A technique for validating image-guided gene therapy

Delivery of gene therapy by injection remains governed by a limited diffusion distance. We propose the use of image-guidance to increase the accuracy of delivery, allowing for multiple delivery locations within the tumor. An outcome based approach to validation was developed. We have developed a series of optically tracked devices including an optically tracked syringe used for gene therapy delivery. Experiments were designed to quantify the accuracy in recording known points (fiducial localization error) and delivering a substance to a target within a phantom. The second experiment required the design of a rigid structure with mounted fiducials capable of securely holding an apple. This apparatus was CT scanned and targets in the apple we recorded and inserted in the images. The tracked syringe was guided to the target and a small amount of barium was injected. The apparatus was then re-imaged and the distal points of injections were determined. The mounted fiducials allow the two image sets to be registered and the distance between the targets and injection points to be calculated. This experiment was also performed on a rat carcass. The apple possesses no intrinsic traits possible to help guided the syringe to a known location, thus the validation process remains blind to the user.