There are hundreds of non-medical monitors (called COTS (commercial off the shelf) monitors) available in the market that could be considered capable of making it to Radiology-Grade.
Standard home monitors in general do not make the grade even though they may appear to be suitable. For Radiology the monitors of interest are those designed specifically for professionals like graphic designers, photographers, film/video makers, etc. Another market to consider is gaming.
Many of these COTS monitors have been designed to have reasonably high response rates to ensure smooth graphics rendering. For Radiology, the response rate is not of great importance as most routine Radiology applications do not require fast graphic rendering.
Specifications are not always as they appear
The key specifications for Radiology are: panel type; screen size; resolution; brightness; uniformity; grayscale contrast; and connectivity options to your workstation.
Finding COTS monitors that are capable of meeting all these requirements is more difficult than it may appear and information listed on the websites is not always as it may appear.
When conducting our research, the only reliable data you can take from a listed monitor’s specifications are: size; resolution; and panel type. Specifications like brightness; uniformity; grayscale contrast; and connectivity have to be tested.
Even during testing, we have learned that brightness is misleading and requires specific adjustments in the monitor’s properties to ensure they are bright enough. These adjustments make it almost impossible to set the monitor to DICOM Grayscale standard. In fact meeting the DICOM Grayscale standard without using software that can manage the monitor’s brightness and contrast tables is near impossible.
From our experience, the failure rate is at least 95% of those that appear to meet the criteria. This is perhaps why the more expensive traditional monitors are still being bought. Most Radiology Practices don’t have the time or the money to spend (these monitors start at around $800 and can go up to $4500 for the latest 8K monitors) to determine which monitors are the best.
Confidence
The 5% of COTS monitors that did make the grade are built for a professional market and so one thing you can be sure of is that they have a higher than standard home market build quality.
They are designed for commercial use and so are expected to be used for longer than normal domestic use hours.
They also have higher than usual grade graphic connections/interfaces. For example, at least DisplayPort, and some have considerably more powerful Thunderbolt 3 interfaces.
They are also designed with table-driven grayscale, and color settings. Without this capability, setting the monitor to meet a Radiology standard is almost impossible as OSD (on-screen display) settings are not enough to set a monitor precisely enough to meet Radiology Standards.
Resolution
In general HDMI grade or 2k monitors do not have the resolution required to Radiology Standard.
There is however a good range of 3k, 4k, 5k, and now 8k monitors available. All of these will meet most General Radiology Standards. Some standards require at least 4k for mammography.
Brightness
When you search articles and research on the requirement for brightness most of them cite that there is no need to go beyond the brightness of 250 nits.
The Radiology standards have been determined after considerable research into the manufacture of monitors and human’s ability to see changes in the images.
The research has determined that brightness of at least 350 nits is required to observe changes in images that are trying to show certain medical conditions in patients.
For a monitor to reach the minimum levels required for Radiology there is a requirement for at least 350 nits.
The subtle indicators of these conditions could be missed if the monitor is not set optimally.
Uniformity
Uniformity is often not listed as a parameter of a COTS monitor and can only be determined to be acceptable by measurement. Patchy uniformity of brightness distorts the viewer’s image and changes grayscale contrast characteristics.
You can measure a monitor’s uniformity manually, however, we found it to be better to measure using a software-driven uniformity tool.
Not all Radiology Standards specify Uniformity levels to be met. However, we believe it is important to ensure the view of the monitor is consistent throughout the monitor’s panel.
Grayscale
Together with brightness, this is the single most important factor.
Most COTS monitors will not specify DICOM standards. When they do it needs to be tested as monitors electronic properties change with use and time.
We found it almost impossible to set using the OSD setting. You can only really set with any degree of confidence using
Conclusion
Using COTS monitors for Radiology is a no-brainer – they provide a wider variety of brands and drastically reduce the cost of kitting up a Radiology department as they are up to 90% cheaper than traditional Barco and Eizo medical monitors.
COTS monitors are suitable for Radiology, but finding COTS monitors that meet the requirements is not obvious by just looking at a monitor’s specs. They have to be tested.
Setting COTS monitors to meet Uniformity and DICOM standards requires calibration software and tools to achieve. In order to determine whether a monitor meets the requirements, the monitor needs to be tested.