Research On Ultrasonic Bone Mineral Density Measurement Technology Based On Flexible Sensors

Bone density is an important indicator of bone health.The higher the bone density,the stronger the bones,and the lower the risk of osteoporosis.When astronauts are in the state of microgravity in Earth orbit or long-term space flight,the speed of bone loss is significantly accelerated,and if not found in time,it may lead to serious bone mass decline.Secondly,as age increases,the body’s ability to absorb calcium decreases,and calcium loss intensifies,which can also lead to the occurrence of osteoporosis.Flexible ultrasound sensors have high flexibility and variability,which can adapt to various shapes of surfaces and accurately characterize bone.This article proposes an application of a flexible substrate based ultrasound sensor in bone condition detection,with the specific work as follows:(1)Reviewed the development of flexible devices in recent years and analyzes some applications of flexible electronic technology in human function detection.Analyzed the generation,propagation forms,and attenuation patterns of ultrasound,and quantified bone health status through ultrasound velocity.Analyzed the influencing factors of bone structure,causes of osteoporosis formation,symptoms,and fracture risk.By analyzing and comparing various diagnostic methods for osteoporosis,quantitative ultrasound technology was selected as the research method of this article.This article summarizes the current research status of bone detection instruments both domestically and internationally,and analyzes the feasibility of flexible bone detection equipment.(2)Two techniques for quantitative ultrasound detection of bone density were analyzed,and the axial transmission detection method was selected as the detection method in this article.An error correction method was proposed to improve the detection accuracy.A new type of piezoelectric material PMN-PT was selected as the sensor core,with PDMS as the flexible substrate.A flexible ultrasonic sensor was designed,and its energy transfer efficiency was measured after preparation.The energy transfer efficiency can reach 35% at a specific distance.Based on quantitative ultrasound and axial transmission technology,multiple peripheral modules are designed with FPGA chips as the core,including power supply circuit,pulse excitation transmission circuit,gain control circuit,A/D conversion circuit,and wireless transmission module.(3)Software design and simulation of each module based on FPGA to demonstrate the feasibility of UART communication,FIFO module,and A/D conversion module.A visual humanmachine interface was designed on the mobile end using the Qt Creator platform,which can display the propagation speed of ultrasound in the bone,the T-value and Z-value of bone evaluation indicators,and the system’s evaluation of this bone detection.The hardware volume has been reduced to 14.1cm in length,6.3cm in width,0.2mm in thickness,and 346 g in weight,allowing for 157°bending.(4)Test each hardware module,and the power circuit can stably generate DC voltages such as 3V,3.3V,and 5V;The ultrasonic excitation transmission circuit can generate 1.15 MHz,80V pulse excitation;The A/D conversion circuit can successfully convert analog signals into digital signals.The entire bone condition information collection system was tested on a total of 30 subjects of different age groups.The patella,radius,and tibia were selected as the measurement sites,and the detection results were compared with clinical measurement results of similar products on the market.The results showed that the system had high accuracy and reliability in measuring the ultrasound velocity of specific areas,with an error of less than 0.3%.