Table 1.

Amounts of ${\mathrm{Al}}_2{\mathrm{O}}_3$ particles (determined by mass) added to 100 ml PDMS to fabricate grit-size-specific phantoms of differing concentrations (i.e., magnitude of scattering) across a physiologically relevant range in skin.

	Concentrations of ${\mathrm{Al}}_2{\mathrm{O}}_3$ per 100 ml PDMS
	“Low” (g)	“Mid” (g)	“High” (g)
400 grit	7	10	14
800 grit	3	5	9
1000 grit	2	4	6
1200 grit	1.5	3	5