STATEMENT OF PURPOSE
In Physics, the understanding of light has evolved over the past few centuries and has enabled it to play a critical role in shaping each and every branch of science and engineering. Medical field has benefited from it the most where light forms the basis of optical imaging. Indeed, what intrigued me most is the “production of sound by light” when I was first introduced to a concept of photoacoustic (PA) imaging in my master’s thesis. While working on my thesis, I studied many articles including “Listening for the sound of cancer” which altogether inspired me to pursue research in the area of PA imaging. I feel the need to strengthen my fundamentals in Biomedical Engineering and therefore, in line with my goal of pursuing a career in research I find graduate studies in Biomedical Physics as a stepping stone to achieve this goal.
I had obtained my Integrated Master’s degree in Biomedical Engineering (BME) from Indian Institute of Information Technology, Allahabad, one of the prestigious engineering institute in India. My curiosity in BME arose due to my exposure to various biomedical instrumentation, surgical procedures and treatment protocols because of my mother who was then suffering from chronic kidney disease. My motivation in the field grew stronger when she passed away in my third semester. That was a biggest shock of my life and it also affected my studies throughout the year. Nevertheless, the support of my family and friends helped me to overcome that situation. The experiences I got during her illness helped me to meticulously work on my semester projects involving development of ECG and EMG circuits with their signal analysis. Working on projects provided me a good understanding in electronics, bio-signal processing and coding. Later on, these skills proved instrumental in learning Medical Imaging when I was introduced to it in seventh and eighth semester by Dr. Ratan Saha who taught us Physics of Medical Imaging. The theoretical knowledge acquired from his lectures became handy when he took our entire batch to a Cancer Hospital in our city. My interaction with technicians and doctors of medical imaging gave me an exhilarating experience. That day I was so overwhelmed and enthusiastic to learn and work in the area of biomedical imaging. As an old proverb say “where there is a will there is a way”, similarly, I got an opportunity to work on PA imaging (an emerging biomedical imaging modality) in my Master’s thesis under the guidance of Dr. Saha in my ninth semester.
My Master’s thesis entitled “Photoacoustic signal computation from different erythrocytes” has given a firm understanding of basic building blocks of PA phenomenon. I also studied how to calculate the PA field from single cell using Green’s function and Exact methods. I thoroughly studied the works of Prof. Kolios and Dr. Saha which helped me to discern the influence of shape and size of the PA source on the spectrum at ultra-high frequency range (>100 MHz). The PA spectral features at high frequency may play a critical role in differentiating between normal and abnormal RBCs. In my thesis, I investigated about the dependence of PA signal on the distribution of optical absorption coefficient inside a single RBC. The results suggested that chromophore distribution affected the PA spectrum. Also, these results leaded to a conference article entitled “Effect of Gaussian distributed optical absorption profile of red blood cell on photoacoustic field ” in WESPAC-2018 (Western Pacific Acoustic Conference) held in New Delhi.
Moreover, my thesis experience facilitated me to work with Mr. Anuj Kaushik, a PhD student of Dr. Saha. In this collaborative work, we first studied how differential PA cross-section (DPACS) vary with polar angle theta for different spheroidal and non-spherical axisymmetric particles. After that, we determined the morphological parameters of a normal and abnormal RBC by fitting with different form factor models (tri-axes ellipsoid and finite cylinder model). Our result established that both models provided a good fitting in the case of normal RBC where the error was within 4%. This work has leaded to a publication “Study on angular distribution of differential photoacoustic cross section and its implication in source size determination” which was recently published in Journal of Optical Society of America A. The part of the work has also been submitted to European Conference on Biomedical Optics (ECBO-2019). During this work, I also did simulations of PA field in k-Wave Matlab toolbox. This manuscript gave me a first-hand experience of working in a group, the importance of perseverance in a research field and taking criticisms of a reviewer as a positive feedback. Overall, I think the research experience I got while working under Dr. Saha helped me to build my attitude as a researcher.
I have taken a careful decision of choosing Dr. Micheal C Kolios as my potential supervisor for the graduate studies in your university because I am very familiar with his research and also the collaboration of Dr. Saha with Kolios lab has kept me eager to learn more about his research works. My supervisor Dr. Ratan K Saha also encouraged me to apply for Master’s program at Ryerson University. In Kolios's lab, I would like to gain theoretical and experimental knowledge in the area of PA imaging and photoacoustic microscopy (PAM). In conclusion, I am aware that a strong dedication, devotion and determination is required to pursue a career in research. Nevertheless, I am sure that my motivation, quest for knowledge and a strong passion to contribute in the field of biomedical imaging will drive me to achieve my carrier objective. I, therefore, look forward to begin my journey as a graduate student in your university.