Since 2019, the clinical team at Willis Knighton Health in Shreveport, Louisiana has been using Catalyst™ Surface Guided Radiation Therapy (SGRT) routinely for a variety of cases, most commonly for patients with breast cancer using the DIBH technique, but also with chest wall and extremities cases. The center evaluated surface tracking systems several years ago and ultimately selected Catalyst for its exceptional interoperability and simple workflow with the department’s Elekta Versa HD linacs.
“We were an early SGRT adopter and evaluated multiple systems during various site visits. Our view was that C-RAD products seemed simpler, would require less maintenance, provide better uptime, and be easier to use,” explains Chief Therapist Daniel Speir, RTT.
What the team didn’t expect was to encounter a case in which they could confidently say that treatment was only possible with C-RAD technology.
Catalyst surface tracking may sometimes be the only option for patients whose ability to comply with certain setup requirements is limited or hindered by their physical characteristics. In one case involving both factors, Catalyst proved to be indispensable in completing the treatment, as Speir and his colleague Lead Therapist William Burrell, RTT describe.
With some patients undergoing treatment for head-and-neck cancers, head immobilization with a tight-fitting thermoplastic mask often feels uncomfortable and highly claustrophobic. During a recent consult, Speir describes how the patient’s physician discovered such debilitating fears of confinement that the patient considered the possibility of declining treatment entirely.
“The doctor and the patient agreed to at least schedule the CT-sim so we could figure out if anything would work,” Speir explains.
Burrell and Speir recruited a multi-disciplinary group to attend the CT simulation, including the CT technologist, the patient’s physician – Dr. Michael Durci – as well as members of the physics and dosimetry teams.
“The patient had severe anxiety and wanted nothing to do with a mask touching his face,” Speir recalls. “I couldn’t even touch his face. He was adamant that he didn’t want any medication to ease his fears, and he even rejected our open-field mask,” he adds.
The positioning difficulty was exacerbated by the patient’s BMI, which made it impossible for him to lay down due to breathing problems.
The team figured out that positioning the patient at an incline on a breast board would solve his breathing challenge while laying supine. However, the possibility of movement was still a significant concern.
“That’s when William and I looked at each other and said: ‘Why can’t we use Catalyst to monitor his movement and set him up with that every day?’” Speir remembers.
The isocenter was marked on the patient and the CT simulation was done.
Due to the inclined breast board, there were some initial difficulties with the treatment system clearance, necessitating a second pre-treatment CT-sim to move the patient’s CT-sim isocenter mark lower.
“Catalyst allowed us the flexibility to set up the patient in the manner needed to accommodate his needs,” Speir points out.
Burrell agrees: “Catalyst was the perfect way to get this patient set up every day, because we were treating from the top of his head down to his neck. To get his head and neck aligned properly, we needed something that would allow us to see where to turn his head. Obviously, the C-RAD system was the best option.”
Once the patient was in the treatment room, the team used Catalyst to position the patient’s head and chin where they needed to be because he had arrived with no isocenter marks, as they had washed off.
“The patient was immobilized using only a piece of tape across his forehead, so real-time monitoring was critical for treatment accuracy. We did a cone beam to double-check, and it turned out well,” Burrell adds.
Due to the patient’s broad shoulders, the therapist team also used shoulder retractors with adjustable ropes to pull his shoulders down – as they had done during the CT-sim. Catalyst’s large field of view helped confirm the entirety of this positioning as well.
“Everything lined up well considering how involved the setup was,” Burrell recalls. “Catalyst didn’t have a problem seeing what it needed to see on him, despite the absence of an isocenter mark. And during treatment we got a live feed from Catalyst that was giving us information about his movement down to the millimeter, so we were confident in treating him.”
“And I asked the patient: ‘Can you do this every day for 30 treatment sessions?’ and he said he could,” Burrell explains. “Dr. Durci also was completely satisfied with this way of treating him.”
“We had very limited options for treating this patient, but Daniel and William did a terrific job devising a setup to help him,” Dr. Durci recalls. “I wouldn’t have considered it if I weren’t totally confident in the real-time monitoring capabilities of Catalyst.”
Real-time monitoring with Catalyst
Willis Knighton Health is currently involved in the MOBILE – LDRT Osteoarthritis Study, a clinical trial designed to examine the effects of using radiation in low doses to treat osteoarthritis with a protocol of 3 Gy over six 0.5 Gy fractions. The trial also includes Vanderbilt University Medical Center (Nashville, TN), UT San Antonio (San Antonio, TX), and Cancer Care Northwest (Coeur D’Alene, ID).
“We’ve treated more than 50 patients with LDRT, including those with osteoarthritis of the hands, shoulders, knees, feet, ankles or hips,” Burrell notes. “In certain situations, Catalyst has also helped us reproduce difficult treatment positions with some of these cases as well.”
For example, the team used Catalyst recently for a female patient’s knee that was awkwardly bent a certain way. The only way to accurately monitor her treatment position was to use Catalyst.
“We used Catalyst to look at the knee to show us which way we needed to get the rotation straight,” Burrell recalls. “While we don’t use Catalyst for most of our osteoarthritis treatments, when these special cases come up, it’s nice to know we have a way to set up patients that won’t require frequent X-ray exposures.”
“We’ve always been committed to using the most advanced technology for our patients, and the decision to use C-RAD has helped keep us on the leading edge not only for our cancer patients but also for others who may benefit from radiation therapy as well,” Speir concludes.
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