Efficacy of 18F-Fluorodeoxyglucose positron emission tomography/computed tomography for detecting renal cell carcinoma in patients with end-stage renal disease.

PURPOSE: Dialysis patients are at an increased risk of developing renal cell carcinoma (RCC); however, differentiating between RCC and benign cysts can sometimes be difficult using modalities, such as computed tomography (CT) and ultrasonography. 18F-Fluorodeoxyglucose positron emission tomography (FDG-PET)/CT efficiently detects malignant tumors; however, physiological accumulation of FDG in the kidney limits its efficacy in detecting renal tumors. However, in patients with severely impaired renal function, the renal accumulation of FDG is decreased, possibly improving the detection of renal malignancies in this patient population. This study evaluated the usefulness of FDG-PET/CT as a screening tool for detecting RCC in patients with end-stage renal disease. MATERIALS AND METHODS: This prospective study recruited 150 participants from 2012 to 2016 who were on dialysis or underwent renal transplantation and were on dialysis until transplantation. FDG-PET/CT was performed to screen for RCC. Three radiologists independently evaluated the images. No protocol was defined for the additional management of positive examinations, leaving decisions to the discretion of each participant. Negative examinations were observed until the end of 2019. RESULTS: In total, 150 participants (mean age, 58 ± 13 years; 105 men) underwent FDG-PET/CT. Twenty patients (13.4%) were diagnosed as positive. Fifteen patients underwent additional examinations and/or procedures, and RCC was found in seven patients. Of the four patients who underwent surgical resection, the pathological results were clear cell RCC in one, papillary RCC in one, and acquired cystic disease-associated RCC in two. Two participants were diagnosed with RCC on bone biopsy, and one was diagnosed on dynamic CT but opted for observation. The sensitivity, specificity, and negative predictive value were 100%, 93.9%, and 100%, respectively. CONCLUSION: FDG-PET/CT was useful for detecting RCC in patients with end-stage renal disease. Our findings show the potential use of FDG-PET/CT as a screening tool for RCC in this patient population.

Evaluation of bone marrow invasion on the machine learning of 18 F-FDG PET texture analysis in lower gingival squamous cell carcinoma.

OBJECTIVES: Lower gingival squamous cell carcinoma (LGSCC) has the potential to invade the alveolar bone. Traditionally, the diagnosis of LGSCC relied on morphological imaging, but inconsistencies between these assessments and surgical findings have been observed. This study aimed to assess the correlation between LGSCC bone marrow invasion and PET texture features and to enhance diagnostic accuracy by using machine learning. METHODS: A retrospective analysis of 159 LGSCC patients with pretreatment 18 F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) examination from 2009 to 2017 was performed. We extracted radiomic features from the PET images, focusing on pathologic bone marrow invasion detection. Extracted features underwent the least absolute shrinkage and selection operator algorithm-based selection and were then used for machine learning via the XGBoost package to distinguish bone marrow invasion presence. Receiver operating characteristic curve analysis was performed. RESULTS: From the 159 patients, 88 qualified for further analysis (59 men; average age, 69.2 years), and pathologic bone marrow invasion was identified in 69 (78%) of these patients. Three significant radiological features were identified: Gray level co-occurrence matrix_Correlation, INTENSITY-BASED_IntensityInterquartileRange, and MORPHOLOGICAL_SurfaceToVolumeRatio. An XGBoost machine-learning model, using PET radiomic features to detect bone marrow invasion, yielded an area under the curve value of 0.83. CONCLUSION: Our findings highlighted the potential of 18 F-FDG PET radiomic features, combined with machine learning, as a promising avenue for improving LGSCC diagnosis and treatment. Using 18 F-FDG PET texture features may provide a robust and accurate method for determining the presence or absence of bone marrow invasion in LGSCC patients.

Biomarkers Predictive of Distant Disease-free Survival Derived from Diffusion-weighted Imaging of Breast Cancer.

PURPOSE: To investigate whether intravoxel incoherent motion (IVIM) and/or non-Gaussian diffusion parameters are associated with distant disease-free survival (DDFS) in patients with invasive breast cancer. METHODS: From May 2013 to March 2015, 101 patients (mean age 60.0, range 28-88) with invasive breast cancer were evaluated prospectively. IVIM parameters (flowing blood volume fraction [fIVIM] and pseudodiffusion coefficient [D*]) and non-Gaussian diffusion parameters (theoretical apparent diffusion coefficient [ADC] at a b value of 0 s/mm2 [ADC0] and kurtosis [K]) were estimated using a diffusion-weighted imaging series of 16 b values up to 2500 s/mm2. Shifted ADC values (sADC200-1500) and standard ADC values (ADC0-800) were also calculated. The Kaplan-Meier method was used to generate survival analyses for DDFS, which were compared using the log-rank test. Univariable Cox proportional hazards models were used to assess any associations between each parameter and distant metastasis-free survival. RESULTS: The median observation period was 80 months (range, 35-92 months). Among the 101 patients, 12 (11.9%) developed distant metastasis, with a median time to metastasis of 79 months (range, 10-92 months). Kaplan-Meier analysis showed that DDFS was significantly shorter in patients with K > 0.98 than in those with K ≤ 0.98 (P = 0.04). Cox regression analysis showed a marginal statistical association between K and distant metastasis-free survival (P = 0.05). CONCLUSION: Non-Gaussian diffusion may be associated with prognosis in invasive breast cancer. A higher K may be a marker to help identify patients at an elevated risk of distant metastasis, which could guide subsequent treatment.

Evaluation of moyamoya disease in CT angiography using ultra-high-resolution computed tomography: Application of deep learning reconstruction.

PURPOSE: The aim of this study was to examine the evaluation of ultra-high-resolution computed tomography angiography (UHR CTA) images in moyamoya disease (MMD) reconstructed with hybrid iterative reconstruction (Hybrid-IR), model-based iterative reconstruction (MBIR), and deep learning reconstruction (DLR). METHODS: This retrospective study with institutional review board approval included patients with clinically suspected MMD who underwent UHR CTA between January 2018 and July 2020. CTA images were reconstructed with three reconstruction methods. Qualitative visualization was evaluated in comparison with digital subtraction angiography. Quantitative evaluation included assessment of edge sharpness, full width at half maximum (FWHM), vessel contrast, and tissue signal-to-noise ratio (SNRtissue). One-way analysis of variance was used to analyze differences. In addition, reconstruction time were assessed. RESULTS: Qualitative evaluation of CTA for 33 sides did not differ significantly between reconstruction methods. In quantitative evaluation for 54 patients, edge sharpness for right and left cortical segments of the middle cerebral artery was significantly higher for Hybrid-IR than for other reconstructions. No significant difference was seen between MBIR and DLR. Edge sharpness for STA-MCA bypass was significantly higher for Hybrid-IR than for MBIR, but no significant difference was seen between Hybrid-IR and DLR. FWHM for STA-MCA showed no significant difference between the three reconstruction methods. DLR displayed the highest SNRtissue. The time required for reconstruction was 40 s for Hybrid-IR, 2580 s for MBIR, and 180 s for DLR. CONCLUSION: UHR CTA with DLR adequately visualized vessels in patients with MMD within a clinically feasible reconstruction time.

Patients' radiation dose in computed tomography-fluoroscopy-guided percutaneous cryoablation for small renal tumors.

PURPOSE: This study aimed to evaluate patients' radiation dose in computed tomography (CT)-fluoroscopy-guided cryoablation for small renal tumors and assess the possible factors affecting it. METHODS: In our institution, cryoablation was performed in 152 patients between 2013 and 2020. Procedures that were not for renal tumors and did not have radiation dose records and detailed information were excluded from the analysis. The size-specific dose estimates (SSDE), volume CT dose index (CTDIvol), dose-length product (DLP), and entrance skin dose (ESD) were evaluated for both spiral scan and CT-fluoroscopy. The effects of the number of cryoneedle punctures; combined use of hydro- and/or pneumodissection procedures; patients' characteristics, such as body-mass index (BMI); and the tumor-related factors, such as tumor location, were determined by the univariate and multivariate analyses. RESULTS: In the 72 included procedures, the median SSDE was 658 mGy and the median CTDIvol was 456 mGy. The median percentage dose of CT-fluoroscopy to the total procedure dose was estimated as 89.8% (591/658 mGy) with SSDE and 41.4% (611/1,475 mGy cm) with DLP. The combined use of hydro- and/or pneumodissection and number of cryoneedle punctures were significantly associated with the total ESD, and the maximum total ESD was 863 mGy in our cases. CONCLUSIONS: Using SSDE as an index, 89.8% of patients' radiation dose was attributed to CT-fluoroscopy, and ESD for the total procedure did not exceed 1 Gy. The increased number of cryoneedle punctures and combined use of hydro- and/or pneumodissection increased the total ESD.

Usefulness of model-based iterative reconstruction in low-dose lumbar spine CT after spine surgery with metal implant: a phantom study.

BACKGROUND: The major problems of computed tomography (CT) imaging include radiation exposure and severe artifacts caused by operative implants. PURPOSE: To evaluate the usefulness of the metal artifact reduction algorithm and model-based iterative reconstruction (MBIR) in postoperative low-dose (LD) spine CT. MATERIAL AND METHODS: A CT torso phantom was scanned at standard-dose (SD) and LD settings. The CT images were reconstructed by three methods: hybrid iterative reconstruction (HIR); metal artifact reduction; and MBIR. The radiation dose of the phantom imaging was evaluated by volume CT dose index (mGy), dose length product (DLP, mGy × cm), and effective dose (mSv). The image quality of the six images was visually evaluated and analyzed using Scheffe's paired comparison method. The average preference of each method was calculated based on the comparative scores. The task transfer function (TTF) and noise power spectrum for HIR and MBIR were also measured. RESULTS: The respective radiation-dose-related parameters of the SD and LD conditions were: volume CT dose index = 10.2 and 1.2 mGy; DLP = 277.9 and 33.9 mGy × cm; and effective dose = 4.2 and 0.5 mSv. The average preference for diagnostic acceptability of MBIR at LD was not significantly different from the other reconstructions of SD data. MBIR successfully reduced metal artifacts in the LD condition. The 10% TTF was higher for HIR at SD and higher for MBIR at LD. CONCLUSION: MBIR is useful for LD spine CT after spine surgery with metal implant.

Cervical spinal computed tomography utilizing model-based iterative reconstruction reduces radiation to an equivalent of three cervical X-rays.

PURPOSE: To evaluate radiation dose and image quality of cervical spinal computed tomography scanned with low-radiation dose (LD-CT) utilizing model-based iterative reconstruction (MBIR). METHODS: We retrospectively examined 14 patients (65.5 ± 13.9 years) who underwent both standard-radiation-dose CT (SD-CT) reconstructed with hybrid iterative reconstruction and LD-CT of cervical spine. The radiation dose, objective image quality indicator, which includes signal-to-noise and contrast-to-noise, and subjective image quality score of the anatomical landmarks in the SD-CT and LD-CT were statistically compared. In addition, the measurement errors of the length of C3 vertebrae (height, anteroposterior length, inner and outer pedicle diameters) between SD-CT and LD-CT were analyzed. RESULTS: Radiation dose of LD-CT was reduced to one-sixth of the dose of SD-CT. The objective image quality indicator of LD-CT was significantly better than that of SD-CT. The subjective image quality of LD-CT was relatively worse than that of SD-CT but generally graded as clinically accepted or higher. There was no remarkable difference between SD-CT and LD-CT in the measurement value of height and anteroposterior length. Inner pedicle diameter was significantly (0.21 ± 0.13 mm) smaller, and outer pedicle diameter was (0.24 ± 0.14 mm) larger on LD-CT than on SD-CT. CONCLUSION: Cervical spinal LD-CT that utilized MBIR enabled radical decrease in radiation dose and provided sufficient image quality for clinical use. This scanning protocol can be a good alternative for protecting patients from exposure to unnecessary radiation, especially when a patient requires multiple CT scans.

Radiation Exposure of Interventional Radiologists during Computed Tomography Fluoroscopy-Guided Percutaneous Cryoablation.

Purpose: The principal aim of this study was to evaluate radiation exposure of interventionalists during computed tomography (CT) fluoroscopy-guided percutaneous cryoablation (PCA) using radiophotoluminescent glass dosimeters (RPLDs). The radioprotective effects of safety glasses and lead apron were also evaluated. Materials and Methods: Radiation exposure of interventionalists during 46 CT fluoroscopy-guided PCA procedures was evaluated. Entrance surface dose (ESD) was measured using RPLDs on multiple sites: five sites, representing eye lens exposure; five sites, representing body exposure; and four sites, representing skin exposure. The ESD values on multiple sites were compared between different PCA procedures (renal, liver, and bone). Results: The mean ESD on the X-ray-side hand exhibited the highest value (358.8 µGy). Regarding evaluation sites representing exposure to the eye lens, the highest ESD inside the radiation protective glasses was detected on the X-ray-side cheek (167.1 µGy). Most ESD values among multiple sites (10/14) were linearly correlated with CT fluoroscopy time. Among them, the ESD values measured during renal and liver PCA were relatively higher than those measured during bone PCA, especially on the chest area outside the lead apron, and on the X-ray tube-side elbow and hand during renal and bone PCA. Radioprotective effects of safety glasses and lead apron ranged from 44.6 to 50.6% and from 30.2 to 79.6%, respectively, on each evaluation site. Conclusion: The site with the highest radiation exposure on interventionalists during CT fluoroscopy-guided PCA was the X-ray tube-side hand. Radiation exposure of interventionalists was at acceptable levels and consistent with the recommended dose limits.

Utility of Thoracolumbar Low-Dose CT With Model-Based Iterative Reconstruction for Measuring Pedicle Diameter Using a Radiation Dose Less Than a One-Time Lumbar X-Ray.

STUDY DESIGN: Retrospective. OBJECTIVE: To evaluate the image quality of low-radiation-dose computed tomography (LD-CT) of the thoracolumbar spine, using model-based iterative reconstruction (MBIR) for measuring pedicle diameter. SUMMARY OF BACKGROUND DATA: MBIR can drastically reduce radiation dose but its utility in spine surgery planning is unknown. METHODS: We identified patients (mean age, 70.5 ±â€Š13.3 yrs) who incidentally underwent both standard-radiation-dose CT (SD-CT) with hybrid iterative reconstruction and LD-CT with MBIR of the thoracolumbar spine within 2 years. We compared radiation dose, subjective image sharpness, signal-to-noise ratio, and contrast-to-noise ratio for the two tests. Additionally, inner pedicle diameters were measured on SD-CT (DSD) and LD-CT (DLD), and statistically compared. RESULTS: We included 24 CT and 84 pedicles for each CT group. The radiation dose of LD-CT estimated by volume CT dose index was 1.21 ±â€Š0.42 mGy, one-sixth the dose of SD-CT. The effective dose of LD-CT was 0.58 ±â€Š0.31 mSv, equivalent to or less than that of a one-time lumbar X-ray in a previous report. LD-CT was significantly inferior in subjective image sharpness for the contour of vertebrae and trabecular structure, but superior for signal-to-noise ratio and contrast-to-noise ratio. The intra-rater reliability (intra-RR) and inter-RR for DLD were 0.985 and 0.892, respectively, comparable to those of DSD. DLD was consistently 0.30 mm smaller than DSD when compared within the same pedicle, regardless of pedicle diameter. CONCLUSION: LD-CT with MBIR produced a radiation dose equivalent to a one-time lumbar X-ray and provided excellent images for measuring pedicle diameter. LD-CT can be a substitute for SD-CT when planning spine surgery if the relationship between DSD and DLD is sufficiently understood. LEVEL OF EVIDENCE: 3.

[Incident Analysis in Radiography Focusing on the Experience Period of Radiological Technologist].

We investigated the causes and trends of incidents related to radiography. From April 2014 to March 2016, 384 incident reports related to radiography were posted. We analyzed based on the nature of the incidents and the experience period of radiological technologist (RT). The types of incidents were 'Incorrect examination order by medical doctor' (50.0%), 'X-ray retake' (24%), 'Incorrect examination procedure' (9.9%), 'Fall or injury of the patient under examination' (3.6%), 'selection error of X-ray detector' (3.1%), 'patient mismatch' (1.8%), 'overdose' (1.3%), and 'others' (a malfunctioning device, trouble of systems and the other) (6.5%). There was no relationship between the number of incidents per person and the experience period as RT; (7.8/person for <3 years of experience, 9.7/person for 3-10 years, 6.4/person for 11-25 years of experience, 7.4/person for <25 years of experience). The experience period as RT are related to some types of incident reduction. 'Fall or injury of the patient under examination' and 'overdose' were more frequently reported by RTs of shorter experience (<3 years and 3-10 years of experience) than RTs of longer experience (11-25 years and <25 of experience). On the other hand, 'patient mismatch' and 'selection error of X-ray detector' were more frequently reported by RTs of long experience than RTs of short experience.

Prognostic value of metabolic tumor volume of pretreatment 18F-FAMT PET/CT in non-small cell lung Cancer.

BACKGROUND: This study aimed to determine the prognostic value of positron emission tomography (PET) metabolic parameters-namely metabolic tumor volume (MTV), total lesion glycolysis (TLG), and total lesion retention (TLR)-on fluorine-18 (18F) fluorodeoxyglucose (FDG) and L- [3-18F]-α-methyltyrosine (18F-FAMT) PET/CT in patients with non-small-cell lung cancer (NSCLC). METHODS: The study group comprised 112 NSCLC patients who underwent 18F-FDG and 18F-FAMT PET/CT prior to any therapy. The MTV, TLG, TLR, and maximum standardized uptake value (SUVmax) of the primary tumors were determined. Automatic MTV measurement was performed using PET volume computer assisted reading software. (GE Healthcare). Cox proportional hazards models were built to assess the prognostic value of MTV, TLG (for 18F-FDG), TLR (for 18F-FAMT), SUVmax, T stage, N stage, M stage, clinical stage, age, sex, tumor histological subtype, and treatment method (surgery or other therapy) on overall survival (OS). RESULTS: Higher TNM, higher clinical stage, inoperable status, and higher values for all PET parameters (both 18F-FAMT and 18F-FDG PET) were significantly associated (P < 0.05) with shorter OS. Multivariate analysis revealed that a higher MTV of 18F-FAMT (hazard ratio [HR]: 2.88, CI: 1.63-5.09, P < 0.01) and advanced clinical stage (HR: 5.36, CI: 1.88-15.34, P < 0.01) were significant predictors of shorter OS. CONCLUSIONS: MTV of 18F-FAMT is of prognostic value for OS in NSCLC cases and can help guide decision-making during patient management.

[Exposure Dose Reduction for Radiologists with Combination of Angular Beam Modulation and Radiation Protection Drape in CT Fluoroscopy: A Phantom Study].

PURPOSE: To assess the dose reduction of radiologists by using angular beam modulation (ABM) and radiation protection drape during computed tomography (CT) fluoroscopy. MATERIALS AND METHODS: The phantom was set on the lower that is 15 cm from the isocenter position. We measured the radiation exposure around the phantom with radiophotoluminescence glass dosimeters. The space radiation dose rate was measured with an ionization chamber dosimeter in the CT room. RESULTS: The dose rate of finger radiation exposure was 67% at assumed assist tool position with ABM. And the dose rate of finger radiation exposure with the combination of ABM and radiation protection drape was 33%. The space dose rate of exposure with the combination of ABM and radiation protection drape was 49% at 150 cm. CONCLUSION: The combination of ABM and radiation protection drape can reduce finger radiation exposure at assumed assist tool position. The space dose rate of the standing position of radiologists can get a clear dose of radiation reduction by the combination of both.

Usefulness of model-based iterative reconstruction in semi-automatic volumetry for ground-glass nodules at ultra-low-dose CT: a phantom study.

This study aimed to investigate the effects of parameter presets of the forward projected model-based iterative reconstruction solution (FIRST) on the accuracy of pulmonary nodule volume measurement. A torso phantom with simulated nodules [diameter: 5, 8, 10, and 12 mm; computed tomography (CT) density: - 630 HU] was scanned with a multi-detector CT at tube currents of 10 mA (ultra-low-dose: UL-dose) and 270 mA (standard-dose: Std-dose). Images were reconstructed with filtered back projection [FBP; standard (Std-FBP), ultra-low-dose (UL-FBP)], FIRST Lung (UL-Lung), and FIRST Body (UL-Body), and analyzed with a semi-automatic software. The error in the volume measurement was determined. The errors with UL-Lung and UL-Body were smaller than that with UL-FBP. The smallest error was 5.8% ± 0.3 for the 12-mm nodule with UL-Body (middle lung). Our results indicated that FIRST Body would be superior to FIRST Lung in terms of accuracy of nodule measurement with UL-dose CT.

Optimal Recycling of Steel Scrap and Alloying Elements: Input-Output based Linear Programming Method with Its Application to End-of-Life Vehicles in Japan.

Importance of end-of-life vehicles (ELVs) as an urban mine is expected to grow, as more people in developing countries are experiencing increased standards of living, while the automobiles are increasingly made using high-quality materials to meet stricter environmental and safety requirements. While most materials in ELVs, particularly steel, have been recycled at high rates, quality issues have not been adequately addressed due to the complex use of automobile materials, leading to considerable losses of valuable alloying elements. This study highlights the maximal potential of quality-oriented recycling of ELV steel, by exploring the utilization methods of scrap, sorted by parts, to produce electric-arc-furnace-based crude alloy steel with minimal losses of alloying elements. Using linear programming on the case of Japanese economy in 2005, we found that adoption of parts-based scrap sorting could result in the recovery of around 94-98% of the alloying elements occurring in parts scrap (manganese, chromium, nickel, and molybdenum), which may replace 10% of the virgin sources in electric arc furnace-based crude alloy steel production.

Contrast-induced nephropathy (CIN) of patients with renal dysfunction in CT examination.

PURPOSE: To investigate the incidence and risk factors of contrast induced nephropathy (CIN) after contrast enhanced (CE) computed tomography (CT) in patients with renal dysfunction. MATERIALS AND METHODS: Two hundred sixteen inpatients with estimated glomerular filtration rates (eGFR) <60 ml/min/1.73 m2 underwent CE CT using iodine doses of 420 or 480 mg I/kg. Data of all enrolled patients was collected for baseline serum creatinine level (SCr), post-CE CT SCr within 3 days after CE CT, and conditions considered risk factors for CIN [renal dysfunction, contrast media dose, advanced age, diabetes mellitus, no intravenous hydration, cardiac dysfunction (left ventricular ejection fraction <60%) and intensive-care unit (ICU) admission]. CIN was defined as an increase in SCr level of more than 0.5 mg/dl or more than 25% from baseline within 3 days post-CE CT without any other identifiable cause of acute kidney injury. RESULTS: The incidence of CIN was 11/216 (5.1%) and was associated with cardiac dysfunction [odds ratio (OR) 6.540; 95% confidence interval (CI) 1.090-39.300; p = 0.040] and ICU admission (OR 11.500; 95% CI 2.050-64.100; p = 0.005). CONCLUSION: Our results suggested that cardiac dysfunction and ICU admission may be risk factors for CIN in patients with preexisting renal dysfunction.

The Impact of Gadolinium-based Contrast Agent for Carbon Ion Radiotherapy.

PURPOSE: The contrast agent used in the diagnostic department has high atomic numbers and might influence dose deposition in the particle therapy. In particular, the influence of gadolinium-based (Gd) contrast agent on range in carbon ion radiotherapy has not yet been evaluated. For this reason, we avoid carbon treatment and planning computed tomography (CT) acquisition on days when the contrast-enhanced magnetic resonance image (MRI) is performed. In this study, we evaluated the time required for this beam range effect to vanish by evaluating the temporal changes in the CT values after an enhanced MRI as well as the stopping power of Gd solution. MATERIALS AND METHODS: Two types of diluted solutions with Gd contrast agent were used for comparing their transferred stopping power (TSP) and measured stopping power (MSP). The TSP was calculated with a CT value to stopping power ratio table that was created previously. Additionally, to evaluate in vivo attenuation, we measured the CT values in the renal pelvis from the CT images with and without contrast agent for 73 patients. RESULTS: The maximum difference between the TSP and MSP was 85%. The difference between the TSP after 4 hours and the TSP with non-enhanced cases was less than 1%. Moreover, the difference between the MSP after 1 hour and the MSP with non-enhanced cases was less than 0.1%. CONCLUSION: It was found that the impact of Gd contrast agent can be neglected 1 hour after administration for carbon beam irradiation and 4 hours after for planning the CT image acquisition.

Prefecture-wide multi-centre radiation dose survey as a useful tool for CT dose optimisation: report of Gunma radiation dose study.

The aim of this study was to verify the usefulness for the dose optimisation of setting a diagnostic reference level (DRL) based on the results of a prefecture-wide multi-centre radiation dose survey and providing data feedback. All hospitals/clinics in the authors' prefecture with computed tomography (CT) scanners were requested to report data. The first survey was done in July 2011, and the results of dose-length products (DLPs) for each CT scanner were fed back to all hospitals/clinics, with DRL set from all the data. One year later, a second survey was done in the same manner. The medians of DLP in the upper abdomen, whole body and coronary CT in 2012 were significantly smaller than those of the 2011 survey. The interquartile ranges of DLP in the head, chest, pelvis and coronary CT were also smaller in 2012. Radiation dose survey with data feedback may be helpful for CT dose optimisation.

Perfusion evaluation of lung cancer: assessment using dual-input perfusion computed tomography.

PURPOSE: The aim of this study was to investigate the feasibility of separately evaluating bronchial (BAP) and pulmonary arterial perfusion (PAP) of lung cancers using dual-input perfusion computed tomography. MATERIALS AND METHODS: Twenty-nine lesions from 28 patients [19 men and 9 women; age, 65.8±11.3 y (mean±SD); range, 39 to 85 y] were included in this study (1 patient had 2 tumors). From computed tomography data, quantitative maps of PAP and BAP were created using the dual-input maximum-slope method. Total blood perfusion (TBP) was defined as the sum of PAP and BAP, and the percentage of PAP to TBP was defined as %PAP. Correlation of these values with tumor size, location, and pathologic type was statistically analyzed. RESULTS: PAP ranged from 2.0 to 93.1 mL/min/100 mL (mean±SD, 26.8±26.4), BAP was 0 to 65.4 (25.1±19.12), TBP was 20.7 to 132.0 (52.0±29.0), and %PAP was 4% to 100% (48.8%±31.9%). PAP, TBP, and %PAP correlated negatively with tumor size (P<0.05). PAP and %PAP were higher in the peripheral zone than in the central zone (P<0.05). There was significant correlation between pathologic type and the respective perfusion parameters (P>0.05). CONCLUSIONS: We were successful in separating the dual vascular supply to assess dual-input perfusion of lung cancer. We found perfusion of lung cancers to depend on tumor size and location. Acknowledging and assessing the dual vascular supply in lung perfusion may have clinical implications in the management of lung cancer treatment.

Material and energy balances of an integrated biological hydrogen production and purification system and their implications for its potential to reduce greenhouse gas emissions.

The materials and energy in an integrated biological hydrogen production and purification system involving hydrolysis, dark fermentation, photo fermentation, CO2 fixation and anaerobic digestion are balanced by integrating the results from multiple experiments, simulations and the literature. The findings are two fold. First, using 1000 kg rice straw as a substrate, 19.8 kg H2 and 138.0 kg CH4 are obtained. The net energy balance (NEB) and net energy ratio (NER) are -738.4 kWh and 77.8%, respectively, both of which imply an unfavorable energy production system. Opportunities to improve the performance particularly lie in the photo fermentation process. Second, greenhouse gas emissions are evaluated for various options. The results were comparable with the emission inventory of electricity generated from fossil fuels. NEB and NER under a zero-carbon-emission constraint were discussed in detail to clarify completely the implications of the energy and material balances on greenhouse gas emissions.

Greenhouse gas and air pollutant emission reduction potentials of renewable energy--case studies on photovoltaic and wind power introduction considering interactions among technologies in Taiwan.

To achieve higher energy security and lower emission of greenhouse gases (GHGs) and pollutants, the development of renewable energy has attracted much attention in Taiwan. In addition to its contribution to the enhancement of reliable indigenous resources, the introduction of renewable energy such as photovoltaic (PV) and wind power systems reduces the emission of GHGs and air pollutants by substituting a part of the carbon- and pollutant-intensive power with power generated by methods that are cleaner and less carbon-intensive. To evaluate the reduction potentials, consequential changes in the operation of different types of existing power plants have to be taken into account. In this study, a linear mathematical programming model is constructed to simulate a power mix for a given power demand in a power market sharing a cost-minimization objective. By applying the model, the emission reduction potentials of capacity extension case studies, including the enhancement of PV and wind power introduction at different scales, were assessed. In particular, the consequences of power mix changes in carbon dioxide, nitrogen oxides, sulfur oxides, and particulates were discussed. Seasonally varying power demand levels, solar irradiation, and wind strength were taken into account. In this study, we have found that the synergetic reduction of carbon dioxide emission induced by PV and wind power introduction occurs under a certain level of additional installed capacity. Investigation of a greater variety of case studies on scenario development with emerging power sources becomes possible by applying the model developed in this study.