• The Journal of Korean Society for Radiation Therapy
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• v.26 no.1
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• pp.91-98
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• 2014

Purpose : To compare the dosimetry for the left breast cancer treatment between three dimensional conformal radiation radiotherapy (3D-CRT) and Hybrid planning and to estimate usefulness of Hybrid planning Materials and Methods : Five patients with left breast cancer were included in the study. They were planned using several different radiotherapy techniques including: 1)open rectangular field, 2)tangential wedge-based field 3)field in field, 4)hybrid planning(energy, wedge combine). For each patient planning was using Light Speed RT-16 CT and PINNACLE planning system-ver.9.2. Hybrid plan was made using same system and using the same targets and optimization goals. We comparing the Homogeneity Index(HI), normal organs at the does-volume histogram(DVH) Results : In all plans, the Homogeneity Index(HI) of Hybrid planning was significantly better than other. Dose comparison of HI= 2D-RT:38.32, TW:38.32, FIF:29.22, HYBRID:30.57. 2D-RT, TW, FIF Hybrid$V_{75_-lung}$=112.33, 125.14, 121.3, 123.78. $V_{50_-lung}$=155.43, 159.62, 157.96, 159.06. $V_{25_-lung}$=199.86, 200.22, 198.65, 200.31. $V_{50_-heart}$=26.07, 27.1, 26.85, 27.17 $V_{30_-heart}$=33.71, 34.37, 34.15, 34.65 Conclusion : In summary, 3D-CRT, Hybrid planning techniques were found to have acceptableCTV coverage in our study. However the Hybrid planning increased radiation dose exposure to normal tissue. If you apply for treatment of inhomogeneity areas like lung, For best results will be achieved.

• The Journal of Korean Society for Radiation Therapy
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• v.16 no.2
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• pp.69-79
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• 2004

In the process of photon treatments, linear accelerators with energies higher than 10 MV produce neutrons through the (${\gamma}$, n) interactions with the composite materials of the linac head md these materials further produce the induced radiations. We investigate the possible risks from these induced radiations especially in the wedge filters to the radiation workers. Wedge filters are used to modify the isodose profiles in the radiation treatment using the linear accelerator and always be handled by the radiation workers. For the background radiation, we measured the radiation in both the waiting room and the outside of the building for two hospitals, S and H. The results of S hospital were $0.11\;{\mu}Sv/hr$ and $0.10\;{\mu}Sv/hr$ for waiting room and outside respectively, and in the case of H hospital, they were $0.12\;{\mu}Sv/hr$ and $0.11\;{\mu}Sv/hr$. Using a survey meter, we measured the radiation from wedge filters inserted in 10 MV and 15 MV Siemens linear accelerators. The time series measurements were done in ${\sim}1$ minutes after exposure of 5 Gy of monitor units for the field size of $25{\times}25cm^2$. The starting value of 10 MV machine was about $3.26\;{\mu}Sv/hr$, which was three times higher than that of 10 MV. The measured radiation was from $^{28}Al$ and $^{53}Fe$ with a half life of 3.5 min. If the treatment patients are $20{\sim}50$ per day and the number of process of wedge filter change per patient is one or two, the annual dose equivalent is $0.08{\sim}0.4\;mSv$ for 10 MV, and $0.27{\sim}1.36\;mSv$ for 15 MV, which are in the range of dose equivalent limits of radiation workers.

• Radiation Oncology Journal
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• v.13 no.3
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• pp.215-223
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• 1995

Purpose : The aim of this study was to assess the effectiveness, survival rate and complication of radiation in nasopharyngeal cancer. Materials and Methods : From January 1980 to May 1989. Fifty patients who had nasopharyngeal carcinoma treated with curative radiation therapy at Kosin Medical Center were retrospectively studied. Thirty seven patients($74{\%}$) were treated with radiation therapy alone(Group I) and 13 patients ($26{\%}$) treated with combination of chemotherapy and radiation (Group II). Age distribution was 16-75 years(median : 45.8 years). In histologic type, squamous cell carcinoma was in 30 patients($60{\%}$), undifferentiated carcinoma in 17 patients($34{\%}$), and lymphoepithelioma in 3 patients($6{\%}$). According t AJCC staging system. 4 patients($8{\%}$) were in $T_1$, 13 patients($26{\%}$) in $T_2$. 20 patients($40{\%}$) in $T_3$, 13 patients($26{\%}$) in $T_4$ and 7 patients($14{\%}$) in $N_0$, 6 patients($12{\%}$) $N_1$, 23 patients($46{\%}$) in $N_2$, 14 patients($28{\%}$) in $N_3$. Total radiation dose ranges were 5250-9200cGy(median : 7355 cGy) in Group I and 5360-8400cGy(median : 6758cGy) in Group II Radiotherapy on 4-6MV linear accelerator and/or 6-12MeV electron in boost radiation was given with conventional technique to 26 patients($52{\%}$), with hyperfractionation(115-120cGy/fr., 2times/day) to 16 patients($32{\%}$), with accelerated fractionation(160cGy/fr., 2 times/day) to 8 patients($16{\%}$). In chemotherapy, 5 FU 1000mg daily for 5 consecutive days, pepleomycin 10mg on days 1 and 3, and cisplatin 100mg on day 1 were administered with 3weeks interval, total 1 to 3 cycles(average 1.8cycles) prior to radiation therapy. Follow up duration was 6-140 months(mean : 58 months). Statistics was calculated with Chi-square and Fisher's exact test. Results : Complete local control rates in Group I and II were $75.7{\%},\;69.2{\%} Overall 5 year survival rates in Group I and II were $56.8{\%},\;30.8{\%}$. Five year survival rates by histologic type in Group I and II were $52.2{\%},\;14.3{\%}$ is squamous cell carcinoma and $54.5{\%},\;50{\%}$ in undifferentiated carcinoma. Survival rates in Group I were superior to those of Group II though there were not statistically significant. In both group, survival rates seem to be increased according to increasing total dose of radiation up to 7500cGy, but not increased beyond it. There were not statistically significant differences in survival rates by age, stage, and radiation techniques in both group. Twenty four patients($48{\%}$) experienced treatment failures. Complications were found in 12 patients($24{\%}$). The most common one was osteomyelitis(4 patients, $33.3{\%}$) involving mandible (3 patients) and maxilla(1 patient). Conclusion : Chemotherapy in combination with radiotherapy was found to be not effective to nasopharyngeal cancer and the survival rate was also inferior to that of radiation alone group though it was statistically not significant due to small population in chemotherapy combined group.

• Radiation Oncology Journal
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• v.28 no.2
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• pp.79-84
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• 2010

Purpose: We retrospectively analyzed the long-term results of radical surgery and intraoperative radiation therapy (IORT) in patients with stomach cancer. Materials and Methods: From 1988 to 1994, 51 patients were treated with curative surgery and IORT. Postoperative external beam radiotherapy (EBRT) was administered to 30 patients, while adjuvant chemotherapy was administered to 35 patients. A dose of 15 Gy was irradiated with a 9 MeV electron beam as the IORT and a median dose of EBRT was 43.2 Gy (range, 7.2 to 45 Gy). The follow-up period ranged from 1~254 months, with a median follow-up period of 64 months. Results: The median age of all the patients was 58 years (range, 30 to 71 years). The distribution of pathologic stage (American Joint Committee on Cancer [AJCC] 2002 tumor-note-metastasis [TNM]) was as follows: 13 stage I (25.5%), 10 stage II (19.6%), 25 stage III (49.0%), and 3 stage IV (5.9%). Distant metastases occurred in 11 patients (10 in the peritoneum and 1 in bone), including one patient with concurrent local recurrence (anastomosis site). The 5-year locoregional control, disease free survival and overall survival rates were 94.7%, 66.5%, and 51.7%, respectively. For the multivariate analysis, age, TNM stage, and EBRT were significant prognostic factors for overall survival, and only TNM stage for disease free survival. Conclusion: We could have achieved a high loco-regional control rate in patients with locally advanced stomach cancer by adding IORT to radical surgery. However, the benefit of IORT on survival remains to be elucidated.

• Radiation Oncology Journal
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• v.28 no.2
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• pp.85-90
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• 2010

Purpose: To evaluate the rate of tumor response, local control, and treatment-related complications after hypofractionated radiotherapy for recurrent hepatocelluar carcinoma (HCC) less than 5 cm in size. Materials and Methods: Among the HCC patients who were treated by radiotherapy (RT) between 2006 and 2007 after the failure of previous treatment, a total of 12 patients were treated with hypofractionated RT. The criteria for hypofractionated RT was as follows: 1) HCC less than 5 cm, 2) HCC not adjacent to a critical organ, 3) HCC without portal vein tumor thrombosis, and 4) less than 15% of normal liver volume that irradiated 50% of the prescribed dose. Hypofractionated RT was performed with 50 Gy delivered in 10 fractions, at a rate of 5 fractions per week. The evaluation of tumor response was determined by CT scans performed at 3 months after the cessation of RT, followed by the evaluation of toxicity by Common Terminology Criteria for Adverse Events version 3.0. The median follow-up period after radiotherapy was 18 months. Results: A complete response (CR) was achieved in 5 of 12 lesions (41.7%) at CT performed at 3 months after the cessation, whereas the overall complete response was observed in 7 of 12 cases (58.3%). In-field local control rate was sustained in 83.3% of patients. All patients developed intra-hepatic metastases except for 2 patients. The overall survival rate was 90.0% at 1 year and 67.5% at 2 years, respectively. Three patients developed Grade 1 nausea during RT and 1 patient showed a progression of ascites after RT. There was no grade 3 or greater treatment-related toxicities. Conclusion: Hypofractionated RT for small-sized HCC as a salvage therapy showed a 58.3% CR rate and 83.3% of local control. Fifty Gy administered in 10 fractions of partial liver irradiation is considered as a tolerable dose that does not cause severe complications.

• Radiation Oncology Journal
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• v.29 no.1
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• pp.36-43
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• 2011

Purpose: To evaluate the effectiveness of radiation therapy (RT) for hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT) and to analyze the prognostic factors. Materials and Methods: From December 2004 to April 2009, 70 patients who had HCC with PVTT were treated with RT at Keimyung University Dongsan Medical Center. Nineteen patients whose total dose was below 30 Gy and one patient who underwent liver transplantation were excluded. The remaining 50 patients (45 males, 5 females; median age 55 years) were analyzed. According to the LCSGJ TNM stage, there were 27 patients (54.0%) with stage III and 23 (46.0%) with stage IV. Total dose of 30~54 Gy was administered (median 45). Thirty patients (60.0%) were treated with concurrent chemoradiation therapy (CCRT). The median follow-up duration was from 13.5 months (range, 3 to 70 months). Results: The median survival time from the start of RT was 9 months. One-year and 2-year overall survival rates were 24.9% and 11.2%, respectively. At the follow-up time, three patients (6.0%) displayed no evidence of disease. Seven patients (14.0%) were alive with disease, and 40 (80.0%) patients had expired due to disease progression. CCRT was associated with worse survival than RT alone (p=0.034), Response to RT (p=0.037), CLIP stage (p=0.017), and TNM stage (p=0.041) were statistically significant prognostic factors. There was no radiation-induced liver disease. Conclusion: RT is an effective and safe modality for HCC with PVTT. Further studies such as prospective randomized trials are needed to confirm the role of RT for HCC with PVTT.

• Radiation Oncology Journal
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• v.16 no.4
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• pp.497-504
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• 1998

Purpose : To evaluate the usefulness of electronic portal imaging device through objective compare of the images acquired using an EPID and a conventional port film Materials and Methods : From Apr. to Oct. 1997, a total of 150 sets of images from 20 patients who received radiation therapy in the pelvis area were evaluated in the Inha University Hospital and Severance Hospital. A dual image recording technique was devised to obtain both electronic portal images and port film images simultaneously with one treatment course. We did not perform double exposure five to ten images were acquired from each patient. All images were acquired from posteroanterior (PA) view except images from two patients. A dose rate of 100-300 Mu/min and a 10-MV X-ray beam were used and 2-10 MUs were required to produce a verification image during treatment. Kodak diagnostic film with metal/film imaging cassette which was located on the top of the EPID detector was used for the port film. The source to detector distance was 140 cm. Eight anatomical landmarks (pelvic brim, sacrum, acetabulum. iliopectineal line, symphysis, ischium, obturator foramen, sacroiliac joint) were assessed. Four radiation oncologist joined to evaluate each image. The individual landmarks in the port film or in the EPID were rated - very clear (1), clear (2), visible (3), not clear (4), not visible (5). Results : Using an video camera based EPID system. there was no difference of image quality between no enhanced EPID images and port film images. However, when we provided some change with window level for the portal image, the visibility of the sacrum and obturator foramen was improved in the portal images than in the port film images. All anatomical landmarks were more visible in the portal images than in the port film when we applied the CLAHE mode enhancement. The images acquired using an matrix ion chamber type EPID were also improved image qualify after window level adjustment. Conclusion : The quality of image acquired using an electronic portal imaging device was comparable to that of the port film. When we used the enhance mode or window level adjustment. the image quality of the EPID was superior to that of the port film. EPID may replace the port film.

• Radiation Oncology Journal
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• v.16 no.4
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• pp.441-446
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• 1998

Purpose : The incidence of esophageal carcinoma is increasing. Radical surgery is the treatment of choice, but large proportion of the esophageal cancer patients are with unresectable disease at the time of initial diagnosis, so radiation therapy has been the major treatment modality. We carried out retrospective analysis to see the outcome and prognostic factors of radiation therapy alone for esophageal carcinoma. Methods and Materials : From June of 1979 through December 1992, 289 patients with esophageal carcinoma were treated with radiation therapy alone at Department of Therapeutic Radiology, Seoul National University Hospital. Of these patients, 84 patients were excluded as they were ineligible for the current analyses. Twenty-two patients had distant metastasis other than supraclavicular lymph node metastasis, 52 patients received less than 45 Gy, and 10 patient were lost from follow-up. Therefore 205 patients constituted the base population of this study. According to AJCC s1aging system, there were 2 patients with stage 1, 104 with stage IIA, 26 with stage IIB, 48 with stage III, and 25 with stage IV Radiation dose ranged from 4500 cGy to 6980 cGy with median dose of 5940 cGy. Follow-up period of the alive patients ranged from 77 to 180 months. Results : The Median survival period of all the patients was II months and the 2-, 5-, and 10-year overall survival rates were 22.4$\%$, 10.2$\%$ and 5.3$\%$, respectively. Most of the failures were local recurrences. Of 169 failures, 134 had local failure as a component and 111 had local recurrence only. The Lymph node was most common distant metastatic site and the next was the lung. The stage, T-stage, N-stage, functional status, tumor size, and aim of treatment were statistically significant prognostic factors for survival by univariate analyses. But only tumor size and N-stage were significant by multivariate analyses. Conclusion : We could get 10.2$\%$ of 5 year survival rate and 5.3$\%$ of 10 year survival rate with radiation therapy alone. The size of tumor and N-stage were statistically significant prognostic factors for survival on multivariate analyses.

• Pediatric Infection and Vaccine
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• v.18 no.2
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• pp.109-116
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• 2011

Purpose : Pneumococcus is one of the most important causes of invasive infection through the childhood period. In January 2008, the Clinical and Laboratory Standards Institute (CLSI) published revised penicillin breakpoints for Streptococcus pneumoniae and penicillin susceptibility rates of S. pneumoniae increased in Korea. This study was performed to determine the probability of oral amoxicillin for the empirical treatment achieving bactericidal exposure against pneumococcus using pharmacodynamics model. Methods : Twenty-three isolates of pneumococci were subjected to determine minimum inhibitory concentration (MIC) for ${\beta}$-lactams and macrolide. For the ${\beta}$-lactams, exposure of fT >MIC (time that free drug concentrations remain above the MIC) for 50% of the administration interval have determined the probability of target attainment (PTA), and regimens that had a PTA >90% were considered optimal. An analysis was performed by applying MIC of 23 isolates to a 5000-patient Monte Carlo simulation model. Results : Among 23 isolates from healthy children, 7 (30.4%) isolates were MIC ${\leq}$1.0 ${\mu}g$/mL and 19 (82.6%) were MIC ${\leq}$2 ${\mu}g$/mL for amoxicillin. Amoxicillin 40 mg/kg/day achieved PTA >90% at MIC ${\leq}$1.0 ${\mu}g$/mL but PTA decreased to 52% at MIC 2 ${\mu}g$/mL, whereas amoxicillin 90 mg/kg/day can predict 97% of PTA at MIC 2 ${\mu}g$/mL. Overall, oral amoxicillin 90 mg/ kg/day for the empirical treatment against pneumococcus can expect more successful response in Korean children. Conclusion : Considering the resistantce pattern of pneumococci in Korean children, we estimate that oral amoxicillin 90 mg/kg/day will provide a pharmacodynamic advantage for the empirical treatment against pneumococcus. And low dose amoxicillin or macrolide are expected to have higher chance of treatment failure than high dose oral amoxicillin.

• Radiation Oncology Journal
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• v.26 no.4
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• pp.247-256
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• 2008

Purpose: The purpose of this study is to evaluate anal sphincter preservation rates, survival rates, and prognostic factors in patients with rectal cancer treated with preoperative chemoradiotherapy. Materials and Methods: One hundred fifty patients with pathologic confirmed rectal cancer and treated by preoperative chemoradiotherapy between January 1999 and June 2007. Of the 150 patients, the 82 who completed the scheduled chemoradiotherapy, received definitive surgery at our hospital, and did not have distant metastasis upon initial diagnosis were enrolled in this study. The radiation dose delivered to the whole pelvis ranged from 41.4 to 46.0 Gy (median 44.0 Gy) using daily fractions of $1.8{\sim}2.0\;Gy$ at 5 days per week and a boost dose to the primary tumor and high risk area up to a total of $43.2{\sim}54\;Gy$ (median 50.4 Gy). Sixty patients (80.5%) received 5-fluorouracil, leucovorin, and cisplatin, while 16 patients (19.5%) were administered 5-fluorouracil and leucovorin every 4 weeks concurrently during radiotherapy. Surgery was performed for 3 to 45 weeks (median 7 weeks) after completion of chemoradiotherapy. Results: The sphincter preservation rates for all patients were 73.2% (60/82). Of the 48 patients whose tumor was located at less than 5 cm away from the anal verge, 31 (64.6%) underwent sphincter-saving surgery. Moreover, of the 34 patients whose tumor was located at greater than or equal to 5 cm away from the anal verge, 29 (85.3%) were able to preserve their anal sphincter. A pathologic complete response was achieved in 14.6% (12/82) of all patients. The downstaging rates were 42.7% (35/82) for the T stage, 75.5% (37/49) for the N stage, and 67.1% (55/82) for the overall stages. The median follow-up period was 38 months (range $11{\sim}107$ months). The overall 5-year survival, disease-free survival, and locoregional control rates were 67.4%, 58.9% and 84.4%, respectively. The 5-year overall survival rates based on the pathologic stage were 100% for stage 0 (n=12), 59.1% for stage I (n=16), 78.6% for stage II (n=30), 36.9% for stage III (n=23), and one patient with pathologic stage IV was alive for 43 months (p=0.02). The 5-year disease-free survival rates were 77.8% for stage 0, 63.6% for stage I, 58.9% for stage II, 51.1% for stage III, and 0% for stage IV (p<0.001). The 5-year locoregional control rates were 88.9% for stage 0, 93.8% for stage I, 91.1% for stage II, 68.2% for stage III, and one patient with pathologic stage IV was alive without local recurrence (p=0.01). The results of a multivariate analysis with age (${\leq}55$ vs. >55), clinical stage (I+II vs. III), radiotherapy to surgery interval (${\leq}6$ weeks vs. >6 weeks), operation type (sphincter preservation vs. no preservation), pathologic T stage, pathologic N stage, pathologic overall stage (0 vs. I+II vs. III+IV), and pathologic response (complete vs. non-CR), only age and pathologic N stage were significant predictors of overall survival, pathologic overall stage for disease-free survival, and pathologic N stage for locoregional control rates, respectively. Recurrence was observed in 25 patients (local recurrence in 10 patients, distant metastasis in 13 patients, and both in 2 patients). Acute hematologic toxicity ($\geq$grade 3) during chemoradiotherapy was observed in 2 patients, while skin toxicity was observed in 1 patient. Complications developing within 60 days after surgery and required admission or surgical intervention, were observed in 11 patients: anastomotic leakage in 5 patients, pelvic abscess in 2 patients, and others in 4 patients. Conclusion: Preoperative chemoradiotherapy was an effective modality to achieve downstaging and sphincter preservation in rectal cancer cases with a relatively low toxicity. Pathologic N stage was a statistically significant prognostic factor for survival and locoregional control and so, more intensified postoperative adjuvant chemotherapy should be considered in these patients.