Low-energy X and γ radiations (for example of 210Pb: Eγ = 46.5 keV) are effectively self-absorbed even in thin environmental samples, including air filters with captured dust or contaminated soil, as well as in bottom sediment matrixes with limited quantities of the samples. In this paper, a simple method for the direct analysis of 210Pb (T1/2 = 22.3 years) by gamma-ray spectrometry in environm...

The electric field in streamer discharges in air can be easily determined by the ratio of luminous intensities emitted by N2(C 3 u) and N2(B 2 + u ) if the steady-state assumption of the emitting states is fully justified. At ground pressure, the steady-state condition is not fulfilled and it is demonstrated that its direct use to determine the local and instantaneous peak electric field in the...

Geophysical research has been carried out using the gravity method on Adonara island in east Flores Regency, East Nusa Tenggara. This study aims to determine subsurface rock geological conditions of area free air anomaly data from GGMplus and ERTM2160. The is reduced by atmospheric correction, simple bouguer curvature correction produce a complete anomaly. After regional anomalies residual are ...

statement of problem: one of the main goals in periodontal therapy is the correction of recession defects; therefore the efficacy and predictability of the various techniques are important considerations for clinicians. purpose: the purpose of this pilot study was to compare the outcomes of gingival recession therapy using the semilunar coronally repositioned flap (scrf) alone and in conjunctio...

PURPOSE Attenuation correction with an X-ray CT image is a new method to correct attenuation on SPECT imaging, but the effect of the registration errors between CT and SPECT images is unclear. In this study, we investigated the effects of the registration errors on myocardial SPECT, analyzing data from a phantom and a human volunteer. METHODS Registerion (fusion) of the X-ray CT and SPECT ima...

Department of Medical Physics and Biomedical Engineering and Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran Recently introduced PET/MRI scanners present significant advantages in comparison with PET/CT. However, the lack of accurate method for generation of μmap from MR images for implementation of MRAC is hampering further development. I...

Reliable attenuation correction represents an essential component of the long chain of modules required for the reconstruction of artifact-free, quantitative brain positron emission tomography (PET) images. In this work we demonstrate the proof of principle of segmented magnetic resonance imaging (MRI)-guided attenuation and scatter corrections in three-dimensional (3D) brain PET. We have devel...

PURPOSE TomoTherapy (Accuray Co.) has an image-guided radiotherapy system with megavoltage (MV) X-ray source and the on-board imaging device. With the MV computed tomography (MVCT), it became feasible to perform the efficient daily-3D registration of the patient position before each treatment delivery. This system also allows one to acquire the delivery sinogram during the actual treatment, whi...

Introduction: Functional MRI methods have been used to study sensorimotor processing in the brain and the Spinal cord. However, these techniques confront unwanted contributions to the measured signal from physiological fluctuations. For the spinal cord imaging, most of the challenges are consequences of cardiac and respiratory movement artifacts that are considered as signifi...

Background: In treating patients with radiation, the degree of accuracy for the delivery of tumor dose is recommended to be within ± 5% by ICRU in report 24. The experimental studies have shown that the presence of low-density inhomogeneity in areas such as the lung can lead to a greater than 30% change in the water dose data. Therefore, inhomogeneity corrections should be used in treatment pla...