FIG. 5.

IVIS sensitivity limits hybrid detection in vivo. (a) IVIS spectrum images taken post-injection of control (no cells), luciferase + (MCF7-luc), PyVT, and Co cell cultures into the fat pad. (b) Primary tumor and lungs did not express a luciferase signal when imaged ex vivo. (c) IVIS sensitivity was tested by injecting different cell numbers of MCF7-luc into the fat pad to determine the level of cells needed to obtain a signal (d). PyVT, Cre_PyVT; Co, PyVT-MSC co-culture; and Luciferase +, MCF7 cells that constitutively express luciferase.