[INVITED] Time reversal optical tomography: Detecting and locating tumors in an ex vivo model human breast

• Time reversal optical tomography (TROT) investigated a model cancerous breast.
• The model breast comprised two tumor pieces embedded in ex vivo breast tissues.
• Multi-source probing with 750-nm light and multi-detector detection scheme was used.
• Both the tumors were detected and their locations were determined.
• TROT is a promising fast approach for detecting and locating small breast tumors.

Time reversal optical tomography (TROT), a recently introduced diffuse optical imaging approach, is used to detect, locate, and obtain cross-section images of tumors inside a “model human breast.” The model cancerous breast is assembled as a semi-cylindrical slab of uniform thickness using ex vivo human breast tissues with two pieces of tumors embedded in it. The experimental arrangement used a 750-nm light beam from a Ti:sapphire laser to illuminate an end face (source plane) of the sample in a multi-source probing scheme. A multi-detector signal acquisition scheme measured transmitted light intensity distribution on the other end face (detector plane). The perturbations in light intensity distribution in the detector plane were analyzed using TROT to obtain locations of the tumor pieces in three dimensions and estimate their cross sections. The estimated locations and dimensions of targets are in good agreement with the results of a corroborating magnetic resonance imaging experiment.