CT’s Future: What’s New in Dose Reduction

DUBAI – In recent years, much work has been done to improve upon CT, but there are more innovations on the way that will impact providers and augment patient care.

In a presentation Tuesday, during the Arab Health 2020 annual meeting, Shane Foley, Ph.D., associate professor at the University College Dublin School of Medicine, discussed developments in the near future for CT, as well as various steps radiologists and radiographers can take to control radiation dose as best as possible.

“CT contributes roughly two-thirds of the total population dose in medical imaging, so it’s the modality we need to focus our efforts on in terms of radiation protection,” he told Diagnostic Imaging. “The growing use of CT means we must take steps and make sure we are conscious of radiation dose.”

In the coming years, Foley said, photon counting detectors – an emerging technology focused on radiation dose-efficiency, high spatial resolution, and energy discrimination – will revolutionize CT practice. The technology is still in the research stage, but it’s currently being tested at the Mayo Clinic with results that have shown an 80-percent dose reduction.

The goal, he said, is to push CT doses toward 1 mSv, what he called the Holy Grail for dosing.

In addition, there will be other advancements in filters that will help remove softer energy radiation from X-ray beams. When it comes to region-of-interest imaging, technology is under development to change the shape of CT beams to target specific organs, limiting the amount of radiation dose patients receive. It can be particularly useful with certain types of scans, such as cardiac CT, he said.

“Hopefully, filters will allow us to limit the exposure of adjacent organs that aren’t of clinical interest,” he explained. “Breast and lung tissue are two of the most radiosensitive areas in the body, and in a cardiac CT, they’re exposed to the same high dose as the cardiac tissue even though we don’t look at those images.”

There are also several things radiologists can do to maximize dose optimization technologies currently available on most CT scanners, Foley said. For example, they should lower the kilovoltage, particularly for angiographic exams, and they should monitor routine dose levels to identify errant practices. Additionally, based on clinical need, they can use clinical indication-based CT protocols to individualize radiation dose.

Alongside technological advancements and strategies to optimize existing technologies, there are other things providers can do to control radiation dose, Foley said. In addition to following appropriateness guidelines for conducting scans, it’s also important to remember that radiation dose isn’t standardized from one facility to another. According to an article published last year in the British Journal of Radiology, he said, average CT doses can range between 4-to-17 fold based on practice preferences and protocols. Being aware of what other facilities do can help control radiation exposure if patients switch between settings for scans.“Dose monitoring is important, and we have access to automated dose-monitoring software,” he said. “But, taking the simple step of keeping an eye out and comparing the common values in your institution or region can help keep dose in the forefront of your mind and, hopefully, encourage a radiation safety culture.”

Ultimately, he said, radiology, as an industry, has already done a great job at reducing CT dose, and in most cases the clinical benefit of the scan outweighs the risk of radiation exposure. But, providers still must remain vigilant to ensure they’re controlling the radiation dose to safeguard patient safety while providing optimal care.

“I want to reinforce that we can’t be complacent. We’re in an era where we have a volume of data and information available to us. We preach a lot about evidence-based practices, but we must apply this clinically” Foley said. “The industry should remember where we are and the great work that has been done to this point, but radiation protection is a continuous process. We need to pay attention and reinforce it all.”

Hopefully, he said, the continued CT advancements will encourage departments and practices to give everyone – not just one person – shared responsibility for keeping tabs on doses related to CT and other modalities.