• Radiation Oncology Journal
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• v.26 no.2
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• pp.91-95
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• 2008

Purpose: To evaluate the response and survival rate after three-dimensional conformal radiation therapy(3D-CRT) of patients with a solitary sternal relapse of breast cancer. Materials and Methods: Seventeen patients between May 1996 and June 2005 were evaluated with the salvage 3D-CRT treatment of a solitary sternal relapse of breast cancer. The treatment fields included the gross tumor volume with 2 cm margins. The total radiation dose was $35.0{\sim}61.5$ Gy(biologic effective dose of $43.7{\sim}76.9Gy_{10}$ using an $\alpha/\beta$ ratio of 10 Gy), with a daily dose of $1.8{\sim}3.0$ Gy. The tumor response was evaluated by the change in maximum tumor size via follow up CT scans $1{\sim}3$ months after the completion of treatment. Results: An objective tumor response was achieved in all patients, with a complete response in 5 patients and a partial response in 12 patients. The 5-year overall survival rate was 51.9%(median survival time: 27 months), and the most important factor affecting overall survival was the disease-free interval(interval from primary surgery of breast cancer to the development of sternal metastasis): The 5-year overall survival rate was 61.8% for patients with a disease-free interval ${\geq}12$ months and 0.0% for patients with disease-free interval <12 months(p=0.03). Conclusion: The response to 3D-CRT was good in patients with solitary sternal relapse of breast cancer. Particularly, patients with long disease-free interval from primary surgery survived significantly longer than patients with short disease-free interval from primary surgery.

• Radiation Oncology Journal
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• v.21 no.1
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• pp.94-99
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• 2003

Purpose : To explore a 3D conformal radiotherapy technique for a posterior fossa boost, and the potential advantages of a prone position for such radiotherapy. Materials and Methods :A CT simulator and 3D conformal radiotherapy Planning system was used for the posterior fossa boost treatment on a 13-year-old medulloblastoma patient. He was placed In the prone position and Immobilized with an aquaplast mask and immobilization mold. CT scans were obtained of the brain from the top of the skull to the lower neck, with IV contrast enhancement. The target volume and normal structures were delineated on each slice, with treatment planning peformed using non-coplanar conformal beams. Results : The CT scans, and treatment In the prone position, were peformed successfully. In the prone position, the definition of the target volume was made easier due to the well enhanced tentorium, In audition, the posterior fossa was located anteriorly, and with the greater choice of beam arrangements, more accurate treatment planning was possible as the primary beams were not obstructed by the treatment table. Conclusion : .A posterior fossa boost, in the prone position, Is feasible in cooperating patients, but further evaluation is needed to define the optimal and most comfortable treatment positions.

• 대한두경부종양학회:학술대회논문집
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• 2005.11a
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• pp.217-217
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• 2005

• 대한두경부종양학회:학술대회논문집
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• 1999.12a
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• pp.291-291
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• 1999

• Journal of Radiation Protection and Research
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• v.31 no.4
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• pp.187-195
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• 2006

The purpose of this study was to investigate the optimal beam arrangements for hepatic tumors, according to the location of the hepatic tumor and its relationship to organs at risk (OARs). The virtual gross tumor volumes were divided into four groups according to the Couinaud's classification. Several plans were made for each virtual target, and these plans were compared for the normal tissue complication probabilities (NTCP). For group I, NTCP improved as the number of the beam ports increased. However, plans with more than 5 ports had little advantage. For group II, plans with the beam directions from the anterior side showed better results. Group III contained many OARs near the target, which placed restrictions on the beam-directions. Multi-directional plans yielded a higher dose to the OARs than a simple two-port plan using right anterior oblique and posterior beam (RAO/PA). For group IV, a simple RAO/PA port plan was adequate for protection of remaining liver. NTCP can significantly vary between radiotherapy plans when the location of the tumor and its neighboring OARs are taken into consideration. The results in this study of optimal beam arrangements could be a useful set of guidelines for radiotherapy of hepatic tumors.

• The Journal of Korean Society for Radiation Therapy
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• v.12 no.1
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• pp.144-146
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• 2000

삼차원 입체조형치료는 정상조직의 장해를 최소화하고 종양부위에 집중적으로 조사할 수 있는 장점을 가지고 있어 임상 적용범위가 넓어지고 있다. 일반적으로 정상조직의 장해를 줄이기 위해 다양한 방사선 조사방향이 사용되며 특히 비 동일면상에서의 조사가 많이 이루어진다. 따라서 couch 회전이 동반되며 couch는 선형가속기의 다른 기계적 오차보다 많은 오차를 유발할 수 있는 잠재적인 위험을 안고 있다. 저자는 이러한 오차의 정도를 파악하고 이를 개선할 수 있는 방법에 대해 알아보고자 했다. couch 회전에 따른 Isocenter의 변화를 평가하기 위해 3대(Primus, Simens, USA/CL600c & 2100c, Varian, USA)의 선형가속기를 이용하였으며 이중 1대의 장비에는 couch 회전시 오차를 줄이기 위해 고안된 couch 고정장치를 장착하였다. 환자가 테이블에 부하를 주지 않은 상태에서 회전을 실시하여 Isocenter의 변화를 측정하고 환자가 테이블에 누워있는 상황을 재현하기 위해 human phantom을 위치시킨 후 동일한 회전검사를 실시하여 각각의 오차를 비교 분석하였다. 각 실험은 10회씩 반복 측정하여 평균치를 얻었으며 오차의 분석은 AAPM 권고안인 오차중심의 반경으로 표현했다. 3대의 선형가속기를 이용하여 얻은 결과 테이블에 부하를 주지 않은 상태의 회전오차는 평균 2mm, 3.2mm, 2mm로 측정되었으며 휴먼 phantom을 올려놓고 부하를 준 상태에서의 오차는 평균 2.1mm, 4mm, 2.1 mm이였다. 또한 고정장치를 이용한 상태에서의 평균오차는 1.9mm로 나타났다. 삼차원 입체조형치료 시 couch 회전에 따른 Isocenter 오차는 장비의 종류 및 작업자의 사용방법에 따라 다르게 나타났으며 테이블의 부하가 클수록 많은 오차를 보였다. 또한 couch 고정장치를 부착한 장비에서의 결과치 만이 AAPM에서 권고하는 오차의 한계에(${\le}2mm$) 들어감을 알 수 있었다. 따라서 정기적인 QA가 필수적이며 Couch Locking System과 같이 오차를 줄일 수 있는 보조장치의 부착이 많은 도움을 줄 것으로 생각된다. 아울러 이러한 오차를 보정할 수 있는 방법이 강구되어야 할 것으로 사료된다.

• Progress in Medical Physics
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• v.26 no.3
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• pp.137-142
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• 2015

We retrospectively analyzed the outcomes in patients who underwent reirradiation for brain metastasis. Twenty-three patients with brain metastases who were initially treated with palliative brain radiotherapy and were retreated with a second course of brain RT between June 2008 and December 2012. WBRT, 3DCRT and SRS were used for brain metastasis. The median dose of the first course of WBRT was 30 Gy (range, 23.4~30 Gy). The dose of the first course 3DCRT for lesion was 30 Gy in 3 Gy per fraction. The median dose of the first course of SRS was 16 Gy in 1 fraction (range, 12~24 Gy). The median dose of the second course of WBRT was 27.5 (range, 12~30 Gy). The median dose of the second course of 3DCRT for lesion was 30 Gy (range, 25~30 Gy). The dose of the second course of SRS was 16 Gy in 1 fraction. The second course of WBRT was administered on radiographic disease progression with symptom in all patients. With median follow-up of 25 months, overall symptom resolution rates were 47.8%. Rate of palliative efficacy was 82.6% including stable disease. The median survival time after initiation of reirradiation was 3.2 months. Median value of KPS prior to reirradiation was 30. Median value of KPS after reirradiation was 60. Reirradiation of brain metastasis maybe feasible and effective in select patients with a good performance status $KPS{\geq}60$ (: ECOG 0~2) prior to reirradiation.

• Radiation Oncology Journal
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• v.27 no.4
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• pp.189-193
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• 2009

Purpose: To report on the changes in the patterns of care and survival over time for esthesioneuroblastoma. Materials and Methods: We retrospectively analyzed 42 previously untreated and histologically confirmed esthesioneuroblastoma patients seen between March 1989 and June 2007. According to Kadish's classification, 3 patients (7%) were stage A, 6 (14%) at stage B, and 33 (79%) at stage C. Of the 33 Kadish C patients, 19 and 14 patients were treated from 1989 through 2000 and from 2001 through 2007, respectively. Treatment included surgical resection, radiotherapy, chemotherapy, or a combination of these methods. Chemotherapy was administered to 8 of 19 patients (42%) seen from 1989 through 2000, whereas all of the 14 patients seen from 2001 through 2007 received chemotherapy (p<0.001). No patient was treated by three-dimensional conformal radiotherapy (3D-CRT) from 1989 through 2000, however 8 of 14 patients (67%) seen from 2001 through 2007 underwent 3D-CRT (p<0.001). The median follow-up time for surviving patients was 6.5 years (range, 2.2~15.8 years). Results: The 5-year overall survival (OS) and progression-free survival (PFS) rates for the entire cohort were 53% and 39%, respectively. The 5-year OS was 100% for Kadish stages A or B and 39% for stage C (p=0.007). For patients with stage C disease who were treated from 1989 to 2000 and from 2001 to 2007, the 5-year OS rate was 26% and 59% (p=0.029), respectively and the corresponding 5-year PFS rate was 16% and 46% (p=0.001), respectively. Intraorbital extension and treatment era (1989~2000 vs. 2001~2007) were found as independent factors for OS and PFS in a multivariate analyses. Conclusion: The results of this study suggest that treatment era, which features a distinction in treatment modality and technique with the introduction of 3D-CRT, may be the cause of improved OS and PFS in Kadish stage C patients. To achieve better outcomes for patients with Kadish stage C, combined chemoradiotherapy, especially 3D-CRT, is recommended in addition to surgery.

• Progress in Medical Physics
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• v.16 no.4
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• pp.166-175
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• 2005

The purpose of this study is to develop the optimization method for adjusting the film isocenter shift and to suggest the quantitative acceptable criteria for film dosimetry after optimization In the dynamic conformal arc radiation therapy (DCAR). The DCAR planning was peformed In 7 patients with brain metastasis. Both absolute dosimetry with ion chamber and relative film dosimetry were peformed throughout the DCAR using BrainLab's micro-multileaf collimator. An optimization method for obtaining the global minimum was used to adjust for the error in the film isocenter shift, which is the largest pan of systemic errors. The mean of point dose difference between measured value using ion chamber and calculated value acquired from planning system was $0.51{\pm}0.43\%$ and maximum was $1.14\%$ with absolute dosimetry These results were within the AAPM criteria of below $5\%$. The translation values of film isocenter shift with optimization were within ${\pm}$1 mm in all patients. The mean of average dose difference before and after optimization was $1.70{\pm}0.35\%$ and $1.34{\pm}0.20\%$, respectively, and the mean ratios over $5\%$ dose difference was $4.54{\pm}3.94\%$ and $0.11{\pm}0.12\%$, respectively. After optimization, the dose differences decreased dramatically and a ratio over $5\%$ dose difference and average dose difference was less than $2\%$. This optimization method is effective in adjusting the error of the film isocenter shift, which Is the largest part of systemic errors, and the results of this research suggested the quantitative acceptable criteria could be accurate and useful in clinical application of dosimetric verification using film dosimetry as follows; film isocenter shift with optimization should be within ${\pm}$1 mm, and a ratio over $5\%$ dose difference and average dose difference were less than $2\%$.

• Radiation Oncology Journal
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• v.21 no.2
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• pp.135-142
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• 2003

Purpose: The purpose of this study was to investigate the positional change of the uterus during radiotherapy. Materials and Methods: Between 1997 and 2001, 47 patients received definitive radiotherapy for cervical cancer at the Samsung Medical Center. For each patient, two MRI scans were taken; one before and the other 3$\~$4 weeks after the radiotherapy treatment. In T2 weighted MRI images, the positional change of the uterine was quantified by measuring six quantities; the distance from the cervix os to the isthmus of the uterus (Dcx), the maximum length from the isthmus of the uterus to the uterine fundus (Dco), the maximum vertical distance of the uterine body (Dco-per), the angle between the vertical line and the cervical canal in the sagittal images (Acx), the angle of the uterine corpus from the vertical line in the sagittal plan (Aco-ap), and the relative angle of the uterine corpus from a fixed anatomical landmark in the axial images (Aco-axi). Results: The mean Dcx values, before and during the treatment, were 36.7 and 27.8 mm, respectively. The Dco deviated by more than 10 mm in 14 cases (29.8$\%$). The change in the Acx ranged from 0.1 to 67.8$^{\circ}$ (mean 13.2$^{\circ}$). The Aco-ap changed by a maximum of 84.8$^{\circ}$ (mean 16.9$^{\circ}$). The differences in the Dcx plus the Dco in the smaller (<4 cm) and larger ($geq$4 cm) tumors were 5.3 and 19.4 mm, respectively. With patients less than 60 years old, or with a tumor size larger than 4 cm, the difference in the Acx was statistically significant. Conclusion: The positional changes of the uterus, during radiation treatment, should be considered in the 3DCRT or IMRT treatment planning, particularly in patients under 60 years of age or in those with a tumor size greater than 4 cm in maximum diameter.