From Human Oncology
A New Tool to Help Position Patients for Radiation Therapy
The Radiation Oncology Clinic at UW Health East has a new tool to help ensure proper patient positioning during radiation treatments.
AlignRT is a patient position monitoring system that uses three ceiling-mounted cameras to create a 3D model a patient’s body in real time. The system continuously compares these 3D images to the optimal positioning determined during treatment planning to aid in patient setup and treatment accuracy.
If the patient moves out of a predetermined tolerance range during treatment (due to a cough, sneeze or other voluntary or involuntary motion), the system alerts the radiation therapist, who can then turn off the radiation beam and reposition the patient before continuing. The system can also be programed to shut off the beam when the treatment site moves out of range. This can help spare healthy tissue from exposure to radiation.
“This system gives us another set of eyes that helps us know during treatment whether the patients are in the position that we worked so hard to put them in before we started the treatment,” says Dustin Jacqmin, assistant professor in the UW Department of Human Oncology (DHO). “It uses light instead of ionizing radiation, which means we can use it as much as we want without having to worry about patients getting any radiation in addition to the treatment they’re already getting.”
So far, the system has been used mostly on patients with breast cancer.
“The main benefit is that it provides continuous feedback on the patient’s position,” says Jessica Strang, radiation therapist at UW Health East. “If we take an image at the beginning of every treatment, we can confirm that the patient is in the correct position. But that image only provides information for that one moment. With this system, we can make sure that the patient doesn’t move throughout treatment. This gives us more confidence that we’re delivering precise treatment.”
AlignRT will also be used to monitor other disease sites near the body’s surface where external contours are a good indicator of the position of the tumor. Jacqmin says it will help ensure the proper positioning of extremities, which are particularly challenging to align because arms and legs have a wide range of motion.
More patients will benefit from this system when it is installed at the Radiation Oncology Clinic at UW Hospital as part of a treatment room upgrade.
Dr. Bethany Anderson, DHO assistant professor and radiation oncologist who specializes in treating breast cancer, anticipates using AlignRT to improve reproducibility of deep inspiration breath holds. This technique is used to minimize radiation to the heart during treatment of the left breast.
AlignRT may also be used to provide external monitoring of breath holds during radiation treatment for lung cancer. “It’s another way of documenting whether or not the patient’s position changes during treatment, which is especially useful for these highly precise treatments,” says Dr. Greg Cooley, DHO clinical associate professor and radiation oncologist at UW Health East.
AlignRT may be used more broadly “if for no other reason that it’s a simple technique to make sure than the patient lines up initially and remains in position during treatment,” Cooley says.
Except for the red lights that dot the patient’s body during use, the system is unobtrusive and may even improve the patient experience. “When we explain to patients that this blanket of red lights means that we are closely monitoring their position, I think it makes them feel more confident during treatment,” says Katie Keyes, a radiation therapist at UW Health East. “I think it provides reassurance for therapists and patients.”