• Radiation Oncology Journal
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• v.26 no.4
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• pp.213-221
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• 2008

Purpose: The objective of this retrospective study was to identify predictive factors for the complete pathologic response and tumor downstaging after preoperative concurrent chemoradiotherapy for locally advanced rectal cancer. Materials and Methods: Between the years 2000 and 2008, 39 patients with newly diagnosed rectal cancer without prior evidence of distant metastasis received preoperative concurrent chemoradiotherapy followed by surgery. The median radiation dose was 50.4 Gy (range, $45{\sim}59.4\;Gy$)). Thirty-eight patients received concurrent infusional 5-fluorouracil and leucovorin, while one patient received oral capecitabine twice daily during radiotherapy. Results: A complete pathologic response (CR) was demonstrated in 12 of 39 patients (31%), while T-downstaging was observed in 24 of 39 patients (63%). N-downstaging was observed in 18 of 28 patients (64%), with a positive node in the CT scan or ultrasound. Two patients with clinical negative nodes were observed in surgical specimens. The results from a univariate analysis indicated that the tumor circumferential extent was less than 50% (p=0.031). Moreover, the length of the tumor was less than 5 cm (p=0.004), while the post-treatment carcinoembryonic antigen (CEA) levels were less than or equal to 3.0 ng/mL (p=0.015) and were significantly associated with high pathologic CR rates. The univariate analysis also indicated that the adenocarcinoma (p=0.045) and radiation dose greater than or equal to 50 Gy (p=0.021) were significantly associated with high T-downstaging, while a radiotherapy duration of less than or equal to 42 days (p=0.018) was significantly associated with N-downstaging. The results from the multivariate analysis indicated that the lesser circumferential extent of the tumor (hazard ratio [HR] 0.150; p=0.028) and shorter tumor length (HR, 0.084; p=0.005) independently predicted a higher pathologic CR. The multivariate analysis also indicated that a higher radiation dose was significantly associated with higher T-downstaging (HR, 0.115; p=0.025), while the shorter duration of radiotherapy was significantly associated with higher N-downstaging (HR, 0.028; p=0.010). Conclusion: The circumferential extent of the tumor and its length was a predictor for the pathologic CR, while radiation dose and duration of radiotherapy were predictors for tumor downstaging. Hence, these factors may be used to predict outcomes for patients and to develop further treatment guidelines for high-risk patients.

• Radiation Oncology Journal
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• v.3 no.1
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• pp.29-33
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• 1985

흉선종은 비교적 드문 종양으로 알려져 있다. 예후를 알 수 있는 가장 중요한 인자는 수술시 육안적인 종양의 침윤정도이며, 치료는 수술에 의한 종양의 제거가 무엇보다 중요하고, 방사선 치료 역시 수출 후 국소적 계발의 방지를 위해 쓰이고 있다. 근치적 목적의 방사선 치료도 수술이 어려운 경우에 시행되고 있는 형편이다. 저자들은 1977년 1월부터 1984년 12월까지 세브란스병원 연세암센타 치료방사선과에서 흉선종 진단받고 치료한 14명의 환자를 후향성 분석에 의해 다음과 같은 결과를 얻었다. 1. 6명의 환자$(14\%)$가 근무력증을 나타냈다. 2. 주변조직의 침윤이 $86\%(12/14)$에서 관찰되었다. 3. $43\%$에서 육안적 완전 절제를 시행하였고 $14\%$에서 부분결제, 그리고 $43\%$에서는 생검만 시행 하였다. 4. 수술 후 혹은 근치적 목적의 방사선치료는 8명의 환자에서 시행하였으며 그중 현재 5명은 생존(4년, 2.8년, 1.6년, 1.4년, 1.3년), 3명은 사망(1년, 0.6년, 0.6년)하였다. 5. 방사선 치료선량은 대체료 $4,000\~4,500rad(1950\~7,000rad)$를 전후 흉곽 부위에 외부 조사하였다.

• Radiation Oncology Journal
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• v.28 no.4
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• pp.238-248
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• 2010

Purpose: To compare the dose distributions between three-dimensional (3D) and four-dimensional (4D) radiation treatment plans calculated by Ray-tracing or the Monte Carlo algorithm, and to highlight the difference of dose calculation between two algorithms for lung heterogeneity correction in lung cancers. Materials and Methods: Prospectively gated 4D CTs in seven patients were obtained with a Brilliance CT64-Channel scanner along with a respiratory bellows gating device. After 4D treatment planning with the Ray Tracing algorithm in Multiplan 3.5.1, a CyberKnife stereotactic radiotherapy planning system, 3D Ray Tracing, 3D and 4D Monte Carlo dose calculations were performed under the same beam conditions (same number, directions, monitor units of beams). The 3D plan was performed in a primary CT image setting corresponding to middle phase expiration (50%). Relative dose coverage, D95 of gross tumor volume and planning target volume, maximum doses of tumor, and the spinal cord were compared for each plan, taking into consideration the tumor location. Results: According to the Monte Carlo calculations, mean tumor volume coverage of the 4D plans was 4.4% higher than the 3D plans when tumors were located in the lower lobes of the lung, but were 4.6% lower when tumors were located in the upper lobes of the lung. Similarly, the D95 of 4D plans was 4.8% higher than 3D plans when tumors were located in the lower lobes of lung, but was 1.7% lower when tumors were located in the upper lobes of lung. This tendency was also observed at the maximum dose of the spinal cord. Lastly, a 30% reduction in the PTV volume coverage was observed for the Monte Carlo calculation compared with the Ray-tracing calculation. Conclusion: 3D and 4D robotic radiotherapy treatment plans for lung cancers were compared according to a dosimetric viewpoint for a tumor and the spinal cord. The difference of tumor dose distributions between 3D and 4D treatment plans was only significant when large tumor movement and deformation was suspected. Therefore, 4D treatment planning is only necessary for large tumor motion and deformation. However, a Monte Carlo calculation is always necessary, independent of tumor motion in the lung.

• 대한두경부종양학회:학술대회논문집
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• 2004.11a
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• pp.257-257
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• 2004

• Radiation Oncology Journal
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• v.25 no.1
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• pp.1-6
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• 2007

[ $\underline{Purpose}$ ]: To investigate current status of SCI (Science Citation Index) and SCI Expanded publications of Korean radiation oncologists. $\underline{Materials\;and\;Methods}$: Published SCI and SCIE articles the conditions of first author's address as "Korea" and "Radiation Oncology" or "Therapeutic Radiology" were searched from Pubmed database. $\underline{Results}$: From 1990 to 2006, 146 SCI articles and 32 SCIE articles were published. Most frequently published journal was International Journal of Radiation Oncology Biology Physics, where 56 articles were found. Articles with 30 or more citations were only five and 10 or more citations were 26. Yonsei University, which had 57 published articles, was the top among 19 affiliations which had one or more SCI and SCIE articles. Authors with five or more articles were 9 and Seong J. of Yonsei University was the top with 19 articles. $\underline{Conclusion}$: The investigations showed disappointing results. The members of Korean Society of Radiation Oncologists must consider a strategy to increase SCI and SCIE publications.

• The Journal of Korean Society for Radiation Therapy
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• v.33
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• pp.71-78
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• 2021

Purpose: To evaluate the inter-fractional position and respiratory reproducibility of lung and liver tumors using pressure conserving type(P-type) abdominal compressor in volumetric modulated arc therapy(VMAT). Materials and methods: Six lung cancer patients and three liver cancer patients who underwent VMAT using a P-type abdominal compressor were included in this study. Cone-beam computed tomography(CBCT) images were acquired before each treatment and compared with planning CT images to evaluate the inter-fractional position reproducibility. The position variation was defined as the difference of position shift values between target matching and bone matching. 4-dimensional cone-beam computed tomography(4D CBCT) images were acquired weekly before treatment and compared with planning 4DCT images to evaluate the inter-fractional respiratory reproducibility. The respiratory variation was calculated by the magnitude of excursions by breathing. Results: The mean ± standard deviation(SD) of overall position variation values, 3D vector in the three translational directions were 1.1 ± 1.4 mm and 4.5 ± 2.8 mm for the lung and liver, respectively. The mean ± SD of respiratory variation values were 0.7 ± 3.4 mm (p = 0.195) in the lung and 3.6 ± 2.6 mm (p < 0.05) in the liver. Conclusion: The use of P-type compressor in lung and liver VMAT was effective for stable control of inter-fractional position and respiratory variation by reproduction of abdominal compression. Appropriate PTV margin must be considered in treatment planning, and image guidance before each treatment are required in order to obtain more stable reproducibility

• Proceedings of the Korean Society of Radiological Science
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• 2002.06b
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• pp.34.2-34.2
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• 2002

• Korean Journal of Head & Neck Oncology
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• v.30 no.2
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• pp.104-108
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• 2014

주로 작은 침샘에서 발생하는 샘낭암종의 치료 방침은 수술과 수술 후 보조적 방사선치료가 주로 행해져 왔다. 그러나 설근부에 발생한 샘낭암종에 대해서는 수술적 치료가 가져오는 삶의 질의 저하가 크기 때문에 수술적 치료를 적용하기 쉽지 않다. 또한 샘낭암종의 치료에 있어서 항암제의 역할이 거의 없는 상황에서 방사선치료가 중요한 역할을 할 수 있겠다. 이에 본 저자들은 설근부에 발생한 샘낭암종 세 증례의 방사선치료 결과를 보고 하며 샘낭암종의 치료에 대해서 문헌고찰을 통해 논의하고자 한다.

• Journal of radiological science and technology
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• v.42 no.3
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• pp.217-222
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• 2019

The purpose of this study is to evaluate the dose distribution by gantry rotation and MLC moving speed on treatment planning system(TPS) and linear accelerator. The dose analyzer phantom(Delta 4) was scanned by CT simulator for treatment planning. The planning target volumes(PTVs) of prostate and pancreas was prescribed 6,500 cGy, 5,000 cGy on VMAT(Volumetric Modulated Arc Therapy) by TPS while MLC speed changed. The analyzer phantom was irradiated linear accelerator using by planned parameters. Dose distribution of PTVs were evaluated by the homogeneity index, conformity index, dose volume histogram of organ at risk(rectum, bladder, spinal cord, kidney). And irradiated dose analysis were evaluated dose distribution and conformity by gamma index. The PTV dose of pancreas was 4,993 cGy during 0.1 cm/deg leaf and gantry that was the most closest prescribed dose(5,000 cGy). The dose of spinal cord, left kidney, and right kidney were accessed the lowest during 0.1 cm/deg, 1.5 cm/deg, 0.3 cm/deg. The PTV dose of prostate was 6,466 cGy during 0.1 cm/deg leaf and gantry that was the most closest prescribed dose(6,500 cGy). The dose of bladder and rectum were accessed the lowest during 0.3 cm/deg, 2.0 cm/deg. For gamma index, pancreas and prostate were analyzed the lowest error 100% at 0.8, 1.0 cm/deg and 99.6% at 0.3, 0.5 cm/deg. We should used the optimal leaf speed according to the gantry rotation if the treatment cases are performed VMAT.

• 대한두경부종양학회:학술대회논문집
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• 2001.11a
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• pp.255-255
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• 2001