Room: AAPM ePoster Library
Low scatter spherical lesion phantoms are useful tools for assessing detailed spatial resolution of ultrasound scanners, including those equipped with multi-row, linear and curvilinear arrays, and for tuning system presets for specific applications. Current commercially available lesion phantoms, such as the SunNuclear Sono408, with spherical targets arranged in a plane are costly to manufacture and are difficult to use because of the need for precise alignment of the scan plane with the lesion centers. To lower the cost and ease the scan setup process, a new phantom was designed with a mixture of mainly 2mm and 4 mm diameter anechoic spheres randomly distributed. This project compares the usefulness of this prototype void phantom to the Sono408 for assessing lesion detectability for various transducers and scan setups.
Two multi-row transducers (9L4 on a Siemens S3000; ML6-15-D on a GE Logiq E9) were utilized. For each probe, very similar image settings were used to scan the two phantoms. For each phantom, five consecutive focal depths starting from the shallowest depth were utilized. For the new phantom, multiple scan planes were tested before a plane with ample random lesions was selected for comparison with the Sono408.
Spherical lesions were easily seen in the prototype void phantom, a challenging task with the Sono408. Very similar patterns of lesion detectability were observed for the two phantoms using 1.5D probes. As the focal depth increases, lesion detectability vs depth changes dramatically, especially when the elevational aperture expands with focus setting. This phenomenon was apparent for both phantoms.
The new phantom with randomly arranged anechoic spheres showed similar patterns of lesion detectability as the Sono408 phantom when scanned with 1.5D probes. It could be very useful for evaluating lesion detectability of transducers, establishing presets on scanners, and transducer and system comparisons.