Line-pair phantoms are commonly used for evaluating screen-film systems. When imaged digitally, aliasing effects give rise to additional periodic patterns. This paper examines one such effect that medical physicists are likely to encounter, and which can be used as an indicator of super-resolution.

Our purpose in this study was to establish a selection standard for anti-scatter grids for a direct conversion flat-panel detector (FPD) system. As indices for grid evaluation, we calculated the selectivity, Bucky factor, and the signal-to-noise ratio improvement factor (SIF) by measuring rates of scatter transmission, primary transmission, and total transmission (based on the digitally display...

We present a novel temperature-sensing technique using thermoacoustic and photoacoustic measurements. This noninvasive method has been demonstrated using a tissue phantom to have high temporal resolution and temperature sensitivity. Because both photoacoustic and thermoacoustic signal amplitudes depend on the temperature of the source object, the signal amplitudes can be used to monitor the tem...

A new super-resolution method is presented to overcome limitations of spatial resolution in MRI. In contrast to previous attempts that are based on simple field of view shifts, the new method additionally modulates the longitudinal magnetization within the imaging plane for each shift, allowing the acquisition of new and independent k-space data. With this approach, resolution improvements in u...

This study evaluates the use of 3D printed phantoms for super-resolution ultrasound imaging (SRI) algorithm calibration. The main benefit presented method is ability to do absolute micro-positioning sub-wavelength sized scatterers in a material having speed sound comparable that tissue. Stereolithography used printing soft calibration micro-phantoms containing eight randomly placed nominal size...

This paper describes a technique of forming images of the average size and scattering strength of scatterers in a random medium using ultrasound. Quantitative ultrasound images provide a more direct interpretation of the underlying structure of the medium, e.g. size, shape, number and elastic properties of scatterers, and increased detectability for regions of varying structure. A signal-to-noi...

Regional two-dimensional (2D) echocardiographic amplitude patterns, or image texture, may be of diagnostic importance. Echocardiographic image texture is due in part to acoustic speckle, a complex pattern of interference of reflections from many small scatterers in tissue. The regional speckle pattern appears to be altered in several disorders associated with abnormalities in myocardial structu...

It is shown that using elliptically polarized light permits selecting well-defined subsurface volumes in a turbid medium. This suggests the possibility of probing biological tissues at specific depths. First, we present the method and preliminary results obtained on an Intralipid phantom. We next report on the method's performance on a biological phantom (chicken breast) and, finally, on the ex...