In February, the FDA announced a new initiative to reduce unnecessary radiation exposure from CT, nuclear-medicine, and fluoroscopy exams. The agency’s three-pronged approach will include issuing safeguard requirements for device manufacturers, incorporating quality-assurance measures in mandatory CMS accreditation for imagers, and creating national dose registries to aid in the development of diagnostic-radiation reference levels.
For imaging centers and hospitals, the renewed focus on radiation creates a conundrum: How can cumulative dose be efficiently and effectively tracked?
“Both the PACS and the RIS need to be involved because one of the problems is including information from previous exams.”
—Steven Horii, MD, professor of radiology and clinical director of medical informatics
University of Pennsylvania, Philadelphia
“For old film-based studies where we don’t have radiation exposure in a machine-readable form, we can compute an average dose based on the exam type, but the PACS holds the images with the DICOM headers, whereas the RIS has the historical record of all exams done and may extend back to before there was a PACS,” Horii explains.
Horii adds that DICOM has the elements necessary to transmit dose information, but there’s no database or archival standard for the information. “There are elements in the DICOM standard that will allow for communicating radiation exposure,” he says, “but we’re asking to have a lifelong record for the patient. That’s a huge length of time, so it’s a real challenge.”
Another challenge is determining what, exactly, dose and exposure mean, and standardizing the definitions so that all stakeholders are using the same language. “Do we mean skin dose or absorbed dose?” Horii asks. “What do we mean by exposure? Is it only medical exposure? What about people who are occupationally exposed? We have to agree on what is meant by these numbers so they can be compared.”
If the challenge can be broken into two parts—determining how to transmit dose information and then determining how to track it—vendor cooperation is essential to achieving the first component effectively, Horii says. He compares the standardization of dose information to the advent of DICOM in the early 1990s.
“With DICOM, the FDA said that it could mandate the adoption of this standard or it could make it voluntary, and the vendors decided they’d much rather do it voluntarily,” he says. “Integrating the Healthcare Enterprise and vendor groups like NEMA can put pressure on vendors to include dose data. Some of them put these data in private elements, but I think they could all be encouraged to put the data in standard groups and elements.”
When it comes to the second component of the challenge, keeping track of dose information for many years and across multiple locations, Horii sees one promising route: cloud storage.
“I think that’s going to be what it takes: a system where you can push information to the cloud, no matter where you are,” he says. “Microsoft has done something like this with its HealthVault. The question is what kind of business model that is. How do you make money from it?” Horii suspects that third-party companies will write applications that upload dose information to cloud-based medical records, and the cloud providers will charge them for the privilege—a model along the lines of that offered by Apple with the iPhone.
“We’re looking at a record that has to be updated, potentially, every time a patient has radiography,” Horii says. “That’s a real challenge, but there are certainly applications that can do it. It’s going to take some hard work on the informatics side, but I think we will get there.”
Cat Vasko is editor of Medical Imaging Review.