By Laura Freeman
Published: September 13, 2022
Up, down, left, right–pitch and pivot to the optimum angle–advances in CT innovation have mastered spatial coordinates for cancer detection, radiation planning and treatment. Now precision timing is enhancing accuracy for the Cancer Treatment Center at Ascension St. Vincent’s East.
The center’s new Varian TrueBeam Linear Accelerator is one of only three in Alabama. The system’s next-generation hardware and software track the micromovements of breathing to deliver radiation only when the patient is in the optimum position. This is particularly helpful in treating cancers in the lungs, breast and torso where immobilization devices aren’t able to prevent small changes in position as the lungs expand to take in air and contract to release it.
“With precision down to less than a millimeter, this system makes it possible for us to deliver higher doses of radiation for maximum effectiveness while protecting more healthy tissue and minimizing side effects,” radiation oncologist Laura Dover, MD, said. “This also allows us to complete the course of treatment sooner. Patients who have had radiation before are usually surprised and pleased to find they will be finished with fewer appointments than they expected, particularly those who have to travel a long distance or take time off work to schedule treatments.”
The CT system is designed to combine diagnostic imaging with mapping and planning capabilities that are used to guide radiation delivery. It’s an all-in-one place, in one system.
“When a malignancy is detected, we pinpoint its location and begin using the data to develop the most effective treatment plan,” Dover said. “We bring the patient in for a preliminary appointment to calculate placement and create a custom mold around the body. It’s a bit like working with wet sand on the beach. The mold helps us precisely position the patient at each appointment and it provides support to make it easier for patients to stay in the right place for an extended period.
“The anatomy of each patient is unique, and the locations and types of cancers tend to differ and can come with different challenges. Each cancer has to be individually evaluated, mapped and matched to the radiation delivery system. The CT and treatment couch give us wonderful control in programming the best position. We can move from side to side, and roll the pitch for the best angle. I can also tilt the head and foot of the couch up and down to make the patient more comfortable and get the exact placement we need.
“Staying still can be difficult for anyone. The mold helps patients maintain the best position and we also use other immobilization tools to help them, which can vary depending on the type of cancer and where it’s located. For example, if we are dealing with a brain tumor, a custom mask could be created to support the head and neck and keep the patient perfectly positioned. Treating brain or spinal tumors is a good example of how the new system’s accuracy down to the millimeter or less can be so important. Neurons vital to cognitive or physical function are sometimes very close to the malignant tissue we’re trying to eliminate. The more precise our targeting, the better the outcome is likely to be.”
In some cases, the ability to work with greater precision may also allow more leeway to treat tumors that might have been considered too difficult to reach in the past.
A native of Alabama, Dover was working at Memorial Sloan Kettering in New York when she was recruited to come home to launch the new CT system in the Cancer Treatment Center.
“It’s wonderful to be back and I have to say I consider it an honor to help bring such world class CT diagnostic and treatment capabilities to the people in my home state,” she said.