title: Evaluation of the particulate concentration in a gelatin-based phantom for sonographically guided lesion biopsy.
abstract: OBJECTIVE
  The purpose of this study was to determine the particulate concentration in a gelatin-based ultrasound phantom for lesion biopsy at 6 cm in depth to reduce visualization of the biopsy needle in the near field, simulating subcutaneous fat and tissue echogenicity, and maintain target lesion visualization.
  
  
  METHODS
  Four gelatin-based phantoms with cornstarch at concentrations of 4, 8, 12, and 16 g/L and an anechoic gelatin target at 7 cm in depth were rated on a 5-point scale by readers for visibility of the target lesion, similarity of near-field to abdominal subcutaneous fat echogenicity, and visibility of a 22-gauge spinal needle in the phantom. A timed sonographically guided localization task was performed on the anechoic target by 4 radiology residents using the 22-gauge spinal needle. Results were analyzed by comparative statistical analysis.
  
  
  RESULTS
  An increasing particulate concentration did not alter the similarity of near-field to abdominal subcutaneous fat echogenicity (P = .6) but did significantly reduce visibility of the anechoic target at a cornstarch concentration of 16 g/L (P = .04) and the 22-gauge needle at 12 g/L (P = .03). Decreased visualization of the needle or target lesion did not affect the time for needle localization of the anechoic target (P = .96).
  
  
  CONCLUSIONS
  The optimal ultrasound phantom cornstarch concentration was 12 g/L to reduce visualization of the spinal needle, simulating subcutaneous fat echogenicity while maintaining target lesion visualization.
authors.affiliation: Department of Radiology, St Vincent's University Hospital, Elm Park, Dublin 4, Ireland. gerstenmaierj@fastmail.us
authors.forename: Jan F
authors.initials: JF
authors.lastname: Gerstenmaier
authors.forename: Colin J
authors.initials: CJ
authors.lastname: McCarthy
authors.forename: David P
authors.initials: DP
authors.lastname: Brophy
authors.forename: Colin P
authors.initials: CP
authors.lastname: Cantwell
mesh_terms: D061765:Endoscopic Ultrasound-Guided Fine Needle Aspiration / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005780:Gelatin / Q000032:analysis / Q000737:chemistry*; D010316:Particle Size; D019047:Phantoms, Imaging; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013213:Starch / Q000032:analysis / Q000737:chemistry*
chemical_list: D005780:Gelatin; D013213:Starch
keywords: biopsy; education; phantom; sonographically guided; training