Cutting CT radiation dose should be the goal of every medical imaging facility. A new paper in European Radiology offers a promising technique that slashed CT dose to one-tenth of conventional CT – and just twice that of a standard chest X-ray.
CT’s wide availability, excellent image quality, and relatively low cost make it an invaluable modality for many clinical applications.
- CT proved particularly useful during the COVID-19 pandemic for diagnosing lung pathology caused by the virus, and it continues to be used to track cases of long COVID.
But patient monitoring can involve multiple CT scans, leading to cumulative radiation exposure that can be concerning, especially for younger people.
- Researchers in Austria wanted to see if they could use commercially available tools to produce ultra-low-dose CT scans, and then assess how they compared to conventional CT for tracking patients with long COVID.
Using Siemens Healthineers’ Somatom Drive third-generation dual-source CT scanner, they adjusted the parameters on the system’s CAREDose automated exposure control and ADMIRE iterative reconstruction to drive down dose as much as possible.
- Other ultra-low-dose CT settings versus conventional CT included fixed tube voltage (100 kVp vs. 110 kVp), tin filtration (enabled vs. disabled), and CAREDose tube current modulation (enabled – weak vs. enabled – normal).
They then tested the settings in a group of 153 patients with long COVID seen from 2020 to 2021; both ultra-low-dose and conventional CT scans were compared by radiologists, finding …
- Mean entrance-dose radiation levels with ultra-low-dose CT were less than one-tenth those of conventional CT in (0.21 mSv vs. 2.24 mSv); a two-view chest X-ray is 0.1 mSv
- Image quality was rated 40% lower on a five-point scale (3.0 vs. 5.0)
- But all ultra-low-dose scans were rated as diagnostic quality
- Intra-reader agreement between the two techniques was “excellent,” at 93%
The findings led the researchers to conclude that ultra-low-dose CT could be a good option for tracking long COVID, such as in younger patients.
The Takeaway
The study demonstrates that CT radiation dose can be driven down dramatically through existing commercially available tools. While this study covers just one niche clinical application, such tools could be applied to a wider range of uses, ensuring that the benefits of CT will continue to be made available at lower radiation doses than ever.
