[Therapeutic technology utilizing focused ultrasound]

Area of Science:

• Oncology
• Biophysics
• Medical Ultrasound

Background:

• Ultrasound exhibits two primary biological effects for tumor treatment: thermal heating and cavitation.
• High-intensity focused ultrasound (HIFU) induces coagulation by rapidly heating tissue, but small treatment volumes limit throughput.
• Sonodynamic therapy (SDT) leverages ultrasonic cavitation to activate porphyrins, generating antitumor effects.

Purpose of the Study:

• To address the low treatment throughput of HIFU coagulation therapy.
• To explore methods for enhancing the efficacy and reducing the threshold for sonodynamic therapy.
• To investigate novel ultrasound-based tumor treatment strategies.

Main Methods:

• Split-focus technology was employed to enlarge the ultrasound focal spot laterally, increasing the coagulation volume.
• Sonodynamic treatment was investigated, utilizing ultrasonic cavitation to activate porphyrins for antitumor effects.
• The ultrasonic intensity threshold for cavitation was reduced by superimposing the second harmonic onto the fundamental frequency.

Main Results:

• Split-focus technology effectively multiplies the coagulation volume, addressing the throughput limitation of conventional HIFU.
• Ultrasonic cavitation was shown to activate porphyrins, leading to significant antitumor effects in vitro and in vivo.
• Superimposing the second harmonic significantly reduced the cavitation threshold, particularly when combined with xanthene dye administration, decreasing lesion formation thresholds in murine liver tissue by orders of magnitude.

Conclusions:

• Split-focus technology offers a viable solution for improving the efficiency of ultrasound-induced coagulation therapy.
• Sonodynamic therapy, enhanced by harmonic superposition and specific dyes, presents a promising approach for ultrasound-mediated cancer treatment.
• These advancements in ultrasound technology hold potential for more effective and efficient oncological interventions.