A thermal dose controller for laser interstitial thermal therapy

Laser interstitial thermal therapy (LITT) is a minimally invasive technique for destroying localized solid tumors by heating with light. An obstacle to widespread adoption of LITT is the lack of adequate control of heating of surrounding healthy tissue and prevention of tissue and fiber-tip charring. An LITT thermal dose controller was developed to address these issues. The goal of the controller is to deliver prescribed thermal dose at a target location in tissue in a present treatment time. The developed feedback controller has a cascade structure with primary thermal dose control loop continuously generating the reference temperature for the secondary, constrained, model predictive temperature controller. The performance of controller was evaluated in simulated linear and non-linear tissue models and in albumen phantoms. The control system demonstrated the ability to achieve treatment goals across all evaluation models by delivering 240 eq. min dose at 5 mm in various preset treatment times.