Animal experiments were conducted under the protocol approved by the Institutional Animal Care and Use Committee of Tsinghua University. DsRed expressing MDA-MB-231 human breast carcinoma cells were injected subcutaneously into the back of two BALB/c-nude mice (five weeks old), respectively, and treatment was initiated on day 16. One tumor-bearing mouse was administered cisplatin () intratumorally every day for 2 consecutive weeks, while the other tumor-bearing mouse was injected with saline solution to serve as the nontreated control. To monitor the therapeutic response, subsurface FMT was conducted on days 16, 18, 21, 23, 25, 27, 29. In the in vivo study, fluorescent images were acquired with a excitation filter and a emission filter. Background images were acquired with a excitation filter for background signal reduction.11 72 white-light images were collected to recover the 3-D surface of the mouse.12 The mice were anesthetized by isoflurane-oxygen gas mixture during the imaging process. The optical properties used in subsurface FMT reconstruction were , , which were calculated according to 13. Tumors were measured with a caliper after fluorescence imaging and tumor volume was estimated based on the formula , where was the longest diameter and was the shortest diameter. The 3-D geometry of the two mice were both discretized with a voxel size of , and the reconstructed tumor volumes were calculated by the product of voxel size and the number of voxels in the tumor region.