MRI-compatible breast/rib phantom for evaluating ultrasonic thermal exposures

Int J Med Robot. 2018 Feb;14(1). doi: 10.1002/rcs.1849. Epub 2017 Jul 17.

Abstract

Introduction: The target of this study was the development of a magnetic resonance imaging (MRI) compatible breast phantom for focused ultrasound which includes plastic (ABS) ribs. The objective of the current study was the evaluation of a focused ultrasound procedure using the proposed phantom that eliminates rib heating.

Material and methods: The proposed phantom was evaluated using two different focused ultrasound exposures. The surrounding breast tissue was mimicked using an agar-silica-evaporation milk gel (2% w/v - 2% w/v - 40% v/v).

Results: The attenuation of the ABS was similar to that of ribs. MR thermometry of focused ultrasound exposures were acquired using the breast/rib phantom. In one exposure focused ultrasound was applied with far-field targeting of the ribs. In the other exposure, the transducer was positioned laterally, thus avoiding exposure of the rib to focused ultrasound.

Conclusions: Due to growing interest in using MRI guided focused ultrasound (MRgFUS) for patients with breast cancer, the proposed breast/rib phantom can be utilized as a very useful tool for evaluating ultrasonic protocols.

Keywords: MRI; breast; cancer; rib; ultrasound.

MeSH terms

  • Acoustics
  • Adult
  • Agar / chemistry
  • Aged
  • Breast / diagnostic imaging*
  • Female
  • Gels
  • Hot Temperature
  • Humans
  • Lipids / chemistry
  • Magnetic Resonance Imaging / instrumentation
  • Magnetic Resonance Imaging / methods*
  • Middle Aged
  • Motion
  • Phantoms, Imaging*
  • Ribs / diagnostic imaging*
  • Robotics
  • Silicon Dioxide / chemistry
  • Software
  • Surgery, Computer-Assisted / methods
  • Tomography, X-Ray Computed
  • Transducers
  • Ultrasonic Therapy / instrumentation*
  • Ultrasonic Therapy / methods

Substances

  • Gels
  • Lipids
  • Silicon Dioxide
  • Agar