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)
- Conformal thermal therapy using planar ultrasound transducers and adaptive closed-loop MR temperature control: demonstration in gel phantoms and ex vivo tissues.
- Tang K, Choy V, Chopra R, Bronskill MJ Phys Med Biol 2007 May 52 10 2905-19
- Analysis of factors important for transurethral ultrasound prostate heating using MR temperature feedback.
- Chopra R, Wachsmuth J, Burtnyk M, Haider MA, Bronskill MJ Phys Med Biol 2006 Feb 51 4 827-44
- Method for MRI-guided conformal thermal therapy of prostate with planar transurethral ultrasound heating applicators.
- Chopra R, Burtnyk M, Haider MA, Bronskill MJ Phys Med Biol 2005 Nov 50 21 4957-75
- Multi-modality tissue-mimicking phantom for thermal therapy.
- McDonald M, Lochhead S, Chopra R, Bronskill MJ Phys Med Biol 2004 Jul 49 13 2767-78
- Multifrequency ultrasound transducers for conformal interstitial thermal therapy.
- Chopra R, Luginbuhl C, Foster FS, Bronskill MJ IEEE Trans Ultrason Ferroelectr Freq Control 2003 Jul 50 7 881-9
- Interstitial ultrasound heating applicator for MR-guided thermal therapy.
- Chopra R, Luginbuhl C, Weymouth AJ, Foster FS, Bronskill MJ Phys Med Biol 2001 Dec 46 12 3133-45
Honors & Awards
- CPRIT Rising Star Award