Patient-specific templates for image-guided intervention - a phantom study

Abstract

Purpose: To evaluate the in vitro accuracy of a new device and method for simultaneous stereotactic CT-guided punctures.

Material and methods: 240 needle paths were planned in 1 mm, 1.5 mm and 3 mm slice thickness with a custom-designed software. The data were transferred to a three-axis tabletop CNC machine that then drilled the hole pattern for the needles into square plastic plates. Kirschner wires were slid through the holes of the two parallel fixed plates to aim at the chosen targets inside the phantom. The accuracy was calculated by taking control CTs and measuring the Euclidean distance and the normal distance between the wire and the entry and target point.

Results: The mean Euclidean distance of the wire tip to the target for the 1 mm, 1.5mm and 3 mm slice thickness were 2.5 mm (SD ± 0.64), 2.71mm (SD ± 0.78) and 2.8 mm (SD ± 1.0). The mean normal distance was 1.42 mm (SD ± 0.65), 1.43mm (SD ± 0.75) and 1.9 mm (SD ± 1.1), respectively.

Conclusion: The system yields satisfactory accuracy comparable to other image-guided intervention systems. Involuntary movements of the patient need to be taken into account in a clinical setting.

Keywords:

• Percutaneous
• radiofrequency ablation
• phantom study
• accuracy evaluation

Acknowledgements

We would like to thank Andras Lasso and Gabor Fichtinger of the Department of Computer Science Queens University for assistance with the planning software used in this study.

Declaration of interest

Neil Glossop has a financial and business interests in a company (ArciTrax Inc.) that may be affected by the research reported in the enclosed paper.

The other authors do not have any conflicts of interest.