MultiCare leading the way with low-dose CT scans for kids, adults
Anytime a TV talk show highlights the benefits of low-dose radiation CT scans, the phones starts ringing inside the medical imaging department that serves Mary Bridge Children’s Hospital and Tacoma General Hospital.
The most common question: “When my child was scanned recently, was it on the low-dose machine?”
If they brought their child to Mary Bridge, parents don’t have to worry.
Mary Bridge is the only children’s hospital in the Puget Sound region that has a dual-source CT scanner available for kids. That scanner is also available for adults who are at MultiCare Tacoma General Hospital, and another dual-source CT scanner is at MultiCare Good Samaritan Hospital in Puyallup.
The goal is to provide patients with the highest level of protection and safety — including radiation-dose reduction — while maintaining diagnostic image quality.
“This staff has always been very dose conscious for everyone, especially pediatric patients,” said Diane McCoy, lead CT Technologist in the medical imaging department that serves Mary Bridge and Tacoma General. “I’m proud of everybody here, because we were ahead of the game. This staff was protecting people long before this was vogue.”
In fact, the department was chosen as one of five sites in the world to test the low-dose software from Siemens in 2010 and 2011.
The low-radiation dose is achieved in part because of the CT machine and the software. The Tacoma General and Mary Bridge imaging department, and the Good Samaritan imaging department, both have a 128-slice Siemens Definition AS+ CT as well as dual-source Flash scanners. They’re equipped with several dose-reduction technologies, all of which increase the quality of the images while decreasing the time in the scanner and the radiation dose.
(To learn more about those technologies, scroll to the end of this story.)
At Mary Bridge, the staff members' many years of experience working with kids is another key part of making sure young patients receive the lowest dose possible.
The imaging staff doesn’t repeat scans – they scan once, not twice. The staff doesn’t scan if someone is moving. The staff checks to make sure the patient didn’t have a scan the day before. The staff makes sure they’re scanning the right part of the body.
All of that prevents repeated scans, because they do it right the first time.
“We are very conscious to not expose a child to non-diagnostic scans,” McCoy said. “If the child cannot hold still, if the scan isn’t going to be diagnostic, we would not proceed."
The Imaging Department reviews CT studies and works with a medical physicist to ensure the radiation doses meet or are below guidelines from the American College of Radiology. In a review of studies for three types of CT exams for both adults and children, the average radiation dose was 44 percent below the ACR guideline. In a review of CT Pediatric abdomen studies, the average dose at Mary Bridge was 54 percent below the ACR guideline.
“Radiologists trust us to get the images they need,” McCoy said. “Our passion for our work translates to patient dose, and I think that’s what makes us a better place.”
Technological advance to lower dose in CT scans
Some of the technology used in the imaging departments that serve Mary Bridge, Tacoma General and Good Samaritan hospitals:
128-slice Siemens Definition AS+ CT with Dual-source Flash scanners: The system is one of the world’s first adaptive scanners that not only provides exceptional image quality but is suited to any patient, from pediatric to bariatric, or any clinical need, according to Siemens. The AS+ makes complex examinations routine including scans in cardiology, neurology and oncology.
Adaptive dose shielding: Opens and closes shields so only the part of the body that is being scanned is dosed. It prevents “scatter.”
Care kV: This chooses the right amount of kV (basically, the strength of the radiation energy that passes through the body) based on each individual’s body, reducing the dose significantly. kV levels can be automatically selected to fit every patient’s body type, while maintaining excellent image quality.
Care Dose 4D: Automatically adapts radiation dose to the size and shape of the patient. It modulates the dosage as it goes through the thickness of the body.
SAFIRE: Without getting too technical, the program allows staff members to lower the dose even more. Called iterative reconstruction, it interprets a lower dose scan and fills in the pixels.
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