42 research outputs found

    Dosimetric Effects of Rotational Setup Error in Volumetric Modulated Arc Radiotherapy on Brain Tumor Patients

    Get PDF
    Introduction: This study examined the dosimetric effects based on the rotational setup error to correct patient setup errors occur during volumetric modulated arc radiotherapy (VMAT) for brain tumor patients. Material and Methods: This study included 1129 cases of cone beam computed tomography (CBCT) images obtained from 46 brain tumor patients, who experienced VMAT and used the 6DoF (degree of freedom) treatment couch. The dosimetric effects regarding the application of the rotational setup error were examined by comparing the treatment plans. Results: The mean patient setup errors at the lateral (X-axis), longitudinal (Y-axis), and vertical (Z-axis) directions were 0.1±1.4, 0.0±1.1, and -0.4±1.2 mm, respectively. The pitch, roll, and yaw were -0.29±0.61°,-0.42±0.98°, and -0.53±0.69°, respectively. When an absolute value was taken for the setup error, the mean error was 1.06±0.14 mm at the three translation directions, and the error of rotation was 0.82±0.14°, showing a larger error than that of translation. In terms of the mean dose difference by each region of interest (ROI) before and after correcting for the rotational setup error on the treatment plan, Brain_max was 2.17 Gy, and Brain_mean was 0.28 Gy, whereas the maximum and mean of Brain_stem were -3.58 and -4.43 Gy, respectively. These findings suggested a dose difference according to the correction of the rotational setup error. Conclusion: This study indicated that the dose effect is influenced by the rotational setup error in VMAT of brain tumor patients. Moreover, the 6DoF positional correction could reduce the positional uncertainties and deliver a more accurate dose

    The effects of direct hemoperfusion with polymyxin B-immobilized fiber in patients with acute exacerbation of interstitial lung disease

    Get PDF
    Background Acute exacerbation of interstitial lung disease (AE-ILD) causes clinically significant deterioration and has an extremely poor prognosis with high mortality. Recently, several studies reported the effectiveness of direct hemoperfusion with a polymyxin B-immobilized fiber column (PMX-DHP) in patients with AE-ILD as a potential therapy. This study describes the clinical effectiveness and safety of PMX-DHP in patients with AE-ILD. Methods We retrospectively reviewed the medical records of 10 patients (11 episodes) with AE-ILD treated with PMX-DHP from January 2018 to June 2019. We compared laboratory and physiologic data of the ratio of partial pressure arterial oxygen to fraction of inspired oxygen (P/F ratio) and level of inflammatory markers before and after implementation of PMX-DHP. Results Ten patients were included according to the 2016 revised definition of acute exacerbation of idiopathic pulmonary fibrosis (IPF). Nine patients had IPF and one patient had fibrotic nonspecific interstitial pneumonia. Most patients (90.9%) were treated with a steroid pulse, and four patients (36.4%) were treated with an immunosuppressant. The median number of PMX-DHP cycles was 2, and the median duration of each cycle was 6 hours. After PMX-DHP, the mean P/F ratio improved (86 [range, 63–106] vs. 145 [86–260], P=0.030) and interleukin-6 and c-reactive protein decreased (79 [35–640] vs. 10 [5–25], P=0.018 and 14 [4–21] vs. 5 [2–6], P=0.019, respectively). The 30-day mortality rate was 27.3% and the 90-day mortality rate was 72.7%. Conclusions PMX-DHP treatment improved P/F ratio and reduced inflammatory markers in AE-ILD patients

    The 'Harmonizing Optimal Strategy for Treatment of coronary artery stenosis - sAfety & effectiveneSS of drug-elUting stents & antiplatelet REgimen' (HOST-ASSURE) trial: study protocol for a randomized controlled trial

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Second-generation drug-eluting stents (DES) have raised the bar of clinical performance. These stents are mostly made from cobalt chromium alloy. A newer generation DES has been developed from platinum chromium alloy, but clinical data regarding the efficacy and safety of the platinum chromium-based everolimus-eluting stent (PtCr-EES) is limited, with no comparison data against the cobalt chromium-based zotarolimus-eluting stent (CoCr-ZES). In addition, an antiplatelet regimen is an integral component of medical therapy after percutaneous coronary intervention (PCI). A 1-week duration of doubling the dose of clopidogrel (double-dose antiplatelet therapy (DDAT)) was shown to improve outcome at 1 month compared with conventional dose in acute coronary syndrome (ACS) patients undergoing PCI. However in Asia, including Korea, the addition of cilostazol (triplet antiplatelet therapy (TAT)) is used more commonly than doubling the dose of clopidogrel in high-risk patients.</p> <p>Methods</p> <p>In the 'Harmonizing Optimal Strategy for Treatment of coronary artery stenosis - sAfety & effectiveneSS of drug-elUting stents & antiplatelet REgimen' (HOST-ASSURE) trial, approximately 3,750 patients are being prospectively and randomly assigned in a 2 × 2 factorial design according to the type of stent (PtCr-EES vs CoCr-ZES) and antiplatelet regimen (TAT vs DDAT). The first primary endpoint is target lesion failure at 1 year for the stent comparison, and the second primary endpoint is net clinical outcome at 1 month for comparison of antiplatelet therapy regimen.</p> <p>Discussion</p> <p>The HOST-ASSURE trial is the largest study yet performed to directly compare the efficacy and safety of the PtCr-EES versus CoCr-ZES in an 'all-comers' population. In addition, this study will also compare the clinical outcome of TAT versus DDAT for 1-month post PCI.</p> <p>Trial registration</p> <p>ClincalTrials.gov number <a href="http://www.clinicaltrials.gov/ct2/show/NCT01267734">NCT01267734</a>.</p

    Clinical features and outcomes of gastric variceal bleeding: retrospective Korean multicenter data

    Get PDF
    Background/AimsWhile gastric variceal bleeding (GVB) is not as prevalent as esophageal variceal bleeding, it is reportedly more serious, with high failure rates of the initial hemostasis (>30%), and has a worse prognosis than esophageal variceal bleeding. However, there is limited information regarding hemostasis and the prognosis for GVB. The aim of this study was to determine retrospectively the clinical outcomes of GVB in a multicenter study in Korea.MethodsThe data of 1,308 episodes of GVB (males:females=1062:246, age=55.0±11.0 years, mean±SD) were collected from 24 referral hospital centers in South Korea between March 2003 and December 2008. The rates of initial hemostasis failure, rebleeding, and mortality within 5 days and 6 weeks of the index bleed were evaluated.ResultsThe initial hemostasis failed in 6.1% of the patients, and this was associated with the Child-Pugh score [odds ratio (OR)=1.619; P<0.001] and the treatment modality: endoscopic variceal ligation, endoscopic variceal obturation, and balloon-occluded retrograde transvenous obliteration vs. endoscopic sclerotherapy, transjugular intrahepatic portosystemic shunt, and balloon tamponade (OR=0.221, P<0.001). Rebleeding developed in 11.5% of the patients, and was significantly associated with Child-Pugh score (OR=1.159, P<0.001) and treatment modality (OR=0.619, P=0.026). The GVB-associated mortality was 10.3%; mortality in these cases was associated with Child-Pugh score (OR=1.795, P<0.001) and the treatment modality for the initial hemostasis (OR=0.467, P=0.001).ConclusionsThe clinical outcome for GVB was better for the present cohort than in previous reports. Initial hemostasis failure, rebleeding, and mortality due to GVB were universally associated with the severity of liver cirrhosis

    Crop Cultivation Underneath Agro-Photovoltaic Systems and Its Effects on Crop Growth, Yield, and Photosynthetic Efficiency

    No full text
    Agro-photovoltaics (APV) could be the optimal means of sustainable development in agricultural areas once a few challenges are overcome, perhaps the greatest of which is the constant shading from AVP structures. This study examined how the growth and yield of rice, potato, sesame, and soybean crops could be optimized when grown underneath different APV systems. The solar radiation, shading levels, and temperatures during crop cultivation were measured. In addition, the photosynthetic efficiency was measured at different growth stages. Adjacent to the APV systems were the control plots with full sun. In these studies with potato crops grown under APV systems, most growth and yield parameters were similar to those grown in the control plot except for the plant height. On the other hand, sesame crops grown underneath the APV systems had a lower stem length, effective branching number, 1000 seed weight, and a reduced yield of 19% compared to the crops from the control plot. In two distant locations (Paju and Youngkwang), soybean crops grown underneath APV systems at both sites showed increased ungrained ratios per pod and a reduced yield of 18&ndash;20% compared to the control plot. Finally, rice crops cultivated underneath the APV systems had a lower panicle number per hill, spikelet number per panicle, 1000 seed weight, and yield reduction of 13&ndash;30% compared to the control plot. Overall, crops grown underneath the APV systems had a greater plant height and stem length. Moreover, the solar radiation and PAR underneath the APV systems were also lower than in the control plots. The photosynthetic efficacy in rice plants grown underneath the APV systems was lower than in the control plots. The photosynthetic efficacy may help lower the crop yield when cultivation is underneath an APV system

    Crop Cultivation Underneath Agro-Photovoltaic Systems and Its Effects on Crop Growth, Yield, and Photosynthetic Efficiency

    No full text
    Agro-photovoltaics (APV) could be the optimal means of sustainable development in agricultural areas once a few challenges are overcome, perhaps the greatest of which is the constant shading from AVP structures. This study examined how the growth and yield of rice, potato, sesame, and soybean crops could be optimized when grown underneath different APV systems. The solar radiation, shading levels, and temperatures during crop cultivation were measured. In addition, the photosynthetic efficiency was measured at different growth stages. Adjacent to the APV systems were the control plots with full sun. In these studies with potato crops grown under APV systems, most growth and yield parameters were similar to those grown in the control plot except for the plant height. On the other hand, sesame crops grown underneath the APV systems had a lower stem length, effective branching number, 1000 seed weight, and a reduced yield of 19% compared to the crops from the control plot. In two distant locations (Paju and Youngkwang), soybean crops grown underneath APV systems at both sites showed increased ungrained ratios per pod and a reduced yield of 18–20% compared to the control plot. Finally, rice crops cultivated underneath the APV systems had a lower panicle number per hill, spikelet number per panicle, 1000 seed weight, and yield reduction of 13–30% compared to the control plot. Overall, crops grown underneath the APV systems had a greater plant height and stem length. Moreover, the solar radiation and PAR underneath the APV systems were also lower than in the control plots. The photosynthetic efficacy in rice plants grown underneath the APV systems was lower than in the control plots. The photosynthetic efficacy may help lower the crop yield when cultivation is underneath an APV system

    Growth, Yield, and Grain Quality of Barley (Hordeum vulgare L.) Grown across South Korean Farmlands with Different Temperature Distributions

    No full text
    Climate change has disrupted several aspects of food systems, but perhaps one of the most alarming effects on global nutrition is the decrease in grain production as well as the reduction in the protein content and quality of the grain. Over the last several decades, due to climate change, suitable areas in Korea for barley cultivation have been moving northward compared to the past. Thus, the objective of this study was to determine how different climatic factors such as temperature impact barley growth at different stages (December, February, and April) and the yield at harvest in four group areas (G1, G2, G3, and G4) with different climates. Differences in the temperatures between areas during the growing season and the variability in growth and yields were noted. Additionally, the chemical composition of the soils and the mineral content of the leaves at the heading stage as well as the main constituents and amino acid composition of the barley seeds grown in different areas were considered. On average, the tiller number/m2, plant height, and dry aboveground plant parts/m2 in G1 areas were lower than in other group areas when measured before overwintering (December), after overwintering (February), and at the heading stage (April). However, there was no difference in these parameters between G2 and G3 areas. In 2020, the order of yield levels was G4 &gt; G2 = G3 &gt; G1. The yield in G1 areas was 37% less than in G4 areas. In 2021, yield levels were similar with the order of yield being G4 = G3 &gt; G1 = G2. Also similar to the prior year, yield in G1 areas was 39% less than in G4 areas. The minimum and daily average temperatures during the growing season (October to June) were in the order of G4 &gt; G3 &gt; G2 &gt; G1. Growth parameters in the colder G1 areas were lower than in other group areas, which suggests that the minimum and daily average temperatures in December, February, and April may be responsible for the lower crop growth and yield. Crude protein, lipid, and ash contents in the G1 and G2 areas were higher than in G3 and G4 areas. There was no variation in most kinds of amino acids between the group areas. Organic matter, available phosphoric acid, potassium (K), calcium (Ca), and zinc (Zn) contents in the soil of G1 areas were higher than in soils elsewhere. In addition, there was no consistency among most other mineral contents in the plants between the group areas. Overall, the growth and yield in G1 areas were lower than in other areas. Thus, it was concluded that these areas were still not suitable for barley cultivation regardless of climate change

    Effects of Si Addition on Microstructure and Mechanical Properties of the Al Alloys with High Cr Content Prepared by Gas Atomization and SPS Processes

    No full text
    This research describes effects of Si addition on microstructure and mechanical properties of the Al-Cr based alloys prepared manufactured using gas atomization and SPS (Spark Plasma Sintering) processes. The Al-Cr-Si bulks with high Cr and Si content were produced successfully using SPS sintering process without crack and obtained fully dense specimens close to nearly 100% T. D. (Theoretical Density). Microstructure of the as-atomized Al-Cr-Si alloys with high contents of Cr and Si was composed multi-phases with hard and thermally stable such as Al13Cr4Si4, AlCrSi, Al8Cr5 and Cr3Si intermetallic compounds. The average hardness values were 703 Hv for S5, 698 Hv for S10 and 824 Hv for S20 alloy. Enhancement of hardness value was resulted from the formation of the multi-intermetallic compound with hard and thermally stable and fine microstructure by the addition of high Cr and Si using rapid solidification and SPS process
    corecore