Characterization of luciferase expression in mice injected intratumorally with luciferase expressing DNA with or without laser treatment using luminescence imaging. C57BL/6 mice were challenged subcutaneously with 1 × 105/mouse of TC-1 tumor cells/mouse in the right leg. When tumors reached a diameter of ~0.7 cm, mice were injected intratumorally with pcDNA3-Luc, followed by either femtosecond laser treatment for 110 sec at a laser power density of 0.04 GW/cm2 or no treatment. Mice were injected with luciferin and imaged using the IVIS Imaging System Series 200 using methods as described previously . Bioluminescence signals were acquired for 1 minute. (A) Representative luminescence images of injected mice with or without laser treatment. (B) Bar graphs depicting the quantification of luciferase activity in mice with or without laser treatment.