Ultrasound thermal monitoring with an external ultrasound source for customized bipolar RF ablation shapes

  • Younsu Kim
  • Chloé Audigier
  • Jens Ziegle
  • Michael Friebe
  • Emad M. Boctor
Original Article



Thermotherapy is a clinical procedure which delivers thermal energy to a target, and it has been applied for various medical treatments. Temperature monitoring during thermotherapy is important to achieve precise and reproducible results. Medical ultrasound can be used for thermal monitoring and is an attractive medical imaging modality due to its advantages including non-ionizing radiation, cost-effectiveness and portability. We propose an ultrasound thermal monitoring method using a speed-of-sound tomographic approach coupled with a biophysical heat diffusion model.


We implement an ultrasound thermometry approach using an external ultrasound source. We reconstruct the speed-of-sound images using time-of-flight information from the external ultrasound source and convert the speed-of-sound information into temperature by using the a priori knowledge brought by a biophysical heat diffusion model.


Customized treatment shapes can be created using switching channels of radio frequency bipolar needle electrodes. Simulations of various ablation lesion shapes in the temperature range of 21–59 \(^\circ \)C are performed to study the feasibility of the proposed method. We also evaluated our method with ex vivo porcine liver experiments, in which we generated temperature images between 22 and 45 \(^\circ \)C.


In this paper, we present a proof of concept showing the feasibility of our ultrasound thermal monitoring method. The proposed method could be applied to various thermotherapy procedures by only adding an ultrasound source.


Thermal monitoring Speed-of-sound reconstruction Ultrasound RFA modeling Bipolar ablation Hyperthermia Ablation therapy Thermotherapy 



The research reported in this paper was supported by the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health under Award Number R01EB021396 and National Science Foundation under Proposal Number 1653322.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

For this type of study formal consent is not required.

Informed consent

This article does not contain patient data.


  1. 1.
    Ali G, Krug JW, Friebe M (2017) A four-electrode radiofrequency ablation system designed for more complex and tumor specific ablation patterns. In: Proceedings of BioSpine 2017, 6th international Congress on biotechnologies for spinal surgeryGoogle Scholar
  2. 2.
    Lewis MA, Staruch RM, Chopra R (2015) Thermometry and ablation monitoring with ultrasound. Int J Hyperth 31(2):163–181CrossRefGoogle Scholar
  3. 3.
    Seo CH, Shi Y, Huang S-W, Kim K, O’Donnell M (2011) Thermal strain imaging: a review. Interface Focus 1(4):649–664CrossRefPubMedPubMedCentralGoogle Scholar
  4. 4.
    Zhang S, Zhou F, Wan M, Wei M, Quanyou F, Wang X, Wang S (2012) Feasibility of using Nakagami distribution in evaluating the formation of ultrasound-induced thermal lesions. J Acoust Soc Am 131(6):4836–4844CrossRefPubMedGoogle Scholar
  5. 5.
    Ghoshal G, Luchies AC, Blue JP, Oelze ML (2011) Temperature dependent ultrasonic characterization of biological media. J Acoust Soc Am 130(4):2203–2211CrossRefPubMedPubMedCentralGoogle Scholar
  6. 6.
    Duric N, Boyd N, Littrup P, Sak M, Myc L, Li C, West E, Minkin S, Martin L, Yaffe M, Schmidt S, Faiz M, Shen J, Melnichouk O, Li Q, Albrecht T (2013) Breast density measurements with ultrasound tomography: a comparison with film and digital mammography. Med Phys 40(1):013501CrossRefPubMedPubMedCentralGoogle Scholar
  7. 7.
    Aalamifar F, Khurana R, Cheng A, Guo X, Iordachita I, Boctor EM (2017) Enabling technologies for robot assisted ultrasound tomography. Int J Med Robot Comput Assist Surg 13(1):e1746CrossRefGoogle Scholar
  8. 8.
    Norton SJ, Testardi LR, Wadley HNG (Oct 1983) Reconstructing internal temperature distributions from ultrasonic time-of-flight tomography and dimensional resonance measurements. In: 1983 ultrasonics symposium, pp 850–855Google Scholar
  9. 9.
    Audigier C, Mansi T, Delingette H, Rapaka S, Mihalef V, Carnegie D, Boctor E, Choti M, Kamen A, Ayache N, Comaniciu D (2015) Efficient lattice boltzmann solver for patient-specific radiofrequency ablation of hepatic tumors. IEEE Trans Med Imaging 34(7):1576–1589CrossRefPubMedGoogle Scholar
  10. 10.
    Kim Y, Audigier C, Ellens N, Boctor EM (2017) A novel 3D ultrasound thermometry method for HIFU ablation using an ultrasound element. In: 2017 IEEE international ultrasonics symposium (IUS), pp 1–4Google Scholar
  11. 11.
    Pennes HH (1998) Analysis of tissue and arterial blood temperatures in the resting human forearm. J Appl Physiol 85(1):5–34CrossRefPubMedGoogle Scholar
  12. 12.
    Audigier C, Mansi T, Delingette H, Rapaka S, Passerini T, Mihalef V, Jolly M-P, Pop R, Diana M, Soler L, Kamen A, Comaniciu D, Ayache N (2017) Comprehensive preclinical evaluation of a multi-physics model of liver tumor radiofrequency ablation. Int J Comput Assist Radiol Surg 12(9):1543–1559CrossRefPubMedGoogle Scholar
  13. 13.
    Payne S, Flanagan R, Pollari M, Alhonnoro T, Bost C, O’Neill D, Peng T, Stiegler P (2011) Image-based multi-scale modelling and validation of radio-frequency ablation in liver tumours. Philos Trans R Soc Lond A Math Phys Eng Sci 369(1954):4233–4254CrossRefGoogle Scholar
  14. 14.
    Sun Z, Ying H (1999) A multi-gate time-of-flight technique for estimation of temperature distribution in heated tissue: theory and computer simulation. Ultrasonics 37(2):107–122CrossRefPubMedGoogle Scholar
  15. 15.
    Siddon RL (1985) Fast calculation of the exact radiological path for a three-dimensional CT array. Med Phys 12(2):252–255CrossRefPubMedGoogle Scholar
  16. 16.
    Rice DA (1983) Sound speed in pulmonary parenchyma. J Appl Physiol 54(1):304–308CrossRefPubMedGoogle Scholar
  17. 17.
    Belogol’skii VA, Sekoyan SS, Samorukova LM, Stefanov SR, Levtsov VI (1999) Pressure dependence of the sound velocity in distilled water. Meas Tech 42(4):406–413CrossRefGoogle Scholar
  18. 18.
    Guo X, Kang H-J, Etienne-Cummings R, Boctor EM (2014) Active ultrasound pattern injection system (AUSPIS) for interventional tool guidance. PLoS ONE 9(10):1–13Google Scholar
  19. 19.
    Mikhail AS, Negussie AH, Graham C, Mathew M, Wood BJ, Partanen A (2016) Evaluation of a tissue-mimicking thermochromic phantom for radiofrequency ablation. Med Phys 43(7):4304–4311CrossRefPubMedPubMedCentralGoogle Scholar

Copyright information

© CARS 2018

Authors and Affiliations

  • Younsu Kim
    • 1
  • Chloé Audigier
    • 1
  • Jens Ziegle
    • 2
  • Michael Friebe
    • 2
  • Emad M. Boctor
    • 1
  1. 1.Johns Hopkins UniversityBaltimoreUSA
  2. 2.Otto-von-Guericke UniversityMagdeburgGermany

Personalised recommendations