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Magnetic resonance (MRI)-guided high intensity focused ultrasound (HIFU) to treat limb osteosarcoma in dogs: a pilot study



To determine the feasibility, efficacy, side effects and treatment outcomes in dogs with limb osteosarcoma (OSA) treated with MR-guided high intensity focused ultrasound (HIFU).


Bone cancer or osteosarcoma (OSA) is a common, highly aggressive cancer that can affect the long bones of large breed dogs. Current standard of care therapy consists of limb amputation plus chemotherapy. However, despite therapy, most patients die as a result of the cancer spreading to other parts of their bodies within 12 months. Not all pet owners wish to pursue this type of invasive treatment and opt for a palliative therapy instead. Furthermore, standard of care treatment for canine osteosarcoma has not changed in over 20 years and alternative effective options are much sought after.

High-intensity focused ultrasound (HIFU) delivers ultrasonic energy that heats a target tissue above 60oC to produce tissue destruction without harming overlying and adjacent tissues within the path of the heat beam. No incision of the skin is required. The thermal injury created by HIFU is focal, extremely precise and is typically guided by magnetic resonance imaging (MRI).

Osteosarcoma is a tumour that diminishes the integrity of the bone increasing the risk for pathologic fracture. It has been proposed that HIFU does not diminish bone integrity but may in fact increase it, which could potentially reduce the risk of pathologic fracture. It is also hypothesized that treating the tumour without removing the limb could provide an opportunity for the immune system to mount an immunity against OSA and could possibly reduce the frequency and/or speed of occurrence of metastasis.

The proposed pilot study will allow us to determine the response of your pet’s tumour to HIFU and to develop standardized protocols for use in our patients and possibly in children with similar tumours. Our long-term goal is to make HIFU available to our patients as a safe, non-invasive, and effective new treatment for various tumours for which there is either no alternative treatment at this time or for which pet owners are not willing to pursue more invasive options.

HIFU Treatment:

HIFU will be performed under general anesthesia at the Hospital for Sick Children in Toronto by a team of veterinary specialists (including a board certified veterinary anesthesiologist) in collaboration with pediatric interventional radiologists experienced with HIFU and HIFU scientists. Two (2) visits to the Hospital for Sick Children (Toronto) are required.


  • HIFU treatment is covered by the study
  • Two MRI scans – one before and one ~2-6 weeks after HIFU treatment are covered by the study
  • For patients who choose to follow Standard of Care therapy (amputation & chemotherapy) following HIFU treatment, the study will pay $1000 towards the cost of the amputation procedure fee.

Samples required:

  • Bone tissue biopsies before and ~2-6 weeks after HIFU treatment. Bone biopsies are minimally invasive and performed through a 1-2mm skin incision using a bone biopsy needle.  

Inclusion Criteria:

  • Confirmed diagnosis of osteosarcoma
  • No previous surgical/radiation treatment
  • No evidence of metastasis
  • Undergone complete work-up (bloodwork, chest radiographs and abdominal ultrasound)
  • Clients live within ~2hr drive of the OVC


  • Dr. Brigitte Brisson (PI)


Vicky Sabine (PhD), Clinical Research Coordinator, OVC
Email:; Work Cell #: 226-218-0338

Funded by OVC Pet Trust.

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