الفهرس 
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Abstract
measurement of bone density for women is of great. importance especially f, r certain age as by aging bone density and percentage of bone mineral con.cnt decrease causing weakness in bones. There are several techniques for bone density measurement but the most important 0one is via ultrasonic waves, which are widely used in medical application- In this study, ultrasonic waves are used III measuring bone density to evaluate its changes from normal limits. The ultrasonic system consists of two transducers, one as a source and the other as a detector, amplifier and oscilloscope. When voltage is applied, high frequency longitudinal waves are produced and measurements are made of the ultrasonic attenuation. The sample is positioned between two broadband ultrasonic transducers, one of them transmits short pulses of broadband ultrasound and the other receives. A relationship exists between ultrasonic attenuation and frequency. Measurements of frequency against attenuation were determined for different samples, fresh bone sample and decalcified ’bones in nitric acid for different periods of time. From these relations between frequency and attenuation for different samples bone density is calculated through several steps: First, a correlation between attenuation coefficient and demineralization time is achieved, then between demineralization time and porosity and finally between demineralization time and hone density. Prom these correlations, a relation between attenuation coefficient and bone density is determined.