2.3. Photodynamic Therapy Treatment Protocol

BPD (trademark Visudyne^®) at a dosage of 1mg/kg was injected through the mouse tail vein as described previously.^16,19 At a 15-min DLI, superficial irradiation of the tumor was performed with a 690-nm diode laser with a maximum output power of 8 W (B&W Tek Inc., Newark, Delaware). A microlens fiber was coupled to the laser to irradiate the tumor uniformly [see Fig. 1(a)]. Mice were treated with in-air fluence rates (ϕair) of 75 to 250mW/cm2 and total in-air fluences of 22.5 to 166.7J/cm2 to induce different PDT outcomes and to assess the reciprocity between BPD concentration and light dose. The “in-air fluence rate” is defined as the calculated irradiance determined by laser power divided by the treatment area. The “in-air fluence” was calculated by multiplying the “in-air fluence rate” by the treatment time. Animals were assigned to six light dose groups (see Table 2). RIF tumor-bearing mice that received neither light irradiation nor BPD were used as controls.

In-air light fluence, in-air light fluence rate ϕair, photosensitizer concentrations pre-PDT [BPD]pre, PDT dose at 3-mm depth, reacted oxygen species concentration [ROS]rx at 3-mm depth, tumor regrowth rate k, and CI for each PDT treatment group. Number of mice per group is shown in the second column.