• Radiation Oncology Journal
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• v.6 no.1
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• pp.81-84
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• 1988

Since the entity of postmastectomy lymphangiosarcoma was first reported by Stewart and Treves in 1948, postmastectomy lymphangiosarcoma has become a well recognized, uncommon malignant tumor which occurs in the upper extremity following mastectomy for mammary carcinoma. The postmastectomy lymphangiosarcoma occurred at an average age of 63.9 years and at an average of 10 years and 3 months following mastectomy. The lymphangiosarcoma raised from blood and lymphatic vessel. The histologic appearance has been observed edematous dermiss and dilated lymphatics lining with malignant cells. Most authors recommend radical amputation for treatment, either shoulder disarticulation or forequarter amputation. Other modalities of treatment including radiotherapy were considered as ineffetive. The present report provides a case of the regression of postmastectomy lymphangiosarcoma with chronic lymphedema by external irradiation. Radiation therapy was used as primary therapy. Total tumor dose of 6500 cGy in 9 wks was delivered using 6 MV x-ray and 8 MeV electron.

• Radiation Oncology Journal
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• v.20 no.2
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• pp.130-138
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• 2002

Purpose : This study analyzed the prognostic factors affecting the survival rate and evaluated the role of radiation therapy in muscle-invading bladder cancer. Materials and Methods : Twenty eight patients with bladder cancer who completed planned definitive radiotherapy in the Departments of Therapeutic Radiology and Urology, Chonnam National University Hospital between Jan. 1986 to Dec. 1998 were retrospectively analyzed. The reviews were peformed based on the patients' medical records. There were 21 males and 7 females in this study. The median of age was 72 years old ranging from 49 to 84 years. All patients were confirmed as having transitional cell carcinoma with histological grade 1 in one patient, grade 2 in 15, grade 3 in 9, and uninformed in 3. Radiation therapy was peformed using a linear accelerator with 6 or 10 MV X-rays. Radiation was delivered daily with a 1.8 or 2.0 Gy fraction size by 4 ports (anterior-posterior, both lateral, alternatively) or 3 ports (Anterior and both lateral). The median radiation dose delivered to the isocenter of the target volume was 61.24 Gy ranging from 59 to 66.6 Gy. The survival rate was calculated by the Kaplan-Meier method. Multivariate analysis was peformed on the prognostic factors affecting the survival rate. Results : The survival rate was $76\%,\;46\%,\;33\%,\;33\%$ at 1, 2, 3, 5 years, respectively, with 19 months of median survival. The potential factors of age (less than 70 years vs above 70), sex, diabetes mellitus, hypertension, hydronephrosis, 1-stage (T3a vs T3b), TUR, chemotherapy, total duration of radiotherapy, radiation dose (less than 60 Gy vs above 60 Gy), and the treatment response were investigated with uniand multivariate analysis. Un univariate analysis, the T-stage (p=0.078) and radiation dose (p=0.051) were marginally significant, and the treatment response (p=0.011) was a statistically significant factor on the survival rate. Multivariate analysis showed there were no significant prognostic factors affecting the survival rate. Conclusion : The treatment response and radiation dose are suggested as th은 statistically significant factors affecting the survival rate of muscle invasive bladder cancer. A Further prospective randomized study is needed to confirm these prognostic factors.

• Journal of Radiation Protection and Research
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• v.31 no.4
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• pp.181-186
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• 2006

A radiophotoluminescent glass rod detector (GRD) system has recently become commercially available. We investigate the dosimetric properties of the GRD regarding the reproducibility of signal, dose linearity and energy dependence. The reproducibility of five measurements for 50 GRDs is presented by an average of one standard deviation of each GRD and it is ${\pm}1.2%$. It is found to be linear in response to doses of $^{60}Co$ beam in the range 0.5 to 50 Gy with a coefficient of linearity of 0.9998. The energy dependence of the GRD is determined by comparing the dose obtained using cylindrical chamber to that by using the GRD. The GRD response for each beam is normalized to the response for a $^{60}Co$ beam. The responses for 6 and 15 MV x-ray beams are within ${\pm}1.5%$ (1SD). The energy response of GRD for high-energy photon is almost the same as the energy dependence of LiF:Mg:Ti (TLD-100)and shows little energy dependence unlike p-type silicon diode detector. The GRDs have advantages over other detectors such diode detector, and TLD: linearity, reproducibility and energy dependency. It has been verified to be an effective device for small field dosimetry for stereotactic radiosurgery.

• Progress in Medical Physics
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• v.26 no.4
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• pp.223-228
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• 2015

Double-focused micro-Multileaf Collimator (${\mu}MLC$) is able to create radiation fields having sharper dose gradients at the field edges than common MLC. Therefore, ${\mu}MLC$ has been used for the stereotactic radiosurgery (SRS) and Stereotactic Radiotherapy (SRT). We evaluated the dosimetric characteristics of a doublefocused Dynamic-${\mu}MLC$ (DMLC) attached to the Elekta Synergy linear accelerator. For this study, the dosimetric parameters including, Percent Depth Dose (PDD), Leaf leakage and penumbra, have been measured by using of the radiochromic films (GafChromic EBT2), EDGE diode detector and three-dimensional water phantom. All datas were measured on 6 MV x-ray. As a result, The DMLC shows transmission below to 1% and because of double-focused construction of the DMLC, the penumbras of fields with DMLC are independent from the field sizes. In this paper, the resulting dosimetric evaluations proved the applicability of the DMLC attached to the Elekta Synergy linear accelerator.

• Journal of the Korean institute of surface engineering
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• v.29 no.6
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• pp.809-815
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• 1996

$Y_2O_3$-based metal-insulator-semiconductor (MIS) structure on p-Si(100) has been studied. Films were prepared by UHV reactive ionized cluster beam deposition (r-ICBD) system. The base pressure of the system was about $1 \times 10^{-9}$ -9/ Torr and the process pressure $2 \times 10^{-5}$ Torr in oxygen ambience. Glancing X-ray diffraction(GXRD) and in-situ reflection high energy electron diffracton(RHEED) analyses were performed to investigate the crystallinity of the films. The results show phase change from amorphous state to crystalline one with increasingqr acceleration voltage and substrate temperature. It is also found that the phase transformation from $Y_2O_3$(111)//Si(100) to $Y_2O_3$(110)//Si(100) in growing directions takes place between $500^{\circ}C$ and $700^{\circ}C$. Especially as acceleration voltage is increased, preferentially oriented crystallinity was increased. Finally under the condition of above substrate temperature $700^{\circ}C$ and acceleration voltage 5kV, the $Y_2O_3$films are found to be grown epitaxially in direction of $Y_2O_3$(1l0)//Si(100) by observation of transmission electron microscope(TEM). Capacitance-voltage and current-voltage measurements were conducted to characterize Al/$Y_2O_3$/Si MIS structure with varying acceleration voltage and substrate temperature. Deposited $Y_2O_3$ films of thickness of nearly 300$\AA$ show that the breakdown field increases to 7~8MV /cm at the same conditon of epitaxial growing. These results also coincide with XPS spectra which indicate better stoichiometric characteristic in the condition of better crystalline one. After oxidation the breakdown field increases to 13MV /cm because the MIS structure contains interface silicon oxide of about 30$\AA$. In this case the dielectric constant of only $Y_2O_3$ layer is found to be $\in$15.6. These results have demonstrated the potential of using yttrium oxide for future VLSI/ULSI gate insulator applications.

• Radiation Oncology Journal
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• v.11 no.2
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• pp.321-330
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• 1993

Purpose: A retrospective analysis was performed to evaluate the incidence of radiation induced lung damage after the radiation therapy for the patients with carcinoma of the lung. Method and Materials: Sixty-six patients with lung cancer (squamous cell carcinoma 27, adenocarcinoma 14, large cell carcinoma 2, small cell carcinoma 13, unknown 10) were treated with definitive, postoperative or palliative radiation therapy with or without chemotherapy between July 1987 and December 1991. There were 50 males and 16 females with median age of 63 years (range: 33~80 years). Total lung doses ranged from 500 to 6,660 cGy (median 3960 cGy) given in 2 to 38 fractions (median 20) over a range or 2 to 150 days (median in days) using 6 MV or 15 MV linear accelerator. To represent different fractionation schedules of equivalent biological effect, the estimated single dose (ED) model, $ED=D{\dot}N^{-0.377}{\dot}T^{-0.058}$ was used in which D was the lung dose in cGy, N was the number of fractions, and T was the overall treatment time in days. The range of ED was 370 to 1357. The endpoint was a visible increase in lung density within the irradiated volume on chest X-ray as observed independently by three diagnostic radiologists. Patients were grouped according to ED, treatment duration, treatment modality and age, and the percent incidence of pulmonary damage for each group was determined. Result: In 40 of 66 patients, radiation induced change was seen on chest radiographs between 11 days and 314 days after initiation of radiation therapy. The incidence of radiation pneumonitis was increased according to increased ED, which was statistically significant (p=0.001). Roentgenographic changes consistent with radiation pneumonitis were seen in $100\%$ of patients receiving radiotherapy after lobectomy or pneumonectomy, which was not statistically significant. In 32 patients who also received chemotherapy, there was no difference in the incidence of radiation induced change between the group with radiation alone and the group with radiation and chemotherapy, among the sequence of chemotherapy No correlation was seen between incidence of radiation pneumonitis and age or sex. Conclusions: The occurrence of radiation pneumonitis varies. The incidence of radiation pneumonitis depends on radiation total dose, nature of fractionation, duration of therapy, and modifying factors such as lobectomy or pneumonectomy.

• Journal of radiological science and technology
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• v.24 no.2
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• pp.49-52
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• 2001

We compared the characteristics of Siemens virtual wedge device with physical wedges for clinical application. We investigated the characteristics of virtual and physical wedges for various wedge angles (15, 30, 45, and 60) using 6- and 15-MV photon beams. Wedge factors were measured in water using an ion chamber for various field sizes and depths. In case of virtual wedge device, as upper jaw moves during irradiation, wedge angles were estimated by accumulated doses. These measurements were performed at off-axis points perpendicular to the beam central axis in water for a $15\;cm\;{\times}\;20\;cm$ radiation field size at the depth of 10 cm. Surface doses without and with virtual or physical wedges were measured using a parallel plate ion chamber at surface. Field size was $15\;cm\;{\times}\;20\;cm$ and a polystyrene phantom was used. For various field sizes, virtual and physical wedge factors were changed by maximum 2.1% and 3.9%, respectively. For various depths, virtual and physical wedge factors were changed by maximum 1.9% and 2.9%, respectively. No major difference was found between the virtual and physical wedge angles and the difference was within 0.5. Surface dose with physical wedge was reduced by maximum 20% (x-ray beam : 6 MV, wedge angle : 45, SSD : 80 cm) relative to one with virtual wedge or without wedge. Comparison of the characteristics of Siemens virtual wedge device with physical wedges was performed. Depth dependence of virtual wedge factor was smaller than that of physical wedge factor. Virtual and physical wedge factors were nearly independent of field sizes. The accuracy of virtual and physical wedge angles was excellent. Surface dose was found to be reduced using a physical wedge.

• The Journal of Korean Society for Radiation Therapy
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• v.13 no.1
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• pp.91-103
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• 2001

In those patients who underwent radiation therapy with 10 MV X-ray for bone marrow transfer, compared the effect of high dose irradiation on peripheral blood were investigated in randomly selecting 18 patients. thus, changes in the levels of peripheral blood (WBC, Seg. neutrophil, Lymphocyte, RBC, Hemoglobin, Hematocrit ratio, GOT, GPT) were observed for 25 days after irradiation with the peripheral blood levels before irradiation in these patients and in 32 controls. Among changes in peripheral blood, the level of WBC was $8.63\%$ after radiation therapy with as much decrease as $0.22{\times}103{\pm}0.19{\times}103/mm^3$ compared with $2.51{\times}103{\pm}1.29{\times}103/mm^3$ before radiation therapy, and was only $6.35\%$ of $7.17{\times}103/mm^3{\pm}1.46{\times}103/mm^3$ in the controls, showing statistical significance (P<0.01, r2=0.9151). In the morphologic test of WBC, the level of Seg. neutrophil was decreased as much as to $20.53\%$ with $14.17{\pm}21.60\%$ compared with $69.00{\pm}25.60\%$ before irradiation, and decreased down to $24.39\%$ compared with $58.09{\pm}7.62\%$ in the controls (P<0.05, r2=0.6316). The number of lymphocyte increased as much as 3.94 folds at $79.91{\pm}27.30\%$ compared with $20.29{\pm}21.15\%$ before irradiation and was 2.39 times higher than $33.46{\pm}6.79\%$ in the controls (P<0.05, r2=0.7337). Although the change in the number of RBC was little with $3.18{\times}106{\pm}0.41{\times}106/mm^3$ before irradiation and $4.66{\times}106{\pm}0.43{\times}106/mm^3$ in the controls, no statistical significance was present (P>0.05). In addition, The number of hemoglobin was low compared with before irradiation and with the controls, but none showed statistical significance (P>0.05). Similarly, although the hematocrit ratio was low compared with before irradiation and with the controls, no statistical significance was present (P>0.05). In the values of the histologic examinations GOT and GPT, there is statistical significance between those from with before irradiation and with the controls (P<0.05). Thus, among peripheral blood, the number of WBC decreased drastically for a certain period after total body irradiation with high dose radiation, and the levels of Seg. neutriphil and lymphocyte decreased significantly after irradiation in the lymphocyte morphologic test. The results of the present study suggest that the possibility of developing the first to determine initially those patients who might develop radiation acute impairment using the usual peripheral blood test of patients to be exposed to high dose irradiation.

• Radiation Oncology Journal
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• v.14 no.4
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• pp.291-297
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• 1996

Purpose : This study was performed to evaluate survival, failure patterns, and prognostic factors of MMR patients after radiation therapy. We also discussed the need for chemotherapy. Materials and Methods : A retrospective analysis was done for 23 patients with MMR who were treated with radiation therapy from June 1985 to November 1992. There were 19 male and 4 female patients, The patients' age ranged from 17 to 71 years (median 39 years). Systemic symptoms including fever, weight loss, or malaise were found in $30\%$ of the patients. The nasal cavity was most frequently involved No patients had nodal involvement at diagnosis. There were 2 patients with distant metastasis at presentation. Radiation therapy was delivered five times a week, 1.8 Gy daily, total $45\~54$ Gy (median 50.4 Gy) using 6 MV X-ray No patients received chemotherapy as initial treatment. Results : Overall 5-year and 10-year survival rates were $52.4\%$ and $44.1\%$, respectively. Seventy Percent(12/17) of the patients achieved complete response to radiotherapy, and $29.4\%$ (5/17) achieved partial response. The Patients with complete response showed a better 5-year survival rate than those with partial response ($66.9\%$ vs. $20\%$. p=0.004). Symptom duration before diagnosis, the presence of systemic symptom, and the number of primary sites had no influence on survival. The patterns of failure were as follows: local failure(1), failure in adjacent site(1), local and distant failure(1) distant metastasis(2). and conversion to malignant lymphoma(1). We could not find factors associated with the patterns of failure. Conclusion : The most important facto associated with survival was the response to radiotherapy. Seventeen percent of the patients had distant metastasis, and the salvage after distant metastasis was not successful. However. about $50\%$ of the patients could achieve long-term survival with local radiation therapy alone. Therefore, chemotherapy of MMR should be done after a prospective randomized study for the factors associated with distant metastasis.

• Radiation Oncology Journal
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• v.18 no.4
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• pp.226-232
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• 2000

Purpose :This study was performed to find out the prognostic factors affecting local control in early glottic cancer treated with radiation therapy alone. Materials and Methods :We analysed 37 patients of histologically confirmed early glottic cancer treated at Chonnam National University Hospital between July Im and December 1995, retrospectively. Age of patients ranged from 30 to 73 years (median; 59 years). Thirty-five (95$\%$) patients were male. Histological type was all squamous cell carcinoma. According to the staging system of 1997 American Joint Committee on Cancer, 37 patients were restaged as follows: Tla; U (73$\%$), Tlb; 3 (8$\%$), 72: 7 (19$\%$). Radiation therapy was done using 6 MV X-ray of linear accelerator The range of total radiation dose delivered to the glottic lesion was between 5,040 cGy and 7,020 cGy (median; 6,600 cGy). Median follow-up period was U months. local control rates were calculated by Kaplan-Meier method. Generalized Wilcoxon test was used to evaluate the difference of control rates between comparable groups. Multivariate analysis using Cox proportional hazard model was done to find out prognostic factors affecting local control. Results:5 year survival rate of 37 patients was 89$\%$. Local control rate of 37 patients was 74$\%$ in 5 years. We included age, 7-stage, anterior commissure involvement, fraction size, total radiation dose, treatment time of radiotherapy as potential prognostic factors in univariate and multivariate analysis. As a result, treatment time had statistical significance in local control rate in both univariate (p=0.026) and multivariate (p=0.017) analysis. Complication was not recorded except one patient with hypothyroidism. Conclusion :This study revealed that overall treatment time of radiation was a significant factor affecting local control rate.