Abstract
Fluoroscopic C-arms are operated by medical radiography technologists (RTs) in Canadian operating rooms (ORs). While they do receive formal, accredited training, most of it is theoretical, rather than hands-on. During their first encounters in the OR, new RTs can experience difficulty achieving the radiographic views required by surgeons, often needing several scout X-rays during C-arm positioning. Furthermore, ambiguous language by surgeons often inadequately conveys their request. The result is often frustration, unnecessary radiation exposure, and added OR time. The purpose of this study was to evaluate the value of artificial X-rays in improving C-arm positioning performance, with inexperienced C-arm users.
We developed an Artificial X-ray Imaging System (AXIS) that generates Digitally Reconstructed Radiographs (DRRs), or artificial X-ray images, based on the relative position of a C-arm and manikin. 30 participants were enrolled in the user study and performed four activities: an introduction session, an AXIS-guided evaluation, a non-AXIS-guided evaluation, and a questionnaire. The main goal of the study was to assess C-arm positioning performance with and without AXIS guidance. For each evaluation, the participants had to replicate a set of target X-ray images by taking real radiographs of the manikin with the C-arm. During the AXIS evaluation, artificial X-rays were generated at 2 Hz for guidance, while in the non-AXIS evaluation, the participants had to acquire real scout X-rays to guide them toward the correct view.
For each imaging task the number of real X-rays and time required per task was recorded, and the C-arm's pose was tracked and compared to the target pose to determine positioning accuracy; these were averaged for each participant and condition. Hypothesis testing on the means and paired t-tests were carried out using a significance level of α=0.05.
On average, users took significantly fewer real scout X-ray images (53% fewer (2.8 vs 6.0), p<0.001) when guided by AXIS. Lateral distance accuracy was improved by 10% for final C- arm positions and by 26% for the most accurate intermediate C-arm positions when guided by AXIS (p<0.05). There was no significant difference in average task time or angular accuracies between the AXIS and non-AXIS evaluations. Overall, we are encouraged by these findings and plan to further develop this system with the goal of deploying it both for training and intraoperative uses.
