A novel matrix-array-based MR-conditional ultrasound system for local hyperthermia of small animals

Steffen H. Tretbar (Lead / Corresponding author), Marc Fournelle, Daniel Speicher, Franz Josef Becker, Pavlos Anastasiadis, Lisa Landgraf, Upasana Roy, Andreas Melzer

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Objective: The goal of this work was to develop a novel modular focused ultrasound hyperthermia (FUS-HT) system for preclinical applications with the following characteristics: MR-compatible, compact probe for integration into a PET/MR small animal scanner, 3D-beam steering capabilities, high resolution focusing for generation of spatially confined FUS-HT effects.

Methods: For 3D-beam steering capabilities, a matrix array approach with 11 11 elements was chosen. For reaching the required level of integration, the array was mounted with a conductive backing directly on the interconnection PCB. The array is driven by a modified version of our 128 channel ultrasound research platform DiPhAS. The system was characterized using sound field measurements and validated using tissue-mimicking phantoms. Preliminary MR-compatibility tests were performed using a 7T Bruker MRI scanner.

Results: Four 11 11 arrays between 0.5 and 2 MHz were developed and characterized with respect to sound field properties and HT generation. Focus sizes between 1 and 4 mm were reached depending on depth and frequency. We showed heating by 4C within 60 s in phantoms. The integration concept allows a probe thickness of less than 12 mm.

Conclusion: We demonstrated FUS-HT capabilities of our modular system based on matrix arrays and a 128 channel electronics system within a 3D-steering range of up to 30. The suitability for integration into a small animal MR could be demonstrated in basic MR-compatibility tests. Significance: The developed system presents a new generation of FUS-HT for preclinical and translational work providing safe, reversible, localized, and controlled HT.

Original languageEnglish
Pages (from-to)758-770
Number of pages13
JournalIEEE Transactions on Biomedical Engineering
Issue number2
Early online date16 Aug 2021
Publication statusPublished - Feb 2022


  • -3D-beamforming
  • Animals
  • chemotherapy
  • focused ultrasound
  • hyperthermia
  • Hyperthermia
  • image-guidance
  • Magnetic resonance imaging
  • matrix array
  • Medical treatment
  • MRgFUS
  • MRI
  • multichannel electronics
  • radiation therapy
  • Transducers
  • Tumors
  • Ultrasonic imaging
  • ultrasound hyperthermia

ASJC Scopus subject areas

  • Biomedical Engineering


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