Project Details
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Real-time feedback control of laser ablation therapies using volumetric optoacoustic imaging

Subject Area Medical Physics, Biomedical Technology
Term from 2015 to 2020
Project identifier Deutsche Forschungsgemeinschaft (DFG) - Project number 279589762
 
Final Report Year 2021

Final Report Abstract

Therapeutic interventions based on thermal ablation are commonly employed medical procedures for annihilating malignant tumors and treating other disorders that require selective tissue targeting. Although thermal ablation presents important advantages with respect to alternative therapeutic options, the lack of haptic feedback during ablative treatments remains a major drawback. As a consequence, clinical interventions commonly result in a high number of undesired outcomes, excessive collateral damage to healthy tissues or ineffective treatments that need to be repeated. In this project, we investigated on the feasibility of using optoacoustics, a fast-growing biomedical imaging and sensing modality, to provide real-time feedback during thermal ablation and to assess the outcome of these procedures. In this context, two types of ablation treatments were studied, namely laser surgery, aimed to generate incisions replacing traditional scalpels, and thermal therapies using variety energy sources, such as photothermal, focused ultrasound and radiofrequency current. Mathematical models of thermal diffusion as well as new hardware configurations based on air-coupled transducers and radio-frequency catheters were further developed in order to fully exploit the optoacoustic monitoring capabilities. The experimental results achieved during this project indicate the powerful performance of optoacoustics as a real-time feedback tool providing quantitative readings of the critical ablation parameters during thermal ablation procedures. In particular, feasibility of noncontact optoacoustic monitoring of incision depth in laser surgery has been demonstrated. We further develop new algorithms to compute volumetrically the temperature distribution in real-time from temperature-induced OA signal increases. We then quantitatively assessed thermal treatment procedures by monitoring the lesion progression and temperature maps generated during photothermal procedures. In vivo demonstration has also been accomplished by imaging laserbased tumor ablation. Finally, we demonstrated applicability of the newly developed methodology for real-time optoacoustic monitoring of radiofrequency ablation procedures.

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