Program Information
A Dose Assessment Summary for Participants in the National Lung Screening Trial Receiving PA Chest X-Ray and Low-Dose CT Examinations
R Kruger1*, C Lee2 , (1) Marshfield Clinic, Marshfield, WI, (2) Radiation Epidemiology Branch, DCEG, NCI, NIH, DHHS, Rockville, MD
Presentations
PO-BPC-Exhibit Hall-9 (Saturday, March 18, 2017) Room: Exhibit Hall
Purpose: The National Lung Screening Trial (NLST) was a multi-center randomized, controlled trial comparing a helical chest CT to a posterior-anterior chest x-ray (CXR) examination in screening older, current and former heavy smokers for early detection of lung cancer. Recruitment was launched in September 2002 and ended in April 2004 when 53,454 participants had been randomized at 33 screening sites in equal proportions. The objective of this study is to provide a comprehensive review of the participant dosimetry investigations and assessments completed using individual NLST participant CT and CXR examinations.
Methods: This study summarizes two independent assessments, a CXR assessment and the findings of a CT investigation calculating individual organ dosimetry values. The CXR assessment reviewed a total of 73,733 chest x-ray participant examinations of which 66,157 were used. The effective dose per entrance skin air kerma (ESAK) for each CXR exam was determined using a Monte Carlo-based program. The CT organ dosimetry investigation collected participant-specific technical parameters from 23,734 NLST CT participants. The study computed body size-specific organ and effective doses using the National Cancer Institute dosimetry system for CT, which is based on dose coefficients derived from a library of body size-dependent adult male and female computational phantoms.
Results: The CXR assessment found a mean effective dose of 0.052 mSv. Organ-specific dose calculations were determined. The CT investigation found a median effective dose with a range of 2.01 mSv to 2.8 mSv (obese to underweight participants).
Conclusion: This study summarizes the individualized doses to major organs and the mean effective dose for 66,157 CXR participant examinations and computed body size-specific organ and effective doses for 23,734 CT NLST participants.
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