title: Guidelines for anti-scatter grid use in pediatric digital radiography.
abstract: BACKGROUND
  Pediatric radiography presents unique challenges in balancing image quality and patient dose. Removing the anti-scatter grid reduces patient dose but also reduces image contrast. The benefit of using an anti-scatter grid decreases with decreasing patient size.
  
  
  OBJECTIVE
  To determine patient thickness thresholds for anti-scatter grid use by comparing scatter-to-primary ratio for progressively thinner patients without a grid to the scatter-to-primary ratio for a standard adult patient with a grid.
  
  
  METHODS
  We used Solid Water™ phantoms ranging in thickness from 7 cm to 16 cm to simulate pediatric abdomens. The scatter-to-primary ratio without a grid was measured for each thickness at 60 kVp, 70 kVp and 80 kVp for X-ray fields of view (FOV) of 378 cm(2), 690 cm(2) and 1,175 cm(2) using indirect digital radiography (iDR) and computed radiography (CR). We determined thresholds for anti-scatter grid use by comparing the intersection of a fit of scatter-to-primary ratio versus patient thickness with a standard adult scatter-to-primary ratio measured for a 23-cm phantom thickness at 80 kVp with an anti-scatter grid. Dose area product (DAP) was also calculated.
  
  
  RESULTS
  The scatter-to-primary ratio depended strongly on FOV and weakly on kVp; however DAP increased with decreasing kVp. Threshold thicknesses for grid use varied from 5 cm for a 14 × 17-cm FOV using iDR to 12 cm for an 8 × 10-cm FOV using computed radiography.
  
  
  CONCLUSIONS
  Removing the anti-scatter grid for small patients reduces patient dose without a substantial increase in scatter-to-primary ratio when the FOV is restricted appropriately. Radiologic technologists should base anti-scatter grid use on patient thickness and FOV rather than age.
authors.affiliation: Department of Imaging Physics, The University of Texas, M. D. Anderson Cancer Center, 1400 Pressler St., Houston, TX, 77030, USA, shannon.fritz@gmail.com.
authors.forename: Shannon
authors.initials: S
authors.lastname: Fritz
authors.forename: A Kyle
authors.initials: AK
authors.lastname: Jones
mesh_terms: D002648:Child; D019544:Equipment Failure Analysis; D005374:Filtration / Q000295:instrumentation / Q000379:methods; D006801:Humans; D010372:Pediatrics / Q000592:standards*; D019047:Phantoms, Imaging; D017410:Practice Guidelines as Topic; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000295:instrumentation* / Q000592:standards*; D011871:Radiology / Q000592:standards*; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D014481:United States; D014965:X-Rays