• The Journal of Korean Society for Radiation Therapy
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• v.26 no.2
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• pp.171-176
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• 2014

Purpose : Changing the calculation grid of AAA in Lung SABR plan and to analyze the changes in target dose, and investigated the effects associated with it, and considered a suitable method of application. Materials and Methods : 4D CT image that was used to plan all been taken with Brilliance Big Bore CT (Philips, Netherlands) and in Lung SABR plan($Eclipse^{TM}$ ver10.0.42, Varian, the USA), use anisotropic analytic algorithm(AAA, ver.10, Varian Medical Systems, Palo Alto, CA, USA) and, was calculated by the calculation grid 1.0, 3.0, 5.0 mm in each Lung SABR plan. Results : Lung SABR plan of 10 cases are using each of 1.0 mm, 3.0 mm, 5.0 mm calculation grid, and in case of use a 1.0 mm calculation grid $V_{98}$. of the prescribed dose is about $99.5%{\pm}1.5%$, $D_{min}$ of the prescribed dose is about $92.5{\pm}1.5%$ and Homogeneity Index(HI) is $1.0489{\pm}0.0025$. In the case of use a 3.0 mm calculation grid $V_{98}$ dose of the prescribed dose is about $90{\pm}4.5%$, $D_{min}$ of the prescribed dose is about $87.5{\pm}3%$ and HI is about $1.07{\pm}1$. In the case of use a 5.0 mm calculation grid $V_{98}$ dose of the prescribed dose is about $63{\pm}15%$, $D_{min}$ of the prescribed dose is about $83{\pm}4%$ and HI is about $1.13{\pm}0.2$, respectively. Conclusion : The calculation grid of 1.0 mm is better improves the accuracy of dose calculation than using 3.0 mm and 5.0 mm, although calculation times increase in the case of smaller PTV relatively. As lung, spread relatively large and low density and small PTV, it is considered and good to use a calculation grid of 1.0 mm.

• The Korean journal of internal medicine
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• v.33 no.6
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• pp.1137-1142
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• 2018

Background/Aims: This study tested the hypothesis that prolonged low-dose cyclophosphamide (CTX) treatment after pulse therapy attenuate paraquat (PQ)-induced lung injury in rats. Methods: PQ (25 mg/kg) was administered intraperitoneally to induce PQ-intoxicated rat model. The rats were randomly divided into four groups: control group (1 mL/day saline solution for 14 days), PQ group (1 mL/day saline solution for 14 days after PQ exposure), pulse group (15 mg/kg/day CTX in 1 mL of saline solution for 2 days and subsequent 1 mL/day saline solution for 12 days), and prolonged low-dose group (15 mg/kg/day CTX in 1 mL of saline solution for 2 days and subsequent 1.5 mg/kg/day CTX in 1 mL of saline solution for 12 days). A 14-day follow-up was conducted to determine the survival rat, and lung hydroxyproline (HYP), wet-to-dry weight ratios (W/Dc) and histopathological changes were evaluated. Results: Results showed similar survival rate (55% vs. 50%, p > 0.05) between prolonged low-dose and pulse groups. Lung W/Dc ($4.94{\pm}0.38$ vs. $5.47{\pm}0.28$, p < 0.01), HYP ($3.34{\pm}0.29{\mu}g/mg$ vs. $3.65{\pm}0.19{\mu}g/mg$, p < 0.001), and fibrosis score ($2.69{\pm}0.84$ vs. $3.13{\pm}0.63$, p < 0.05) were lower in prolonged low-dose group than those in the pulse group. Conclusions: These findings suggested prolonged low-dose CTX treatment after pulse therapy could attenuate PQ-induced lung injury in rats.

• Progress in Medical Physics
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• v.34 no.4
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• pp.48-54
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• 2023

Purpose: In this study, the dosimetric characteristics of lung stereotactic body radiotherapy (SBRT) plans using the new Halcyon system were analyzed to assess its suitability. Methods: We compared the key dosimetric parameters calculated for the Halcyon SBRT plans with those of a conventional C-arm linear accelerator (LINAC) equipped with a high-definition multileaf collimator (HD-MLC)-Trilogy Tx. A total of 10 patients with non-small-cell lung cancer were selected, and all SBRT plans were generated using the RapidArc technique. Results: Trilogy Tx exhibited significant superiority over Halcyon in terms of target dose coverage (conformity index, homogeneity index, D_{0.1 cc}, and D_95%) and dose spillage (gradient). Trilogy Tx was more efficient than Halcyon in the lung SBRT beam delivery process in terms of the total number of monitor units, modulation factor, and beam-on time. However, it was feasible to achieve a dose distribution that met SBRT plan requirements using Halcyon, with no significant differences in satisfying organs at risk dose constraints between both plans. Conclusions: Results confirm that Halcyon is a viable alternative for performing lung SBRT in the absence of a LINAC equipped with HD-MLC. However, extra consideration should be taken in determining whether to use Halcyon when the planning target volume setting is enormous, as in the case of significant tumor motions.

• Journal of Preventive Medicine and Public Health
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• v.55 no.3
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• pp.273-279
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• 2022

Objectives: The aim of this study was to present the baseline results of a pilot project conducted to evaluate the effectiveness of lung cancer screening using low-dose chest computed tomography (CT) in regions with excessive radon levels in the Republic of Kazakhstan. Methods: In total, 3671 participants were screened by low-dose chest CT. Current, former, and never-smokers who resided in regions with elevated levels of radon in drinking water sources and indoor air, aged between 40 and 75 with no history of any cancer, and weighing less than 140 kg were included in the study. All lung nodules were categorized according to the American College of Radiology Lung Imaging Reporting and Data System (Lung-RADS 1.0). Results: Overall, 614 (16.7%) participants had positive baseline CT findings (Lung-RADS categories 3 and 4). Seventy-four cancers were detected, yielding an overall cancer detection rate of 2.0%, with 10.8% (8/74) stage I and a predominance of stage III (59.4%; 44/74). Women never-smokers and men current smokers had the highest cancer detection rates, at 2.9% (12/412) and 6.1% (12/196), respectively. Compared to never-smokers, higher odds ratios (ORs) of lung cancer detection were found in smokers (OR,2.48; 95% confidence interval [CI], 1.52 to 4.05, p<0.001) and former smokers (OR, 2.32; 95% CI, 1.06 to 5.06, p=0.003). The most common histologic type of cancer was adenocarcinoma (58.1%). Conclusions: Implementation of low-dose CT screening for lung cancer in regions with elevated radon levels is an effective method for both smokers and never-smokers.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.174-176
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• 2002

A total of 134 patients with stage 1 of non-small cell lung cancer treated by carbon ion beam of HIMAC NIRS were investigated for control rate and delivered dose. The delivered dose of every patient was converted to biological effective dose (BED) of LQ model using fraction number, dose per fraction and alpha beta ratio which shows the maximum correlation between BED and tumor control. The BED of every patient was classified to establish a BED response curve for control. Assuming fraction numbers, dose response curves were introduced from BED response curve. The total doses to realize several control rates were obtained for the treatment of small fraction number.

• Progress in Medical Physics
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• v.7 no.2
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• pp.47-55
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• 1996

Total Body Irradiation(TBI) is one of the essential treatment modalities in bone marrow transplantation for leukemia and lymphoma. Various techniques and dose regimens were introduced with sevelal advantages and disadvantages. In TBI, lung block could reduce lung dose to 75％ of original beam for decreasing lung dose with homogenous total body irradiation. Accurate provision for specified dose and the desired homogeneity are essential before clinical total body irradiation. When performed in total body irradiation, the problem obtain uniform dose distribution in brain, neck, lung, umbilicus, pelvis and leg. Authors compared to dose distribution with method 1 and method 2. The method 1 used compensating filters for homogeneous dose distribution(Minesota University Method). The method 2 used fixing frame made in aeryl developing authors. Results were following. 1. Method 1 was showed dose distribution from 95.6％ to 100％, method 2 showed dose distribution from 95.4％ to 100％. 2. Method 2 was showed different to 3.4％ at skin region and midline in the brain. In the neck, showed different to 1.5％. In the umbilicus. showed different to 2.3％.

• The Journal of Korean Society for Radiation Therapy
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• v.31 no.1
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• pp.7-15
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• 2019

Purpose: The purpose of this study is to evaluate beam delivery accuracy for small sized lung SBRT through experiment. In order to assess the accuracy, Eclipse TPS(Treatment planning system) equipped Acuros XB and radiochromic film were used for the dose distribution. Comparing calculated and measured dose distribution, evaluated the margin for PTV(Planning target volume) in lung tissue. Materials and Methods : Acquiring CT images for Rando phantom, planned virtual target volume by size(diameter 2, 3, 4, 5 cm) in right lung. All plans were normalized to the target Volume=prescribed 95 % with 6MV FFF VMAT 2 Arc. To compare with calculated and measured dose distribution, film was inserted in rando phantom and irradiated in axial direction. The indexes of evaluation are percentage difference(%Diff) for absolute dose, RMSE(Root-mean-square-error) value for relative dose, coverage ratio and average dose in PTV. Results: The maximum difference at center point was -4.65 % in diameter 2 cm size. And the RMSE value between the calculated and measured off-axis dose distribution indicated that the measured dose distribution in diameter 2 cm was different from calculated and inaccurate compare to diameter 5 cm. In addition, Distance prescribed 95 % dose($D_{95}$) in diameter 2 cm was not covered in PTV and average dose value was lowest in all sizes. Conclusion: This study demonstrated that small sized PTV was not enough covered with prescribed dose in low density lung tissue. All indexes of experimental results in diameter 2 cm were much different from other sizes. It is showed that minimized PTV is not accurate and affects the results of radiation therapy. It is considered that extended margin at small PTV in low density lung tissue for enhancing target center dose is necessary and don't need to constraint Maximum dose in optimization.

• Radiation Oncology Journal
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• v.13 no.2
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• pp.199-203
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• 1995

Purpose: To evaluate the dose under lung block as a function of depth and the effectiveness of a block as a function of block width. Materials and Methods : Field size of mantle field was $22.8{\times}32.4cm^2.$ Dose distribution of the mantle field was measured with two dimensional water phantom system. To analyze the effectiveness of the lung block. central axis plane, 5cm off-axis plane, and 10cm off-axis plane were studied. Results: The dose under the lung block was recorded with maximum at the depth between 5cm and 10cm. In the central axis plane, dosimetric block width was $10-15\%$ less than physical block width. In the 5cm off-axis plane, dosimetric block width was $4-9\%$ less than physical block width. In the 10cm off-axis plane, dosimetric block width was $2\%$ less than physical block width. Conclusion: Depth dependence of the dose under the lung block was founded. Also, block width dependence of the lung block was founded. To induce the accurate relation between the physical block width and the 'effective' block width, it needs more detailed understanding of the variables involved.

• Nuclear Engineering and Technology
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• v.40 no.7
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• pp.539-550
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• 2008

Lung cancer is the most prevalent global cancer, ${\sim}90%$ of which is caused by cigarette smoking. The LNT hypothesis has been inappropriately applied to estimate lung cancer risk due to ionizing radiation. A threshold of ${\sim}1\;Gy$ for lung cancer has been observed in never smokers. Lung cancer risk among nuclear workers, radiologists and diagnostically exposed patients was typically reduced by ${\sim}40%$ following exposure to <100 mSv low LET radiation. The consistency and magnitude of reduced lung cancer in nuclear workers and occurrence of reduced lung cancer in exposed non-worker populations could not be explained by the HWE. Ecologic studies of indoor radon showed highly significant reductions in lung cancer risk. A similar reduction in lung cancer was seen in a recent well designed case-control study of indoor radon, indicating that exposure to radon at the EPA action level is associated with a decrease of ${\sim}60%$ in lung cancer. A cumulative whole-body dose of ${\sim}1\;Gy$ gamma rays is associated with a marked decrease in smoking-induced lung cancer in plutonium workers. Low dose, low LET radiation appears to increase apoptosis mediated removal of $\alpha$-particle and cigarette smoke transformed pulmonary cells before they can develop into lung cancer.

• Journal of Trauma and Injury
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• v.18 no.1
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• pp.53-63
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• 2005

Purpose: This study was designed to determine if methylene blue inhibited the lipid peroxidation, the production of NO, and the gene expression of iNOS in acute lung injury induced by paraquat and if the inhibitory effect was dose dependent. Methods: Female Sprague-Dawley rats were divided into four groups: the control group, the group treated with paraquat only, the group treated with paraquat and a low dose of methylene blue (2 mg/kg), and the group treated with paraquat and a high dose of methylene blue (20 mg/kg). Methylene blue was administered via the jugular vein 1 h after paraquat administration, and animals were sacrificed 6 and 24 h after paraquat administration. Malondialdehyde (MDA) as lipid peroxidation, reduced glutathione (GSH) as an antioxidant defense, the plasma NO concentration, and the expression of iNOS mRNA in the lung tissue were measured Results: Lung MDA contents decreased, with no significant difference between the methylene-blue groups and the paraquat-only group. Lung GSH contents were significantly elevated at 24 h in the methylene-blue groups compared with the paraquat-only group. Plasma NO concentrations were significantly reduced at 6 and 24 h in the methylene-blue groups compared with the paraquat-only group. There was also a significant decrease in the plasma NO concentration at 6 h in the high-dose methylene-blue group compared with the low-dose methylene-blue group. The expression of iNOS mRNA in the lung tissue was slightly decreased in the methylene-blue groups. It was also markedly increased at 24 h in the paraquat-only group compared with the methylene-blue groups. The gene expression was relatively decreased in the high-dose methylene-blue group compared with the low-dose methylene-blue group. Conclusion: This study suggests that methylene blue has an inhibitory effect on the plasma NO concentration and the expression of iNOS mRNA in lung injury induced by paraquat. No inhibitory effect of methylene blue on lipid peroxidation or dose-dependent inhibitory effects were clearly shown.