Acoustic holograms for homogeneous hyperthermia over several tumor spheroids

• Published in: 2023 IEEE International Ultrasonics Symposium (IUS) pp. 1 - 4
• Main Authors: Andres, Diana, Rivens, Ian, Mouratidis, Petros, Jimenez, Noe, Camarena, Francisco, Haar, Gail Ter
• Format: Conference Proceeding
• Language: English
• Published: IEEE 03.09.2023
• Subjects: acoustic holograms; acoustic lenses; Heating systems; Temperature measurement; Temperature sensors; thermal dose; Three-dimensional displays; Transducers; tumour spheroids; Ultrasonic imaging; Ultrasonic variables measurement; ultrasound hyperthermia
• ISSN: 1948-5727
• DOI: 10.1109/IUS51837.2023.10307873

In this work we use 3D printed holographic lenses to enlarge the natural focus of a curved transducer with the aim of producing a uniform region of iso-thermal dose. With this system, we exposed several U87-MG glioma cell spheroids, located inside an IEC tissue mimicking phantom, to a uniform and real-time monitored temperature. Spheroids were exposed with this system until different thermal iso-effective doses (7.5, 30, 60, 120 CEM43) (TIDs) were reached. Also, the effects of ultrasound-delivered hyperthermia on the response of these spheroids were compared with heating using a polymerase chain reaction (PCR) thermal cycler in terms of viability and growth measured on a 10-day schedule. Using acoustic holograms designed to deliver iso-thermal doses, we observe a 6 mm wide uniform region of hyperthermia over the three targets, with temperature differences of less than 3%. In addition, tumor spheroid responses show that ultrasound delivered hyperthermia is more damaging than PCR heating for TIDs ≥ 30 CEM43. This system could help in future in-vitro studies of hyperthermia delivered with ultrasound.