We spoke to radiation oncology physicist Nataliya Kovalchuk, PhD, to learn how Chornobyl set her on a career trajectory to use radiation for the common good and so much more.
How did the Chornobyl nuclear disaster directly impact you and, ultimately, your decision to become a radiation oncology physicist?
I was a 6-year-old girl in Ukraine when it happened. We lived about 350 miles from the reactor. Unfortunately, the disaster was hidden from the public by the Soviet powers for weeks. There was a lot of fear when we found out, with beeping Geiger-Muller counters everywhere because of poisoned water and soil, contaminated rain, and acid puddles. In our area, children were sick with hepatitis probably due to the radionuclide accumulation in the liver. I was one of those kids too, staying in the hospital in a very crowded common room full of children. I remember making friends with a girl Marichka from the Chornobyl zone. She had leukemia and died while I was in the hospital. That was my first encounter with death and cancer. I never forgot that experience… From that moment on, radiation accompanied me through all stages of my life, at first feared as a child, then understood as a student, to finally being used for healing as a radiation oncology physicist.
Can you tell us about your innovative VMAT TBI project?
I feel that’s where my life came full circle. For kids with leukemia (like Marichka), there is an option to treat the whole body with radiation to irradicate the residual cancer cells that are not killed by the chemo agent and suppress the immune system to prepare the body for the marrow transplant. This treatment was introduced in the 1950s by E.D. Thomas who received a Nobel Prize in Medicine in 1990. But the TBI technique has not really changed since the 1950s. This type of radiation is associated with high rates of side effects: pneumonitis, thyroid and kidney dysfunction, sterility, cataracts, etc. We implemented a modern TBI treatment using Volumetric Modulated Arc Therapy (VMAT) and image guidance with a patient comfortably laying on their back on the treatment table. The treatment is more comfortable for a patient, more accurate, and less toxic as we can decrease radiation to the lungs, kidneys, brain, thyroid, testes/ovaries, and lenses. Since its introduction in 2019, we have treated 40 patients with this technique without major side effects. Together with a bright physicist, Eric Simiele, we automated the treatment planning process, which we shared with the public. Inspired by our success, the Children's Oncology Group is planning to set up a multi-institutional clinical trial for VMAT TBI to prove its efficacy for children. I am very proud of this achievement and hope that many cancer centers will follow our lead to improve TBI treatments for children.
What was it like to be part of the team of physicists who commissioned the first-in-human use, PET-guided LINAC -- RefleXion X1?
This is a very exciting project originating with Sam Mazin, a Stanford grad student coming up with a bright idea of creating a first in the world PET-guided LINAC after attending the lecture given by our chief of physics, Lei Xing, PhD. I was lucky to be a part of the physics team responsible for the testing and clinical implementation of this technology. It took us 9 months of hard work culminating in our first patient being treated in May 2021. PET-guided LINAC opens a door into a new era of personalized biology-guided radiotherapy (BgRT) exploiting patient- and tumor-specific biological features that have the potential to guide the radiotherapy and improve treatment outcomes. As the first adopters of this technology, we are continuously providing feedback on shaping its features and functionalities to better fit the patient and clinic needs. I am very enthusiastic to make my mark in this endeavor.
What do you find most rewarding about your work?
My most rewarding work is creating and implementing new technologies, automating processes and making them safer and easier to use, and developing creative radiation treatment plans for our cancer patients, many of whom are pediatric patients. I will always remember a toddler with twice recurrent ependymoma. I spent days crafting her plan to deliver very high and potentially debilitating cumulative doses to her brainstem and simultaneously carving out the dose to spare vital function. It was truly the most complicated planning I have done, together with radiation oncologist, Susan Hiniker, MD, consulting with national experts from various institutions and scouring every bit of literature to arrive at a safe treatment plan for this beautiful little girl. I met this cheerful sunshine and her mother before her treatments and during her follow-up visits to explain and reassure them. Knowing that I had a hand in making a real difference in their lives makes my heart smile.
What can be done to increase the representation of women in medical physics?
In the US women are grossly under-represented in physics and in medical physics, in particular. A 2018 survey found that the percentage of female medical physicists was only 23%. Stanford medical physics division was at that mark when I joined in 2016. Since then, due to the efforts to increase diversity, the female representation within our group has increased to 35%. Even if a woman becomes a medical physicist, there is still a significant gender gap in the leadership roles. To bridge this gender gap in medical physics, we need to look at the leaky pipelines of supply starting from schools and all the way up to hiring and promotion. It’s not enough to just increase the number of women and think that the problem is solved. We also need to change our unconscious biases and create an inclusive environment at workplaces, create protection laws for pregnant and young mothers, etc. I am lucky to have a very supportive husband, who is also a medical physicist, and parents who help with childcare, so I can take on large projects and travel to conferences, but not all women have this support at home. Nevertheless, I am optimistic: my daughter is growing up in a better environment than I did, watching cartoons with women superheroes, women scientists, she is a much more confident girl than I was her age. She tells me she wants to be a doctor when she grows up, but when she grows up even further, she wants to become a physicist, like me. I guess I am a role model for her like my mathematician/physicist mother was for me. In my everyday work, I am trying to foster female physics students, medical physicists, and residents and serve as a role model for them.
What do you most admire about Marie Curie?
Marie Curie is my superhero. Growing in neighboring Poland, she was denied entry into the university because she was a woman. She did not give up and moved to France to pursue her PhD and inspired by Roentgen’s discovery of X-rays and Becquerel’s study of uranium salts, she decided to take on studying uranium rays as her PhD thesis. Together with her husband, after laborious and physical processing of tons of uranium ore, they were able to discover and separate new elements polonium and radium and open the door to the new field of radiation sciences. My favorite quote from her: “Life is not easy for any of us. But what of that? We must have perseverance and above all confidence in ourselves. We must believe that we are gifted for something and that this thing must be attained.” Powerful, isn’t it? I would say radioactive…
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