title: An in-vitro study to understand successful free-hand ultrasound guided intervention.
abstract: OBJECTIVE
  To describe the optimum conditions for successful free-hand ultrasound guided intervention using an in-vitro experiment.
  
  
  METHODS
  Optimal free-hand biopsy conditions were determined using targets buried in a purpose-built interventional phantom. The needle/probe distance and probe/phantom surface angle were changed whilst recording the needle track lengths and needle conspicuity.
  
  
  RESULTS
  Optimal free-hand conditions included a needle/probe distance of 2-3 cm in combination with a needle/probe angle 55-60 degrees. This enabled excellent needle conspicuity with short needle track length and early needle tip visualization.
  
  
  CONCLUSIONS
  Understanding how to optimize the free-hand conditions will help the interventionalist to obtain greater performance using a variety of puncture devices. This concept is likely to be particularly important to the novice interventionalist as well as to those teaching the free-hand technique.
authors: Department of Clinical Radiology, Southmead Hospital, Bristol, Westbury-on-Trym, BS10 5NB, U.K.
authors: M J
authors: MJ
authors: Bradley
mesh_terms: D001707:Biopsy, Needle / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D019047:Phantoms, Imaging; D012044:Regression Analysis; D018084:Ultrasonography, Interventional / Q000295:instrumentation / Q000379:methods*