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The promulgation of the Biogas Act in South Korea has increased the number of organic waste treatment facilities and the amount of food waste digestion sludge (FWDS), a byproduct of the biogas process. FWDS recovery involves various challenges, which leads to the accumulation or improper disposal of sludge. Hence, FWDS needs to be treated in environmentally sound and safe ways. In this study, anaerobic digestion sludges were mixed with unused forest biomass to produce fuel. The results showed that pellets produced via mixing of FWDS with unused forest biomass had improved durability, bulk density, and fine particle performance compared to surface-carbonized wood pellets. Carbonized pellets manufactured with 30% FWDS had a moisture content of 11.746% and met all biosolid waste fuel (SRF) standards, except for moisture content. Carbonized pellets prepared with 15% FWDS met the L2 wood pellet standards for ash content (less than 3.0%) and bulk density (greater than 550 kg/m3), as well as all other standard values in both the industrial wood pellet quality standards and bio-SRF criteria. This study confirmed the potential and suitability of digestion sludge and unused forest biomass for fuel utilization by addressing their respective limitations.

Background/Aim The Barcelona Clinic Liver Cancer (BCLC) guidelines recommend systemic therapy as the only first-line treatment for patients with BCLC stage C hepatocellular carcinoma (HCC) despite its heterogeneity of disease extent. We aimed to identify patients who might benefit from combined transarterial chemoembolization (TACE) and radiation therapy (RT) by subclassifying BCLC stage C. Methods A total of 1,419 treatment-naïve BCLC stage C patients with macrovascular invasion (MVI) who were treated with combined TACE and RT (n=1,115) or systemic treatment (n=304) were analyzed. The primary outcome was overall survival (OS). Factors associated with OS were identified and assigned points by the Cox model. The patients were subclassified into three groups based on these points. Results The mean age was 55.4 years, and 87.8% were male. The median OS was 8.3 months. Multivariate analysis revealed a significant association of Child-Pugh B, infiltrative-type tumor or tumor size ≥10 cm, main or bilateral portal vein invasion, and extrahepatic metastasis with poor OS. The sub-classification was categorized into low (point ≤1), intermediate (point=2), and high (point ≥3) risks based on the sum of points (range, 0–4). The OS in the low, intermediate, and high-risk groups was 22.6, 8.2, and 3.8 months, respectively. In the low and intermediate-risk groups, patients treated with combined TACE and RT exhibited significantly longer OS (24.2 and 9.5 months, respectively) than those who received systemic treatment (6.4 and 5.1 months, respectively; P

Background/Aim We aimed to investigate the efficacy and safety of stereotactic body radiation therapy (SBRT) in elderly patients with small hepatocellular carcinomas (HCC). Methods Eighty-three patients (89 lesions) with HCC who underwent SBRT between January 2012 and December 2018 were reviewed in this retrospective observational study. The key inclusion criteria were as follows: 1) age ≥75 years, 2) contraindications for hepatic resection or percutaneous ablative therapies, 3) no macroscopic vascular invasion, and 4) no extrahepatic metastasis. Results The patients were 75-90 years of age, and 49 (59.0%) of them were male. Most patients (94.0%) had an Eastern Cooperative Oncology Group performance status of 0 or 1. Seventy-four patients (89.2%) had Child-Pugh class A hepatic function before SBRT. The median tumor size was 1.6 cm (range, 0.7-3.5). The overall median follow-up period was 34.8 months (range, 7.3-99.3). The 5-year local tumor control rate was 90.1%. The 3-year and 5-year overall survival rate was 57.1% and 40.7%, respectively. Acute toxicity grade ≥3 was observed in three patients (3.6%) with elevated serum hepatic enzymes; however, no patient experienced a worsening of the Child-Pugh score to ≥2 after SBRT. None of the patients developed late toxicity (grade ≥3). Conclusions SBRT is a safe treatment option with a high local control rate in elderly patients with small HCC who are not eligible for other curative treatments.

Abstract Background To evaluate the clinical outcomes of patients who received stereotactic body radiation therapy (SBRT) for single viable hepatocellular carcinoma (HCC) at the site of incomplete transarterial chemoembolization (TACE). Methods Patients treated with SBRT for single viable HCC after incomplete TACE between 2012 and 2017 at Asan Medical Center (Seoul, South Korea) were included. Incomplete TACE was defined as (1) evidence of viable HCC at the site of TACE on follow-up dynamic computed tomography (CT) or magnetic resonance imaging following one or more consecutive TACEs, (2) no definite tumor staining on superselective hepatic angiogram, or (3) no definite iodized oil uptake on post-embolization angiogram or CT. Doses of 10–15 Gy per fraction were given over 3–4 consecutive days. The primary outcome was local control rate at 3 years and secondary outcome included tumor response, overall survival rate, out-of-field intrahepatic recurrence-free survival, distant metastasis-free survival and treatment-related toxicities. Treatment-related adverse events were evaluated according to the common terminology criteria for adverse events, version 4.03. Results A total of 302 patients were analyzed. The median follow-up duration was 32.9 months (interquartile range [IQR], 23.6–41.7) and the median tumor size was 2.0 cm (range, 0.7–6.9). The local control (LC) and overall survival rates at 3 years were 91.2 and 72.7%, respectively. 95.4% of the tumors reached complete response (CR) during the entire follow-up period (anyCR). The median interval from SBRT to anyCR was 3.4 months (IQR, 1.9–4.7), and 39.9 and 83.3% of the lesions reached CR at 3- and 6-months after SBRT, respectively. Radiation-induced liver disease was observed in 8 (2.6%) patients. No patients experienced gastroduodenal bleeding within the radiation field. Conclusion SBRT could be considered a feasible salvage treatment option for HCC after incomplete TACE.

Abstract Cancer of unknown primary (CUP) is a heterogeneous malignancy in which the primary site of the tumor cannot be identified through standard work-up. The survival outcome of CUP is generally poor, and there is no consensus for treatment. Here, we comprehensively analyzed the real-world data of 218 patients with CUP (median age, 62 years [range, 19–91]; male, 62.3%). Next-generation sequencing was conducted in 22 (10%) patients, one of whom showed level 1 genetic alteration. Most (60.3%) patients were treated with empirical cytotoxic chemotherapy, and two patients received targeted therapy based on the NGS results. The median OS was 8.3 months (95% confidence interval [CI] 6.2–11.4), and the median progression-free survival of patients treated with chemotherapy was 4.4 months (95% CI 3.4–5.3). In multivariate Cox regression analysis, Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 or 1 and localized disease were significantly associated with favorable survival outcomes. Collectively, we found that CUP patients had a poor prognosis after standard treatment, and those with localized disease who received local treatment and those with better PS treated with multiple lines of chemotherapy had better survival outcomes. Targeted therapies based on NGS results are expected to improve survival outcomes.

Abstract Purpose To study the performance of a proposed deep learning-based autocontouring system in delineating organs at risk (OARs) in breast radiotherapy with a group of experts. Methods Eleven experts from two institutions delineated nine OARs in 10 cases of adjuvant radiotherapy after breast-conserving surgery. Autocontours were then provided to the experts for correction. Overall, 110 manual contours, 110 corrected autocontours, and 10 autocontours of each type of OAR were analyzed. The Dice similarity coefficient (DSC) and Hausdorff distance (HD) were used to compare the degree of agreement between the best manual contour (chosen by an independent expert committee) and each autocontour, corrected autocontour, and manual contour. Higher DSCs and lower HDs indicated a better geometric overlap. The amount of time reduction using the autocontouring system was examined. User satisfaction was evaluated using a survey. Results Manual contours, corrected autocontours, and autocontours had a similar accuracy in the average DSC value (0.88 vs. 0.90 vs. 0.90). The accuracy of autocontours ranked the second place, based on DSCs, and the first place, based on HDs among the manual contours. Interphysician variations among the experts were reduced in corrected autocontours, compared to variations in manual contours (DSC: 0.89–0.90 vs. 0.87–0.90; HD: 4.3–5.8 mm vs. 5.3–7.6 mm). Among the manual delineations, the breast contours had the largest variations, which improved most significantly with the autocontouring system. The total mean times for nine OARs were 37 min for manual contours and 6 min for corrected autocontours. The results of the survey revealed good user satisfaction. Conclusions The autocontouring system had a similar performance in OARs as that of the experts’ manual contouring. This system can be valuable in improving the quality of breast radiotherapy and reducing interphysician variability in clinical practice.

The pyrolysis of food waste has high economic potential and produces several value-added products, such as gas, bio-oil, and biochar. In South Korea, biochar production from food waste is prohibited, because dioxins are generated during combustion caused by the chloride ions arising from the high salt content. This study is the first to examine the water quality and the applicability of food waste-based biochar as solid refuse fuel (SRF) based on a demineralization process. The calorific value increased after demineralization due to the removal of ionic substances and the high carbon content. The chloride ion removal rate after demineralization increased with the increasing pyrolysis temperature. A proximate analysis of biochar indicated that the volatile matter decreased, while ash and fixed carbon increased, with increasing pyrolysis temperature. At 300 °C pyrolysis temperature, all domestic bio-SRF standards were met. The organic matter concentration in water decreased with increasing carbonization temperature, and the concentrations of soluble harmful substances, such as volatile organic compounds (VOCs), were within the standards or non-detectable. These results suggest that biochar can be efficiently generated from food waste while meeting the emission standards for chloride ions, dissolved VOCs, ash, and carbon.

Abstract Background This study analyzed the clinical results of palliative radiotherapy for bleeding control in patients with unresectable advanced gastric cancer. Methods We retrospectively reviewed the medical records of patients who met the following inclusion criteria between January 2002 and June 2018: histologically proven gastric cancer, gastric tumor bleeding confirmed by upper gastrointestinal endoscopy, and palliative radiotherapy performed for hemostasis. The median radiotherapy dose was 30 Gy, with a daily dose ranging from 1.8 to 3 Gy. Results Sixty-one patients were included in this analysis. The study population was predominantly male (72.1%), with a median age of 62 years (range: 32–92). The median baseline hemoglobin level was 7.1 g/dL, and the most common presenting symptom of gastric tumor bleeding was melena (85.2%). Bleeding control was achieved in 54 (88.5%) patients. The median levels of hemoglobin at 1, 2, and 3 months after completion of radiotherapy were 10.1 g/dL, 10.2 g/dL, and 10.4 g/dL, respectively; these values were significantly different from that before radiotherapy (7.1 g/dL; p

Purpose: This study was aimed to assess the outcome of radiotherapy and determine prognostic factors for survival in breast cancer patients with clinically overt metastasis to the internal mammary lymph node (IMN+). Methods: We retrospectively reviewed the medical records of 193 patients with IMN + breast cancer who received neoadjuvant chemotherapy (NAC), breast surgery without internal mammary lymph node (IMN) dissection, and postoperative radiotherapy at 9 hospitals between 2009 and 2013. Breast-conserving surgery or mastectomy was performed after taxane-based NAC. Radiotherapy was administered to the whole breast/chest wall and regional nodes. IMN-covering radiotherapy was performed in 92.2% of patients with median dose of 58.4 Gy (range, 44.9–69.1 Gy). The overall survival (OS), disease-free survival (DFS), and IMN failure-free survival (IMNFFS) were analyzed. Results: After median follow-up of 71 months, 9 patients (4.7%) developed IMN failure and simultaneous distant metastasis. The 5-year DFS, OS, and IMNFFS was 68.6%, 81.8%, and 95.3%, respectively. Non-triple-negative breast cancer, Ki-67 ≤ 10%, pathological complete response (CR) in tumor and axillary node, and radiologic CR of IMN after NAC were significant factors for predicting higher DFS; however, IMN radiation dose was not significant determinants for DFS. The 5-year DFS of patients with IMN-dose ≤ 50.0 Gy and those with >50.0 Gy was 86.7% and 76.7%, respectively (p = 0.41). Conclusions: A multimodality strategy including NAC, breast surgery, and IMN-covering radiotherapy was effective for patients with overt IMN + breast cancer. Even without an IMN dissection, most patients were IMN failure-free with an IMN-focusing radiotherapy.

Objectives:To prevent eutrophication and algal blooms, Ministry of Environment in Korea has reinforced the effluent standards of wastewater treatment facilities. In the last 20 years, various advanced wastewater treatment processes have been introduced nationwide. The sedimentation･dissolved air flotation (SeDAF) process has been developed for efficient enhanced phosphorus removal in the previous researches. In the study, several factors were reviewed to examine the operation characteristics of the SeDAF process. In particular, the applicability of aluminium/phosphorus (Al/P) and aluminium/turbidity (Al/T) ratios were investigated intensively. Methods:To derive the appropriate operating conditions for the SeDAF process, several sets of lab-scale tests were carried out. For each operating condition, Al/P (Al/T-P), Al/PO43--P, and Al/T (Al/Turbidity) ratios were analyzed, compared and reviewed respectively. Results and Discussion:Al/P ratio was revealed as the most prominent factor in terms of stability and feasibility of operation, and Al/P values of the SeDAF process could achieve lower values than those of other processes in the previous researches. Conclusions:It could be expected that the coagulant dosage decision using Al/P ratio has many advantages to reduce coagulant dosage and to decrease the amount of sludge production in the SeDAF process.

Objectives:In order to prevent eutrophication and algal blooms, Ministry of Environment in Korea reinforced the effluent standards of wastewater treatment facilities. As a result, many advanced wastewater treatment processes have been implemented nationwide. Current conventional treatment systems have usually been facing high operational costs and large sludge production problems. Therefore, it is essential to develop more economic and efficient process to cope with these issues. Methods:The sedimentation and dissolved air flotation (SeDAF) process has been developed, that integrates sedimentation and dissolved air flotation. Several simulation experiments were carried out to verify and optimize the operation conditions of the SeDAF process. Removal efficiencies of each water quality item and sludge mass balance were analyzed intensively in the SeDAF process using the modified jar-test. Results and Discussion:Removal efficiencies of the SeDAF process were higher and more stable than those of sedimentation process. Several ‘sludge production/coagulant dosage’ ratios were analyzed and the representative value of 4 mg･L-1 as SS/mg･L-1 as Al2O3 was obtained in the SeDAF process. Fractions of suspended solids (SS) and total phosphorus (T-P) in sludge were measured; the ratios of flotation sludge to sedimentation sludge and fractions of flotation sludge in total sludge had their typical convergence ranges for the conditions of optimal coagulant dosage. Conclusions:The ratios or fractions of SS and T-P in sludge could be applied as the evaluation indicators of the SeDAF process. The reduction of coagulant dosage could be corresponded directly to the reduction of sludge production.

Background/Aims Stereotactic body radiation therapy (SBRT) is used as an alternative ablative treatment in patients with hepatocellular carcinoma (HCC) not suitable for curative treatments. The purpose of this prospective study was to evaluate the long-term efficacy of SBRT for small (≤5 cm) HCCs. Methods A phase II, single-arm clinical trial on SBRT for small HCCs was conducted at an academic tertiary care center. The planned SBRT dose was 45 Gy with a fraction size of 15-Gy over 3 consecutive days. The primary endpoint was 2-year local control rate. Radiologic responses were assessed according to the Response Evaluation Criteria in Solid Tumors (RECIST, version 1.1) and the modified RECIST criteria. Results Between 2013 and 2016, 50 patients (53 lesions) were enrolled, with a median follow-up period of 47.8 months (range, 2.9–70.6). Patients’ age ranged from 41 to 74 years, and 80% were male. Median tumor size was 1.3 cm (range, 0.7–3.1). The 2- and 5-year local control rates were 100% and 97.1%, respectively. The 5-year overall survival rate was 77.6%. Six months after SBRT, radiologic responses were evident in 44 lesions (83%) according to the RECIST criteria and 49 (92.4%) according to the modified RECIST criteria. None of the patients showed grade ≥3 adverse events. Conclusions SBRT showed excellent results as an ablative treatment for patients with small HCCs while showing minimal toxicities. SBRT can be a good alternative for both curative and salvage intents in patients with HCCs that are unsuitable for curative treatments.

Abstract Segmentation of normal organs is a critical and time-consuming process in radiotherapy. Auto-segmentation of abdominal organs has been made possible by the advent of the convolutional neural network. We utilized the U-Net, a 3D-patch-based convolutional neural network, and added graph-cut algorithm-based post-processing. The inputs were 3D-patch-based CT images consisting of 64 × 64 × 64 voxels designed to produce 3D multi-label semantic images representing the liver, stomach, duodenum, and right/left kidneys. The datasets for training, validating, and testing consisted of 80, 20, and 20 CT simulation scans, respectively. For accuracy assessment, the predicted structures were compared with those produced from the atlas-based method and inter-observer segmentation using the Dice similarity coefficient, Hausdorff distance, and mean surface distance. The efficiency was quantified by measuring the time elapsed for segmentation with or without automation using the U-Net. The U-Net-based auto-segmentation outperformed the atlas-based auto-segmentation in all abdominal structures, and showed comparable results to the inter-observer segmentations especially for liver and kidney. The average segmentation time without automation was 22.6 minutes, which was reduced to 7.1 minutes with automation using the U-Net. Our proposed auto-segmentation framework using the 3D-patch-based U-Net for abdominal multi-organs demonstrated potential clinical usefulness in terms of accuracy and time-efficiency.

How can we model node representations to accurately infer the signs of missing edges in a signed social graph? Signed social graphs have attracted considerable attention to model trust relationships between people. Various representation learning methods such as network embedding and graph convolutional network (GCN) have been proposed to analyze signed graphs. However, existing network embedding models are not end-to-end for a specific task, and GCN-based models exhibit a performance degradation issue when their depth increases. In this paper, we propose Signed Diffusion Network (SidNet), a novel graph neural network that achieves end-to-end node representation learning for link sign prediction in signed social graphs. We propose a new random walk based feature aggregation, which is specially designed for signed graphs, so that SidNet effectively diffuses hidden node features and uses more information from neighboring nodes. Through extensive experiments, we show that SidNet significantly outperforms state-of-the-art models in terms of link sign prediction accuracy.

The uncertainties of four-dimensional computed tomography (4DCT), also called as residual motion artefacts (RMA), induced from irregular respiratory patterns can degrade the quality of overall radiotherapy. This study aims to quantify and reduce those uncertainties. A comparative study on quantitative indicators for RMA was performed, and based on this, we proposed a new 4DCT sorting method that is applicable without disrupting the current clinical workflow. In addition to the default phase sorting strategy, both additional amplitude information from external surrogates and the quantitative metric for RMA, investigated in this study, were introduced. The comparison of quantitative indicators and the performance of the proposed sorting method were evaluated via 10 cases of breath-hold (BH) CT and 30 cases of 4DCT. It was confirmed that N-RMSD (normalised root-mean-square-deviation) was best matched to the visual standards of our institute's regime, manual sorting method, and could accurately represent RMA. The performance of the proposed method to reduce 4DCT uncertainties was improved by about 18.8% in the averaged value of N-RMSD compared to the default phase sorting method. To the best of our knowledge, this is the first study that evaluates RMA indicators using both BHCT and 4DCT with visual-criteria-based manual sorting and proposes an improved 4DCT sorting strategy based on them.

Introduction: We evaluated the radiologic response rate of combined transarterial chemoembolization (TACE) plus radiotherapy (RT) in treatment-naïve patients with liver-confined hepatocellular carcinoma (HCC) with macroscopic vascular invasion (MVI) and analyzed its clinical importance in overall survival (OS) outcomes. Methods: Patients who were treated with TACE plus RT as a first-line treatment for HCC with MVI between January 2010 and December 2015 were retrospectively reviewed. Radiologic response was assessed according to the modified Response Evaluation Criteria in Solid Tumors (mRECIST) at 2- and 4-months after completion of RT. Landmark analysis at 2- and 4-months and time-dependent Cox regression analysis using response as a time-dependent covariate were performed for univariable and multivariable analyses. Results: The 2-month landmark analysis included 427 patients, and the 4-month landmark analysis included 355 patients after excluding patients without imaging studies for response evaluation at 4 months. Radiologic responses were observed in 210 (49.2%) patients at 2 months and 181 (51.8%) at 4 months. In multivariable analyses, radiologic response was identified as an independent prognosticator for OS at 2 months (median OS: responders, 23.1 months vs. non-responders, 8.0 months; hazard ratio [HR], 3.194; P < 0.001) and 4 months (median OS: responders, 26.5 months vs. non-responders, 9.3 months; HR, 4.534; P < 0.001). Conclusion: Radiologic response assessed by mRECIST was a significant prognostic factor for OS in patients with advanced-stage HCC showing MVI treated with combined TACE plus RT.

BackgroundAlthough the guidelines recommend gynecological assessment and close monitoring for symptoms of endometrial cancer in postmenopausal breast cancer survivors taking tamoxifen (TAM), the risk of endometrial cancer in young breast cancer survivors has not yet been fully assessed. This study aimed to investigate the risk of developing endometrial cancer and the frequencies of gynecological examinations in young breast cancer survivors taking TAM in South Korea.MethodsA nationwide retrospective cohort study was conducted using the Health Insurance Review and Assessment Service claims data. Kaplan–Meier analyses and log-rank tests were used to assess the probability of endometrial cancer, benign endometrial conditions, and the probability of invasive endometrial procedure. To analyze the risk of endometrial cancer and benign endometrial conditions, we used a multivariable Cox proportional hazards regression model.ResultsBetween 2010 and 2015, 60,545 newly diagnosed female breast cancer survivors were included. The total person–years were 256,099 and 140 (0.23%) patients developed endometrial cancer during the study period. In breast cancer survivors aged ≥60 years [hazard ratio (HR), 5.037; 95% confidence interval (CI), 2.185–11.613], 50–59 years (HR, 4.343; 95% CI, 2.122–8.891), and 40–49 years (HR, 2.121; 95% CI, 1.068–4.213), TAM was associated with an increased risk of endometrial cancer. In subjects aged below 40 years, TAM did not significantly increase the risk of endometrial cancer. However, among the TAM subgroups, breast cancer survivors aged below 40 years [1.61 per 1,000 person–years (PY); HR, 12.460; 95% CI, 2.698–57.522] and aged 40–49 years (2.22 per 1,000 PY; HR, 9.667; 95% CI, 4.966–18.819) with TAM-related endometrial diseases showed significantly increased risks of endometrial cancer. Among the TAM subgroup with benign endometrial conditions, the ratios of the frequency of invasive diagnostic procedures to the incidence of endometrial cancer were higher in subjects under 40 than subjects aged 60 or more.ConclusionYoung breast cancer survivors with TAM-related benign endometrial diseases are at a higher risk of developing endometrial cancer. Gynecological surveillance should be tailored to the risk of endometrial cancer in young breast cancer survivors to improve the early detection of endometrial cancer and avoid unnecessary invasive procedures.

Background: No studies evaluating the clinical outcomes of radiotherapy (RT) for hepatocellular carcinoma (HCC) in the caudate lobe have been available to date. The purpose of this study was to evaluate the effectiveness and safety of RT for HCC in the caudate lobe.Material and Methods: Seventy patients with HCC in the caudate lobe treated with RT from a multi-institutional database were included in this study. The median equivalent dose in 2 Gy (EQD2) was 80.0 Gy10 (range, 31.3–99.3), and freedom from local progression (FFLP), progression-free survival (PFS), and overall survival (OS) rates were evaluated.Results: The median time of follow-up was 47.9 months (range, 3.4–127), and the 5-year FFLP, PFS, and OS rates were 80.6% [95% confidence interval (CI), 70.8–91.8], 13.8% (95% CI, 7.5–25.4), and 51.3% (95% CI, 39.9–66.1), respectively. In the multivariate analysis, the radiation dose was significantly associated with the FFLP rate [hazard ratio (HR), 0.57 per 10 Gy10 increase, p = 0.001], and the status of FFLP was significantly associated with OS (HR, 2.694, p = 0.014). The overall rate of ≥grade 3 adverse events was 5.7% (4 of 70), and RT-related mortality was not observed.Conclusion: RT for HCC in the caudate lobe showed promising FFLP and OS rates with safe toxicity profiles. These findings suggest that RT may be a promising treatment option for HCC in the caudate lobe.

PurposeMore than half of patients with bile duct cancer (BDC) develop recurrence even after curative resection. Recurrent BDC has a poor prognosis, and no optimal treatment modality has been established. We therefore analyzed our experience on the survival outcomes of radiation therapy (RT) for recurrent extrahepatic bile duct cancer (EHBDC).Patients and methodsWe retrospectively analyzed the records of patients with recurrent EHBDC who underwent concurrent chemoradiation therapy (CCRT) or RT alone at our institution between January 2001 and June 2015. Freedom from locoregional progression (FFLP), progression-free survival (PFS), and overall survival (OS) were assessed, and univariate and multivariate analyses were performed to identify the prognostic factors.ResultsA total of 76 patients were included in the analysis. The median OS was 16 months and the rates of 2-year FFLP, PFS, and OS were 61%, 25%, and 33%, respectively. Among the evaluable patients, the first site of failure was the locoregional area in 16 patients, distant metastasis in 27, and both sites in 8. On univariate analysis, disease-free interval (p = 0.012) and concurrent chemotherapy (p = 0.040) were found as significant prognostic factors for OS. One patient with CCRT developed a grade 3 hematologic toxicity, and two patients experienced late grade 3 toxicities including duodenal ulcer bleeding and obstruction.ConclusionsRT for recurrent EHBDC showed favorable survival and local control with limited treatment-related toxicities. Considering that the most common pattern of failure was distant metastasis, further studies on the optimal scheme of chemotherapy and RT are warranted.

Given a trained deep graph convolution network (GCN), how can we effectively compress it into a compact network without significant loss of accuracy? Compressing a trained deep GCN into a compact GCN is of great importance for implementing the model to environments such as mobile or embedded systems, which have limited computing resources. However, previous works for compressing deep GCNs do not consider the multi-hop aggregation of the deep GCNs, though it is the main purpose for their multiple GCN layers. In this work, we propose MustaD (Multi-staged knowledge Distillation), a novel approach for compressing deep GCNs to single-layered GCNs through multi-staged knowledge distillation (KD). MustaD distills the knowledge of 1) the aggregation from multiple GCN layers as well as 2) task prediction while preserving the multi-hop feature aggregation of deep GCNs by a single effective layer. Extensive experiments on four real-world datasets show that MustaD provides the state-of-the-art performance compared to other KD based methods. Specifically, MustaD presents up to 4.21%p improvement of accuracy compared to the second-best KD models.

The efficiency of methane production by anaerobic digestion (AD), during which energy is generated from organic waste, can be increased in various ways. Recent research developments have increased the volume of gas production during AD using biochar. Previous studies have used food waste itself in AD, or, added wood-biochar or sewage sludge charcoal as an accelerant of the AD process. The application of food-waste biochar in AD using activated sludge has not yet been studied and is considered a potential method of utilizing food waste. Therefore, this study investigated the use of biochar prepared by the thermal decomposition of food waste as an additive to AD tanks to increase methane production. The addition of food-waste biochar at 1% of the digestion tank volume increased the production of digestion gas by approximately 10% and methane by 4%. We found that food-waste biochar served as a medium with trace elements that promoted the proliferation of microorganisms and increased the efficiency of AD.

Abstract Background The 2-week schedule of hypofractionated radiotherapy as a salvage treatment for hepatocellular carcinoma (HCC) has previously exhibited promising results; this study aimed to assess its long-term clinical outcomes in patients with recurrent HCC ineligible for curative treatments. Methods We retrospectively enrolled 77 patients (84 lesions) with HCC who were treated with hypofractionated radiotherapy between December 2008 and July 2013. Primary inclusion criteria were HCC unsuitable for curative treatments and HCC located within 2 cm of a critical normal organ. We administered 3.5–5 Gy/fraction for 2 weeks, resulting in a total dose of 35–50 Gy. Results The median follow-up period was 33.6 (range, 4.8–78.3) months. The 3- and 5-year overall survival rates were 52.3% and 40.9%, respectively, and local control rates were 79.5% and 72.6% in all treated lesions, respectively. The 5-year local control rate was better in the higher radiation dose group than in the lower radiation dose group (50 Gy: 79.7% vs.

Abstract Background Volumetric-modulated arc therapy (VMAT) is a highly sophisticated linear accelerator-based treatment method, and allows dose rate-changing intensity modulation with gantry rotation. We report our clinical experiences with stereotactic body radiation therapy (SBRT) using a respiratory-gated VMAT technique for patients with hepatocellular carcinoma (HCC) when established curative treatments cannot be applied. Methods A total of 119 patients (139 lesions) with HCC who were treated with SBRT were registered between March 2012 and July 2013 at our institution. A dose of 10–15 Gy per fraction was applied over 3–4 consecutive days, resulting in a total dose of 30–60 Gy. Results The median follow-up period was 25.8 months (range, 3.2–36.8 months). The overall 3-year survival rate was 83.8%. The local control rate at 3 years was 97.0% in all treated lesions. Multivariate analysis revealed that the Child-Pugh class before SBRT had significant effects on overall survival (Child-Pugh A: hazard ratio = 0.463; 95% CI, 0.262–0.817; p = 0.008). Conclusions SBRT using a respiratory-gated VMAT technique was an excellent ablative treatment modality for patients with HCC. SBRT is a good alternative treatment for patients with small HCCs that are unsuitable for surgical resection or local ablative therapy.

Food waste is an important constituent of municipal solid waste, and research has been conducted to develop various methods for treating food waste and recycling it (e.g., fuel, landfilling, composting, conversion into animal feed, drying, and carbonization). Among these, the drying and carbonization techniques can change food waste into fuel; however, they need more energy than fermentation and anaerobic digestion procedures. In this study, we investigated the physicochemical properties of food waste biochar produced under torrefaction (270 °C) and pyrolysis (450 °C) conditions to establish its applicability as fuel by comparing temperatures, residence times, and conditions before and after demineralization. The higher heating value increased after the demineralization process under both temperature conditions (270 °C and 450 °C), and the chlorine level was lower at 270 °C temperature demineralization than at 450 °C. During the demineralization process, Na and K were better removed than Ca and Mg. Additionally, Cr, Hg, Cd, and Pb levels were lower than those according to the European Union and Korean domestic bio-SRF recovered fuel criteria, confirming the applicability of biochar as fuel.

PurposeStereotactic body radiation therapy (SBRT) is a promising treatment modality for locally advanced pancreatic cancer (LAPC). We evaluated the clinical outcomes of SBRT in patients with LAPC.Patients and methodsWe retrospectively analyzed the medical records of patients with LAPC who underwent SBRT at our institution between April 2011 and July 2016. Fiducial markers were implanted using endoscopic ultrasound guidance one week prior to 4-dimensional computed tomography (CT) simulation and daily cone beam CT was used for image guidance. Patients received volumetric modulated arc therapy or intensity modulated radiotherapy using respiratory gating technique. A median dose of 28 Gy (range, 24-36 Gy) was given over four consecutive fractions delivered within one week. Survival outcomes including freedom from local disease progression (FFLP), progression-free survival (PFS), and overall survival (OS) were analyzed. Acute and late toxicities related to SBRT were assessed.ResultsA total of 95 patients with LAPC were analyzed, 52 of which (54.7%) had pancreatic head cancers. Most (94.7%) had received gemcitabine-based chemotherapy. The 1-year FFLP rate was 80.1%. Median OS and PFS were 16.7 months and 10.2 months, respectively; the 1-year OS and PFS rates were 67.4% and 42.9%, respectively. Among 79 patients who experienced failure, the sites of first failures were isolated local progressions in 12 patients (15.2%), distant metastasis in 55 patients (69.6%), and both in 12 patients (15.2%). Seven patients (7.4%) were able to undergo surgical resection after SBRT and four had margin-negative resections. Three patients (3.2%) had grade 3 nausea/vomiting during SBRT, and late grade 3 toxicity was observed in another three patients.ConclusionsLAPC patients who received chemotherapy and SBRT had favorable FFLP and OS with minimal treatment-related toxicity. The most common pattern of failure was distant metastasis, which warrants further studies on the optimal scheme of chemotherapy and SBRT.

Given a real-world graph, how can we measure relevance scores for ranking and link prediction? Random walk with restart (RWR) provides an excellent measure for this and has been applied to various applications such as friend recommendation, community detection, anomaly detection, etc. However, RWR suffers from two problems: 1) using the same restart probability for all the nodes limits the expressiveness of random walk, and 2) the restart probability needs to be manually chosen for each application without theoretical justification. We have two main contributions in this paper. First, we propose Random Walk with Extended Restart (RWER), a random walk based measure which improves the expressiveness of random walks by using a distinct restart probability for each node. The improved expressiveness leads to superior accuracy for ranking and link prediction. Second, we propose SuRe (Supervised Restart for RWER), an algorithm for learning the restart probabilities of RWER from a given graph. SuRe eliminates the need to heuristically and manually select the restart parameter for RWER. Extensive experiments show that our proposed method provides the best performance for ranking and link prediction tasks.

PURPOSE:To develop a 4D dose reconstruction method and to evaluate the delivered dose in respiratory-gated volumetric modulated arc therapy (VMAT). MATERIALS AND METHODS:A total 112 treatment sessions of gated VMAT for 30 stereotactic body radiotherapy (SBRT) patients (10 lung, 10 liver, and 10 pancreas) were evaluated. For respiratory-gated SBRT, 4DCT was acquired, and the CT data at the end-exhale phase was used for a VMAT plan. The delivered dose was reconstructed using a patient's respiratory motion and machine motion acquired during the beam delivery. The machine motion was obtained from the treatment log file, while the target position was estimated from an external respiratory marker position. The target position was divided into 1-mm position bins, and sub-beams with beam isocenters corresponding to each position bin were created in a motion mimicking plan, reflecting motion data including MLC leaf positions and gantry angle and target position data during beam treatment. The reconstructed 4D dose was compared with the dose of the original plan using these dosimetric parameters; the maximum dose (Dmax) and mean dose (Dmean) of gross target volume (GTV) or organs at risk (spinal cord, esophagus, heart, duodenum, kidney, spinal cord, and stomach). The minimum dose (Dmin) to GTV was also calculated to verify cold spots in tumors. RESULTS:There was no significant difference of dose parameters regard to the GTV in all tumors. For the liver cases, there were significant differences in the Dmax of duodenum (-4.2 ± 1.4%), stomach (-3.5 ± 4.2%), left kidney (-4.1 ± 2.8%), and right kidney (-3.2 ± 1.3%), and in the Dmean of duodenum (-3.8 ± 1.4%), stomach (-3.9 ± 2.2%), left kidney (-3.1 ± 2.8%), and right kidney (-4.1 ± 2.6%). For the pancreas cases, there were significant differences in the Dmax of stomach (2.1 ± 3.0%), and in the Dmean of liver (1.5 ± 0.6%), duodenum (-1.0 ± 1.4%), stomach (2.1 ± 1.6%), and right kidney (-1.3 ± 0.9%). The average gamma pass rates were 97.6 ± 4.8% for lung cases, 99.6 ± 0.5% for liver cases, and 99.5 ± 0.5% for pancreas cases. Most cases showed insignificant dose variation, with gamma pass rates higher than 98%, except for two lung cases with gamma pass rates of 86.9% and 90.6%. The low gamma pass rates showed larger global motion ranges resulting from the baseline shift during beam delivery. CONCLUSION:The actual delivered dose in thoracic and abdominal VMAT under breathing motion was verified by 4D dose reconstruction using typical treatment equipment and software. The proposed method provides a verification method for the actual delivered dose and could be a dosimetric verification QA tool for radiation treatment under various respiratory management techniques.

Although the adrenal glands are not common sites of metastasis from hepatocellular carcinoma (HCC), this metastasis can be met in patients with advanced HCC in some clinical settings. However, the effectiveness of radiotherapy against such metastases is unclear. Therefore, we performed the present multi-institutional study to investigate tumor response, overall survival (OS), treatment-related toxicity, and prognostic factors after radiotherapy. We retrospectively reviewed 134 patients who completed a planned radiotherapy for their adrenal metastases. Complete response was noted in 6 (4.3%), partial response in 48 (34.0%), and stable disease in 78 patients (55.3%). The median OS was 12.8 months, and the 1-, 2-, and 5-year OS rates were 53.1%, 23.9%, and 9.3%, respectively. Grade 3 anorexia occurred in 2 patients, grade 3 diarrhea in 1, and grade 3 fatigue in 1. Multivariate analyses revealed that the following factors had significant effects on OS: controlled intrahepatic tumor; controlled extrahepatic metastasis; and Child-Pugh class A. Although patients with adrenal metastasis from HCC had poor OS, radiotherapy provided an objective response rate of 38.3% and disease stability of 93.6%, with minimal adverse events. Therefore, radiotherapy for these patients could represent a good treatment modality, especially for patients with controlled intrahepatic tumors, controlled extrahepatic metastasis, and good hepatic function.

Introduction. To evaluate the dose distribution and coverage of axilla using only tangential field for whole breast radiotherapy (RT) at three institutions in Korea. Methods. We used computed tomography (CT) images of nine consecutive 1-2 sentinel lymph node-positive patients who underwent breast conserving surgery and whole breast RT without axillary lymph node (ALN) dissection for clinical T1-2N0 breast cancer. The CT data were transferred to three radiation oncologists in 3 institutions and each radiation oncologist created treatment plans for all nine patients; a total of 27 treatment plans were analyzed. Results. The mean doses delivered to levels I and II were 31.9 Gy (9.9–47.9 Gy) and 22.3 Gy (3.4–47.7 Gy). Ninety-five percent of levels I and II received a mean dose of 11.8 Gy (0.4–43.0 Gy) and 3.0 Gy (0.3–40.0 Gy). The percent volumes of levels I and II covered by 95% of the prescribed dose were only 29.0% (0.2–74.1%) and 11.5% (0.0–70.1%). The dose distribution and coverage of axilla were significantly different between three institutions (p=0.001). Conclusion. There were discrepancies in ALN coverage between three institutions. A standardization of whole breast RT technique through further research with a nationwide scale is needed.