نتایج جستجو برای: Mini- phantom
تعداد نتایج: 48571 فیلتر نتایج به سال:
Introduction: The Sc is an important parameter to monitor unit (MU) calculation in radiation therapy procedure. The aim of this study is to measurement and comparison of head scatter factor (Sc) for 9MV photon beam using the build-up cap and a columnar mini-phantom. Materials and Methods: The measurements performed using a calibrated ion chamber (Scanditron...
The characterization of the incident photon beam is usually divided into its dependence on collimator setting (head-scatter factor) and off-axis position (primary off-axis ratio). These parameters are normally measured "in air" with a build-up cap thick enough to generate full dose build-up at the depth of dose maximum. In order to prevent any influence from contaminating electrons, it has been...
Introduction: The head scatter factor (Sc) is important to measurements radiation beam and beam modeling of treatment planning systems used for advanced radiation therapy techniques. This study aimed to investigate the design of a mini-phantom to measurement variations in collimator Sc in the presence of shielding blocks for shaping the beam using different field sizes. <str...
A mini-ridge filter is often used to widen the Bragg peak in the longitudinal direction at low energies but not high energies. To facilitate the clinical use of a mini-ridge filter, we performed a planning study for the feasibility of a mini-ridge filter as an integral part of the synchrotron nozzle (IMRF). Dose models with and without IMRF were commissioned in a commercial Treatment planning s...
BACKGROUND A phantom shock-the sensation of an implantable cardioverter defibrillator (ICD) discharge in the absence of an actual discharge-is a phenomenon that can occur in ICD patients. Little is known about the influence of psychological factors on the incidence of phantom shocks. We evaluated psychological correlates of phantom shocks 2 years post-ICD implant in a cohort of Dutch ICD recipi...
Introduction: In nuclear medicine, the use of a pixelated semiconductor detector such as CZT is an of growing interest for introducing new devices. Especially, the spatial resolution can be improved by using a pixelated parallel-hole collimator with equal holes and pixel sizes based on the pixelated detector. The purpose of this study was to compare the effect of pixelated and ...
Localization of a needle tip is important for biopsy examinations in clinics. However, the needle tip is sometimes difficult to discern under the guidance of sonography due to its poor visibility. A mini actuator that radiates a low-intensity ultrasound wave was manufactured using micro-electro-mechanical system (MEMS) technology. Interference between the radiated and diagnostic ultrasound puls...
BACKGROUND Mini-c-arm fluoroscopy has become an important resource to the orthopaedic surgeon. Exposure of the orthopaedic surgical team to radiation during standard large-c-arm fluoroscopy has been well studied; however, little is known about the amount of exposure to which a surgical team is subjected with the use of mini-c-arm fluoroscopy. Moreover, there is controversy regarding the use of ...
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