Design and Experimental Validation of Intracardiac Photoacoustic Catheter

Abstract

Atrial fibrillation is a cardiac arrhythmia resulting from abnormal electrical conduction and impulse formation within the atria. To address this condition, a minimally invasive procedure called cardiac ablation is performed. Real-time visual feedback during this procedure plays a critical role in determining its success.

Photoacoustic imaging is a technique capable of providing real-time visual feedback. Integrating photoacoustic capabilities into existing Radiofrequency ablation catheters poses a significant challenge, which this thesis addresses. The proposed integrated solution employs optical fibers for light delivery and an ultrasound transducer for signal reception.

This work investigates the design of two light delivery systems for integrated photoacoustic-guided surgery. Monte Carlo simulations are employed to study three-dimensional light propagation in tissue, informing the catheter design specifications. Optimal fiber distances and orientations within the catheter are determined based on normalized fluence values and illumination spot size—critical parameters for assessing the amount of delivered light, its area of coverage, and depth of penetration. The methodology presented applies to various photoacoustic applications.

The simulation study was able to successfully inform design specifications and it was able to establish a relation between design variables and the evaluation criteria such that it can be referred to for future designs. The comparative study yielded a better-performing design configuration and its optimal specifications were found out. This proves the use of a simulation-based evaluation to design a photoacoustic intracardiac catheter. In the final phase of this research, an experiment is set up to validate the light delivery of the design, which provides a clear outlook for the future of these designs into fabricated products.