Patients with scoliosis receive low-dose X-rays at the Northern California Shriners Hospital. Young patients liken the X-ray unit to a spaceship. Parents are often surprised at how quick and efficient it is – capturing AP and lateral view images at the same time.
EOS technology is something of a wonder.
The low-dose X-rays are of great reassurance to the patients and their parents, as patients with scoliosis generally get many, repeated X-rays during their lifetimes, and the exposures add up.
An image captured by the machine, an EOS imaging unit, is reported to use about 70-80% less radiation than a digital X-ray — approximately 0.5 millisieverts, versus 2.5 millisieverts for a regular spine X-ray. And, once a patient has an initial scan, the machine is often dropped down to a microdose setting that exposes the patient to just a 50th of the amount of radiation.
The technological advance behind the machine is based on a more sensitive detector – a multiwire proportional chamber – invented in the late 1960s at the European Laboratory for Particle Physics (CERN), Geneva, Switzerland, by Georges Charpak, an invention for which he won the Nobel Prize. Charpak went on to found the imaging company that became EOS in 1989, and began selling medical imaging systems to hospitals in 2008.
Experts debate about whether the risk of cancer from ionizing radiation exposure is something that is cumulative, and can add up to an appreciable risk with many low dose exposures, or whether the risk is only significant when you get a high-dose exposure from something like a CT machine.
But it is estimated that Americans’ exposure to ionizing radiation has doubled since 1980, and that most of the excess comes from medical imaging.
Studies examining the link between cancer in scoliosis patients and imaging appear to confirm a correlation of increased cancer risk. In one Danish cohort study, patients with scoliosis were found to have a five-times higher cancer risk – breast and endometrial primarily – than the general Danish public (Eur Spine J 2016;25:3366-70).
All of which is why Shriners Hospitals for Children — Northern California is so grateful to the generous donors whose gifts allowed the purchase of the EOS unit and remodeling of the hospital imaging suite to accommodate the new machine. The EOS system is not yet widely available – with only nine units in California.
For Shriners Hospitals for Children — Northern California, obtaining the EOS unit was practically essential. Last year, nearly 500 patients were referred to the hospital for scoliosis and that number continues to grow. Images are taken with the patient standing, and both a lateral and an AP view are captured at the same time. This helps with throughput in the hospital’s busy imaging department. And clinicians think that having onsite low-dose imaging has proved better for patients’ long-term care.
To be imaged, patients simply step into the unit, line themselves up with the markings on the floor and in front of them, and hold on to a bar that helps them remain stable. That simplicity makes running the unit highly efficient.
Erick Sencil, MBA, manager of diagnostic imaging at the Northern California Shriners Hospital, said that the look of the unit, with its bright orange and yellow letters and stripes on the sides — coloring so vibrant the big boxy unit almost seems to glow — actually has a benefit. “It relaxes kids a little more,” he said. “They think it looks like a space ship.” Last year, the hospital’s unit was one of the two busiest EOS units in the country west of Chicago, with an average of 22 scans per week, according to EOS imaging’s customer program director Aaron Cook.
“It’s just the right thing to do,” Mr. Sencil said. “It’s the right thing to do because it is so lowdose. It’s the right thing to do because kids aren’t afraid in there. It’s the right thing to do because the image quality is so good.”