نتایج جستجو برای: ionization chamber
تعداد نتایج: 78250 فیلتر نتایج به سال:
This study investigated the clinical performance of a novel solid-state diagnostic dosimeter, the RaySafe Xi transparent detector, by comparing its performance to a reference-class ionization chamber. Firstly a comparison of dosimeter response "free-in-air" with standard beam qualities was made, followed by an investigation into its relative transparency in an X-ray field and angular sensitivit...
This paper aims to inform the public and scientists not in the field of radioactivity on the way secondary activity measurements are undertaken at NMISA to ensure the quality of life of South Africans. Various secondary standard nuclear instruments are used for routine activity measurements for dissemination to the user community such as the nuclear medicine industry. Three instrument types are...
The response of an integrating ionization chamber at 10 g/cm •' depth in the atmosphere to particles of various rigidities is evaluated by using the change of ionization with latitude. This procedure yields the differential response curves at solar minimum and solar maximum and also the mean rigidity of response at any given latitude. For high latitude and Minneapolis, the mean responses are 2....
Purpose: Cylindrical ionization chambers as the PinPoint and the CC01 have high-spatial resolution and cylindrical symmetry in relevance to small fields. Dosimetry of newly advanced technologies that include non-coplanar beams, such as in Gamma-Knife, VMAT and IMRT treatment plans, the angular dependence of the ion chamber is essential. Therefore in this study we simulated two common used ion c...
This work presents the first use of capillary vibrating sharp-edge spray ionization as a nebulization technique for ICP-MS and discusses fused deposition modeling to create dedicated sample introduction chamber.
introduction: in radiotherapy, methods of treatment planning are becoming increasingly more complicated. this requires verification of the doses delivered to increasingly smaller and more precise regions. radiotherapy techniques are continuously employing smaller and smaller field sizes to deliver tighter radiation doses with higher therapeutic ratios, generating interest among researchers to p...
A helicon antenna that sits remotely outside the vacuum system is attached to a magnetron sputtering system. This increases the electron temperature, which increases the ionization of the sputter flux for achieving ionized physical vapor deposition (IPVD). There are no shadowing and contamination problems, unlike other IPVD devices with immersed coils, since the helicon antenna is outside the v...
Introduction: In radiotherapy, methods of treatment planning are becoming increasingly more complicated. This requires verification of the doses delivered to increasingly smaller and more precise regions. Radiotherapy techniques are continuously employing smaller and smaller field sizes to deliver tighter radiation doses with higher therapeutic ratios, generating interest among researchers to p...
The motivation for this study was to reduce physics workload relating to patient- specific quality assurance (QA). VMAT plan delivery accuracy was determined from analysis of pre- and on-treatment trajectory log files and phantom-based ionization chamber array measurements. The correlation in this combination of measurements for patient-specific QA was investigated. The relationship between del...
Introduction: Electronic portal imaging devices (EPIDs) could be used to dose verification of radiotherapy treatment plans. In vivo dose verification is performed to reduce differences found between dose delivered to the patient and the prescribed dose. The aim of this study was to perform a fast and efficient technique for the verification of delivered dose to the patient usin...
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