A handheld-probe-based optical imager has recently been developed toward three-dimensional tomography. In this study, the improvement of target depth recovery was demonstrated using a multi-projection technique on large slab phantoms using $0.45\mathrm{cc}$ fluorescing target(s) (with $1:0$ contrast ratio) of 1.5 to $2.5\mathrm{cm}$ deep. Tomographic results using single- and multi- (here dual) projection measurements (with and without a priori information of target location) were compared. In all experimental cases, the use of multi-projection measurements along with a priori information recovered target depth and location closer to their true values, demonstrating its applicability for clinical translation.