Comparative Analysis of the Multi-Frequency Bio-impedance and Dual-energy X-ray Absorptiometry on Body Composition in Obese Subjects

To examine accuracy of body composition predicted by the Multi-Frequency Bioelectric Impedance Analysis （MF-BIA） compared with the Dual-energy X-ray Absorptiometry （DXA） in adults with obese. We measured body composition of 749 adults with obese both by the MF-BIA and DXA. The Lin＇s concordance correlation and the Bland-Altman plots were used to examine the consistency. The concordance correlation coefficient of %BF between the MF-BIA and DXA in men and women was 0.560, and 0.669, respectively. Compared with the DXA, the MF-BIA significantly underestimated %BF by 4.33% in men （P 〈 0.001）, however overestimated %BF by 0.50% in women （P 〈 0.001）. After corrected by the correction equations established in this study, the differences were significantly decreased. Therefore, the MF-BIA （TANITA MC-180） may need to be corrected in estimating body composition for adults with obese.

Prevalence and risk factors of osteoporosis detected by dual-energy X-ray absorptiometry among Chinese patients with primary biliary cholangitis

BACKGROUND Osteoporosis is an extrahepatic complication of primary biliary cholangitis(PBC)that increases the risk of fractures and mortality.However,Epidemiological studies of osteoporosis in patients with PBC in China and the Asia-Pacific region is lack.AIM To assess the prevalence and clinical characteristics of osteoporosis in Chinese patients with PBC.METHODS This retrospective analysis included consecutive patients with PBC from a tertiary care center in China who underwent bone mineral density(BMD)assessment using dual-energy X-ray absorptiometry between January 2013 and December 2021.We defined subjects with T-scores≤-2.5 in any sites(L1 to L4,femoral neck,or total hip)as having osteoporosis.Demographic,serological,clinical,and histological data were collected.Independent risk factors for osteoporosis were identified by multivariate logistic regression analysis.RESULTS A total of 268 patients with PBC[236 women(88.1%);mean age,56.7±10.6 years;163 liver biopsies(60.8%)]were included.The overall prevalence of osteoporosis in patients with PBC was 45.5%(122/268),with the prevalence of osteoporosis in women and men being 47.0%and 34.4%,respectively.The prevalence of osteoporosis in postmenopausal women was significantly higher than that in premenopausal women(56.3%vs 21.0%,P<0.001).Osteoporosis in patients with PBC is associated with age,fatigue,menopausal status,previous steroid therapy,body mass index(BMI),splenomegaly,gastroesophageal varices,ascites,Mayo risk score,histological stage,alanine aminotransferase,albumin,bilirubin,platelet and prothrombin activity.Multivariate regression analysis identified that older age,lower BMI,previous steroid therapy,higher Mayo risk score,and advanced histological stage as the main independent risk factors for osteoporosis in PBC.CONCLUSION Osteoporosis is very common in Chinese patients with PBC,allowing for prior screening of BMD in those PBC patients with older age,lower BMI,previous steroid therapy and advanced liver disease.

Study on absorption coefficients of dual-energy γ-rays in determining phase fractions of multiphase flows

This paper discusses the principle and mathematical method to measure the phase fractions of multiphase flows by using a dual-energy gamma-ray system. The dual-energy gamma-ray device is composed of radioactive isotopes of 241Am and 137Cs with emission energies of 59.5 keV and 662 keV respectively. A rational method to calibrate the absorption coefficient was introduced in detail. The statistical error has been analyzed on the basis of the accurate absorption coefficient which enables determination phrase fractions almost independent of the flow regime. Improvement has been achieved on the measurement accuracy of phase fractions.

Theory and method of dual-energy x-ray grating phase-contrast imaging

The principle of dual-energy x-ray grating phase-contrast imaging(DEPCI) is clarified by using the theory of x-ray interference and Fresnel diffraction. A new method of retrieving phase from the two interferograms is proposed for DEPCI,and its feasibility is verified via simulation. Finally, the proposed method applied to DEPCI experiment demonstrates the effectiveness of the method. This paper lays the theoretical foundation for performance optimization of DEPCI and the further integration of DEPCI and computed tomography.

Measurement of the high energyγ-rays from heavy ion reactions usingČerenkov detector

The energetic bremsstrahlung photons up to 100 MeV produced in heavy ion collisions can be used as a sensitive probe for short-range correlation in atomic nuclei. The energy of the γ-rays can be measured by collecting the Čerenkov light in the medium induced by the fast electrons generated in the Compton scattering or electromagnetic shower of the incident γray. Two types of detectors based on pure water and lead glass as sensitive materials were designed for this purpose. The γresponse and optical photon propagation in the detectors were simulated based on electromagnetic and optical processes in Geant4. The inherent energy resolutions of 0.022(4) + 0.51(2)∕E^(1/2)_(γ) for water and 0.0026(3) + 0.446(3)∕E^(1/2)_(γ) for lead glass were obtained. The geometry sizes of the lead glass and water were optimized to 30 cm × 30 cm × 30 cm and 60 cm × 60 cm ×120 cm, respectively, to detect high-energy γ-rays at 160 MeV. The Hough transform method was applied to reconstruct the direction of the incident γ-rays, providing the ability to experimentally distinguish the high-energy γ-rays produced in the reactions on the target from random background cosmic-ray muons.

Association between body mass index and body fat measured by dual-energy X-ray absorptiometry (DXA) in China: a systematic review and meta-analysis

Objective:We examined the association between body mass index(BMI)and body fat percentage(BF%)measured by dual-energy X-ray absorptiometry(DXA)among adults and children in China.Methods:We searched four databases-PubMed,China National Knowledge Infrastructure,Wanfang,and Vip for studies published in the past 22 years.Meta-analysis was conducted using random-or fixed-effect models.Results:In total of 21 studies met inclusion criteria and were included in review,and 17 ot them in meta-analysis.They were conducted across China.Their sample size ranged from 62 to 5726,and participants'age ranged from 6-80 years.Meta-analysis revealed strong associations between BMI and BF% measured by DXA in adults(pooled r=0.71,95% CI:0.66 to 0.74)and children(pooled r=0.60,95% CI:0.52 to 0.68).The association was stronger in Northern China than in East China in children(β=-0.40,95%CI:-0.65 to-0.14)and in Central China in adults(β=-0.25;95% CI:-0.51 to-0.01).Urban children's BMI was strongly associated with BF%than rural(β=0.19;95%CI:0.04 to 0.35),whereas it was stronger in adults living in rural than in urban(β=-0.35;95% CI:-0.66 to-0.05).Conclusions:BMI was strongly associated with BF%measured by DXA,and the association in children and adults in China varied by residence and region.

Dual-Energy X-Ray Computed Tomography Scanner Using Two Different Energy-Selection Electronics and a Lutetium-Oxyorthosilicate Photomultiplier Detector

To obtain two kinds of tomograms at two different X-ray energy ranges simultaneously, we have constructed a dual-energy X-ray photon counter with a lutetium-oxyorthosilicate photomultiplier detector system, three comparators, two microcomputers, and two frequency-voltage converters. X-ray photons are detected using the detector system, and the event pulses are input to three comparators simultaneously to determine threshold energies. At a tube voltage of 100 kV, the three threshold energies are 16, 35 and 52 keV, and two energy ranges are 16 - 35 and 52 - 100 keV. X-ray photons in the two ranges are counted using microcomputers, and the logical pulses from the two microcomputers are input to two frequency-voltage converters. In dual-energy computed tomography (CT), the tube voltage and current were 100 kV and 0.29 mA, respectively. Two tomograms were obtained simultaneously at two energy ranges. The energy ranges for gadolinium-L-edge and K-edge CT were 16 - 35 and 52 - 100 keV, respectively. The maximum count rate of dual-energy CT was 105 kilocounts per second with energies ranging from 16 to 100 keV, and the exposure time for tomography was 19.6 min.

Dual-Energy Subtraction X-Ray Digital Tomosynthesis: Basic Physical Evaluation

The present study was performed to determine the potential of applying dual-energy subtraction (DES) digital tomo-synthesis to basic physical evaluations. Volumetric X-ray DES digital tomosysnthesis was used to obtain an image of a detectability phantom (an artificial lesion). The image quality of DES digital tomosynthesis was compared to that of DES radiography. The purpose of this study was to determine enhanced visibility quantified in terms of the contrast- to-noise ratio, figure-of-merit, and root-mean-square error. In the in-focus plane, the image quality is better by DES digital tomosynthesis than by DES radiography. The potential usefulness of DES digital tomosynthesis for evaluating a detectability phantom was demonstrated. Further studies are required to determine the ability of DES digital tomosyn-thesis to quantify the spatial relationships between the artificial lesion components of these devices, as well as to iden- tify lesions with diagnostic consequences.

Artificial neural network-based method for discriminating Compton scattering events in high-purity germaniumγ-ray spectrometer

To detect radioactive substances with low activity levels,an anticoincidence detector and a high-purity germanium(HPGe)detector are typically used simultaneously to suppress Compton scattering background,thereby resulting in an extremely low detection limit and improving the measurement accuracy.However,the complex and expensive hardware required does not facilitate the application or promotion of this method.Thus,a method is proposed in this study to discriminate the digital waveform of pulse signals output using an HPGe detector,whereby Compton scattering background is suppressed and a low minimum detectable activity(MDA)is achieved without using an expensive and complex anticoincidence detector and device.The electric-field-strength and energy-deposition distributions of the detector are simulated to determine the relationship between pulse shape and energy-deposition location,as well as the characteristics of energy-deposition distributions for fulland partial-energy deposition events.This relationship is used to develop a pulse-shape-discrimination algorithm based on an artificial neural network for pulse-feature identification.To accurately determine the relationship between the deposited energy of gamma(γ)rays in the detector and the deposition location,we extract four shape parameters from the pulse signals output by the detector.Machine learning is used to input the four shape parameters into the detector.Subsequently,the pulse signals are identified and classified to discriminate between partial-and full-energy deposition events.Some partial-energy deposition events are removed to suppress Compton scattering.The proposed method effectively decreases the MDA of an HPGeγ-energy dispersive spectrometer.Test results show that the Compton suppression factors for energy spectra obtained from measurements on ^(152)Eu,^(137)Cs,and ^(60)Co radioactive sources are 1.13(344 keV),1.11(662 keV),and 1.08(1332 keV),respectively,and that the corresponding MDAs are 1.4%,5.3%,and 21.6%lower,respectively.

Characterization of tumors of jaw:Additive value of contrast enhancement and dual-energy computed tomography

BACKGROUND Currently,the differentiation of jaw tumors is mainly based on the lesion’s morphology rather than the enhancement characteristics,which are important in the differentiation of neoplasms across the body.There is a paucity of literature on the enhancement characteristics of jaw tumors.This is mainly because,even though computed tomography(CT)is used to evaluate these lesions,they are often imaged without intravenous contrast.This study hypothesised that the enhancement characteristics of the solid component of jaw tumors can aid in the differentiation of these lesions in addition to their morphology by dual-energy CT,therefore improving the ability to differentiate between various pathologies.AIM To evaluate the role of contrast enhancement and dual-energy quantitative parameters in CT in the differentiation of jaw tumors.METHODS Fifty-seven patients with jaw tumors underwent contrast-enhanced dual-energy CT.Morphological analysis of the tumor,including the enhancing solid component,was done,followed by quantitative analysis of iodine concentration(IC),water concentration(WC),HU,and normalized IC.The study population was divided into four subgroups based on histopathological analysis-central giant cell granuloma(CGCG),ameloblastoma,odontogenic keratocyst(OKC),and other jaw tumors.A one-way ANOVA test for parametric variables and the Kruskal-Wallis test for nonparametric variables were used.If significant differences were found,a series of independent t-tests or Mann-Whitney U tests were used.RESULTS Ameloblastoma was the most common pathology(n=20),followed by CGCG(n=11)and OKC.CGCG showed a higher mean concentration of all quantitative parameters than ameloblastomas(P<0.05).An IC threshold of 31.35×100μg/cm^(3) had the maximum sensitivity(81.8%)and specificity(65%).Between ameloblastomas and OKC,the former showed a higher mean concentration of all quantitative parameters(P<0.001),however when comparing unilocular ameloblastomas with OKCs,the latter showed significantly higher WC.Also,ameloblastoma had a higher IC and lower WC compared to“other jaw tumors”group.CONCLUSION Enhancement characteristics of solid components combined with dual-energy parameters offer a more precise way to differentiate between jaw tumors.

Study on γ-Ray Irradiation Mutation of Bacillus subtilis NCD-2

[Objective] To study the effect of 60Co γ-rays irradiation on Botrytis cinerea biocontrol strains—Bacillus subtilis NCD-2. [Method] NCD-2 cells were irradiated at different doses of γ-rays from 100 to 2 000 Gy. The strains were screened by plate confrontation method and Oxford cup diffusion. [Result] The curves of the relationship of irradiation dose and mutation and lethal rate were obtained. The results showed that lethal rate increased with the increasing of irradiation dose. The lethal rate of 1 000 Gy irradiation dose reached 99.50%. The mutation rate increased below 500 Gy and decreased above 500 Gy. The highest mutation rate occurred when the irradiation dose was between 400 and 700 Gy, and the average mutation rate was above 15%. The optimal irradiation dose was 500 Gy, when the average mutation rate was 26.51% and lethal rate was 77.71%. [Conclusion] This study provided references for γ-rays irradiation mutation of Bacillus subtilis.

SRAP Marker Analysis of Genomic Mutation Induced by ^(60)Coγ-Ray Irradiation in Potato (Solanum tuberosum)

[Objective] This study was to explore the mutagenic effect of 60Co γ-ray on Solanum tuberosum chromosomes.[Method] The 60Co γ-ray at different irradiation doses was applied to treat the minitubers of potato variety ＇Favorita＇,and the genomic mutations in VM1 and VM2 gene rations in treatments with different doses were analyzed by SRAP markers.[Resalt] Thirty pairs of SRAP primers out of 88 pairs exhibited polymorphism with a rate of 34.1％ in the bulked selection of VM1 generation.A total of 225 bands were obtained,of which 64 were polymorphic with a rate of 28.4％.The polymorphism was reflected in the forms of deleted bands and added bands.Based on the result of the bulked selection of VM1 generation,25 primers with polymorphism were selected to scan VM2 generation.Five primers performed poorly,and nine of the rest 20 pairs revealed polymorphism and obtained nine polymorphic bands,of which only four bands were detected in VM1 generation and the other five ones were newly deleted bands.Only 9.8％ of the bands detected in VM1 generation were obtained in VM2 generation.Eventually,nine stable and dear polymorphic bands were recovered and cloned,and DNA sequences of six bands of them were acquired by sequencing.According to the comparative analysis,five fragments sequences were similar to potato chromosome with a similarity rate of 77％-89％,three of them located at the resistance gene cluster; another one fragment had a similarity of 93％ with some regions of the No.5 chromosome in tomato.[Conclusion] 60Co γ-ray irradiation can cause mutation of genomic DNA in potato;there is no significant correlation between the number of polymorphic bands and the irradiation dose; potymorphic bands are characterized by a larger number of deleted bands than that of the added ones.

费米耀变体的多波段γ-ray辐射

从Fermi/LAT第3期源表(3FGL)中选取了920个Blazar样本,包含414个平谱射电源(Flat Spectrum Radio Quasar,FSRQ)和506个蝎虎天体(BL Lac object,BL Lac),其中有226个HBL,140个IBL和140个LBL.研究了所有Blazar样本及其子类FSRQ,BL Lac,HBL和LBL样本的射电1.4 GHz光度分别与γ-ray在0.1,0.3,1,3及10 GeV处光度之间的相关性。结果表明:对总样本及所有子类样本,1.4 GHz光度与γ-ray各频率处的光度均存在强的正相关性,但对于不同的子类样本,这种相关性随γ-ray频率的变化趋势不同;BL Lac的相关性好于FSRQ,而HBL的相关性与LBL相似。总的来说,随着γ-ray辐射频率的增加,相关性有减弱的趋势。但是,对于不同的样本,相关性随γ-ray频率增加有不同的变化趋势。因此,同一频率下不同子类Blazar的γ-ray辐射机制存在差异,同一样本在不同频率下的γ-ray辐射机制也有差异.在γ-ray辐射中,BL Lac的辐射来自同步自康普顿(SSC)过程的成分比FSRQ的多,而HBL的与LBL的相似.FSRQ的γ-ray辐射机制比BL Lac更为复杂。

Mutagenic Effect of ^(60)Co γ-rays Irradiation on Turf Characteristics of Buchloe dactyloides (Nutt.) Engelm.

[Objective] This study aimed to investigate the mutagenic effect of 60 Co γ-rays irradiation on turf characteristics of Buchloe dactyloides （Nutt.） Engelm. [Method] Buffalo grass were irradiated with 60 Co γ-rays at five different radiation intensities （1 200, 1 400, 1 600, 1 800, 2 000 Gy） to determine the related turf characteristics and analyze the mutagenic effect of 60 Co γ-rays at different radiation intensities on buffalo grass. [Result] Germination rates of buffalo grass irradiated by different radiation intensities of 60 Co γ-rays varied inconsistently, and the root length and bud length were shorter than the control; compared with the control, the height of irradiated seedlings was significantly reduced, and the number of tillers, plant height, leaf length and leaf blade width were smaller than the control; however, the stolon length, stolon diameter and number of stolon nods had no significant difference compared with the control. [Conclusion] This study laid foundation for determining the appropriate radiation intensity of 60 Co γ-rays and selecting useful mutants of buffalo grass.

电子束和γ-ray对UHMWPE纤维的辐照效应对比研究

γ-ray和电子束是高能辐照源,高能射线不仅可以处理被加工物表面,同时可深入其内部,且工艺控制简单,可进行常温或者低温加工,具有节能、无环境污染等特点.分别采用γ-ray和电子束辐照超高相对分子质量聚乙烯(UHMWPE)纤维,采用电子自旋共振(ESR)、红外光谱(IR)、差示扫描量热法(DSC)、X射线衍射(XRD)、扫描电镜(SEM)、凝胶含量和拉伸实验等表征手段对不同的辐照效应进行研究,旨在改善纤维表面惰性,探索合理使用两种辐射源辐照改性材料的适用范畴,为更好地利用辐照技术对UHMWPE纤维表面改性提供理论依据.

Volumetric fraction measurement in oil-water-gas multiphase flow with dual energy gamma-ray system

Volumetric fraction distribution measurement is a constituent part of process tomography system in oil-water-gas multiphase flow. With the technological development of nuclear radial inspection, dual-energy γ-ray techniques make it possible to investigate the concentration of the different components on the cross-section of oil-water-gas multiphase pipe-flow. The dual-energy gamma-ray technique is based on materials attenuation coefficients measurement comprised of two radioactive isotopes of 241Am and 241Cs which have emission energies at 59.5 keV and 662 keV in this project. Nuclear instruments and data acquisition system were designed to measure the material’s attenuation dose rate and a number of static tests were conducted at the Multiphase Laboratory, Institute of Mechanics, Chinese Academy of Sciences. Three phases of oil-water-gas media were inves- tigated for their possible use to simulate different media volumetric fraction distributions in experimental vessels. Attenuation intensities were measured, and the arithmetic of linear attenuation coefficients and the equations of volumetric fractions were studied. Investigation of an unexpected measurement error from attenuation equations revealed that a modified arithmetic was involved and finally the system achieved acceptable accuracy in experimental research.

Correlation analysis of dual-energy CT iodine maps with quantitative pulmonary perfusion MRI

AIM:To correlate dual-energy computed tomography(DECT) pulmonary angiography derived iodine maps with parameter maps of quantitative pulmonary perfusion magnetic resonance imaging(MRI).METHODS:Eighteen patients with pulmonary perfusion defects detected on DECT derived iodine maps were included in this prospective study and additionally underwent time-resolved contrast-enhanced pulmonary MRI [dynamic contrast enhanced(DCE)-MRI].DCE-MRI data were quantitatively analyzed using a pixel-by-pixel deconvolution analysis calculating regional pulmonary blood flow(PBF),pulmonary blood volume(PBV) and mean transit time(MTT) in visually normal lung parenchyma and perfusion defects.Perfusion parameterswere correlated to mean attenuation values of normal lung and perfusion defects on DECT iodine maps.Two readers rated the concordance of perfusion defects in a visual analysis using a 5-point Likert-scale(1 = no correlation,5 = excellent correlation).RESULTS:In visually normal pulmonary tissue mean DECT and MRI values were:22.6 ± 8.3 Hounsfield units(HU);PBF:58.8 ± 36.0 mL/100 mL per minute;PBV:16.6 ± 8.5 mL;MTT:17.1 ± 10.3 s.In areas with restricted perfusion mean DECT and MRI values were:4.0 ± 3.9 HU;PBF:10.3 ± 5.5 mL/100 mL per minute,PBV:5 ± 4 mL,MTT:21.6 ± 14.0 s.The differences between visually normal parenchyma and areas of restricted perfusion were statistically significant for PBF,PBV and DECT(P < 0.0001).No linear correlation was found between MRI perfusion parameters and attenuation values of DECT iodine maps(PBF:r = 0.35,P = 0.15;PBV:r = 0.34,P = 0.16;MTT:r = 0.41,P = 0.08).Visual analysis revealed a moderate correlation between perfusion defects on DECT iodine maps and the parameter maps of DCE-MRI(mean score 3.6,k 0.45).CONCLUSION:There is a moderate visual but not statistically significant correlation between DECT iodine maps and perfusion parameter maps of DCE-MRI.

γ-Ray Irradiation-Derived MnO/rGO Composites for High Performance Lithium Ion Batteries

We report a γ-ray irradiation reduction method to prepare MnO/reduced graphene oxide （rCO） nanocomposite for the anode of lithium ion batteries. γ-Ray irradiation provides a clean way to generate homogeneously dispersed MnO nanoparticles with finely tuned size on rGO surface without the use of surfactant. The MnO/rGO composite enables a fully charge/discharge in 2 min to gain a reversible specific capacity of 546 （mA-h）/g which is 45 higher than the theoretical value of commercial graphite anode.

Similar therapeutic effects of ^(125I) seed radiotherapy andγ-ray radiotherapy on lacrimal gland adenoid cystic carcinoma

AIM:To evaluate the survival outcomes of patients with lacrimal gland adenoid cystic carcinoma who underwent eye-sparing surgery combined with ^(125I)seed implantation radiotherapy or local externalγ-ray radiotherapy.METHODS:In this retrospective comparative case series,the clinical records of 27 primary and 8 recurrent patients were reviewed.Univariate and multivariate analyses were used to identify risk factors associated with distant metastasis(DM),and the overall survival(OS)after the initial surgery was analyzed.RESULTS:The median follow-up after radiotherapy was 36 mo(range 6-120 mo).At the last follow-up after radiotherapy,26(74.3%)patients had no evidence of disease,7(20%)patients had DM,2(5.9%)patients died of DM,and 1 patient with DM was lost to follow-up.Univariate analyses showed that duration of symptoms,bone destruction,T stage classification,and wide excision surgery were risk factors influencing DM(P<0.05).The 5-year and 10-year OS rates after the initial surgery were 95.8%and 79.9%,respectively.The 5-year DM-free survival and disease-free survival rates after radiotherapy were 66.4%and 52.7%,respectively.CONCLUSION:^(125I)seed radiotherapy and local externalγ-ray radiotherapy may have similar therapeutic effects in preventing DM.Patients with T1/T2 stage disease have a better prognosis than those with T3/T4 stage disease.

Characterization of ureteral stents by dual-energy computed tomography: Clinical implications

Dual-energy computed-tomography(DECT) has been suggested as the method of choice for imaging urinary calculi due to the modality's high sensitivity for detect-ing stones and its capability of accurately differentiat-ing between uric-acid(UA) and non-UA(predominantly calcium) stones. The clinical significance of the latter feature relates to the differences in management of UA vs non-UA calculi. Like calculi, ureteral stents are assigned color by the dual-energy post-processing algorithm, which may lead to improved or worsened stone visualization based on the resulting stent/stone contrast. Herein we depict the case of a nephrolithiasis patient with bilateral stents, each with different color, clearly displaying the effect of stent color on stone vi-sualization. Further, three-dimensional reconstruction of the DECT images illustrates advantages of this enhancement compared to conventional two-dimensional computed tomography. The resulting stent/stone contrast produces an unanticipated potential advantage of DECT in patients with urolithiasis and stents and may promote improved management decision-making.