Flexible Ultrasound System for Quantitative Diagnosis and Therapeutic Ultrasound

This project provides funding to integrate the technology produced by the National Space Biomedical Research Institute (NSBRI) project entitled "Portable Quantitative Ultrasound with DXA/QCT and FEA Integration for Human Longitudinal Critical Bone Quality Assessment (SMST03401)" with NASA’s flexible ultrasound system (FUS).

Skeletal complications, i.e., osteoporosis, induced by microgravity during extended space missions represent a key astronaut health problem. Lack of on-board diagnosis has increased significant risk in astronauts' bone loss during long term space flight. Early diagnosis of such disorders can lead to prompt and optimized treatment that will dramatically reduce the risk of fracture and longitudinal monitoring microgravity and countermeasure effects. Advents in quantitative ultrasound (QUS) techniques provide a method for characterizing the material properties of bone in a manner for predicting both BMD (bone mineral density) and mechanical strength. We have developed a scanning confocal acoustic navigation (SCAN) system capable of generating noninvasive ultrasound images at the site of interest.

To improve the efficiency of the scan in extreme environments, such as space missions, the goal of this study is to develop a 2-D array ultrasound transducer including a pair of 32x32 elements using program/electronic control to generate co-focal ultrasound energy and perform scan in the region of interest for extracting density and quality information bone. This 2-D array setting and scan controlled by programming can conduct the scan at targeted skeletal sites within a few seconds, provide reduced physical footprint, reduced weight, and ease of use. The transducers will be integrated with a GE flexible ultrasound system (FUS). To utilize an electronic scan device, we design the specs for the array system, simulate a 2-D spatial sweep mode, designing of MUX system for connecting FUS and the transducers, and hardware of the transducer. A 2-D array therapeutic portable device and system is also designed and developed, which is currently used in an animal study, and scheduled for a human study.

Technical Summary

Non-invasive assessment of trabecular bone strength and density is extremely important in predicting the risk of fracture in space and ground operation. To overcome the current hurdles such as soft tissue and cortical shell interference, improving the quality of QUS and applying the technology for future clinical applications, a 2-D array transducer system is developed for improving the SCAN efficiency by reducing scan time and performing program controlled electronic scan in the deep tissue. The transducers is designed for integration with the GE flexible ultrasound system (FUS). This phase of the development of array SCAN system is focused on several main areas: 1) acoustic field simulation for scanning angle and spatial region using 32x32 array, 2) design of Maximal element count possible with 192 channel constraint in the GE FUS, 3) 2-D array transducer design and manufacture, 4) MUX system design for array trigger and receiving signal control, 5) integration with GE FUS cabling system, and 6) 2-D therapeutic system design and validation. The transducers will be integrated into the FUS to provide portable rapid array SCAN system combined with imaging capability, and to provide low-intensity ultrasound treatment for bone fracture and low bone mass, which will ultimately provide a portable, noninvasive device for guided imaging monitoring and therapeutic for bone diseases in space.

Earth Applications: Skeletal decay complications are major health problems on Earth, i.e., osteoporosis, and delayed healing of fractures. Development of a low mass, compact, noninvasive diagnostic and treatment technology, i.e., using ultrasound, will have a great potential to prevent and treat bone fracture. Our principal goal is to develop a portable quantitative ultrasound system with therapeutic capability, not only for determination of bone's physical properties, but also for predicting subtle changes of bone during extended flights and diseased condition, which will impact both diagnosis and noninvasive treatment for musculoskeletal disorders. Use of a desktop based non-ionizing bone assessment device has great clinical applications as an in-office quantitative assessment of fracture risk in the general and at-risk populations.

Key findings and milestones

To overcome the current hurdles such as soft tissue and cortical shell interference, improving the quality of QUS and applying the technology for future clinical applications, a 2-D array transducer system is developed for improving the SCAN efficiency by reducing scan time and performing program controlled electronic scan in the deep tissue. This phase of the development of array SCAN system has achieved several milestones. 1) To develop an acoustic field simulation for scanning angle and spatial region using 32x32 array, which provides fundamental analysis for the design of the array transducers and associated specs. 2) To design the 32x32 sensor layout with maximal element count possible with total of 96 channels (determined by the GE FUS system). 3) To design and manufacture the 2-D array transducer at a transducer vendor (Blatek, Inc.). 4) To design schematic layout, and PCB layout for a MUX system for array trigger and receiving signal control, for converting 32x32 total lines to reduced 96 channels. 5) To interface GE cable coupling system and integration with GE FUS cabling system. 6) To develop and validate a 2-D array therapeutic system for low-intensity ultrasound therapeutic treatment for bone loss and fracture. The team is able to closely work with transducer vendor, Blatek, NASA Glenn Center, and GE Global Research Center for the 2-D array system and integration with FUS.

More »