Low-Cost Thermochromic Quality Assurance Phantom for Therapeutic Ultrasound Devices: A Proof of Concept.

Abstract

High-intensity focused ultrasound (HIFU) transducer acoustic output can vary over time as a result of an inconsistent power supply, damage to the transducer or deterioration over time. Therefore, easy implementation of a daily quality assurance (DQA) method is of great importance for pre-clinical research and clinical applications. We present here a thermochromic material-based phantom validated by thermal simulations and found to provide repeatable visual power output assessments in fewer than 15 s that are accurate to within 10%. Whereas current available methods such as radiation force balance measurements provide an estimate of the total acoustic power, we explain here that the thermochromic phantom is sensitive to the shape of the acoustic field at focus by changing the aperture of a multi-element transducer with a fixed acoustic power. The proposed phantom allows the end user to visually assess the transducer's functionality without resorting to expensive, time-consuming hydrophone measurements or image analysis.