Z-PAKY is a modified version of the PAKY needle driver adapted to implement a CT or MRI registration method in addition to PAKY's needle driving capabilities. The driver was constructed in our laboratory in collaboration with the NSF Engineering Research Center for Computer Integrated Surgical Systems and Technology (CISST) at Hopkins and the University of Tokyo.

Z-PAKY supported by the RCM in a CT scanner test

It includes a Z-shaped Brown-Roberts-Wells localizer frame allowing to calculate the registration of the robot in image space from one single image slice. Phantom tests performed under CT showed that the device provides a fast and accurate registration method for cross sectional image guided stereotaxis. One version of the registration marker (Z-Stage) was constructed of plastics and with tubes filled with imaging contrast. This version is MRI compatible.

For needle insertions along the axis of the scanner (such as for transperineal needle access of the prostate), an adapter containing a Z-Stage registration marker was made to mount on the base of the PAKY needle driver, as presented below.

Z-Stage Registration marker attached to a PAKY needle driver, and a CT slice through the marker