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The purpose of this study was to investigate the correlation between GFR and unit renal volume in infants with congenital hydronephrosis measured by 99mTc-DMSA static renal imaging and ultrasonography. According to the classification of hydronephrosis, 38 infants aged 0–12 months with congenital hydronephrosis were divided into six groups: healthy kidney groups, mild hydronephrosis groups, and severe hydronephrosis groups. Within one week, all patients underwent ultrasound, diuretic dynamic renal imaging, static renal imaging and lateral imagings of both kidneys after static renal imaging respectively. Pediatric renal volume was calculated using the improved formula length × width × thickness × 0.674, and then the renal function in per unit volume (GFR/unit volume, ml/cm3) was obtained. All statistical analysis was done with SPSS Statistics version 24.0. The renal function in per unit volume was a minimum of 1.62 ml/cm3 in left healthy kidney in static renal imaging, but the renal function in per unit volume was a maximum value of 2.20 ml/cm3 in right healthy kidney in ultrasonography. There was a strong positive correlation observed between GFR and renal volume in left healthy kidney group and left and right kidneys with mild hydronephrosis groups (r = 0.865, r = 0.872, r = 0.822). A moderate positive correlation was found between GFR and renal volume in right healthy kidney group and left and right kidneys wih severe hydronephrosis groups (r = 0.783, r = 0.542, r = 0.798). GFR in per unit volume ranged from 1.62 to 2.20 ml/cm3 in healthy kidney, and was significantly higher in right kidney as compared to in left kidney, and also decreased with the progression of hydronephrosis. [ABSTRACT FROM AUTHOR]

The obtainment of the neutron multiplicity distribution is the precondition of the neutron coincidence or multiplicity measurement. In related measurements, the calibration of the detector and the optimization of the analysis parameters prefer acquiring the neutron multiplicity distribution through the offline time-correlation analysis of the measured time stamps, while the usual measurement tasks tend to get it online. To meet with the demands of online and offline obtainment of the neutron multiplicity distribution, an online time-correlation analysis method on the basis of list-mode data acquisition technique is proposed in present work. The reliability of the obtained neutron multiplicity distribution is verified through the experiments carried out with a strong and a weak 252Cf neutron sources. [ABSTRACT FROM AUTHOR]

For the reconstructed image of transmission computed tomography, the linear attenuation coefficients of the diagnosed object may improve the image quality by adding additional constraint besides the projection data. In the present work, an image reconstruction method with the constraint of the linear attenuation coefficients is developed and two models including a classical numerical Shepp-Logan model and a Monte Carlo model are used to show the corresponding benefits. The results indicate that the number of the projection angles is potentially decreased to 1/3 of itself while the quality of the reconstructed image is not deteriorated. • An image reconstruction method with the constraint of the linear attenuation coefficients is developed. • The method can decrease the number of the projection angles to 1/3 of itself while the image quality is not deteriorated. • The present method can prevent the image quality from decreasing with the increase of loop iteration. [ABSTRACT FROM AUTHOR]

Scintillators with n - γ discrimination property are widely used in the measurement of neutrons. In sub MeV region, the n - γ discrimination property will be greatly deteriorated so that the neutron and γ -ray events can't be accurately discriminated. As a result, the determination of the proportions of neutron and γ -ray events beyond the discrimination threshold is important if scintillators are applied to measure the low energy neutrons. In the present work, a method based on the time-of-flight technique is proposed to calibrate the proportions of neutron and γ -ray events beyond the discrimination threshold. After the calibration, the numbers of the measured neutron and γ -ray events can be separately determined even if the neutron and γ -ray events can't be perfectly discriminated. • A method was proposed to calibrate the proportions of neutron and γ-ray events beyond the discrimination threshold. • The numbers of the neutron and γ-ray events can be separately determined even if they can't be accurately classified. • After the calibration, a lower detection threshold can be adopted to improve the detection efficiency of the scintillators. [ABSTRACT FROM AUTHOR]