TABLE 7.

Effective scatterer diameters (d) for glass beads in Sphere A and Sphere B from backscatter coefficients measured by the different clinical systems. Also shown are mean square errors (MSE) for each system, with respect to the Faran’s theory model, assuming the estimated effective scatterer diameter. Dashed lines are assigned when no convergence was obtained in the minimization algorithm within the diameter search range.

System	Sphere A		Sphere B
	d (μm)	MSE (10−3)	d (μm)	MSE (10−3)
Low-frequency range (4.9–6MHz)
From ηFaran†	35.2	0.18	85.9	0.13
5.0MHz	---	---	74.8	1.43
7.5MHz	48.6	1.77	79.8	0.63
10MHz	---	---	71.5	0.42
Siemens 9L4	49.7	1.87	88.3	0.38
Siemens 18L6	27.8	0.37	79.1	1.24
Ultrasonix L9-4	53.6	2.20	83.6	1.65
Ultrasonix L14-5	---	---	90.3	0.59
Zonare L8-3	---	---	65.8	4.49
Zonare L14-5	---	---
High-frequency range (8–12MHz)
From ηFaran†	34.7	0.94	85.2	0.95
10MHz	35.9	0.59	76.7	2.99
Siemens 18L6	34.4	1.17	77.9	2.52
VisualSonics MS200	36.0	1.07	76.6	3.30

^†Effective scatterer size was estimated using η_Faran based on glass-bead distributions (Fig. 2) and concentrations.