Tumor ablation and volumetric optoacoustic monitoring with a short-pulsed laser source

Laser ablation (LA) represents a minimally invasive intervention that is gaining acceptance for the treatment of different types of cancer, leading to important advantages such as less pain and shorter recovery time. Accurate monitoring of ablation progression is crucial to prevent damage of non-cancerous tissues and optimize the outcome of the intervention. To this end, imaging techniques such as ultrasound, computed tomography or magnetic resonance imaging have been used for monitoring LA. However, these techniques feature important drawbacks such as the need of contrast agents, poor spatio-temporal resolution or high cost. Optoacoustics (OA, photoacoustic) has recently been shown to provide unique properties to monitor thermal treatments. Herein, we demonstrate the feasibility of optoacoustic laser-ablation (OLA) monitoring in a murine breast tumor model using a single short-pulsed 1064 nm laser source. The effect of irradiation was volumetrically tracked with the OA images acquired with a 256-element spherical array. Structural damage of the tissue was clearly seen during the LA procedure.