FDA, vendors, trade groups tread common path to medical imaging dose reduction

March 24, 2010

Radiologists can anticipate a sea change in the way their facilities monitor and manage CT dose exposure as a series of initiatives now under way begins to bear fruit.

Radiologists can anticipate a sea change in the way their facilities monitor and manage CT dose exposure as a series of initiatives now under way begins to bear fruit.

Next week, the FDA will hold a public hearing on an initiative to better control radiation dose from CT, nuclear medicine, and fluoroscopy studies.

Also planned is a workshop to bring together the FDA, the Medical Imaging Technology Alliance (MITA), and vendors to discuss strategies for reducing dose.

Separately, MITA earlier this year announced two efforts of its own: a listing of eight key principles to be followed in dose reduction efforts, and a software-based radiation dose safeguard program to help CT vendors manage dose.

And in February it was reported that physicians at the National Institutes of Health will begin recording how much radiation patients receive from CT scans and other procedures in their electronic medical records.

“The one thing the practicing radiologist in CT will notice is that there will be more attention paid to dose,” said Richard Morin, Ph.D., chair of the ACR Safety Committee. “It will be a cultural shift. For years the Europeans have been very dose-sensitive, but it hasn’t received the same amount of attention here, except in certain settings, such as pediatrics.”

For now the big push is in CT, where headline stories have revealed damage from excessive dose from CT scans, and studies have shown wide variations in the dose applied to similar studies at different institutions. But other modalities will be covered as well.

Morin, who is also the Brooks-Hollern professor of radiologic physics at the Mayo Clinic in Florida, outlined some of the steps that could be taken by the FDA to call more attention to dose levels.

It used to be that a community hospital could use a CT scanner right out of the box with no changes. The FDA will be taking a close look at labeling and documentation requirements so that operators are more aware of settings, Morin said.

The FDA could also require CT manufacturers to provide more safeguards for protocol setups. That might include requiring special passwords if the protocols are changed. Ideally, it should still be possible to change protocols to accommodate things such as body habitus or special study requirements, but those sorts of changes should not be saved in the scanner. Some facilities do this already, but it’s not a universal requirement, he said.

Another potential change would be to have procedures in place that force the tech to check that the prescribed protocol agrees with the one stored in the machine. There are facilities that do that right now, Morin said. If it’s a big difference, say in a head CT where the mA or pitch had been changed, it could force a “time out” and require more consultations before the scan is performed.

Another thing that’s likely to emerge from all of this are national dose registries. The FDA, in announcing its hearings, endorsed the concept, as did MITA. The ACR, under Morin’s direction, is developing a national dose registry. The idea is to use comparable procedures to establish dose baselines. Once that’s done, facilities can compare their experience with the national experience to see where they are in relation to national norms.

These registries could be tied to CT accreditation programs by requiring a facility to have a program in place to compare its dose levels with registry figures. Under this sort of scheme, over time, as a facility’s quality or safety committee meets and monitors its exposures compared with national levels, the dose range will narrow, Morin said.

“The goal is to narrow the range of exposures for the population and to not use more radiation than is needed to get interpretable images,” he said.

A cornerstone that could make much of this dose control effort possible is the RSNA’s Integrating the Healthcare Enterprise dose profile. Announced in 2008 and rolled out to vendors last year, the profile sets up mechanisms to automatically capture dose 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. See a slide presentation describing the IHE’s radiation exposure monitoring profile.