Room: 221AB
Purpose: X-ray-induced acoustic computed tomography (XACT) is a promising imaging modality combining high x-ray absorption contrast with the 3D propagation advantages provided by high resolution ultrasound waves. The 3D XACT imaging with a single X-ray project is achieved by implementing a cup-shaped ultrasound (US) detector which houses 280 US sensors on a spherical surface. The purpose of this study was to test and optimize the configuration of the 3D XACT imaging system for bone imaging with the spherical ultrasound detector array.
Methods: A 280 ultrasonic sensors with peak frequency of 10 MHz was designed to distribute on a spherical surface to optimize the 3D volumetric imaging capability. The resolving power of the system was tested in three dimensions with small sphericals simulations. Then, the system’s complex structure imaging capability was demonstrated by simulating the X-ray induced acoustic signals from a neuron shaped structure. In addition, simulations were also used to simulate the X-ray induced acoustic signal generation, propagation, and attenuation in a digital phantom mouse paw generated from micro-CT images. The three-dimensional bone density distribution was successfully obtained from the digital phantom simulation.
Results: The resolution tests show that 3D XACT imaging system has a theoretical spatial resolution of 123 -130 µm. The reconstructed complex structure simulation demonstrates the lateral and axial resolving power of the cup-detector based 3D XACT system. In the end, the micro-CT generated digital phantom simulation results successfully revealed the bone microstructures on a mouse paw model.
Conclusion: The study demonstrated the feasibility of XACT system in 3D imaging with single X-ray projection. We performed K-Wave simulations of this optimized XACT imaging configuration with various simulated objects, including a digital phantom from real-world micro-CT slices. Given the advantages of 3D XACT system, the future of XACT system’s application in bone density distribution mapping is very promising.