44 research outputs found
Quiz di fisica per i corsi di fisica medica e di fisica per biologia.
Quiz di Fisica risolti come ausilio didattico per l'esame di Fisica Medica per studenti di Medicina e perl'esame di Fisica per studenti di Biologi
Experimental tests of different solutions to the diffusion equation for optical characterization of scattering media by time-resolved transmittance.
EXPERIMENTAL EVALUATION OF ABSORPTION - COEFFICIENT IN SCATTERING MEDIA USING DIFFERENT SOLUTIONS TO THE DIFFUSION EQUATION
The cesium-induced delay in myoblast membrane fusion is accompanied by changes in cellular subfraction lipid composition.
Menadione induces changes in the membrane electrical properties associated with down-regulation of insulin receptors in human erythrocytes.
SAR Measurement in MRI: an improved method
During an MR procedure, the patient absorbs a portion of the transmitted RF energy, which may result in tissue heating and other adverse effects, such as alterations in visual, auditory and neural functions. The Specific Absorption Rate (SAR), in W/kg, is the RF power absorbed per unit mass of tissue and is one of the most important parameters related with thermal effects and acts as a guideline for MRI safety. Strict limits to the SAR levels are imposed by patient safety international regulations (CEI - EN 60601 - 2 - 33) and SAR measurements are required in order to verify its respect. The recommended methods for mean SAR measurement are quite problematic and often require a maintenance man intervention and long stop machine. For example, in the CEI recommended pulse energy method, the presence of a maintenance man is required in order to correctly connect the required instrumentation; furthermore, the procedure is complex and requires remarkable processing and calculus. Simpler are the calorimetric methods, also if in this case long acquisition times are required in order to have significant temperature variations and accurate heat capacity knowledge (CEI - EN 60601 - 2- 33). The phase transition method is a new method to measure SAR in MRI which has the advantages to be very simple and to overcome all the typical calorimetric method problems. It does not require in gantry temperature measurements, any specific heat or heat capacity knowledge, but only mass and time measurement. Furthermore, in this method, it is possible to show that all deposited SAR power can be considered acquired and measured