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Radiation doses for lung cancer screening CT scans vary across centers
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Many facilities exceed recommended radiation doses for lung cancer screening CT scans. However, institutions following protocols set by a lead radiologist or internal medical physicist had lower doses, according to a study published in JAMA Internal Medicine.
“If CT scans are performed with higher radiation dose than recommended, this will limit the margin of benefit of lung cancer screening,” Joshua Demb, PhD, MPH, a postdoctoral scholar from the Moores Cancer Center at the University of California, San Diego, told Healio Primary Care. “While the risk of radiation-induced cancer from CT is in general lower than the benefit conferred from finding lung cancer early through low-dose lung cancer screening, the risks of radiation-induced cancer rises when doses rise.”
Lung cancer screening CT radiation dose data were collected from institutions in the United States that were included in a University of California, San Francisco registry.
Researchers used mean volume CT dose index (CTDIvol) to measure average radiation dose and mean effective dose to show the estimated future cancer risk from the full radiation dose received in the scan.
A total of 12,529 patients with a median age of 65 years who had lung cancer screening CT scans at 72 institutions were included in analyses. Among the institutions, 21% had median CTDIvol and 65% had median effective doses above those recommended in the American College of Radiology guidelines.
Compared with locations that only allowed lead radiologists to establish dose protocols, those that allowed any radiologist to create protocols had higher mean CTDIvol (mean dose difference = 44%; 95% CI, 19-69) and higher mean effective dose (mean dose difference = 27%; 95% CI, 5-50).
Researchers also found that institutions that had protocols established by a lead radiologist had lower odds of going over guidelines for CTDIvol compared with those who allowed any radiologist to create protocols (OR = 0.01; 95% CI, 0.001-0.1).
In addition, centers that employed internal medical physicists rather than external physicists were associated with lower CTDIvol doses.
“Our findings underscore the need for radiology practices to evaluate their current protocols, ensure that there is standardization and that they have a process/system installed that can limit such wide variation in radiation doses for a scan as specific as the low-dose lung cancer screening scan,” Demb said. – by Erin Michael
Disclosure: Demb reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.