Robotic C-arm Research Articles

Accuracy of electromagnetic tracking with a prototype field generator in an interventional OR setting

The authors have studied the accuracy and robustness of a prototype electromagnetic window field generator (WFG) in an interventional radiology suite with a robotic C-arm. The overall purpose is the development of guidance systems combining real-time imaging with tracking of flexible instruments for bronchoscopy, laparoscopic ultrasound, endoluminal surgery, endovascular therapy, and spinal surgery. The WFG has a torus shape, which facilitates x-ray imaging through its centre. The authors compared the performance of the WFG to that of a standard field generator (SFG) under the influence of the C-arm. Both accuracy and robustness measurements were performed with the C-arm in different positions and poses. The system was deemed robust for both field generators, but the accuracy was notably influenced as the C-arm was moved into the electromagnetic field. The SFG provided a smaller root-mean-square position error but was more influenced by the C-arm than the WFG. The WFG also produced smaller maximum and variance of the error. Electromagnetic (EM) tracking with the new WFG during C-arm based fluoroscopy guidance seems to be a step forward, and with a correction scheme implemented it should be feasible.

Achieving super‐resolution X‐ray imaging with mobile C‐arm devices

The term super-resolution refers to the process of combining a set of low-resolution images into a high-resolution image using image processing methods. This work is concerned with the reconstruction of high-resolution X-ray images. Specifically, we address the problem of acquiring X-ray images from multiple, very close view points. We propose to use a novel experimental robotic C-arm device to create high-resolution X-ray images. For this purpose, we suggest different strategies for acquiring multiple low-resolution images, and we provide the steps to achieve acquisition-error compensation. Compared to visible light images, X-ray images have the particularity that parallax effects render super-resolution very difficult. Using the acquired multi-frame data, we evaluate recent well-known super-resolution reconstruction algorithms. The same algorithms are evaluated based on synthetic 3D phantom data and real X-ray images. In experiments with both synthetic and real projection data, we successfully reconstruct up to four times higher-resolution images. These images reveal structures and details which are not perceivable in the low-resolution images. The advantage of super-resolution techniques for X-ray is the potential reduction of radiation dose for patients and medical personnel. Potential medical applications include the diagnosis of early-stage osteoporosis and the detection of very small calcifications.