Aims: To describe the optimum conditions for successful free-hand ultrasound guided intervention using an in-vitro experiment.
Materials and 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.
Conclusion: 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.