• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.985-991
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• 2023

A tissue-equivalent phantom is necessary for quality control of hyperthermia therapy. However, since there is no phantom for this purpose, phantoms made from agar are being used in various studies. The tissue-equivalent properties of the agar phantom were confirmed by comparison with the tissue-equivalent material bolus in this study. CT images of the agar phantom and bolus were acquired, and tissue equivalent characteristics were analyzed with image analysis and dose calculation using a computerized radiation therapy planning system. The average pixel value was 96.960±10.999 in bolus, 108.559±8.233 in 3% agar phantom, and 111.844±8.651 in 4% agar phantom. Using the SSD technique, 100 cGy was prescribed at a depth of 1.5 cm and 6 MV X -ray was set to irradiated to 10x10 cm2, and the absorbed dose according to depth was calculated from the central axis of the beam. The intraclass correlation coefficient of dose distribution of bolus, 3% agar phantom, and 4% agar phantom was 0.979 (p<.001, 95%CI .957-.991). The density (g/cm3) at the point where the absorbed dose was calculated was 0.990±0.020 at the bolus, 1.018±0.020 at the 3% agar phantom, and 1.035±0.024 at the 4% agar phantom. In this study, the internal density distribution and uniformity of the agar phantom were confirmed to be appropriate as a tissue equivalent material by analysis of CT images and a computerized radiation therapy planning system.

• Journal of Radiation Protection and Research
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• v.14 no.1
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• pp.16-23
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• 1989

To obtain the basic data for protective roles and first-aid of radiation hazard, the present studies were carried out to evaluate the decontamination of radiostrontium by the First-Aid drugs. Each mouse was administered intraperitoneally dose of sodium alginate 5mg, $CaNa_3DTPA$ 8.4mg and saline 5ml following the internal contamination with 1 $\mu$Ci of strontium as $^{85}SrCl_2$. $^{85}Sr$ was determined by the radioactivity of body burden, urinary excretion, fecal excretion and organ distribution by Ge-detector and MCA. The results are summarized as follows. 1. Effective half life on whole body retention $^{85}Sr$ was determined at 33 hours. 2. The decontamination effect of First-Aid durgs on the body $^{85}Sr$ burden were increased $CaNa_3DTPA$ (4.7 times), sodium alginate (1.7 times) and saline (2.4 times) respectively. 3. Strontium were excreted through urine (35.4%), feces (64.4%) and other (0.2%). But on the $^{85}Sr$ excretion routes following First-Aid drugs treatment, strontium-85 mainly were excreted through urine after $CaNa_3DTPA$ and saline treatment, and was excreted through feces after sodium alginate treatment. 4. The organ distribution of strontium-85 is vertebra, femur, sternum and liver in order Finally, the extrapolations from these data to victims were suggested that the rapid administration of $CaNa_3DTPA$, sodium alginate and saline simultaneously were markedly increased the decontamination effects on the internal contamination of radiostrontium.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.4819-4825
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• 2010

In all of dental ceramics, these materials contained the radio-isotopes with natural abundance ratio. After dental treatment, remained dental ceramics in the oral cavity is caused for human internal dose. In this study, the gross beta activity levels were measured in dental materials including 22 dental ceramics, 1 resin, and 2 cements for estimation of human internal dose. In dental ceramic samples, the obtained results showed that the gross beta activity level varied between 1.317 ~ 2.935 Bq/g and the gross beta activity level was 2.379 Bq/g. And the same level for dentine, opacious dentine, translucent and enamel were 2.479 Bq/g, 2.491 Bq/g, 2.470 Bq/g and 2.069 Bq/g, respectively. The gross beta activity level of temporary resin and cements were negligible, compare to the same level of dental ceramics. The high gross beta activity level observed in opacious dentine code OD-A4 is 2.935 Bq/g thus mainly ascribable to 40K. The reduction of the radiation level of natural radio-isotopes and the improvement of the dental ceramic materials should be required for internal dose reduction.

• Radiation Oncology Journal
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• v.24 no.2
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• pp.103-109
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• 2006

Purpose: To evaluate the treatment outcome according to the salvage treatment modalities and identify the prognostic factors influencing the survival. Materials and Methods: Forty-five patients with locally recurrent rectal cancer treated between 1994 to 2003 were reviewed retrospectively. Median time from initial surgery to loal recurrence was 16months. Of the patients, 25 (56%) recurred at presacral and perirectal space. Among the 18 (40%) patients who received salvage surgery, 14 patients were treated with postoperative chemoradiotherapy. Among 27 (60%) patients who didn't receive salvage surgery, 16 were treated with chemoradiotherapy and 11 were treated with radiotherapy alone. Radiotherapy was given with total dose ranging from 37.5 to 64.8 Gy. Results: Five-year locoregional progression-free survival rate and overall survival rate of all patents were 49.5% and 34.3%, respectively. The 5-year locoregional progression-free survival rate and overall survival rate of patients undergoing salvage surgery were 77.0% and 52.1% compared with 36.0% and 37.9% f3r patients treated with chemoradiotherapy and 0% and 0% for patients treated with radiotherapy alone, respectively. The 5-year locoregional progression free survival and overall survival of patients who recurred earlier than 24 months were higher (67.5% and 59.1%) than the other patients (39.5% and 24.9%). Among the 27 patients who didn't receive salvage surgery, there was no significant difference for locoregional progression free survival and overall survival between re-irradiated patients and radiation-naive patients. Conclusion: Surgical resection is preferred to treatment for locally recurrent rectal cancer. If salvage surgery is not possible, chemoradiotherapy may achieve higher locoregional progression free survival and overall survival than radiotherapy alone.

• Radiation Oncology Journal
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• v.24 no.4
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• pp.317-321
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• 2006

A case is reported of a man with malignant fibrous histiocytoma (MFH) in right thigh who developed streptococcal toxic shock syndrome (STSS) during postoperative radiotherapy. Before radiotherapy, a patient complained wax and wane lymphedema following wide excision of tumor mass which was confirmed as MFH. He took some nonsteroidal antiinflammatory drug (NSAID) for about one month. He suffered preexisting hepatitis C virus (HCV) infection, diabetes and well-controlled hypertension. The patient received conventional radiotherapy to right thigh with a total dose of 32.4 Gy at 1.8 Gy per day. At last radiotherapy fraction, cutaneous erythematous inflammation was suddenly developed at his affected thigh. At that time, he also complained of oliguria, fever and chills. The patient was consulted to internal medicine for adequate evaluation and management. The patient was diagnosed as suggested septic shock and admitted without delay. At admission, he showed hypotension, oliguria, constipation, abnormal renal and liver function. As a result of blood culture, Streptococcus pyogenes was detected. The patient was diagnosed to STSS. He was treated with adequate intravenous antibiotics and fluid support. STSS is one of oncologic emergencies and requires immediate medical intervention to prevent loss of life. In this patient, underlying HCV infection, postoperative lymphedema, prolonged NSAID medication, and radiotherapy may have been multiple precipitating factors of STSS.

• Radiation Oncology Journal
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• v.16 no.2
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• pp.147-157
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• 1998

Purpose : The aim of this retrospective study is to assess the necessity of s1aging laparotomy in the management of supradiaphragmatic CS I-II Hodgkin's disease. Prognostic factors and the usefulness of prognostic factor groups were also analyzed. Materials and Methods : From 1985 to 1995, fifty one Patients who were diagnosed as supradiaphragmatic CS I-II Hodgkin's disease at Yonsei Cancer Center in Seoul, Korea were enrolled in this study Age range was 4 to 67 with median age of 30. The number of patients with each CS IA, II A, and IIB were 16, 25, and 10, respectively. Radiotherapy(RT) was delivered using 4 or 6 MV photon beam to a total dose of 19.5 to 55.6Gy (median dose : 45Gy) with a 1.5 to 1.BGy per fraction. Chemotherapy(CT) was given in 2-12 cycles(median : 6 cycles). Thirty one Patients were treated with RT alone, 4 patients with CT alone and 16 patients with combined chemoradiotherapy. RT volumes varied from involved fields(3), subtotal nodal fields(18) or mantle fields(26). Results : Five-year disease-free survival rate(DFS) was $78.0\%$ and overall survival rate(05) was $87.6\%$. Fifty Patients achieved a complete remission after initial treatment and 8 patients were relapsed. Salvage therapy was given to 7 patients, 1 with RT alone, 4 with CT alone, 2 with RT+CT. Only two patients were successfully salvaged. Feminine gender and large media-stinal adenopathy were significant adverse prognostic factors in the univariate analysis for DFS. The significant adverse prognostic factors of OS were B symptom and clinical stage. When patients were analyzed according to European Organization for Research and Treatment of Cancer(EORTC) prognostic factor groups, the DFS in Patients with very favorable, favorable and unfavorable group was 100, 100 and $55.8\%$(p<0.05), and the 05 in each patients' group was 100, 100 and $75.1\%$(p<0.05), respectively. In very favorable and favorable groups, the DFS and 05 were all $100\%$ by RT alone, but in unfavorable group, RT with CT had a lesser relapse rate than RT alone. The subtotal nodal irradiation had better OFS than mantle RT in patients treated with RT. Conclusion : In present study, the DFS and OS in patients who did not undergo s1aging laparotomy were similar with the results in the literatures of which patients were surgically staged. Therefore, we may suggest that staging laparotomy would not influence the outcome of treatments. In univariate analysis, gender, large mediastinal adenopathy. B symptoms and clinical stage were significant prognostic factors for the survival rate. We confirm the usefulness of EORTC prognostic factor groups which may be a good.

• Journal of Cardiovascular Imaging
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• v.31 no.2
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• pp.108-115
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• 2023

BACKGROUND: Minimizing contrast dose and radiation exposure while maintaining image quality during computed tomography angiography (CTA) for transcatheter aortic valve replacement (TAVR) is desirable, but not well established. This systematic review compares image quality for low contrast and low kV CTA versus conventional CTA in patients with aortic stenosis undergoing TAVR planning. METHODS: We performed a systematic literature review to identify clinical studies comparing imaging strategies for patients with aortic stenosis undergoing TAVR planning. The primary outcomes of image quality as assessed by the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were reported as random effects mean difference with 95% confidence interval (CI). RESULTS: We included 6 studies reporting on 353 patients. There was no difference in cardiac SNR (mean difference, -1.42; 95% CI, -5.71 to 2.88; p = 0.52), cardiac CNR (mean difference, -3.83; 95% CI, -9.98 to 2.32; p = 0.22), aortic SNR (mean difference, -0.23; 95% CI, -7.83 to 7.37; p = 0.95), aortic CNR (mean difference, -3.95; 95% CI, -12.03 to 4.13; p = 0.34), and ileofemoral SNR (mean difference, -6.09; 95% CI, -13.80 to 1.62; p = 0.12) between the low dose and conventional protocols. There was a difference in ileofemoral CNR between the low dose and conventional protocols with a mean difference of -9.26 (95% CI, -15.06 to -3.46; p = 0.002). Overall, subjective image quality was similar between the 2 protocols. CONCLUSIONS: This systematic review suggests that low contrast and low kV CTA for TAVR planning provides similar image quality to conventional CTA.

• Radiation Oncology Journal
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• v.27 no.4
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• pp.173-180
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• 2009

Purpose: To investigate the role of radiotherapy for squamous cell carcinomas of the external auditory canal and middle ear. Materials and Methods: A series of 35 patients who were treated at a single institution from 1981 through 2007 were retrospectively analyzed. Thirteen patients were treated by radiotherapy alone; four by surgery only and 18 by a combination of surgery and radiotherapy. The total radiation dose ranged from 39~70 Gy (median, 66 Gy) in 13~35 fractions for radiotherapy alone and 44~70 Gy (median, 61.2 Gy) in 22~37 fractions for the combined therapy. Clinical end-points were the cause of specific survival (CSS) and local relapse-free survival (LRFS). The median follow-up time was 2.8 years (range, 0.2~14.6 years). Results: The 3-year CSS and LRFS rate was 80% and 63%, respectively. Based on a univariate analysis, performance status and residual disease after treatment had a significant impact on CSS; performance status and histologic grade for LRFS. Patients treated by radiotherapy alone had more residual disease following the course of treatment compared to patients treated with the combined therapy; 69% vs. 28%, respectively. Conclusion: Our results suggest that radiation alone was not an inferior treatment modality for CSS compared to the combined therapy for squamous cell carcinoma of the external auditory canal and middle ear. However, local failure after radiotherapy is the main issue that will require further improvement to gain optimal local control.

• Progress in Medical Physics
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• v.19 no.4
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• pp.263-268
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• 2008

The application of a respiratory gated radiotherpy method to the lung radiation surgery was evaluated compared with the conventional method in which the whole tumor motion range is considered in the delineation of PTV (Planning target volume). The four dimensional CT simulation images were acquired for the five NSCLC (Non-small cell lung cancer) patients for radiation surgery. The respiratory gated plan was prepared with the 50% phase CT images and the conventional method was planned based on the ITV (Internal target volume) which include all the target volumes created in each phase CT images within a whole respiratory period. The DVH (Dose volume histogram) of OAR (Organ at risk) which calculated in each method was compared for the evaluation of the plan properness. The relative decrease of OARs' DVH were verified in the application of respiratory gated method. The average decrease rate were $16.88{\pm}9.97%$ in the bronchus, $34.13{\pm}19.15%$ in the spinal cord, $28.42{\pm}18.49%$ in the chest wall and $32.48{\pm}16.66%$ in the lung. Based on these results, we can verified the applicability and the effectiveness of the respiratory gated method in the lung radiation surgery.

• Radiation Oncology Journal
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• v.16 no.4
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• pp.433-440
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• 1998

Purpose : Although small ceil lung cancer (SCLC) has high response rate to chemotherapy and radiotherapy (RT), the prognosis is dismal. The authors evaluated survival and failure patterns according to the prognostic factors in SCLC patients who had thoracic radiation therapy with chemotherapy. Materials and Methods : One hundred and twenty nine patients with SCLC had received thoracic radiation therapy from August 1985 to December 1990. Seventy-seven accessible patients were evaluated retrospectively among 87 patients who completed RT. Median follow-up period was 14 months (2-87months). Results : The two years survival rate was 13$\%$ with a median survival time of 14 months. The two year survival rates of limited disease and extensive disease were 20$\%$ and 8$\%$, respectively, with median survival time of 14 months and 9 months, respectively. Twenty two patients (88$\%$) of limited disease showed complete response (CR) and 3 patients (12$\%$) did partial response (PR). The two year survival rates on CR and PR groups were 24$\%$ and 0$\%$, with median survival times of 14 months and 5 months. respectively (p=0.005). No patients with serum sodium were lower than 135 mmol/L survived 2years and their median survival time was 7 months (p=0.002). Patients whose alkaline phophatase lower than 130 IU/L showed 26$\%$ of 2 year survival rate and showed median survival time of 14 months and those with alkaline phosphatase higher than 130 IU/L showed no 2 year survival and median survival time of 5 the months, respectively (p=0.019). No statistical differences were found according to the age, sex, and performance status. Among the patients with extensive disease, two rear survivals according to the metastatic sites were 14$\%$, 0$\%$, and 7$\%$ in brain, liver, and other metastatic sites, respectively, with median survival time of 9 months, 9 months, and 8 months, respectively (p>0.05). Two year survivals on CR group and PR group were 15$\%$ and 4$\%$, respectively, with a median survival time of 11 months and 7 months, respectively (p=0.01). Conclusion : For SCLC, complete response after chemoradiotherapy was the most significant prognostic tactor. To achieve this goal. there should be further investigation about hyperfractionation, dose escalation, and compatible chemo-radiation schedule such as concurrent chemo-radiation and early radiation therapy with chemotherapy.