title: Effect of radiation dose level on the detectability of pulmonary nodules in chest tomosynthesis.
abstract: OBJECTIVE
  To investigate the detectability of pulmonary nodules in chest tomosynthesis at reduced radiation dose levels.
  
  
  METHODS
  Eighty-six patients were included in the study and were examined with tomosynthesis and computed tomography (CT). Artificial noise was added to simulate that the tomosynthesis images were acquired at dose levels corresponding to 12, 32, and 70% of the default setting effective dose (0.12 mSv). Three observers (with >20, >20 and three years of experience) read the tomosynthesis cases for presence of nodules in a free-response receiver operating characteristics (FROC) study. CT served as reference. Differences between dose levels were calculated using the jack-knife alternative FROC (JAFROC) figure of merit (FOM).
  
  
  RESULTS
  The JAFROC FOM was 0.45, 0.54, 0.55, and 0.54 for the 12, 32, 70, and 100% dose levels, respectively. The differences in FOM between the 12% dose level and the 32, 70, and 100% dose levels were 0.087 (p = 0.006), 0.099 (p = 0.003), and 0.093 (p = 0.004), respectively. Between higher dose levels, no significant differences were found.
  
  
  CONCLUSIONS
  A substantial reduction from the default setting dose in chest tomosynthesis may be possible. In the present study, no statistically significant difference in detectability of pulmonary nodules was found when reducing the radiation dose to 32%.
  
  
  CONCLUSIONS
  • A substantial radiation dose reduction in chest tomosynthesis may be possible. • Pulmonary nodule detectability remained unchanged at 32% of the effective dose. • Tomosynthesis might be performed at the dose of a lateral chest radiograph.
authors.affiliation: Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE-41345, Gothenburg, Sweden, sara.asplund@vgregion.se.
authors.forename: Sara A
authors.initials: SA
authors.lastname: Asplund
authors.forename: Åse A
authors.initials: ÅA
authors.lastname: Johnsson
authors.forename: Jenny
authors.initials: J
authors.lastname: Vikgren
authors.forename: Angelica
authors.initials: A
authors.lastname: Svalkvist
authors.forename: Agneta
authors.initials: A
authors.lastname: Flinck
authors.forename: Marianne
authors.initials: M
authors.lastname: Boijsen
authors.forename: Valeria A
authors.initials: VA
authors.lastname: Fisichella
authors.forename: Lars Gunnar
authors.initials: LG
authors.lastname: Månsson
authors.forename: Magnus
authors.initials: M
authors.lastname: Båth
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055613:Multiple Pulmonary Nodules / Q000000981:diagnostic imaging*; D012372:ROC Curve; D013902:Radiography, Thoracic / Q000379:methods*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult