A lioness led Sennon-Greene to a career in cancer-fighting isotopes

Jillene Sennon-Greene fell in love with radioisotopes when she saw how they helped diagnose and treat medical conditions in animals.

Then she learned what isotopes can do for people - including attacking cancer in novel ways.

At the Department of Energy's Oak Ridge National Laboratory, Sennon-Greene oversees the lab's production of actinim-225 (Ac-225), a high-demand radioisotope used for targeted cancer treatments. As radioisotope manufacturing coordinator in the Isotope Science and Enrichment Directorate's Isotope Processing and Manufacturing Division, she helps ensure Ac-225 is available for potentially life-changing medical treatments.

That was a path she didn't anticipate when she moved from New York City to Knoxville, Tennessee, in 2015 at the urging of her husband, who'd lived in Knoxville before. Sennon-Greene, who was born in the Republic of Trinidad and Tobago and grew up in New York City, found trading New York's 24-hour energy for the quieter pace of East Tennessee came with an adjustment period - and a touch of culture shock.

But Sennon-Greene, who holds degrees in chemistry, biology and anthropology, quickly found work she loved, as a technician in the endocrinology laboratory at the University of Tennessee (UT) College of Veterinary Medicine.

At UT, she learned to work with iodine-125, used to test animals for hormone issues that could cause thyroid problems, Cushing's disease and other health issues.

"That's what started my background in radioisotopes and radioactive medicine," Sennon-Greene said. "It was my first time ever working with isotopes, and I thought the method being used, how we were able to help the animals, was so neat."

Big cat cure sparks fascination

She specifically remembers a lioness, Bridget, who was brought to UT Vet School from an Oklahoma zoo because she'd grown a mane and was being rejected by other members of her pride. Testing with iodine revealed Bridget had an elevated level of androstenedione, a hormone that can contribute to the development of such male features.

"They were able to treat it, and she was welcomed back into her pride," Sennon-Greene said. "I just thought that was so cool."

Sennon-Greene thrived in her job, even co-writing a paper on a side effect caused by a certain medication that changes how a dog's adrenal glands make hormones.

Still, she heeded people who told her ORNL would be a terrific opportunity for her, so when she saw a radiochemical laboratory technician position that was a good fit for her education and skills, she sent in an application. She joined the lab in 2020.

"It was so rewarding working with animals - and then I saw this opportunity," Sennon-Greene said. "We could cure cancer in humans. It was right up my alley. I wanted to be involved in it."

Targeting cancer with isotopes

Studies have shown success using radioisotopes - and Ac-225, in particular - to attack cancer cells through targeted alpha therapy treatments. Targeted alpha therapy combines precision and power: A specially designed molecule carries a radioisotope directly to cancer cells, where it releases particles of alpha radiation, tiny bursts of energy that can destroy the DNA of cancer cells while largely sparing surrounding healthy tissue. ORNL is a leader in both the production of radioisotopes and the research and development of chelators, the molecules that carry them.

The excitement of playing a role in that process prompted Sennon-Greene to apply for the radioisotope manufacturing coordinator position when it opened up in 2023.

"I was already doing a lot of the work as a technician, so I had the skills," she said. "I wanted to advance. I like being hands-on, but I also wanted to be more involved with day-to-day operations and leadership. In this role, I oversee the operations and still get hands-on stuff to do."

Sennon-Greene is involved with scheduling the various professionals involved with processing Ac-225, putting together the infrastructure needed for processing, overseeing waste removal, tracking inventory and other aspects of producing the crucial radioisotope.

"I get to interact with all the different ORNL groups involved," she said. "Everyone wants to get our product out the door. We want to help people. We want to cure cancer. Everyone has the same goal."

Sennon-Greene and her team perform research to learn how science affects the process of producing Ac-225, and rely on collaboration with other scientists and subject matter experts to guide them.

"Jillene is a superstar and a pleasure to work with," said Ryan Hill, group leader for Laboratory Chemical Operations in the Radiochemical Engineering Development Center, where Ac-225 is processed. "There is no way to fully capture the impact she has on our group. Without her, Ac-225 simply would not be where it is today."

With Ac-225 now in human clinical trials, the stakes are high - but so are the benefits.

"The most rewarding part of it is getting our product out the door and knowing it's making an impact on someone's life," Sennon-Greene said. "I hope one day it becomes the go-to drug for cancer treatment that is available to everyone."

She looks forward to someday telling her daughters, who are now 3 and 1, that their mother was a part of getting an important treatment to the people who need it.

"I really love my job at the lab," she said. "It's my dream job. Every day is a different challenge."

UT-Battelle manages ORNL for DOE's Office of Science, the single largest supporter of basic research in the physical sciences in the United States. DOE's Office of Science is working to address some of the most pressing challenges of our time. For more information, visit energy.gov/science. - Kristi Bumpus