Feasibility study into determining osteoporosis in long bones using frequency response method

• Grant number: 24/22969-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2025
• End date: February 28, 2026
• Field of knowledge: Engineering - Mechanical Engineering - Mechanics of Solids
• Principal Investigator: Bruno Agostinho Hernandez
• Grantee: Gustavo Bortonio de Carvalho
• Host Institution: Faculdade de Engenharia (FE). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil

Abstract

Osteoporosis is a disease that often occurs in older people, which consists of a decrease in the mineral density of bones, making them fragile and more susceptible to fractures. The main means of diagnosing this disease comes from bone densitometry, which consists of emitting low-intensity X-ray beams and then measuring the amount of radiation absorbed by the bone tissue. However, there are concerns about the patient's exposure to X-rays, the low supply in the public health system and the high cost of this test. An alternative to densitometry could be the use of the mechanical impedance technique. In this, an excitation is induced in the body under analysis and the vibratory behaviour in the form of a frequency response is obtained. This response is a direct function of density. Therefore, the aim of this work is to carry out an exploratory analysis of the vibratory behaviour of long bones, such as the femur and tibia, and thus analyse the feasibility of a disease diagnosis technique based on an analysis of the frequency response of the bone, using the mechanical impedance technique. For this project, numerical modelling in finite elements and experiments are planned. In the numerical modelling, tomography images of synthetic bones, one in normal condition and the other in osteoporosis (severe) condition, will be obtained and geometries will be created using Simpleware software (v2022, Synopsys, INC, USA). The vibration response will then be simulated in finite elements using Ansys software (v22R2, Ansys INC, USA). Next, it is planned to carry out impedance tests on the two scanned bones. These bones will be hung to simulate a (free-floating) condition and accelerometer-type sensors (tear drop) with a nominal sensitivity of 100 mV/g will be used. An instrumented impact hammer will be used to measure the force applied to the bone. The signals will be obtained in time and recorded by a signal acquisition system and then post-processed into the frequency domain using an H1-type transfer function estimator. Sequentially, CT scans of real patients will be used to reproduce, using modelling and finite element software, models of healthy bones and those with (severe) osteoporosis, in order to analyse the similarity of the responses. Finally, the aim is to build mathematical and experimental models to analyse the feasibility of faster and easier diagnosis of osteoporosis by identifying frequency responses in different directions.