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Focused ultrasound therapy

us_skull.jpg When ultrasound is focused in a small volume of tissue, absorption of acoustical energy results in localized heating and elevation of temperature, which can be utilized to achieve therapeutic effects. The approach is often referred to as high-intensity focused ultrasound (HIFU), or focused ultrasound (FUS). In addition to thermal mechanisms, bioeffects can also be achieved in mechanical manner e.g. by using ultrasound in combination with cavitating ultrasound bubbles.

In a typical treatment setting, a phased array, composed of multiple ultrasonic transducers, is driven such that the ultrasound waves emitted from the device form a millimeter scale focus in a prescribed position in a patient. Since the ultrasound is delivered from outside the patient through an intact skin into the target, the technique has been referred to as bloodless surgery. During the ultrasound treatment sonications, the patient is monitored using e.g. magnetic resonance imaging (MRI) based thermometry, and ultrasound imaging based cavitation monitoring or mapping.

Some of the applications of focused ultrasound therapy under research or clinical use include:

  • Transcranial focused ultrasound for functional neurosurgery
  • Transient blood-brain barrier opening and targeted drug delivery
  • Neuromodulation or neurostimulation

Main lines of research in ultrasound therapy in the group are:

  • Development of tools for treatment planning
  • Optimization of the treatment delivery
  • Methodology research on ultrasound

Seniors working on ultrasound/contact person

Past and present collaborators

  • Focused ultrasound group / professor Kullervo Hynynen, Sunnybrook Research Institute, Canada


  1. A. Hughes, Y. Huang, A. Pulkkinen, M. L. Scwartz, A. M. Lozano, and K. Hynynen
    A numerical study on the oblique focus in MR-guided transcranial focused ultrasound
    Physics in Medicine and Biology 61 (22): 8025-8043 (2016)

  2. A. Pulkkinen, B. Werner, E. Martin, and K. Hynynen
    Numerical simulations of clinical focused ultrasound functional neurosurgery
    Physics in Medicine and Biology 59 (7): 1679-1700 (2014)

  3. J. Song, A. Pulkkinen, Y. Huang, and K. Hynynen
    Investigation of Standing-Wave Formation in a Human Skull for a Clinical Prototype of a Large-Aperture, Transcranial MR-Guided Focused Ultrasound (MRgFUS) Phased Array: An Experimental and Simulation Study
    IEEE Transactions on Biomedical Engineering 59 (2): 435-444 (2012)

  4. N. Ellens, A. Pulkkinen, J. Song, and K. Hynynen
    The utility of sparse 2D fully electronically steerable focused ultrasound phased arrays for thermal surgery: a simulation study
    Physics in Medicine and Biology 56 (15): 4913-4932 (2011)

  5. A. Pulkkinen, Y. Huang, J. Song, and K. Hynynen
    Simulations and measurements of transcranial low-frequency ultrasound therapy: skull-base heating and effective area of treatment
    Physics in Medicine and Biology 56 (15): 4661-4683 (2011)

  6. A. Pulkkinen, and K. Hynynen
    Computational aspects in high intensity ultrasonic surgery planning
    Computerized Medical Imaging and Graphics 34 (1): 69-78 (2010)

Earlier publications

  1. J. Huttunen, M. Malinen, T. Huttunen and J. P. Kaipio
    Determination of heterogenous thermal parameters using ultrasound induced heating and MR thermal mapping
    Physics in Medicine and Biology, 51, 1011-1032, 2006.

  2. M. Malinen, S. R. Duncan, T. Huttunen, and J. P. Kaipio
    Feedforward and feedback control of ultrasound surgery
    Applied Numerical Mathematics, 56, 55-79, 2006.

  3. T. Huttunen, M. Malinen J. P. Kaipio, P. J. White and K. Hynynen
    A full-wave Helmholtz model for continuous-wave ultrasound transmission
    IEEE Transactions in Ultrasonics, Felloelectric and Frequency Control, 52(3), 397-409, 2005.

  4. M. Malinen, T. Huttunen, J. P. Kaipio and K. Hynynen
    Scanning path optimization for ultrasound surgery
    Physics in Medicine and Biology, 50,3473-3490, 2005.

  5. M. Malinen, T. Huttunen, Hynynen, K. and J. P. Kaipio
    A model-based thermal dose optimization method for ultrasound surgery of the breast
    Medical Physics, 5, 1296-1307, 2004.

  6. T. Huttunen, J. P. Kaipio and K. Hynynen
    Modeling of anomalies due to hydrophones in continuous-wave ultrasound fields
    IEEE Transactions in Ultrasonics, Ferroelectric and Frequency Control, 50(11), 1486-1500, 2003.

  7. M. Malinen, T. Huttunen and J. P. Kaipio
    An optimal control approach for ultrasound induced heating
    International Journal of Control, 76, 1323-1336, 2003.

  8. M. Malinen, T. Huttunen and J. P. Kaipio
    Thermal dose optimization method for ultrasound surgery
    Physics in Medicine and Biology, 48, 745-762, 2003.