• Radiation Oncology Journal
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• v.9 no.1
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• pp.111-116
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• 1991

From 1979 to 1987, 33 patients with polymorphic reticulosis (PMR) limited in the upper airway were treated with primary radiation therapy and the analysis of treatment results was undertaken. Systemic symptoms such as fever, night sweats, and weight ioss were noted in $48\%$. The nasal cavity was most frequently involved $(85\%)$, although involvement of PNS $(33\%)$ and palate $(30\%)$ was not uncommon. The 5 and 10 year actuarial survival rates were $47\%\;and\;40\%$, respectively. The difference in NSD between patients with in-field failure and those without it was significant statistically. Also, field size was significantly smaller in patients with marginal failure than those without it. During the follow-up period, systemic failure was found in S patients (diffuse histiocytic Iymphoma in 4, histiocytic medullary reticulosis in 1). In this study, we can suggest that total radiation dose of at least 4500 cGy with generous treatment volume should be delivered to achieve better local control and that the developement of an effective systemic chemotherapeutic regimen is required to improve the survival after systemic relapse.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.2
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• pp.257-264
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• 2014

Purpose : Photoneutron dose in high-energy photon radiotherapy at linear accelerator increase the risk for secondary cancer. The purpose of this investigation is to evaluate the dose variation of photoneutron with different treatment method, flattening filter, dose rate and gantry angle in radiation therapy with high-energy photon beam ($E{\geq}8MeV$). Materials and Methods : TrueBeam $ST{\time}TM$(Ver1.5, Varian, USA) and Korea Tissue Equivalent Proportional Counter (KTEPC) were used to detect the photoneutron dose out of the high-energy photon field. Complex Patient plans using Eclipse planning system (Version 10.0, Varian, USA) was used to experiment with different treatment technique(IMRT, VMAT), condition of flattening filter and three different dose rate. Scattered photoneutron dose was measured at eight different gantry angles with open field (Field size : $5{\time}5cm$). Results : The mean values of the detected photoneutron dose from IMRT and VMAT were $449.7{\mu}Sv$, $2940.7{\mu}Sv$. The mean values of the detected photoneutron dose with Flattening Filter(FF) and Flattening Filter Free(FFF) were measured as $2940.7{\mu}Sv$, $232.0{\mu}Sv$. The mean values of the photoneutron dose for each test plan (case 1, case 2 and case 3) with FFF at the three different dose rate (400, 1200, 2400 MU/min) were $3242.5{\mu}Sv$, $3189.4{\mu}Sv$, $3191.2{\mu}Sv$ with case 1, $3493.2{\mu}Sv$, $3482.6{\mu}Sv$, $3477.2{\mu}Sv$ with case 2 and $4592.2{\mu}Sv$, $4580.0{\mu}Sv$, $4542.3{\mu}Sv$ with case 3, respectively. The mean values of the photoneutron dose at eight different gantry angles ($0^{\circ}$, $45^{\circ}$, $90^{\circ}$, $135^{\circ}$, $180^{\circ}$, $225^{\circ}$, $270^{\circ}$, $315^{\circ}$) were measured as $3.2{\mu}Sv$, $4.3{\mu}Sv$, $5.3{\mu}Sv$, $11.3{\mu}Sv$, $14.7{\mu}Sv$, $11.2{\mu}Sv$, $3.7{\mu}Sv$, $3.0{\mu}Sv$ at 10MV and as $373.7{\mu}Sv$, $369.6{\mu}Sv$, $384.4{\mu}Sv$, $423.6{\mu}Sv$, $447.1{\mu}Sv$, $448.0{\mu}Sv$, $384.5{\mu}Sv$, $377.3{\mu}Sv$ at 15MV. Conclusion : As a result, it is possible to reduce photoneutron dose using FFF mode and VMAT method with TrueBeam $ST{\time}TM$. The risk for secondary cancer of the patients will be decreased with continuous evaluation of the photoneutron dose.

• Radiation Oncology Journal
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• v.18 no.1
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• pp.40-45
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• 2000

Purpose : To evaluate the histopathological prognostic factors, relapse pattern and survival in patients with endometrial carcinoma who were treated with surgery and postoperative adjuvant radiotherapy (RT). Methods and Materials : From September 1991 to December 1997, 27 patients with endometrial carcinoma treated with surgery and postoperative adjuvant RT at Asan Medical Center were entered in this study. Surgery was peformed with total abdominal hysterectomy in six, total abdominal hysterectomy with pelvic lymph node dissection in eight and radical hysterectomy in 13 patients. External RT of 50.4 Gy was done to all patients and among these, additional high dose rate vaginal vault irradiation of 20$\~$25 Gy with fractional dose of 4$\~$5 Gy was boosted In 16 patients. The patients were followed for 6$\~$95 months(median 30). Results : The number of patients according to FIGO stage were I 18 (67$\%$), II 1 ($4\%$) and III 7 ($26\%$). Patients with poor histologic grade, deep myometrial invasion, adnexal involvement, lymphovascular invasion showed more pelvic lymph node involvement, but no statistical significance was indicated. The 5 year overall and disease free survival were 100$\%$ and 76.8$\%$, respectively. Relapse sites were pelvic, para-aortic lymph node, and multiple metastases including lung, and no vaginal relapse was developed. Factors that were associated with disease free survival were FIGO stage (p=0.01), lymphovascular invasion (p=0.03), pelvic lymph node involvement (p=0.0001). There was only one Grade 1 rectal bleeding without moderate to severe complications. Conclusion : Postoperative adjuvant RT is considered to reduce the loco-regional failure, resulting the improvement of survival. The group of patients with the risk of vaginal failure without vaginal vault irradiation should be investigated according to stage and grade.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.65-76
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• 2010

Purpose: he use of PET scanners and the number of patient in Korea have been increased for recent several years dramatically. For this reason, technologists have more possibilities to be exposed to the radiation. The hospitals using PET scanners should make an effort to reduce the radiation exposure dose. The purpose of this study was to evaluate the radiation exposure does when using radiation shielding devices. The evaluation was performed through questionnaire survey and experiment. Materials and Methods: First, the technologists who had experience working in PET center in 2008-2009 were surveyed with questionnaire and TLD Figures, personal opinion of utilization of radiation shielding devices are analyzed. Second, we measured the shielding rate of shielding devices which have been using in PET study procedures. We divided the procedures into four steps; distribution, moving, injection of $^{18}F$-FDG and patient setup. Results: First, the results of this survey, using of L-block+Syringe shield, L-block, Syringe shield, No shield during the injection, were each 58.5%, 20%, 9%, 12.3%. The TLD values according to utilization of radiation shield, using both L-block+Syringe Shield and L-block showed the lower TLD values, and Syringe shield only or No shield showed the higher TLD values. Second, the results of experiments according to PET study procedures measured the shielding rates as follows. The shielding rates during the distribution using L-block, L-block+Apron shield were measured 97.4%, 97.7%. The shielding rates during the $^{18}F$-FDG delivery to the injection room using mobile Syringe shield, Syringe holder, Syringe shield carrier were each 81.7%, 98.9%, 99.7%. The shielding rates during the injection using Syringe shield, L-block, L-block+Syringe shield were measured each 51.9%, 98.3%, 98.7%. The shielding rates of Apron were measured in each 30, 60, 90, 120, 150 cm distance. The measurement were each 16.9%, 14.2%, 16.6%, 17.1%, 18.1%, 18.6%. Conclusion: The most effective method for radiation shielding is to using L-block during the $^{18}F$-FDG distribution and Syringe shield carrier during in moving $^{18}F$-FDG. For the $^{18}F$-FDG injection, L-block+Syringe shield have to be used. The shielding effect of Apron has shown average 16.4%. According to the survey of questionnaire, the operators recognized well risk of the radiation exposure but, tended ignore in working. The radiation dose according to recognition of radiation exposure risk was not relevant. but radiation dose according to utilization of radiation shield lower the more use it. The main reason of no use of shielding devices is cumbersome, 55% of the respondents answered. I'm sure, by use of radiation shield in all PET procedure, radiation exposure will be reduced considerably.

• Progress in Medical Physics
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• v.27 no.2
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• pp.64-71
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• 2016

We develop a manufacture procedure for the production of a patient specific customized bolus (PSCB) using a 3D printer (3DP). The dosimetric accuracy of the 3D-PSCB is evaluated for electron beam therapy. In order to cover the required planning target volume (PTV), we select the proper electron beam energy and the field size through initial dose calculation using a treatment planning system. The PSCB is delineated based on the initial dose distribution. The dose calculation is repeated after applying the PSCB. We iteratively fine-tune the PSCB shape until the plan quality is sufficient to meet the required clinical criteria. Then the contour data of the PSCB is transferred to an in-house conversion software through the DICOMRT protocol. This contour data is converted into the 3DP data format, STereoLithography data format and then printed using a 3DP. Two virtual patients, having concave and convex shapes, were generated with a virtual PTV and an organ at risk (OAR). Then, two corresponding electron treatment plans with and without a PSCB were generated to evaluate the dosimetric effect of the PSCB. The dosimetric characteristics and dose volume histograms for the PTV and OAR are compared in both plans. Film dosimetry is performed to verify the dosimetric accuracy of the 3D-PSCB. The calculated planar dose distribution is compared to that measured using film dosimetry taken from the beam central axis. We compare the percent depth dose curve and gamma analysis (the dose difference is 3%, and the distance to agreement is 3 mm) results. No significant difference in the PTV dose is observed in the plan with the PSCB compared to that without the PSCB. The maximum, minimum, and mean doses of the OAR in the plan with the PSCB were significantly reduced by 9.7%, 36.6%, and 28.3%, respectively, compared to those in the plan without the PSCB. By applying the PSCB, the OAR volumes receiving 90% and 80% of the prescribed dose were reduced from $14.40cm^3$ to $0.1cm^3$ and from $42.6cm^3$ to $3.7cm^3$, respectively, in comparison to that without using the PSCB. The gamma pass rates of the concave and convex plans were 95% and 98%, respectively. A new procedure of the fabrication of a PSCB is developed using a 3DP. We confirm the usefulness and dosimetric accuracy of the 3D-PSCB for the clinical use. Thus, rapidly advancing 3DP technology is able to ease and expand clinical implementation of the PSCB.

• Food Science and Preservation
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• v.16 no.2
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• pp.186-191
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• 2009

An electron beam or gamma-rays(0-5 kGy) were applied to two popular commercial sprout seeds, those of radish and red cabbage, and both physiological and microbiological qualities during germination were examined. Total bacterial counts of radish and red cabbage seeds were 5.02 and 2.86 log CFU/g, respectively, and were reduced by 2-3 logs after irradiation, but nonirradiated and irradiated samples showed similar microbial populations on day 5 after germination, although day 3 levels of irradiated samples were $23{\pm}2%$ lower. Coliforms were absent in both seed types. However, they were detected from the first day of germination, and rose to 4-5 log CFU/g on the fifth day. Coliforms were reduced by about 1-2 log CFU/g in 1 kGy-irradiated samples and were absent in the samples irradiated at 3 kGy. Irradiation at 1 and 3 kGy decreased germination by about 7% and 18%, respectively. Sprout yield and length were also significantly affected by irradiation, with no apparent difference between samples treated with the electron beam and gamma-rays.

• Progress in Medical Physics
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• v.14 no.4
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• pp.218-224
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• 2003

Purpose：By evaluating the dependence of the tray transmission factor (tray factor) on collimator setting and tray thickness, we determined the validity of the clinically used single tray factor for standard radiation field size (10${\times}$10 $\textrm{cm}^2$). Methods and Materials：For each X ray energies (6 and 10 MV), outputs were measured by using 5 steps of tray thickness (0, 6, 8, 10, 12 mm) and 7 steps of radiation field size (5${\times}$5, 10${\times}$10, 15${\times}$15, 20${\times}$20, 25${\times}$25, 30${\times}$30, 35${\times}$35 $\textrm{cm}^2$) at 10 cm phantom depth. Outputs were measured in both 'with tray' and 'without tray' conditions by using radiation with the same monitor units, and the tray factors were determined by the ratios of the two outputs. To evaluate the validity of a single tray factor obtained for standard radiation field, we analyzed the pattern of the field sizes in cases treated at our hospital in 2002. Results : In the 6 MV X-ray, the increases in the tray factor between the standard field (l0${\times}$10 $\textrm{cm}^2$) and the largest field (35${\times}$35 $\textrm{cm}^2$) were 0.517%, 0.835%, 1.058%, 1.066% in 6, 8, 10, and 12 mm thickness tray, respectively. In the 10 MV X-ray, the increases in the fray factor between the standard field (10${\times}$10 $\textrm{cm}^2$) and the largest field (35${\times}$35 $\textrm{cm}^2$) were 0.517%, 0.836%, 1.058%, 1.066% in 6, 8, 10, 12 mm thickness tray, respectively. In a major portion of clinical cases, when the field size was smaller than 20${\times}$20 $\textrm{cm}^2$, the tray factor was in good agreement with the standard tray factor. However, in cases where the field sizes were 30${\times}$30 $\textrm{cm}^2$ and 35${\times}$35 $\textrm{cm}^2$, the error could exceed 1.0%. Conclusion：The tray factor increased with increasing field size or decreasing tray thickness. The difference of tray factor between the small field and the large field increased with increasing tray thickness. Furthermore, the standard tray factor was valid in most clinical cases except for when the field size was greater than 30${\times}$30 $\textrm{cm}^2$, wherein the error could exceed 1.0%.

• Radiation Oncology Journal
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• v.17 no.2
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• pp.91-99
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• 1999

Propose : This study was performed to find out the prognostic factors affecting local control, survival and disease free survival rate in nasopharyngeal carcinomas treated with chemotherapy and radiation therapy. Materials and Methods : We analysed 47 patients of nasopharyngeal carcinomas, histologically confirmed and treated at Chonnam University Hospital between July 1986 and June 1996, retrospectively. Range of patients' age were from 16 to 80 years (median; 52 years). Thirty three (70$\%$) patients was male. Histological types were composed of 3 (6$\%$) keratinizing, 30 (64$\%$) nonkeratinizing squamous cell carcinoma and 13 (28$\%$) undifferentiated carcinoma. Histoiogicai type was not known in 1 patient (2$\%$). We restaged according to the staging system of 1997 American Joint Committee on Cancer Forty seven patients were recorded as follows: 71: 11 (23$\%$), T2a; 6 (13$\%$), T2b; 9 (19$\%$), 73; 7 (15$\%$), 74: 14 (30$\%$), and NO; 7 (15$\%$), Nl: 14 (30$\%$), N2; 21 (45%), N3: 5 (10%). Clinical staging was grouped as follows: Stage 1; 2 (4$\%$), IIA: 2 (4$\%$), IIB; 10 (21$\%$), III; 14 (30$\%$), IVA; 14 (30$\%$) and IVB; 5 (11$\%$). Radiation therapy was done using 6 MV and 10 MV X- ray of linear accelerator. Electron beam was used for the Iymph nodes of posterior neck after 4500 cGy. The range of total radiation dose delivered to the primary tumor was from 6120 to 7920 cGy (median; 7020 cGy). Neoadjuvant chemotherapy was performed with cisplatin +5-fluorouracil (25 patients) or cisplatin+pepleomycin (17 patients) with one to three cycles. Five patients did not received chemotherapy. Local control rate, survival and disease free suwival rate were calculated by Kaplan-Meier method. Generalized Wilcoxon test was used to evaluate the difference of survival rates between groups. multivariate analysis using Cox proportional hazard model was done for finding prognostic factors. Results: Local control rate was 81$\%$ in 5 year. Five year survival rate was 60$\%$ (median survival; 100 months). We included age, sex, cranial nerve deflicit, histologic type, stage group, chemotherapy, elapsed days between chemotherapy and radiotherapy, total radiation dose, period of radiotherapy as potential prognostic factors in multivariate analysis. As a result, cranial none deficit (P=0.004) had statistical significance in local control rate. Stage group and total radiation dose were significant prognostic factors in survival (P=0.000, P=0.012), and in disease free survival rates (P=0.003, P=0.008), respectively. Common complications were xerostomia, tooth and ear problems. Hypothyroidism was developed in 2 patients. Conclusion : In our study, cranial none deficit was a significant prognostic factor in local control rate, and stage group and total radiation dose were significant factors in both survival and disease free survival of nasopharyngeal carcinoma. We have concluded that chemotherapy and radiotherapy used in our patients were effective without any serious complication.

• Radiation Oncology Journal
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• v.14 no.2
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• pp.105-113
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• 1996

Purpose : To improve treatment modality and results by analysis of clinical characteristics, local control, survival and recurrence rate in limited stage small cell lung cancer. Materials and Methods : patients with limited stage small cell lung cancer were treated with combined radiation and chemotherapy from Feb. 1986 to Dec. 1992 at the National Medical Center We followed up on 21 patients ($81\%$), who were mostly irradiated with 4,000-5.000cGy ($75\%$ of all Patients) in the results by the analysis retrospectively. Survival rate was evaluated by the Kaplan-Meier method Results : Mean survival of irradiated patients with limited small cell lung cancer was 12 months. 1-rear and 2-rear survival rate were $65.3\%$ and $15.4\%$ Tumor response rate and median survival after combined chemotherapy and irradiation were the following: $50\%$ and 15 months of complete response, and $23\%$ and 11 months of partial response respectively. Response rates by radiation dose were $66\%$ for below 4,000cGy $69\%$ for between 4,000-5,000cGy and $86\%$ for above 5,000cGy. 21 of all patients showed treatment failure($81\%$) which as appeared 9 of local failure.9 of distant failure and 3 of local and distant failure. Conclusion : Local response rate after induction chemotherapy alone in limited stage of small cell lung cancer was $54\%$. Furthermore it was increased to $73\%$ after adding of radiation. We have to increase radiation dose above 5,000cGy and need to try new effective chemotherapy agents for the improvement of local control and survival rate and also will try concurrent chemoradiotherapy in near time.

• Journal of Radiation Protection and Research
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• v.35 no.2
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• pp.49-56
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• 2010

Developments of radioprotective agents are important issues for minimizing the troubles and the effective treatments in radiotherapy. But few agents are useful in clinical and practical fields. It was shown that trace elements in alcohol beverages might have radioprotective effect. In this study, the types of cell death of lymphocytes according to the commercial alcohol beverage was investigated. Normal healthy volunteers ingested distilled water, beer or soju containing $81.5mg{\cdot}dl^{-1}$ ethyl ahcohol, respectively. After 2 hours, their blood were sampled with their consents. Fraction of lymphocytes was isolated by density gradient method with Histopaque-1077 (Sigma) and irradiated with dose from 0.5 to 5 Gy. After 60 hour incubation, the cells were harvested and analysed by flow cytometry. Cell viability was decreased by dose dependent manner. Cell viability of beer group was reduced about 15% compared with control group. Apoptosis in soju group was reduced about 20% compared with control group. Apoptosis of beer and control groups are similar. Necrosis of soju group significantly increased about 35% compared with control group. Early apoptosis of beer group was increased compared with control group. Early apoptosis of soju group was decreased about 25% compared with control group. Late apoptosis of beer and control group was increased by dose dependent manner. Late apoptosis of soju group was increased about 20-30% compared with control group. Late apoptosis of soju was increased and the radioprotective effect of soju was minimal because late apoptosis induced the cell necrosis. In case of soju trace elements, total cell apoptosis was decreased about 20% and early cell apoptosis was remarkably low. In this case, mitotic cells death may be dominant mechanism. Therefore, trace elements in soju may not be effective radioprotective agents.