Biography

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.

Education

Undergraduate
Mcmaster University (1996), Physics
Graduate School
University of Toronto (2002), Biophysics

Research Interest

  • 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)

Publications

Featured Publications LegendFeatured Publications

Thermally-triggered 'off-on-off' response of gadolinium-hydrogel-lipid hybrid nanoparticles defines a customizable temperature window for non-invasive magnetic resonance imaging thermometry.
Shuhendler AJ, Staruch R, Oakden W, Gordijo CR, Rauth AM, Stanisz GJ, Chopra R, Wu XY J Control Release 2012 Feb 157 3 478-84
Investigation of power and frequency for 3D conformal MRI-controlled transurethral ultrasound therapy with a dual frequency multi-element transducer.
N'djin WA, Burtnyk M, Bronskill M, Chopra R Int J Hyperthermia 2012 28 1 87-104
MRI-Controlled Ultrasound Thermal Therapy.
Staruch R, Chopra R, Hynynen K IEEE Pulse 2011 Sep-Oct 2 5 39-47
Development of a platform for co-registered ultrasound and MR contrast imaging in vivo.
Chandrana C, Bevan P, Hudson J, Pang I, Burns P, Plewes D, Chopra R Phys Med Biol 2011 Feb 56 3 861-77
Transurethral prostate magnetic resonance elastography: prospective imaging requirements.
Arani A, Plewes D, Chopra R Magn Reson Med 2011 Feb 65 2 340-9
Early experience in MRI-guided therapies of prostate cancer: HIFU, laser and photodynamic treatment.
Da Rosa MR, Trachtenberg J, Chopra R, Haider MA Cancer Imaging 2011 11 Spec No A S3-8
MRI-guided transurethral ultrasound therapy of the prostate gland using real-time thermal mapping: initial studies.
Siddiqui K, Chopra R, Vedula S, Sugar L, Haider M, Boyes A, Musquera M, Bronskill M, Klotz L Urology 2010 Dec 76 6 1506-11
3D conformal MRI-controlled transurethral ultrasound prostate therapy: validation of numerical simulations and demonstration in tissue-mimicking gel phantoms.
Burtnyk M, N'Djin WA, Kobelevskiy I, Bronskill M, Chopra R Phys Med Biol 2010 Nov 55 22 6817-39
Simulation study on the heating of the surrounding anatomy during transurethral ultrasound prostate therapy: a 3D theoretical analysis of patient safety.
Burtnyk M, Chopra R, Bronskill M Med Phys 2010 Jun 37 6 2862-75
Influence of exposure time and pressure amplitude on blood-brain-barrier opening using transcranial ultrasound exposures.
Chopra R, Vykhodtseva N, Hynynen K ACS Chem Neurosci 2010 May 1 5 391-398

Honors & Awards

  • CPRIT Rising Star Award
    (2013-2018)