personnel, and the quality of life; this study set 199 patients available for investigation from Jan. 25, 2012 until April 30, 2012 as research subjects among the cancer patients undergoing radiation treatment at the Radiation Oncology Department of a university hospital located in Seoul Metropolitan City. In the analysis of collected data, this study conducted t-test using SPSS/WIN 18.0 Statistical Program, and looked into the relevancy between independent variables including social support, and the quality of life as a dependent variable using analysis of variance, correlation analysis and multi-regression analysis. Conclusively, it was found that the higher the family support perceived by a cancer patient undergoing radiation treatment, the higher the quality of his/her life; thus, this study could learn that there exists a significant relation between family support and the quality of life. Accordingly, it is thought that it's necessary to develop an intervention strategy which makes it possible to intensify family support and social support, etc. for the purpose of improving the quality of life of cancer patients undergoing radiation treatment; further, this study thinks that it's necessary to do additional research which could analyze diverse aspects by subdividing the future quality of life by area.

• Progress in Medical Physics
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• v.9 no.4
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• pp.227-245
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• 1998

A most appropriate model of 3-D conformal radiotherapy has been induced by clinical evaluation and animal study, and therapeutic gains were evaluated by numerical equation of tumor control probability(TCP) and normal tissue complication probability (NTCP). The radiation dose to the tumor and the adjacent normal organs was accurately evaluated and compared using the dose volume histogram(DVH). The TCP and NTCP was derived from the distribution of given dosage and irradiated volume, and these numbers were used as the biological index for the assessment of the treatment effects. Ten patients with liver disease have been evaluated and 3 dogs were sacrificed for this study. Based on the 3-D images of the tumor and adjacent organs, the optimum radiation dose and the projection direction which could maximize the radiation effect while minimizing the effects to the adjacent organs could be decided. 3). The most effective collimation for the normal adjacent organs was made through the beams eye view with the use of multileaf collimator. When the dose was increased from 50Gy to 70Gy, the TCP for the conventional 2-port radiation and the 5-port multidimensional therapy was 0.982 and 0.995 respectively, while the NTCP was 0.725 and 0.142 respectively, suggesting that the 3-D conformal radiotherapy might be the appropriate therapy to apply sufficient radiation dose to the tumor while minimizing the damages to the normal areas of the liver. Positive correlation was observed between the NTCP and the actual complication of the normal liver in the animal study. The present study suggest that the use of 3-D conformal radiotherapy and the application of the mathematical models of TCP and NTCP may provide the improvements in the treatment of hepatoma with enhanced results.

• Journal of the Korean Society of Radiology
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• v.11 no.5
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• pp.303-312
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• 2017

The central goal of Gamma Knife radiosurgery(GKRS) is to maximize the conformity of the prescription isodose surface, and to minimize the radiation effect of the normal tissue surrounding the target volume. There are the various kinds of indices related with the quality of treatment plans such as conformity index, coverage, selectivity, beam-on time, gradient index(GI), and conformity/gradient index(CGI). As the best treatment plan evaluation tool, we must check by all means conformity index, GI, and CGI among them. Specially, GI and CGI related with complication of healthy normal tissue is more indispensible than conformity index. Then author calculated and statistically analysed CGI, the newly defined conformity/gradient index as well as GI being applied widely using the treatment planning system Leksell GammaPlan(LGP) and the verification method Variable Ellipsoid Modeling Technique(VEMT). In the study 10 patients with intracranial lesion treated by GKRS were included. Author computed the indices from LGP and VEMT requiring only four parameters: the prescribed isodose volume, the volume with dose > 30%, the target volume, and the volume of half the prescription isodose. All data were analyzed by paired t-test, which is statistical method used to compare two different measurement techniques. No statistical significance in GI at 10 cases was observed between LGP and VEMT. Differences in GI ranged from -0.14 to 0.01. The newly defined gradient index calculated by two methods LGP and VEMT was not statistically significant either. Author did not find out the statistical difference for the prescribed isodose volume between LGP and VEMT. CGI as the evaluation index for determining the best treatment plan is not significant statistically also. Differences in CGI ranged from -4 to 3. Similarly newly defined Conformity/Gradient index for GKRS was also estimated as the metric for the evaluation of the treatment plans through statistical analysis. Statistical analyses demonstrated that VEMT was in excellent agreement with LGP when considering GI, new gradient index, CGI, and new CGI for evaluating the best plans of GKRS. Due to the application of the fast and easy evaluation tool through LGP and VEMT author hopes CGI and newly defined CGI as well as gradient indices will be widely used.

• Radiation Oncology Journal
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• v.17 no.3
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• pp.209-216
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• 1999

Purpose : To evaluate the effectiveness of external radiation therapy and the prognostic factors, we retrospectively analyzed therapeutic results of malignant extrahepatic biliary obstruction (EHBO). Methods and Materials : We analyzed the results of the external radiation therapy in 59 patients of inoperable malignant EHBO who had been treated with more than 10 Gy of external radiation therapy from April 1984 to December 1990. There were 21 stomach cancer ($35.6\%$), 12 pancreas cancer ($20.3\%$), 15 extrahepatic biliary cancer ($18.0\%$) and 11 another cancer ($18.0\%$). Their pathologies were confirmed in 31 patients ($52.5\%$). They divided into 27 adenocarcinoma and 4 nonadenocarcinoma. Their chief complaints were jaundice in 47 patients ($79.7\%$) and abdominal pain in 15 patients ($49.2\%$). Twelve patients had slightly increased bilirubin level in liver function test without jaundice. We treated twenty four patients ($40.6\%$) with percutaneous transhepatic biliary drainage (PTBD) and 32 patients ($54\%$) with systemic chemotherapy (CT). We performed external radiation therapy (ERT) upto $10.8\~55.8$ Gy (median 37.8 Gy) with palliative aim. Results : Overall median survival duration was $7.80\pm1.15$ months. The response rates of jaundice were $81.8\%$ in PTBO group and $66.7\%$ in non-PTBD group without statistical significance. The improving rate of jaundice was not significantly different in decreased ratio of total bilirubin level. But abdominal pain was more decreased in CT group than non-CT group (p<0.05). The significant prognostic factors were high performance status (Karnofski Performance Status >70), total radiation dose more than 35 Gy and good response of pain after therapy. There were increased in bacterial cholagitis in PTBD group and gastrointestinal complications in CT group. Conclusion : External radiotheapy could improve jaundice and abdominal pain in malignant EHBO patients, Overall survival duration was prolonged in patients with higher performance status and patients who had been treated with more than 35 Gy of total radiation dose. In the future, we expect not only better palliative role but also the prolongation of survival of using the ERT combined with other treatment method. But to achieve certain conclusion, we need luther study consisted with many kinds of treatment methods including new technologies in RT.

• Journal of the Korean Society of Radiology
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• v.18 no.5
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• pp.509-513
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• 2024

This study investigated the feasibility of applying the changes in electron dose distribution, observed in high-energy therapeutic radiation using magnetic fields, to low-energy diagnostic radiation. The diagnostic X-ray exposure conditions were set with a tube current of 200 mA, source-to-detector distance (SDD) of 100 cm, exposure time of 1.0 sec, and an irradiation field size of 20 × 20 cm². The tube voltage was varied from 70 to 100 kVp in 10 kVp increments. A 0.5 T permanent Nd magnet was used to create a magnetic field below the collimator. Measurements were repeated 20 times for each tube voltage, both with and without the magnetic field, and were compared using an independent-samples t-test. While slight differences of dose were observed at tube voltages of 70, 80, and 90 kVp, no statistically significant differences were found (p > .05). However, a significant difference was observed at 100 kVp (p = .048). Based on these findings, it is suggested that applying higher energy, longer exposure times, stronger magnetic fields, and high-performance detectors could potentially modify the electron dose distribution in diagnostic radiation. This could contribute to dose reduction for patients and improvement in the quality of medical imaging.