Monitoring Cumulative Dose from Multiple CT Scans

new study presented at the American Roentgen Ray Society (AARS) meeting brought attention to another key point in radiation dose reduction. Currently, a majority of the focus on cutting CT scan radiation is centered on dosage levels, but it is also important to monitor cumulative dosage in patients receiving multiple scans. While government and industry are increasingly focused on single CT scan dosage reduction (which is great news!), there is a lesser concern for decreasing the overall number of CT scans for patients.

The research tracked the amount of repeated CT exams performed on patients in order to calculate cumulative radiation dosage. Some of the results are shocking. The study identified a group of patients from the test population undergoing more than 20 medical imaging exams in one year, and as a result, being exposed to high cumulative dosage—more than 300 mSv per annum!  In fact, one patient received 70 different scans in one year!

This is, of course, something we are working to mitigate continuously. Europe (EEU) has been tracking the cumulative dose of its citizens for about 10 years—by law! This is certainly a good thing for patients and in the U.S, we are beginning efforts towards this direction. Several products are now available that serve as a repository for dose from devises and particular protocols, to keep track for individual patients (including cumulative).

We recently purchased such a product (DoseWatchGE Healthcare) which will be integrated with our RIS and connected to every radiation emitting device in our medical center. This product will pick up cases of unusually high cumulative dose in patients, but also identify protocols which have high dose or devices which are emitting high dose. We are looking forward to implementing DoseWatch a few months from now.

Be sure to check back regularly as we document our experience with the product.

UW’s Team Approach to Radiation Dosage Reduction

A recent article published in the American Journal of Roentgenology touched on the importance of taking a team wide approach to CT radiation dose reduction. While CT only account for about 15 percent of diagnostic imaging exams, it is responsible for contributing up to 70 percent of radiation dosage to the population, according to this study. Hence, the reason why it’s imperative to have the whole team on board when it comes to reducing CT scan radiation exposure in patients.

Ensuring that CT exams are appropriate is a critical component of overall dose reduction. At UW, we use a computerized Decision Support program, which acts at the point of Computerized Physician Order Entry (CPOE) to check appropriateness. Radiologists also double-check at the time of electronic protocoling.

At the time of the scan, the use of external body shields – including breast shielding – is important. Additionally, patient centering in the gantry is critical and can lower dose by as much as 40% compared to off-center exams. The routine use of iterative reconstruction technique – compared to the older FBP – can further substantially lower dose.

By having low- dose protocols and procedures set in place, we can be sure that we are providing our patients with the safest, most effective imaging procedures!