Experimental arrangement for the phase contrast from (a) a thermal plume and (b) a tissue phantom intersected by water columns.
Temperature profile across the plane in the thermal plume measured with a thermocouple.
Simulation arrangement for the phase contrast from a heat source with tissue effects present. The transducer used in the simulation was a 14-ring focused transducer with emission only from rings 8–11. The first case tested the arrangement shown here, whereas the second case did not have the heat source present upon transmit and the third case did not have the heat source present upon reflex transmission.
(a) Temperature in the plume measured across the plane with a thermocouple. The scan started at and moved in increments, scanning along the axis before returning to and moving to the next position on the axis. (b) Phase difference between the heated and reference fields following back projection close to the plume.
(a) Comparison of the simulated plume temperature with the reconstructed temperature. (b) Comparison of the measured and estimated temperature following tomographic reconstruction.
(a) Phase difference between the phase contrast and reference fields following backprojection close to the horizontal water column in the phantom. (b) Phase difference following backprojection of the vertical and horizontal water column.
(a) Backprojected phase difference between the simulated phase contrast and reference fields. Two overlapping water columns were used to produce the phase contrast. (b) Backprojected phase difference after separating the two columns by and offsetting the vertical column from the origin of the lateral axis.
Phase difference between an on-axis water column and reference field following backprojection.
Simulated comparison of the estimated sound speed for multiple heating arrangements in a pulse–echo setup. The case of heating on transmission and echo (dotted) is compared with heating only on echo (solid) and heating only on transmit (dashed). The simulated maximum sound speed was .
Comparison of the simulated 2D phase difference for different heating arrangements in a pulse–echo setup when the outer rings of the transducer are used. Phase differences when heating is simulated (a) on transmission and reflex and (b) only on transmission.
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