Bone densitometer and a method thereof

• US 20070078341A1
• Filed: 08/11/2006
• Published: 04/05/2007
• Est. Priority Date: 10/03/2005
• Status: Active Grant

• Current Assignee: Larsen & Toubro Limited, Larson & Toubro Limited
• Original Assignee: Larson & Toubro Limited
• Inventors: Agarwal, Raj, Sowmya, Mosale, Ghosh, Rajdeep, Umadi, Somashekar, Ravindran, Nagarajan
• Granted Patent: US 7,833,161 B2
• Time in Patent Office: Days
• US Class Current: 600/437
• CPC Class Codes: A61B 5/1075 for measuring dimensions by non-invasive methods, e.g. for determining thickness of tissue layer A61B8/0858 takes precedence
• CPC Class Codes: A61B 5/6829 Foot or ankle
• CPC Class Codes: A61B 8/0875 for diagnosis of bone A61B5/4504 takes precedence
• CPC Class Codes: A61B 8/4281 characterised by sound-transmitting media or devices for coupling the transducer to the tissue

Abstract

The present invention provides a system for improving the accuracy of the measurement of the osteoporosis condition of the human body parts especially bones using more than three parameters, viz., the broadband ultrasonic attenuation (BUA) quantity, the velocity of ultrasound (SOS) in the bone, the broadband ultrasonic back scattering (BUB) intensity, and the Width of received maximum (WORM) values are calculated from received ultrasound signals. The accuracy of each measured diagnostic parameter is improved by measuring the tissue thickness and the squish amount in the coupling pad instead of assuming constant thickness for the tissue. The several operating modes of the device are controlled and the frequency and the timing of the emitted ultrasounds signals are adjusted by using a field programmable gate array. The error generated in the measurement of the bone mineral density due to the variation in the anatomy and the size of the foot, is removed by using a removable footpad. The present invention provides a mechanism to replace the gel pads easily. The generation of cross infection is prevented by using the disposable and replaceable coupling pads.

Claims

1. A ultrasound based diagnostic device for the analysis of bone conditions in human oscalcis comprising:

a) At least two ultrasonic transducers provided at the two ends of a movable assembly in the main body

b) A set of replaceable and disposable gel pads connected to the transducer assembly.

c) A removable foot pad coupled to the transducer assembly and

d) A signal processing and acquisition circuit.

2. The ultrasound based diagnostic device as set forth in claim 1, wherein two ultrasonic transducers are operated as transmitter and reflector or as transceiver in different operating modes to calculate four different parameters from the received ultrasonic signals from the heel of the subject placed between the transducers, to calculate the bone mineral density and bone characteristics.

3. The ultrasound based diagnostic device as set forth in claim 2, wherein the two ultrasonic transducers are initially separated by a fixed distance and moved towards each other to accommodate the heel of a subject under diagnosis.

4. The ultrasound based diagnostic device as set forth in claim 2, wherein the transducers emit the ultrasound signals with a frequency range of 10 KHz-1.2 MHz.

5. The ultrasound based diagnostic device as set forth in claim 1, wherein the signal processing and acquisition circuit processes both the scattered and reflected signals in addition to the transmitted signals to calculate parameters to compute bone mineral density.

6. The ultrasound based diagnostic device as set forth in claim 1, wherein the device is operated in multiple modes so that the BUB, the tissue thickness at heel and the coupling pad squish are measured from the reflected signals, when the transducers are operated as transceivers.

8. The ultrasound based diagnostic device as set forth in claim 1, wherein the device utilizes multivariable approach to measure at least four diagnostic parameters instead of the two or three parameters, from the reflected, scattered and transmitted ultrasound signals for improving the accuracy of the diagnosis.

9. The ultrasound based diagnostic device as set forth in claim 1, wherein the measured diagnostic parameters are the speed of sound (SOS), the broadband ultrasonic attenuation (BUA), the broadband ultrasonic back scattering (BUB) and the width of the received maximum ultrasound signal.

10. The ultrasound based diagnostic device as set forth in claim 1, wherein the device calculates the speed of sound by measuring the tissue thickness at both sides of the heel of the subject instead of assuming a fixed thickness for the tissue surrounding the heel.

11. The ultrasound based diagnostic device as set forth in claim 1, wherein the device measures the squish in the coupling pads from the reflected ultrasound signals instead of assuming a fixed amount of squish in the coupling pads on contact with the heel of the subject.

12. The ultrasound based diagnostic device as set forth in claim 1, wherein the signal processing circuit has a digital signal processor for analyzing the acquired signals from the heel of a subject under diagnosis and a field programmable gate array (FPGA) for controlling the timing and operating modes of device.

13. The ultrasound based diagnostic device as set forth in claim 1, wherein the same transducer in the device is operated as transmitter and receiver to calculate bone density at several locations in the human body in addition to heel.

14. The ultrasound based diagnostic device as set forth in claim 1, wherein the device further has an easily replaceable, disposable and bacteriostatic coupling pads to carry out analysis among heels of different subjects under investigation.

15. The ultrasound based diagnostic device as set forth in claim 1, wherein the device has a removable foot pad to position transducers at the desired region of interest in the heel of a subject under analysis

16. The ultrasound based diagnostic device as set forth in claim 1, wherein the signal processing and acquisition circuit regulates system control, firing, reception and processing operations of ultrasonic signals received from human oscalcis.

17. The ultrasound based diagnostic device as set forth in claim 1, wherein the signal processing and acquisition circuit receives and processes the ultrasonic signals from the heels both in the time and frequency domains to calculate the broadband ultrasonic attenuation and the broadband ultrasonic back scattering.

7. The BUA and the WORM are acquired from the transmitted signals when two transducers are operated as transmitter and receiver respectively.

18. Bone condition evaluating method for estimating osteoporosis using ultrasound based diagnostic device, comprising

a) moving atleast two transducers provided at both ends of a moveable assembly towards each other or away from one another to accommodate the heel of the subject under diagnostic

b) operating the two transducers as transmitter and receiver or as transceiver in different operating modes to transmit and receive the ultrasonic signals from the heel of the subject under diagnosis

c) activating a signal processing circuit coupled to the transducer assembly to process the scattered and reflected ultrasonic signals from the heel in addition to the transmitted ultrasonic signal through the heel to calculate the speed of sound, the broadband ultrasonic attenuation amount, the broadband ultrasonic back scattering amount and the width of the received maximum ultrasound signal to calculate bone mineral density and bone characteristics.

19. The bone condition evaluating method as set forth in claim 18, wherein a replaceable and disposable gel pad comprising bacteriostatic material is connected to the transducer assembly and replaced by a mechanism to prevent cross infection.

20. The bone condition evaluating method as set forth in claim 18, wherein a removable footpad is coupled to the transducer assembly to accommodate various foot sizes and two ensure desired region of interest for analysis.