Exhibit Hall | Forum 9
Purpose: We aimed to incorporate a flexible array as an image guidance tool into radiotherapy for tracking tumors. The main challenge of this application is to reconstruct ultrasound images of a flexible array with changing flexible shape along with reparatory movement in real-time. In this case, we proposed an alternative novel beamformer, align peak response (APR) with an assistant structure for reconstructing ultrasound images.
Methods: Instead of calculating delays based on fixed elements’ positions, the main principle of our APR method is to reconstruct ultrasound images by aligning peak responses generated from markers embedded within the assistant structure. For improving the aligning accuracy, radiofrequency (RF) data were normalized and smoothed before applying the APR method. We conducted simulated and real ultrasound experiments for testing the feasibility and accuracy of this APR method. Three different point-target phantoms and three different scatter-phantoms were simulated as assistant structures and included in simulated experiments for collecting simulated RF data. The real ultrasound image RF data was obtained by the flexible array of in-house phantom embedded with one or three needle targets in different depths.
Results: The results of simulated experiments demonstrated the estimation of the delay curves by using APR is more accurate with the simulated assistant structure including one center point marker. Furthermore, the delays curves were estimated more accurately if the transducer was set with 1 active element in the emit aperture and 128 elements in the receive aperture. According to the real ultrasound image experiments’ results, the APR method performed a more accurate estimation of delays curves if markers are in the shallow depth.
Conclusion: The results proved that our APR is a promising alternative beamformer for estimating delay curves, thereby reconstructing ultrasound images of the flexible array for image-guiding radiotherapy.
Funding Support, Disclosures, and Conflict of Interest: Research reported in this publication was supported by the National Institutes of Health (award numbers R37CA229417). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.