22 research outputs found
Native incretins prevent the development of atherosclerotic lesions in apolipoprotein E knockout mice
A Two-dimensional Transmission Counter with A Backgammon-Drift Read-Out Technique
A new type of two-dimensional position sensitive gas counter for transmission counter with a backgammon-shaped flat electrode has been developed. The two dimensional position read-out can be achieved with the combination of the backgammon-shaped flat electrode read-out. as horizontal position and the drift time measurement read-out as vertical position. The gas counter is designed as a transmission trajectory counter that can be used to determined angle of incident charged particle in the charged particle detecting system. To check the characteristics of this gas counter, test experiments are performed with a coincidence plastic scintillation counter and p - ray source of 90Sr
The Case Fatality Rate of Methicillin-Resistant Staphylococcus aureus (MRSA) Infection among the Elderly in a Geriatric Hospital and Their Risk Factors.
Verification of proton range, position, and intensity in IMPT with a 3D liquid scintillator detector system
Differential Regulation of Chemokine Expression by Th1 and Th2 Cytokines and Mechanisms of Eotaxin/CCL-11 Expression in Human Airway Smooth Muscle Cells
Distribution of residual long-lived radioactivity in the inner concrete walls of a compact medical cyclotron vault room
Clinical characterization of a proton beam continuous uniform scanning system with dose layer stacking
A proton beam delivery system on a gantry with continuous uniform scanning and dose layer stacking at the Midwest Proton Radiotherapy Institute has been commissioned and accepted for clinical use. This paper was motivated by a lack of guidance on the testing and characterization for clinical uniform scanning systems. As such, it describes how these tasks were performed with a uniform scanning beam delivery system. This paper reports the methods used and important dosimetric characteristics of radiation fields produced by the system. The commissioning data include the transverse and longitudinal dose distributions, penumbra, and absolute dose values. Using a 208 MeV cyclotron’s proton beam, the system provides field sizes up to 20 and 30 cm in diameter for proton ranges in water up to 27 and 20 cm, respectively. The dose layer stacking method allows for the flexible construction of spread-out Bragg peaks with uniform modulation of up to 15 cm in water, at typical dose rates of 1–3 Gy∕min. For measuring relative dose distributions, multielement ion chamber arrays, small-volume ion chambers, and radiographic films were employed. Measurements during the clinical commissioning of the system have shown that the lateral and longitudinal dose uniformity of 2.5% or better can be achieved for all clinically important field sizes and ranges. The measured transverse penumbra widths offer a slight improvement in comparison to those achieved with a double scattering beam spreading technique at the facility. Absolute dose measurements were done using calibrated ion chambers, thermoluminescent and alanine detectors. Dose intercomparisons conducted using various types of detectors traceable to a national standards laboratory indicate that the measured dosimetry data agree with each other within 5%