Clinical & Experimental Metastasis

, Volume 32, Issue 3, pp 279–288 | Cite as

Bone targeted bipolar cooled radiofrequency ablation in a VX-2 rabbit femoral carcinoma model

  • Padina S. Pezeshki
  • Margarete K. Akens
  • Michael Gofeld
  • Jason Woo
  • Cari M. Whyne
  • Albert J. M. Yee
Research Paper


To determine the effect of bipolar cooled radiofrequency ablation (BCRF) on bone and tumour in a lapine pathologic femoral model. Under institutional approval, twelve New Zealand white rabbits received a single femoral injection of VX2 carcinoma cells (day 0). The rabbit femora, (n = 24), were block-randomized into four experimental groups: tumour-bearing radiofrequency ablation (RFA) treated, healthy bone RFA treated, tumour-bearing shams and healthy bone shams (n = 6 per group). 15 min of thermally regulated (65 °C) BCRF was applied at day 14. Pre- and post-treatment MR imaging was performed and repeated at day 28 prior to euthanasia. Histologic evaluation was used to determine treatment effect on tumour and bone tissue. A thirteenth injected rabbit served as a histologic control (no BCRF electrode placement). Large volumes (12.9 ± 5.5 cm3) of thermal ablation were achieved. An eight-fold reduction in tumour growth resulted in RFA treated animals compared to tumour-bearing sham controls (p < 0.001). Osteolysis was controlled in the tumour-treated group. Therapeutic effects were best imaged using MR contrast-enhanced SPoiled Gradient Recalled (SPGR) sequences. Osteoclasts and osteoblasts were observed to be sensitive to BCRF but osteocytes were more resilient. A small number of tumour cells within BCRF treated regions appeared viable post treatment. New bone formation was stimulated in the periphery of the targeted BCRF treatment zone. Structurally large VX2 tumour volumes within bone were successfully ablated with BCRF, stimulating new bone formation in the treatment periphery, although viable appearing osteocytes and tumour cells were observed in some treated regions.


Radiofrequency ablation Bone metastases Tumor Animal model VX2 Preclinical Histology MR imaging 



Radiofrequency ablation


Bipolar cooled radiofrequency ablation


New Zealand white




Tartrate-resistant acid phosphatase


Hematoxylin and eosin


Terminal deoxynucleotidyl transferase dUTP nick end labeling


SPoiled Gradient Recalled


Fast imaging employing steady state acquisition





This research was supported by a peer-reviewed grant from the Ontario Centers of Excellence (OCE) with a matching in kind contribution from Baylis Medical Inc., Mississauga, Ontario. We thank Dr. Rita Kandel for her assistance with histological interpretation, Ms. Sara Moore and Ms. Carrie Purcell for their assistance with the animal studies and Mr. Firas Moosvi for his assistance with the MR imaging.

Conflict of Interest

Co-author JW is an employee of Baylis Medical Inc. This author was not involved in the image/data analysis or animal evaluations.


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Copyright information

© Springer Science+Business Media Dordrecht 2015

Authors and Affiliations

  • Padina S. Pezeshki
    • 1
    • 2
  • Margarete K. Akens
    • 1
    • 3
  • Michael Gofeld
    • 4
  • Jason Woo
    • 5
  • Cari M. Whyne
    • 1
    • 2
  • Albert J. M. Yee
    • 1
    • 2
  1. 1.University of TorontoTorontoCanada
  2. 2.Sunnybrook Research InstituteTorontoCanada
  3. 3.Techna InstituteUniversity Health NetworkTorontoCanada
  4. 4.St. Michael’s HospitalTorontoCanada
  5. 5.Baylis Medical CompanyMississaugaCanada

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