• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.3A
• /
• pp.201-209
• /
• 2010

Generally, PSC girder bridge uses total gross cross section to resist applied loads unlike reinforced concrete member. Also, it is used as short and middle span (less than 30 m) bridges due to advantages such as ease of design and construction, reduction of cost, and convenience of maintenance. But, due to recent increased public interests for environmental friendly and appearance appealing bridges all over the world, the demands for longer span bridges have been continuously increasing. This trend is shown not only in ordinary long span bridge types such as cable supported bridges but also in PSC girder bridges. In order to meet the increasing demands for new type of long span bridges, PSC hollow box girder with H-type steel as compression reinforcements is developed for bridge with a single span of more than 50 m. The developed PSC girder applies compressive prestressing at H-type compression reinforcements using unbonded PS tendon. The purpose of compressive prestressing is to recover plastic displacement of PSC girder after long term service by releasing the prestressing. The static test composed of 4 different stages in 3-point bending test is performed to verify safety of the bridge. First stage loading is applied until tensile cracks form. Then in second stage, the load is removed and the girder is unloaded. In third stage, after removal of loading, recovery of remaining plastic deformation is verified as the compressive prestressing is removed at H-type reinforcements. Then, in fourth stage, loading is continued until the girder fails. The experimental results showed that the first crack occurs at 1,615 kN with a corresponding displacement of 187.0 mm. The introduction of the additional compressive stress in the lower part of the girder from the removal of unbonded compressive prestressing of the H-type steel showed a capacity improvement of about 60% (7.7 mm) recovery of the residual deformation (18.7 mm) that occurred from load increase. By using prestressed H-type steel as compression reinforcements in the upper part of cross section, repair and rehabilitation of PSC girders are relatively easy, and the cost of maintenance is expected to decrease.

• Radiation Oncology Journal
• /
• v.14 no.1
• /
• pp.17-23
• /
• 1996

Purpose : To evaluate the role of combination therapy of external radio-therapy and chemotherapy in the management of advanced esophageal cancer as a primary treatment compared with radiation therapy alone. Materials and Methods : A retrospective review of evaluable 55 esophageal cancer patients referred to the Department of Therapeutic Radiology, Paik Hospital for the external radiotherapy between Jul, 1983 and Dec. 1994 was undertaken. Combined therapy patients (A group) were 30 and radiation alone patients (B group) were 25. Median age was 60 years old in A group (ranges : 42-81) and 65 years old in B group (ranges : 50-81). The male patients were 53. The fifty patients had squamous cell carcinomas. Radiation doses of 2520-6480c0y were delivered over a period of 4-7weeks, using 4MV LINAC. Chemotherapy was administered in bolus injection before, after, or during the course of external radiotherapy. The local control rate and patterns of failure according to both treatment modalities and 1, 2 year survival rates according to prognostic factors (stage, tumor length, radiation dose etc.) were analysed. Resuts : Median follow up Period was 7 months (range : 2-73 months). Median survival was 7.5 months (20 days-29 months) in A group and 5 months (20 days-73 months) in B group. The 1, 2 YSRs were $26.7\%$, $8.9\%$ in A group, $12.7\%$, $4.3\%$ in B group (p>0.05), respectively. The 1, 2 YSRs according to stage(II/III), tumor length (5cm more or less). radiation dose (5000cGymore or less) of A and B group were analyzed and the differences of survival rates of both treatments were not statistically significant. But among group B, patients who received 5000cGy or more showed significant survival benefits (p<0.05). The treatment response rates of A and B group were $43.8\%$. $25.0\%$, respectively. Complete response rate of $25.0\%$ in A and $8.3\%$ in B were achieved. The local failure and distant metastsis were $52.4\%$. $23.8\%$ in A group, $64.3\%$, $14.3\%$ in 8 group, respectively. The combination therapy revealed more frequent leukopenia and nausea/vomiting than radiation alone group, but degree of side effects was only mild to moderate. Conclusion : The combined external radiotherapy and chemotherapy for advanced esophageal cancer appears to improve the response rate, local control rate and survival rate, but the improvement was not statistically significant. The side effects of combined modalities were mild to moderate without significant morbidity. Therefore it may be worthwhile to continue the present combined external radiotherapy and chemotherapy in the management of advanced esophageal cancer to confirm our result.

• Radiation Oncology Journal
• /
• v.14 no.1
• /
• pp.25-31
• /
• 1996

Purpose : To evaluate the potential advantage for 'sandwich' technique radiotherapy compared to Postoperative radiotherapy in resectable rectal cancer. Materials and Methods : Between January 1989 and Mar 1994, 60 patients with resectable rectal cancer were treated at Inje University Seoul and Sanggye Paik Hospital. Fifty one patients were available for analysis: 20 patients were treated with sandwich technique radiotherapy and 31 patients were treated with Postoperative radiotherapy. In sandwich technique radiotherapy(RT), Patients were treated with preoperative RT 1500 cGy/5fx, followed by immediate curative resection. Patients staged as Astler-Coiler B2, C were considered for postoperative RT with 2500-4500 cGy. in postoperative RT total radiation dose of 4500-6120 cGy, 180 cGy daily at 4-Sweets was delivered. Patients were followed for median period of 25 months. Results : The overall 5-year survival rates for sandwich RT group and postoperative RT group were $60\%$ and $71\%$, respectively(p>0.05). The 5-rear disease free survival rates for each group were $63\%$. There was no difference in local failure rate between two groups($11\%$ versus $7\%$) Incidence of distant metastasis was $11\%$(2/20) in the sandwich technique RT group and $20\%$(6/31) in the postoperative RT group(p>0.05). The frequencies of acute and chronic complications were comparable in both groups. Conclusion : The sandwich technique radiotherapy group shows local recurrence and survival similar to those of Postoperative RT alone group but reduced distant metastasis compared to Postoperative RT group. But long term follow-up and large number of patients is needed to make an any firm conclusion regarding the value of this sandwich technique RT.

• Radiation Oncology Journal
• /
• v.14 no.1
• /
• pp.9-15
• /
• 1996

Purpose: The traditional approach with surgery and/or radiotherapy(RT) for advanced head and neck cancer Provides anticipated cure rates of $10-65\%$ depending on stages and sites. Recently, combined modality with chemotherapy have been extensively investigated in attempts to improve survival and local control. We retrospectively analysed our experience of 31 patients with advanced head and neck cancer. Materials and Methods : November 1983 to October 1994. 31 Patients with Stage III and IV squamous cell head and neck cancer were treated with RT. Sixteen patients were treated with RT alone, and IS patients were treated with combined RT plus chemotherapy. All patients were treated with 4-MV LINAC and radiation dose ranged from 5000 cGy to 7760 cGy (median 7010 cGy). In combined group, 7 patients were treated with cisplatin plus 5-FU 2 patients were treated with methotrexate plus leucovorin plus 5-FU plus cisplatin or carboplatin, and 6 patients were treated with cisplatin as a radiosensitizer. Results : Median follow up period was 16 months (range 4-134 months). The major responses (CR+PR) were noted in 10 patient ($66.6\%$) of the RT alone group and 14 patient ($93.3\%$) of the chemoradiation group. There was no statistical difference in CR rate between the two groups The overall survival rates at 5 years were $23.4\%$ in the radiation alone group, $23.5\%$ in the chemoradiation group Disease-free survival rates at 3 years were $44.5\%$ in the radiation alone group, $40\%$ in the chemoradiation group. There was no statistical differences in overall survival rates and disease-free survival rates between the two groups. Local recurrences occurred in $71.5\%$ of the radiation alone group, $72.7\%$ of the chemoradiation group and distant metastasis occurred in $14.4\%$ of radiation alone group, $9.1\%$ of the chemoradiation group. The frequencies of complications were comparable in both groups except hematologic toxicity Conclusion : Total response rates in the combined chemotherapy and radiotherapy was relatively higher than radiotherapy alone. But our result failed to show any survival benefit of the combined chemotherapy and radiotherapy. The accrual of large number of patients and long term follow-un may be necessary to confirm the present result of combined chemotherapy and radiotherapy.

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

• Radiation Oncology Journal
• /
• v.13 no.4
• /
• pp.339-348
• /
• 1995

Purpose : Since 1983, authors have conducted a study to evaluate the effect of external radiation therapy and to determine affected factors in management of the patients with malignant obstructive jaundice due to porta hepatis metastasis from stomach cancer. Materials and Methods : Thirty two patients with malignant obstructive jaundice due to porta hepatis metastasis from gastric cancer were presented. We have analysed 23 patients who were treated with external radiation therapy of more than 3000cGy. The radiation dose, disease extent at developement of jaundice, total bilirubin levels before radiation therapy, differentiation of histology, combind treatment, intent of primary surgery, initial stage of gastric cancer were analyzed to determine affected factors in radiation therapy. External radiation therapy was delivered with a daily dose of 180-300cGy, 5 times a week fractionation using 4 MeV linear accelerator. The radiation field included the porta hepatis with tumor mass by the abdominal ultrasonography or CT scan. In twenty three patients received more than 3000cGy, total irradiation dose was ranged from 3000cGy to 5480cGy, median 3770cGy. Among 23 patients, 13 patients were delivered more than equivalant dose of TDF 65(4140cGy/23fx). Results : Among 23 patients, complete, partial and no response were observed in 13, 5, 5 patients, respectively. The median survival for all patients was 5 momths. The significant prolongation of median survival was observed in complete responders(11 months) as compared to partial and no responders(5 months, 5 months respectively) Out of 13 patients with complete response, 6 patients lived more than a year Among 13 patients receiving more than 4140cGy equivalent dose, complete, partial and no response were observed in 10, 2 and 1 patients, respectively. The median survival for all these patients was 9.5 months. The median survival for complete responders(10/13) was 11.5 months. Among 10 patients receiving less than 4140cGy equivalent dose, complete, partial and no response were observed in 3, 3, 4 patients, respetively. The median survival for all these patients was 4.3 months Therefore, the radiation dose affected the results of treatment. For the complete response with prolongation of survival duration, at least 4140cGy equivalant dose should be delivered to porta hepatis. In evaluation of the disease extent, 7 patients of 13 complete responders showed localized disease in porta hepatis or peripancreatic area, but all patients with partial and no response showed wide extensive disease or persistant disease of primary gastric cancer. Therefore. the patients with the localized disease were the higher probability of complete response and long term survival. This study suggested that the radiation dose and the disease extent at developement of jaundice affected in radiation therapy for malignant obstructive jaundice. There were no serious complications related to external radiation therapy. Conclusion : External radiation therapy only could achieve the palliative effect in the patients with malignant obstructive jaundice due to porta hepatis metastasis from stomach cancer. This study suggested that the prolongation of survival duration could be achived in complete responders and radiation dose, extent of disease affected the results of treatment of malignant obstructive jaundice.

• Radiation Oncology Journal
• /
• v.22 no.3
• /
• pp.200-207
• /
• 2004

Purpose: An analysis was to compare the results of radiation alone with those of radiation with dally low dose cisplatin as a radiation sensitizer in locally advanced cervical cancer. Materials and Methods: A retrospective analysis of 59 patients diagnosed with locally advanced uterine cervix cancer between December 1996 and March 2001 was peformed. Thirty one patients received radiation alone and 28 patients received dally low dose cisplatin, as a radiation sensitizer, and radiation therapy. The median follow-up period was 34 months, ranging from 2.5 to 73 months. The radiation therapy consisted of 4500 cGy external beam irradiation to the whole pelvis (midline block after 3060 cGy), a 900$\~$l,000 cGy boost to the involved parametrium and high dose-rate intracavitary brachytherapy (a total dose of 3,000$\~$3,500 cGy/500 cGy per fraction to point A, twice per week). In the chemoradiation group, 10 mg of daily intravenous cisplatin was given daily from the 1st day of radiation therapy to the 20th day of radiation therapy. According to the FIGO classification, the patients were subdivided into 51 (86.4$\%$) and 8 (13.6$\%$) stages IIB and stage IIIB, respectively. Results: The overall 5 year survival rate was 65.65$\%$ and according to treatment modality were 56.75$\%$ and 73.42$\%$ in the radiation alone and chemoradiation groups, respectively (p=0.180). The 5 year disease-free survival rates were 49.39$\%$ and 63.34$\%$ in the radiation alone and chemoradiatoin groups, respectively (p=0.053), The 5 year locoregional control rates were 52.34$\%$ and 73.58$\%$ in the radiation alone and chemoradiation groups, respectively (p=0.013). The 5 year distant disease-free survival rates were 59.29$\%$ and 81.46$\%$ in the radiation alone and chemoradiation groups, respectively (p=0.477), Treatment related hematologic toxicity were prominent in the chemoradiation group. Leukopenia $\geq$grade) occurred in 3.2$\%$and 28.5$\%$ of the radiation alone and chemoradiation groups, respectively (p=0.02). There were no statistical differences in the incidences of vesical, rectal and small bowel complications between two groups. Conclusion: Radiation therapy with low dose cisplatin did not improve the rates of survival and response rates, but did improve the rate of disease free survival and locoregional control rates In locally advanced cervical cancer. The incidence of bone marrow suppression was higher in the chemoradiation group.