Modified Chest X-Ray Radiography through Glass Window for Imaging COVID-19 Pneumonia: Techniques and Radiation Dose

The requirement for infection control during the COVID-19 pandemic led to modifying the exposure parameters in conventional radiography for performing chest X-ray radiography (CXR) through-the-glass (TTG) for imaging COVID-19 pneumonia. Herein, we reviewed and reported the current experiences with the TTG protocol, and summarized the current implementation strategies and modified technique factors. For implementing TTG techniques, measurements are required in a simulated environment using a patient equivalent phantom, and a certain number of investigations must be performed before the patient examination. However, the TTG technique requires modification due to the decrease in photon intensity caused by the attenuation in the glass barrier. This study discussed factors affecting CXR and some related radiation dose terminology required for implementing the TTG technique. Moreover, it summarized the exposure factors of CXR using the TTG technique compared with the standard CXR. Radiation exposure to the patient and the staff using the TTG technique remains within the recommended limits for safe practice. Image quality issues arose following the implementation of the TTG technique, mainly related to suboptimal positioning; image artifacts resulted due to glass attenuation, the increased source-to-image distance (SID), and patient movement. Overall, the reviewed results in this study could help formulate international guidelines and recommendations for the TTG technique for COVID-19 patient imaging, thereby minimizing the cost and time required for setting up the protocol.