RSNA's integration effort tackles radiation exposure

September 1, 2009

You may think you are tracking your CT, x-ray, and mammography dose exposures, but do you really have current, accurate data?

You may think you are tracking your CT, x-ray, and mammography dose exposures, but do you really have current, accurate data? The view from the RSNA's Integrating the Healthcare Enterprise initiative is, probably not. And if you do, you're probably spending more time and effort on it than you'd like.

The initiative's answer: an implementation guide that, if adopted by equipment vendors, would allow an unprecedented level of radiation dose monitoring across time spans, patient and procedure groups, communities, and even the country.

Launched in 2008 and now being rolled out to the vendor community, the IHE Radiation Exposure Monitoring (REM) profile is the one of the latest elements in a more than decade-long effort by the RSNA to promote cross-vendor integration of digital imaging and related data.

It relies on existing dose estimation and collection methods, but sets up mechanisms to automatically capture that information and make it part of the patient record in the PACS. The collected information, in addition to dose, includes details about the order, the procedure, the patient, the equipment, and the anatomy.

Once captured, it can be mined and analyzed to identify trends in radiation dose exposure. Did a new CT imaging protocol actually reduce overall dose exposures? How did the weekend team do in controlling dose compared with the weekday team? What's the dose exposure for a particular patient or category of patients?

And, at the request of the ACR and the Department of Veterans Affairs, a feature is included that will allow the system, with the permission of the site, to anonymize the data and send them to a central repository. The ACR would like to collect data from cooperating facilities to better understand actual dose rates and set national standards.

At this point, the REM profile covers CT, angiography, fluoroscopy, and projection x-ray, but not nuclear medicine or radiation therapy procedures. Those could be undertaken later, said Kevin O'Donnell, a senior manager for systems development at Toshiba who led the effort to create the profile for the IHE.

The role of the IHE profile is to develop protocols that will allow dose data to be collected consistently across different vendors' products.

“The problem the profile solves is how you collect dose information from the various modalities and pull that together where it can be accessed, queried, searched, sorted, and put into a system that's going to do whatever analyses you want to do, in terms of trending, averages, and the like,” O'Donnell said.

He spoke during a presentation at the Society for Imaging Informatics in Medicine earlier this year.

“If you write into an RFP that the equipment you're buying must support a dose-monitoring program, you've only stated a broad intent. But if you specify it must support the IHE REM Profile, those three words bring in about 100 pages of standardized detail on how it should work,” he said.

The dose profile is based on DICOM structured reports, which are standard DICOM objects already familiar to most PACS, O'Donnell said. The profile also gives sites the option to have modalities send the dose objects to a dose-reporting system independent of the PACS.

The report granularity goes down to each irradiation event. In a CT report you'll have one entry for the scanogram and another for each scan run within the series. With angiography, every pedal push gets recorded, its length, its energy, and the table position. In mammography or plain x-ray, each frame is an entry.

A number of vendors are working to adopt the dose-monitoring profile, and Agfa, GE, Siemens, Krucom, EDL, Infimed, MedicalCommunications, and Softway Medical have already cross-tested their implementations at IHE Connectathons earlier this year, O'Donnell said.