Key Points
- Dr. Shekhar is an assistant professor who leads the Medical UltraSound Engineering Laboratory at the Indian Institute of Technology Gandhinagar.
- Learn more about his work and passion for making the technology accessible to the developing world.
Himanshu Shekhar, PhD, is an assistant professor of electrical engineering at the Indian Institute of Technology (IIT) Gandhinagar. He also established and leads the Medical UltraSound Engineering (MUSE) Laboratory there along with Karla Mercado-Shekhar, PhD.
We recently spoke with Dr. Shekhar about his work, what he finds interesting about focused ultrasound, and his passion for making the technology accessible to the developing world.
Focused Ultrasound Work
When and how did you get interested in focused ultrasound?
While I was PhD student at the University of Rochester, I worked in Prof. Marvin Doyley’s laboratory studying ultrasound contrast agents, and my exposure to nonlinear imaging with shelled microbubbles piqued my interest in cavitation. I became aware of the potential of focused ultrasound through my interactions with researchers at symposia. I also wanted to explore the translational and clinical aspects of my research.
Accordingly, I decided to pursue postdoctoral research in Prof. Christy Holland’s laboratory at the University of Cincinnati School of Medicine. My work on sonothrombolysis for stroke applications there was supported in part by the F. V. Hunt Fellowship from the Acoustical Society of America. I evaluated clot lysis with echogenic liposomes encapsulating both a thrombolytic agent and an inert gas, and my findings demonstrated the potential of this approach for rapid recanalization. I worked on nucleating cavitation with ultrasound contrast agents and the morphological structure of echogenic liposomes and their drug-loading capacity. Further, I developed and characterized xenon-loaded microbubbles for neurotherapeutics and nitric oxide-loaded microbubbles for antibacterial applications. Apart from these projects, I collaborated with colleagues on an array of projects encompassing histotripsy, sonobactericide, and microfluidic manufacture of ultrasound-responsive therapeutic agents. These experiences helped me develop a strong interest in therapeutic ultrasound, and I decided to pursue an independent faculty position subsequent to my postdoctoral tenure.
I realized during my academic training that cutting-edge ultrasound technology should be equitable and widely available to have a major impact on healthcare. After exploring the potential of ultrasound in the developing world, I accepted a faculty position at IIT in Gandhinagar (IITGN), in my home country of India in April 2019. I established the MUSE Laboratory, an ultrasound-focused group, along with Dr. Karla Mercado-Shekhar. Starting from scratch, we have been able to develop a well-equipped lab and a vibrant team. We have also established collaborations to address important biomedical challenges, including those in focused ultrasound research.
What are your areas of interest in focused ultrasound?
Our group is working on anticancer and antibacterial sonodynamic therapy, cavitation-mediated therapies, and image-guidance approaches – both active and passive – for cavitation-mediated therapies. We have reported our work on fiber Bragg grating–based optical sensors for cavitation detection and temperature monitoring, characterization of protein-shelled cavitation nuclei, sonodynamic therapy using novel sonosensitizers, contrast-specific imaging of histotripsy bubble clouds for therapeutic monitoring, and algorithms for passive cavitation imaging.
What mechanisms and clinical indications do you study?
The work in our group is largely focused on cavitation-mediated therapies and image guidance for focused ultrasound therapies. We study the interaction of ultrasound with tissue and the biophysical mechanisms relevant to therapy. About 70% of my group’s work is based on therapeutic ultrasound. My trainees and I are also working on related areas, including ultrasound contrast agents, beamforming, and super-resolution imaging.
What is the goal of your work?
Ultrasound is growing rapidly as a therapeutic modality, and its diagnostic role is also expanding. The goal of our group within the MUSE Lab at IITGN is to develop and translate innovative ultrasound-based techniques to aid in the treatment and management of diseases. Our research efforts are multidisciplinary and are grounded in principles of biomedical engineering, imaging, acoustics, signal processing, and instrumentation.
What are your funding sources?
Our work is funded by the Government of India – Science and Engineering Research Board, Department of Biotechnology, Department of Science and Technology, and Ministry of Education. We have also received supplementary funds from the American Cancer Society and Johns Hopkins University.
Research Details
Who are your team members?
At the MUSE Lab, I work directly with a team of five PhD students, one master’s student, one research staff, and two undergraduate students.
Who are your internal and external collaborators?
Because research in our field is inherently interdisciplinary, I engage with several collaborators. At IITGN, I collaborate with Drs. Mercado-Shekhar, Dhiraj Bhatia (Biological Sciences and Engineering), and Iti Gupta (Chemistry). Internationally, I collaborate most actively with Dr. Kenneth Bader at the University of Chicago. I also have ultrasound image guidance–themed collaborations with Drs. Hardik Pandya (Indian Institute of Science) and Vikas Vazhayil and Anita Mahadevan (National Institute of Mental Health and Neuro Sciences).
What are your greatest achievements? Any major disappointments?
The research conducted by my students and postdoctoral fellows from IITGN has already been published in 14 peer-reviewed journal articles and presented at the International Symposium on Therapeutic Ultrasound, the Acoustical Society of America meeting, and IEEE International Ultrasonics Symposia. I am particularly excited about our group’s recent work on histotripsy guidance and optical cavitation sensors. However, as an early career researcher, I am still figuring out my way.
In my opinion, my group’s greatest achievement so far is to be able to contribute toward advancing therapeutic ultrasound in India. I have always believed that high-quality healthcare technology should be equitable and widely accessible. Therapeutic ultrasound is one such technology that has the potential to significantly impact healthcare delivery in developing countries. Although our group started only five years ago, it has played a role in putting India on the map of therapeutic ultrasound research through research, teaching, and outreach. Recently, we conducted the IEEE South Asian Ultrasonics (SAUS) symposium at IITGN along with colleagues Prof. Arun Thittai (IIT Madras), Dr. Mercado-Shekhar (IITGN) and Dr. Mahesh Panicker (Singapore Institute of Technology). This symposium was attended by over 150 delegates in person, which brought the spotlight on ultrasound research in India. The symposium had a considerable international presence and industry participation, which served as a great opportunity to connect the global research community with India to advance ultrasound. This meeting also brought noted researchers in biomedical ultrasound to India, including Drs. Kullervo Hynynen, Christy Holland, Cyril Lafon, Ayache Bouakaz, Mark Schafer, Ashish Ranjan, and F. Levent Degertekin. In the clinical session, Dr. K. Vijayan from the Royal Healthcare Hospital Kerela presented exciting results on using transcranial MRI-guided high-intensity focused ultrasound (HIFU) to treat the motor symptoms of essential tremor and Parkinson’s in more than 75 patients. We received excellent feedback from the keynote and invited speakers and participants. I believe that such efforts will pay considerable dividends in the long term for advancing research and the biomedical ultrasound ecosystem in India.
As far as disappointments, failures are part of research, but I have not encountered what I would call a major setback. One example I can cite would be when I moved to India to start my lab. Within 10 months of my transition, the COVID-19 pandemic struck. Almost all my research, recruitment, and laboratory-building efforts were severely affected for nearly two years. Remote work was unproductive because my students were new. Nonetheless, the pandemic had a devastating effect on the entire scientific community, and I can hardly claim this to be a unique experience. Ultimately, we pivoted and started some computational work on image guidance at that time, which has evolved well. My students are doing well now, and some of my mentees are already advancing ultrasound at leading institutions such as Sunnybrook Research Institute, Johns Hopkins University, the University of Edinburgh, State University of New York, Buffalo, and others.
What do you see as impediments to your success?
Each research ecosystem has its advantages and limitations. In India, medical doctors are extremely busy with clinical duties because of the low number of specialists per capita population. This has made clinical collaborations challenging at times. However, lately I have been able to form excellent collaborations with motivated clinicians at academic health centers, and our work has been enriched by their input. Another challenge is that procurement of high-end instrumentation takes longer in India. None of these challenges are insurmountable, and these limitations are balanced by several exciting opportunities in the nascent Indian academic and startup ecosystem, which is uniquely suited for translating ultrasound technology.
What is on your research wish list?
My research wish list is dynamic, and we are always open to working on interesting problems that have a long-term impact rather than limiting ourselves to a specific clinical indication. Because our group has been in existence for only about five years, our focus is still evolving. Nonetheless, we would like to develop effective techniques for ultrasound image guidance of focused ultrasound therapies, including histotripsy, HIFU, and drug delivery. Furthermore, I would like to advance and translate sonodynamic therapy for anticancer and antibacterial applications. I would like to develop effective ultrasound-responsive agents for enhancing therapeutic outcomes. Further, we would like to leverage frugal innovation to make these technologies affordable and widely accessible. In terms of my research team, I would like to attract talented, passionate, and motivated trainees to our group and empower them to advance clinically important research areas.
Has the Foundation played a role in your work?
I have been greatly inspired by the work of the Focused Ultrasound Foundation. Its efforts and advocacy in advancing treatments in the brain are particularly exciting. I have had essential tremor since I was 10 years old, so I can empathize with the impact of such therapies on the lives of patients.
On the research front, I have benefitted from Foundation workshops, including the one on cavitation mapping. I have also used resources from the Foundation – such as the State of the Field Report – while thinking strategically about my research focus. The State of the Field report also informed me about the focused ultrasound clinical activity in India. Recently, the Foundation provided funds as a silver sponsor for the IEEE SAUS Symposium, and Dr. Chrit Moonen attended and gave an invited talk. I am grateful because this symposium was a watershed moment for the Indian ultrasound research community. In the future, I hope to engage more with the Foundation by applying for research funding.
Any follow-up funding opportunities?
We have submitted proposals to national funding agencies to continue our work on sonodynamic therapy, ultrasound-mediated drug delivery, and image guidance therapies. I am also collaborating with Dr. Bader at the University of Chicago to pursue National Institutes of Health funding for image guidance strategies applied to histotripsy. Our lab has also initiated collaborations with groups at Johns Hopkins University and the Laboratory of Therapeutic Applications of Ultrasound at the French National Institute for Health and Medical Research, and we plan to pursue additional international funding opportunities.
What comes next?
Having developed an interdisciplinary group, we now aspire to make important contributions to the translation of focused ultrasound therapies to the clinic. While we have developed a strong engineering foundation, we would like to further improve our translational infrastructure and collaborate with clinicians and industry to help take these advances to the clinic. I would like to continue advocating for ultrasound as a technology for the developing world, where the clinical context and needs may be different from those in the developed world. One of the most enjoyable aspects of an academic career is the ability to mentor trainees, and I look forward to seeing my students and postdocs make their mark in this exciting field.