• The Journal of Korean Society for Radiation Therapy
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• v.25 no.2
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• pp.159-165
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• 2013

Purpose: Abdominal compressor is used to control breathing in stereotactic body radiotherapy for lung tumors frequently. We evaluated the dynamic variation aspect of internal tumor volume by breathing. Materials and Methods: We reviewed 20 lung cancer patients (7 upper lung patients, 4 middle lung patients, 9 lower lung patients) who received stereotactic body radiotherapy using abdominal compressor between April 2012 to April 2013. Coordinate shift values were obtained by using four-dimensional cone-beam CT (4D-CBCT) to investigate treatment set-up error and moving tumor position error. To investigate how much difference of each part, we compared 95% confidence interval, maximum values and minimum values of three-dimensional vector value and analyzed conformity degree through the Pearson square correlation coefficient. Results: 95% confidence interval of three-dimensional vector value of each part is 1.8~2.9 mm in upper lobe, 2.3~5.4 mm in middle lobe and 2.2~4.0 mm in lower lobe. Conformity degree was the result that respectively is LR direction 0.75, SI direction 0.68 and AP direction 0.63 in upper lobe, LR direction 0.82, SI direction 0.51 and AP direction 0.92 in middle lobe and LR direction 0.63, SI direction 0.50 and AP direction 0.34 in lower lobe. Conclusion: We showed difference by each site in lung tumor due to respiration by using abdominal compressor. Therefore, we must correct treatment set-up error as well as moving tumor position error by breathing. It is also considered to be useful that it is the use of 4D-CBCT when correcting the error due to various dynamic variation.

• The Journal of Korean Society for Radiation Therapy
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• v.29 no.2
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• pp.53-64
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• 2017

Purpose: To evaluate the usefulness of the $HexaPOD^{TM}$ evo RT system(6DoF couch) and the tendency of dose difference according to size of rotational direction error for volumetric rotational modulated radiotherapy(V-MAT) in patients with long target lengths. Therefore, it is suggested to recommend the need for rotational error correction. Materials and Methods: Ten patients with Esophagus cancer or Breast cancer including SCL treated with HexaPOD 6DoF(Six-Degree of Freedom) couch were included in this study. 6DoF couch was used to measure the difference in dose according to the rotation error in the directions of Rx(pitch), Ry(roll), and Rz(yaw). Each rotation error was applied. Positioning variation on x, y and z axis was verified and random variations were made by 6DoF couch with positioning variation. Modified DQA is conducted and point dose and gamma value are analyzed and compared. In addition, after applying the rotation error every $1^{\circ}$ to treatment plans of each target with a diameter of 3 cm, 5, 10, 15, and 20 cm respectively, gamma passing rate is being monitored by its aspect of change according to types and sizes of the target length and rotation error. Results: Mean error of the point dose and Gamma passing rate when the position variation was applied were $2.50{\pm}1.11%$ and $84.1{\pm}7.39%$ in the Rx direction, $2.36{\pm}1.16%$, and $81.0{\pm}8.49%$ in the Ry, $2.35{\pm}1.10%$ and $84.4{\pm}6.99%$ in the Rz direction, respectively. As a result of analysis on gamma passing rate according to types and sizes of the target length and rotation error, the gamma passing rate tended to decrease with increasing rotation error in the Rx and Rz directions except Ry direction. In particular, the lowest gamma passing rate (74.2 %) was in the case of $2.5^{\circ}$ rotation error in Rz direction of the target of 10 cm. Conclusion: The correction of the rotational error is needed for volumetric modulated radiotherapy of the treatment area with a long target length, and the use of 6DoF couch will improve the reproducibility of the patient position and the quality of the treatment.

• The Journal of Korean Society for Radiation Therapy
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• v.29 no.2
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• pp.33-41
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• 2017

Objectives: The aim of this study is to evaluate the reproducibility and usefulness of the images through the fusion of CT(Computed tomography) and MRI(Magnetic resonance imaging) using a self-manufactured phantom. We will also compare and analyze the target dose from acquired images. Materials and Methods: Using a self-manufactured phantom, CT images and MRI images are acquired by 1.5T and 3.0T of different magnetic fields. The reproducibility of the size and volume of the small holes present in the phantom is compared through the image from CT and 1.5T and 3.0T MRI, and dose changes are compared and analyzed on any target. Results: 13 small hole diameters were a maximum 31 mm and a minimum 27.54 mm in the CT scan and the were measured within an average of 29.28 mm 1 % compared to actual size. 1.5 T MRI images showed a maximum 31.65 mm and a minimum 24.3 mm, the average is 28.8 mm, which is within 1 %. 3.0T MRI images showed a maximum 30.2 mm and a minimum 27.92 mm, the average is 29.41 mm, which is within 1.3 %. The dose changes in the target were 95.9-102.1 % in CT images, 93.1-101.4 % in CT-1.5T MRI fusion images, and 96-102 % in CT-3.0T MRI fusion images. Conclusion: CT and MRI are applied with different algorithms for image acquisition. Also, since the organs of the human body have different densities, image distortion may occur during image acquisition. Because these inaccurate images description affects the volume range and dose of the target, accurate volume and location of the target can prevent unnecessary doses from being exposed and errors in treatment planning. Therefore, it should be applied to the treatment plan by taking advantage of the image display algorithm possessed by CT and MRI.

• Radiation Oncology Journal
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• v.27 no.2
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• pp.55-63
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• 2009

Purpose: This study was performed to objectively evaluate the rate of tumor response to hypofractionated radiotherapy for advanced squamous cell carcinomas of the head and neck. Materials and Methods: Thirty-one patients with advanced squamous cell carcinoma of the head and neck, who were treated by hypofractionated radiotherapy with 3 Gy per fraction for palliative purpose between 1998 and 2008, were reviewed retrospectively. Every tumor-volume was measured and evaluated from CT (computed tomography) images obtained before and 2~3 months after radiotherapy. The radiation toxicity was assessed during and after radiotherapy. A statistical analysis was performed to investigate overall survival, progressionfree survival, and the prognostic factors for survival and response. Results: The median age of the study patients was 70 years. In addition, 85% of the patients were in stage 4 cancer and 66.7% had an ECOG performance status of 1~2. The mean tumor-volume was 128.4 cc. Radiotherapy was administered with a total dose of 24~45 Gy (median: 36 Gy) over 10~25 days. Twenty-nine patients were treated with 30 Gy or more. The observed complete response rate was 12.9% and the partial response rate was 61.3%. Median survival time was 8.9 months and the 1-year progression-free survival rate was 12.9%. The treatment response rate was confirmed as a prognostic factor in the rate of survival. The primary site, stage, tumor-volume, radiotherapy field and overall radiation-dose showed a significant relationship with survival and treatment response. No grade 4 toxicity was observed during and after radiotherapy. Conclusion: There was an objective tumor-regression in about 74% of patients treated by hypofractionated radiotherapy. Further evaluation is needed to select the appropriate fraction-size and patient who may require the additional radiotherapy.

• The Korean Journal of Pharmacology
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• v.23 no.1
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• pp.1-7
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• 1987

The renal handling and tissue distribution of pyrazinamide were studied after administration of single dose intravenous injection for 15 min or constant infusion in New Zealand White rabbits. Peak pyrazinamide serum concentration ranged from 57.3 to $105.0{\mu}g/ml$ ($mean{\pm}SD;83.0{\pm}17.8$). The mean half-life of the a phase was $0.143{\pm}0.047$ hr while the ${\beta}$ phase ranged from 1.66 to 3.25 hr($mean{\pm}SD;2.38{\pm}0.57$). The mean steady-state volume of distribution in non-compartmental model was $0.935{\pm}0.362\;L/kg$ Excretion ratio of pyrazinamide was dramatically reduced from 1.02 to 0.30 when unbound serum pyrazinamide concentration was increased from 6.04 to $60.9\;{\mu}g/ml$. The urine flow dependency of renal clearance of pyrazinamide was demonstrated in steady-state serum concentration. The tissue/serum concentration ratio of pyrazinamide was highest in kidney and lowest in skeletal muscle among the tissues examined. The results suggested that a large fraction of pyrazinamide filtered by glomerulus and secreted by renal tubule was reabsorbed and this tubular reabsorption of pyrazinamide might be greatly influenced by urine flow.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.1
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• pp.11-14
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• 2012

Purpose: Anisotropic Analytical Algorithm (AAA) provides more accurate dose calculation regarding impact on scatter and tissue inhomogeneity in comparison to Pencil Beam Convolution (PBC) algorithm. This study tries to analyze the difference of dose distribution according to PBC algorithm and dose calculation algorithm of AAA on breast cancer tangential plan. Materials and Methods: Computerized medical care plan using Eclipse treatment planning system (version 8.9, VARIAN, USA) has been established for the 10 breast cancer patients using 6 MV energy of Linac (CL-6EX, VARIAN, USA). After treatment plan of Conventional Radiation Therapy plan (Conventional plan) and Field-in-Field Intensity Modulated Radiation Therapy plan (FiF plan) using PBC algorithm has been established, MU has been fixed, implemented dose calculation after changing it to AAA, and compared and analyzed treatment plan using Dose Volume Histogram (DVH). Results: Firstly, as a result of evaluating PBC algorithm of Conventional plan and the difference according to AAA, the average difference of CI value on target volume has been highly estimated by 0.295 on PBC algorithm and as a result of evaluating dose of lung, $V_{47Gy}$ and $V_{45Gy}$ has been highly evaluated by 5.83% and 4.04% each, Mean dose, $V_{20Gy}$, $V_{5Gy}$, $V_{3Gy}$ has been highly evaluated 0.6%, 0.29%, 6.35%, 10.23% each on AAA. Secondly, in case of FiF plan, the average difference of CI value on target volume has been highly evaluated on PBC algorithm by 0.165, and dose on ipsilateral lung, $V_{47Gy}$, $V_{45Gy}$, Mean dose has been highly evaluated 6.17%, 3.80%, 0.15% each on PBC algorithm, $V_{20Gy}$, $V_{5Gy}$, $V_{3Gy}$ has been highly evaluated 0.14%, 4.07%, 4.35% each on AAA. Conclusion: When calculating with AAA on breast cancer tangential plan, compared to PBC algorithm, Conformity on target volume of Conventional plan, FiF plan has been less evaluated by 0.295, 0.165 each. For the reason that dose of high dose region of ipsilateral lung has been showed little amount, and dose of low dose region has been showed much amount, features according to dose calculation algorithm need to be considered when we evaluate dose for the lungs.

• The Journal of Korean Society for Radiation Therapy
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• v.31 no.2
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• pp.51-63
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• 2019

Purpose: Radiation therapy for breast cancer should consider the change in breast shape due to breathing and swelling. In this study, we evaluate the benefit of using virtual bolus for IMRT of left breast cancer. Materials and methods: 10 patients with early breast cancer who received radiation therapy after breastconserving surgery compared the VMAT and IMRT plans using the virtual bolus method and without using it. The first analysis compared the V95%, HI, CI of treatment volume, Dmean, V5, V20, V30 of ipsilateral lung, and Dmean of heart in VMAT plan made using the virtual bolus method(VMAT_VB) to the plan without using it(VMAT_NoVB) in case there is no change in the breast. In IMRT, the same method was used. The second analysis compared TCP and NTCP based on each treatment plan in case there is 1cm expansion of treatment volume. Result: If there is no change in breast, V95% in VB Plan(VMAT_VB, IMRT_VB) and NoVB Plan(VMAT_NoVB, IMRT_NoVB) is all over 99% on each treatment plan. V95% in VMAT_NoVB and VMAT_VB is 99.80±0.17% and 99.75±0.12%, V95% in IMRT_NoVB and IMRT_VB is 99.67±0.26% and 99.51±0.15%. Difference of HI, CI is within 3%. OAR dose in VB plan is a little high than NoVB plan, and did not exceed guidelines. If there is 1cm change in breast, VMAT_NoVB and IMRT_NoVB are less effective for treatment. But VMAT_VB and IMRT_VB continue similar treatment effect compared in case no variation of breast. Conclusion: This study confirms the benefit of using a virtual bolus during VMAT and IMRT to compensate potential breast shape modification.

• Tuberculosis and Respiratory Diseases
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• v.59 no.1
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• pp.23-29
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• 2005

Background : Chronic obstructive lung disease is characterized by smoke-related, gradually progressive, fixed airflow obstructions. However, some studies suggested that a reversible bronchial obstruction is common in chronic obstructive lung disease. Such reversibility persists despite the continued treatment with aerosolized bronchodilators and it appears to be related to the diminution in symptoms. The isolated volume response to a bronchodilator is defined as a remarkable increase in the FVC in response to the administration of a bronchodilator whereas the $FEV_1$ remains unchanged. This has been suggested in patients with severe emphysema. Therefore, the aim of this study was to determine the relationship between the response to a bronchodilator and the severity of an airflow obstruction in COPD patients using the GOLD classification. Methods : This study examined 124 patients with an airway obstruction. The patients underwent spirometry, and the severity of the airflow obstruction was classified by GOLD. The response groups were categorized by an improvement in the FVC or $FEV_1$ > 12%, and each group was analyzed. Results : Most subjects were men with a mean age of $65.9{\pm}8.5$ years. The mean smoking history was $41.26{\pm}20.1$ pack years. The isolated volume response group had relatively low $FEV_1$ and FVC values compared with the other groups. (p<0.001) Conclusion : In this study, an isolated volume response to a bronchodilator is a characteristic of a severe airway obstruction, which is observed in patient with a relatively poorer baseline lung function.

• The Journal of Korean Society for Radiation Therapy
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• v.31 no.1
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• pp.33-41
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• 2019

Purpose : To evaluate the effectiveness of Jaw-tracking(JT) technique in Intensity-modulated radiation therapy(IMRT) and Volumetric-modulated arc therapy(VMAT) for radiation therapy of esophageal cancer by analyzing volume dose of perimetrical normal organs along with the low-dose volume regions. Materials and Method: A total of 27 patients were selected who received radiation therapy for esophageal cancer with using $VitalBeam^{TM}$(Varian Medical System, U.S.A) in our hospital. Using Eclipse system(Ver. 13.6 Varian, U.S.A), radiation treatment planning was set up with Jaw-tracking technique(JT) and Non-Jaw-tracking technique(NJT), and was conducted for the patients with T-shaped Planning target volume(PTV), including Supraclavicular lymph nodes(SCL). PTV was classified into whether celiac area was included or not to identify the influence on the radiation field. To compare the treatment plans, Organ at risk(OAR) was defined to bilateral lung, heart, and spinal cord and evaluated for Conformity index(CI) and Homogeneity index(HI). Portal dosimetry was performed to verify a clinical application using Electronic portal imaging device(EPID) and Gamma analysis was performed with establishing thresholds of radiation field as a parameter, with various range of 0 %, 5 %, and 10 %. Results: All treatment plans were established on gamma pass rates of 95 % with 3 mm/3 % criteria. For a threshold of 10 %, both JT and NJT passed with rate of more than 95 % and both gamma passing rate decreased more than 1 % in IMRT as the low dose threshold decreased to 5 % and 0 %. For the case of JT in IMRT on PTV without celiac area, $V_5$ and $V_{10}$ of both lung showed a decrease by respectively 8.5 % and 5.3 % in average and up to 14.7 %. A $D_{mean}$ decreased by $72.3{\pm}51cGy$, while there was an increase in radiation dose reduction in PTV including celiac area. A $D_{mean}$ of heart decreased by $68.9{\pm}38.5cGy$ and that of spinal cord decreased by $39.7{\pm}30cGy$. For the case of JT in VMAT, $V_5$ decreased by 2.5 % in average in lungs, and also a little amount in heart and spinal cord. Radiation dose reduction of JT showed an increase when PTV includes celiac area in VMAT. Conclusion: In the radiation treatment planning for esophageal cancer, IMRT showed a significant decrease in $V_5$, and $V_{10}$ of both lungs when applying JT, and dose reduction was greater when the irradiated area in low-dose field is larger. Therefore, IMRT is more advantageous in applying JT than VMAT for radiation therapy of esophageal cancer and can protect the normal organs from MLC leakage and transmitted doses in low-dose field.

• Spatial Information Research
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• v.20 no.2
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• pp.105-115
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• 2012

This paper is aimed at offering preliminary data that improve the effectiveness of district unit planning, which has adopted to make comfortable environment of national land, to prevent urban sprawl rural area and to perform systematic maintenance of the existing urban area, by case study analysis about the applied possibility of GIS-based augmented reality. To do this, we developed the augmented reality based urban planning support system and checked the parts that can be applied of augmented reality techniques in the process of district units planning. And we analysed about merits and demerits of augmented reality techniques through comparative analysis, which is about form, arrangement, use, and height of building, building coverage ratio, floor area ratio and landscape planning in the case study area, the Yeosu district(located in Seongnam).