Purpose: Remote working developed quickly during the pandemic, and many radiologists had a workstation setup at home to maintain social distancing and to work safely. This study investigates how the setup of the home reading environment can impact low-contrast visibility.
Methods: To understand the factors that impact the reading, five basic factors are considered: (1) The room layout, such as window/light fixture and location, (2) the ambient light level, (3) monitor surface cleanness, (4) clutter in the background, and (5) the reader outfit. Ambient light levels were measured by affordable lux meters with in-house calibration. To quantify the impact of these five factors on low-contrast visibility, a letter-based test pattern was developed to assess minimum detectable contrast at different display background luminance levels. The test pattern was displayed on a consumer-grade monitor, and baseline low-contrast visibility was established in an appropriate reading environment.
Results: Calibration of the affordable lux meter against a NIST traceable calibrated meter showed a linear relationship with a factor of 0.73 (within 10% variances). Increased ambient light level, external light, and specular reflections, and stains made it difficult to see the low contrast letters in dark and white backgrounds. This indicates that radiologists might miss abnormalities when reading under these conditions.
Conclusion: Our results indicate that in-house calibration of an affordable lux meter is feasible, which enables distribution to radiologist reading at home to ensure appropriate ambient light levels. Ambient light not only increases diffuse reflection and degrades the DICOM-14 calibration, but also increases the conspicuity of distracting specular reflections and dirt on display surfaces. The monitor should place in a proper place avoiding reflections from light sources. Also, dark outfits are recommended. A simple step-by-step setup checks minimizing these five factors can help ensure the quality and consistency of remote reading.