SU‐GG‐J‐119: Induction of Plasmonic Heating Inside Breast Tumor Phantom Using Gold Nanorods and Near‐Infrared Laser

Purpose: To demonstrate and quantify gold nanorods (GNRs)‐induced plasmonic heating inside breast tumor phantom during near‐infrared (NIR) laser illumination. Method and Materials: GNRs were fabricated using published procedures. Two types of breast gel phantoms were fabricated. The first phantom was nearly water‐equivalent as it was fabricated using 1.5% agar gel (98.5% water). The second phantom, on the other hand, was fabricated using a more turbid intralipid‐based gel (2% agar, 2% intralipid, and 96% water). Both phantoms contained an identical GNR‐filled cavity with 4 mm inner diameter. The cavity was filled with approximately 0.1 weight percent GNRs and located at the center of a quadrant of hemispherical phantom at 2.5 cm depth measured from the base of the phantom. Both phantoms were illuminated with an 808 nm NIR laser at 1 W power under the identical geometry. Thermocouples were used to measure the temperature changes within the cavity and surrounding medium. Results: There was significant difference between the two gel phantoms in terms of achievable temperature rise within a GNR‐filled cavity. For a 60 second illumination, the cavity inside an agar‐based gel phantom was heated up to 15°C above the background temperature, while there was a temperature change of only about 1.5°C within the cavity inside an intralipid‐based gel phantom. Conclusion: The current results suggest tumors inside breast tissue with high water content may be easily heated up to a few degrees above the surrounding body temperature within a short time interval (e.g., on the order of 10 seconds) without much difficulty. According to the current results, however, it might be difficult to achieve such a temperature change for tumors inside breast tissue similar to intralipid‐based gel in terms of its optical property. This work has been supported by the US Department of Defense, Breast Cancer Research Program, Concept Award, W81XWH‐08‐1‐0686.