My research is concentrated on the development of image-guided therapies. In particular, I have focused on the biomedical applications of HIFU (High-Intensity Focused Ultrasound). Ultrasound is an attractive form of energy for therapeutic use since it can be transmitted through the body from external transducers, can be focused to very localized regions of a few mm, and can be generated from devices of multiple geometries ranging from large focused transducers to catheter based devices. A unique set of capabilities arises when this technology is combined with magnetic resonance imaging (MRI). The ultrasound technology is able to non-invasively deliver energy within the body for applications such as mild heating or tissue ablation, and MRI is able to acquire images of the temperature distribution in the heated tissues during heating. Since the relationship between temperature, time and cell kill is well established, this creates a powerful closed loop method for treating soft tissues.
The other emerging application of HIFU is to potentiate or enable targeted delivery of agents within the body. Ultrasound can be used to trigger release from temperature sensitive liposomes, or to non-invasively open the blood brain barrier. These capabilities open up many possibilities for targeted drug delivery in the brain and other organs with pre-existing vascular barriers (retina, testicles, placenta, etc).
My research has a preclinical component focused on novel applications of HIFU, and a translational component aimed at evaluating established HIFU approaches in patients.
- Mcmaster University (1996), Physics
- Graduate School
- University of Toronto (2002), Biophysics
- Enhancement of radiation and chemotherapy using MRI-controlled HIFU
- Image-guided drug delivery to the brain using ultrasound energy
- Non-invasive tissue ablation and hyperthermia using high-intensity focused Ultrasound (HIFU)
- Temperature-dependent MR signals in cortical bone: Potential for monitoring temperature changes during high-intensity focused ultrasound treatment in bone.
- Ramsay E, Mougenot C, Kazem M, Laetsch TW, Chopra R Magn Reson Med 2014 Oct
- Trans-cranial opening of the blood-brain barrier in targeted regions using a stereotaxic brain atlas and focused ultrasound energy.
- Bing C, Ladouceur-Wodzak M, Wanner CR, Shelton JM, Richardson JA, Chopra R J Ther Ultrasound 2014 2 13
- MR thermometry in the human prostate gland at 3.0T for transurethral ultrasound therapy.
- Ramsay E, Mougenot C, Köhler M, Bronskill M, Klotz L, Haider MA, Chopra R J Magn Reson Imaging 2013 Feb
- Incorporating endorectal MR elastography into multi-parametric MRI for prostate cancer imaging: Initial feasibility in volunteers.
- Arani A, Da Rosa M, Ramsay E, Plewes DB, Haider MA, Chopra R J Magn Reson Imaging 2013 Feb
- Calculation of intravascular signal in dynamic contrast enhanced MRI using adaptive complex independent component analysis.
- Mehrabian H, Chopra R, Martel A IEEE Trans Med Imaging 2012 Dec
- MR Imaging-controlled Transurethral Ultrasound Therapy for Conformal Treatment of Prostate Tissue: Initial Feasibility in Humans.
- Chopra R, Colquhoun A, Burtnyk M, N'djin WA, Kobelevskiy I, Boyes A, Siddiqui K, Foster H, Sugar L, Haider MA, Bronskill M, Klotz L Radiology 2012 Oct 265 1 303-13
- MRI-guided disruption of the blood-brain barrier using transcranial focused ultrasound in a rat model.
- O'Reilly MA, Waspe AC, Chopra R, Hynynen K J Vis Exp 2012 61
- Enhanced drug delivery in rabbit VX2 tumours using thermosensitive liposomes and MRI-controlled focused ultrasound hyperthermia.
- Staruch RM, Ganguly M, Tannock IF, Hynynen K, Chopra R Int J Hyperthermia 2012 28 8 776-87
- The feasibility of endorectal MR elastography for prostate cancer localization.
- Arani A, Plewes D, Krieger A, Chopra R Magn Reson Med 2011 Dec 66 6 1649-57
- Localised drug release using MRI-controlled focused ultrasound hyperthermia.
- Staruch R, Chopra R, Hynynen K Int J Hyperthermia 2011 27 2 156-71
Honors & Awards
- CPRIT Rising Star Award