Assisted needle guidance using smart see-through glasses

摘要

Accurate needle placement largely depends on physicians' visuospatial skills in CT-guided interventions. To reduce the reliance on operator experience and enhance accuracy, we developed an augmented reality system using smart see-through glasses to facilitate and assist bedside needle angle guidance. The AR system was developed using Unity and Vuforia™ SDK. It displays the planned needle angle on the glasses' see-through screens in real-time based on the glasses orientation. The displayed angle is always referenced to the CT table and independent from the physical orientation of the glasses. The see-through feature allows the operator to compare the actual needle and the planned needle angle continuously. The glasses' orientation was tracked by its built-in gyroscope. The offset between the embedded gyroscope and the glasses' display frame was pre-calibrated. A quick one-touch calibration method between the glasses and CT frame was implemented. Hardware accuracy and guidance accuracy was evaluated in phantom studies. In the first test, a needle was inserted in the phantom and scanned with CT. The measured angle in the CT scan was set on the glasses. We took a snapshot from the lens and compared the needle vector and guideline in the saved snapshot. The hardware accuracy was within 0.98 ± 0.85 degree. In the second test, after each insertion guided by the glasses, a CT scan was taken to validate the insertion angle error. The accuracy of the guidance was within 1.33 ± 0.73 degree. Smart glasses can provide accurate guidance for needle based interventions with minimal disturbance of the standard clinical workflow.