In mild hyperthermia (MHTh), targeted tumors are heated to approximately 41 to 44°C, typically to enhance chemo-, radiation, and/or immunotherapy. This study demonstrates the efficacy of a ring-array ultrasound (US) transducer in generating and monitoring MHTh in heterogeneous media. A ring-array provides enhanced focusing and heat localization compared to conventional linear-array US. We simulated scenarios using either one, two, or four 128-element linear-array transducers, or a 256-element ring-array transducer, to generate focused US profiles. The full width half maximum (FWHM) was measured to quantify the results. The ring-array achieved the most accurate and localized focal pressure profile with a focal spot size of 2×2mm. In a simulated heterogeneous breast model, sound speed (SS) compensation with a ring-array resulted in more efficient acoustic focusing than non-compensated fields. The focal point without SS compensation shifted spatially from its target due to acoustic aberrations, highlighting the importance of aberration correction for precise heat localization. Additionally, the ring-array's heat generation capability was evaluated in-vitro using a tissue-mimicking phantom, where the temperature at the focal point was increased by 6°C in 12 minutes and was sustainable. Lastly, the capability of a ring-array to track temperature was evaluated using US tomography (UST) in another in-vitro experiment. Here, a cylindrical inclusion in a tissue-mimicking phantom was filled with preheated water and allowed to passively cool from 45°C to 25°C. A ring-array tracked the temperature changes based on SS images with a mean error of 0.06±0.28°C. In summary, a ring-array transducer (1) achieved the best focal profile compared to standard linear transducers, (2) accomplished superior aberration correction using SS images, resulting in better aberration-free focusing in heterogeneous media, (3) generated sustainable heat at a focal point, and (4) accurately monitored temperature changes with UST.
In this work, we developed a new multimodal technology that can simultaneously measure a subset of mechanical, optical, and acoustical properties of the sample, which is based on the integration of Brillouin and photoacoustic (PA) microscopy. Notably, this integration offers a novel approach to probing the refractive index of the sample, which is inaccessible through each technique alone. As a proof-of-concept, we demonstrated the feasibility of the combined setup to obtain the co-registered Brillouin and time-resolved PA signals in a synthetic phantom made of kerosene and CuSO4 aqueous solution. In addition, we measured the refractive index of saline solutions and validated the result in comparison with previously reported data.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.