A Precision System for Computed Tomography-Guided Needle Placement in the Thorax and Abdomen—Technical Design and Performance Analysis

Background A system was developed for CT-guided needle placement in the thorax and abdomen, providing precise aiming of a needle guide to reach a user-specified target in a single manual insertion. The objective of this work is to present its technical design and analyze its performance in terms of placement error in air. Methods The individual contributions to the placement error of a fiducial marker based system-to-CT registration system, a 2-DOFs drive system to aim the needle guide, and a structural link between needle guide and CT table were experimentally determined, in addition to the placement error of the overall system. Results An error contribution of 0.81±0.34 mm was determined for the registration system, <1.2 mm and <3.3 mm for the drive system, and 0.35 mm and 0.43 mm for two load cases of the structural link. The overall unloaded system achieved 1.0±0.25 mm and 2.6±0.7 mm at 100 mm and 250 mm depth respectively. Conclusions The overall placement errors in air do not exceed the =5 mm error specified as a clinical user requirement for needle placement in tissue.