Purpose: Fiber carbon is the most common material used in treating couch as it causes less beam attenuation than other materials. Beam attenuation replaces build-up region, reduces skin-sparing effect and causes target volume under dosage. In this study, we aimed to evaluate beam attenuation and variation of build-up region in 550 TxT radiotherapy couch.Materials and Methods: In this study, we ...

currently available non-invasive clinical methods for diagnosing osteoporosis are mainly associated with ionizing radiation. ultrasonic assessment of bone disease is a more recent technology. a theoretical explanation for the relationship between ultrasonic parameters and bone structure is necessary. thus, two types of bone samples of perspex (hap) and perspex-glass beads were produced. each ty...

introduction: nowadays, imaging of the myocardial perfusion (mpi) using the single photon emission tomography (spet) in the diagnosis of coronary artery disease, especially myocardial ischemia, is of great importance. in contrast to the coronary artery angiography, mpi is non-invasive, less expensive and more physiological. unfortunately, this image is affected by the some artifacts. these arti...

in recent years, demand for biological sensors which are capable of fast and accurate detection of minor amounts of pathogens inreal‑time form has been intensified. acoustic wave (aw) devices whose performance is determined by mass sensitivity parametersand quality factor are used in biological sensors as platforms with high quality. yet, current aw devices are facing many challengessuch as the...

PURPOSE To prospectively investigate computed tomographic (CT) image quality parameters by using different protocols and to calculate radiation dose estimates for noninvasive coronary angiography performed with dual-source CT in the step-and-shoot (SAS) mode. MATERIALS AND METHODS This study was local ethics board approved; written informed consent was obtained from all patients. In the preli...

We assessed the effect of nedocromil sodium on bronchoconstriction and airway responsiveness induced by platelet-activating factor (PAF) in eight normal subjects, in a double-blind, placebo-controlled cross-over study. Subjects inhaled PAF by a dosimeter method in 5 doses of 18 micrograms each, separated by an interval of 15 min, (total dose of 90 micrograms). Airway calibre was measured by par...

New algorithms for rain attenuation correction of reflectivity factor and differential reflectivity are presented. Following the methodology suggested for the first time by Gorgucci et al., the new algorithms are developed based on the self-consistency principle, describing the interrelation between polarimetric measurements along the rain medium. There is an increasing interest in X-band radar...

It has previously been reported that the region between nucleotides 259 and 383 immediately downstream from the P4 early promoter of parvovirus minute virus of mice, prototype strain (MVMp) is responsible for transcriptional attenuation. Attenuation results from the premature pausing of RNA polymerase II within this sequence (designated to as att) and seems to depend on potential RNA secondary ...

For airand spaceborne weather radars, which typically operate at frequencies of 10 GHz and above, attenuation correction is usually an essential part of any rain estimation procedure. For ground-based radars, where the maximum range within the precipitation is usually much greater than that from airor spaceborne radars, attenuation correction becomes increasingly important at frequencies above ...

We present an 0( N log N) algorithm for the simultaneous evaluation (at all N points of a uniform mesh) of a function conjugate to a periodic spline. The algorithm is based on the attenuation factor theory and makes use of the FFT. It can be applied to other function classes with known attenuation factors also. For the approximation by functions conjugate to splines of odd degree we state sever...