The Covid-19 pandemic has forced many Radiologists to work from home. This guide outlines some easy steps to set up a reporting room and computer display that meets professional standards.
Radiology Display Calibration
Setting up a display that meets professional radiology standards for home reporting can be achieved easily and cost-effectively if some basic room lighting, display selection, and display calibration guidelines are followed. There are a number of simple tricks and tips for improving ergonomics and fine-tuning visual performance that are worth taking the time to implement. With attention to detail, a home reporting station that meets or exceeds professional standards can be easily set up.
Important note: This guide is for all modalities except Mammography which has its own specific requirements not covered in this guide.
Room Lighting
Frequently neglected, reflections from ambient light around diagnostic displays has a strong influence on contrast perception. A radiologist viewing an image may not be conscious of the reflections but it is easy to demonstrate the effect reflections have on their ability to perceive changes in image contrast. The simple solution is to keep ambient light levels low and minimise reflections off the display.
- Locate displays in rooms where ambient lighting can be kept as close to 20 lux as comfortable. (The recommended range is 20 lux to 75 lux). If you don’t have a photometer, try the "Black Shoelace Test".
Tip: The Black Shoelace Test
If you are wearing black lace-up shoes, you should be able to see that you have your shoes on but difficult at a glance to see if your laces are done up. That is, dim but enough light to work comfortably and clearly see the keyboard but as low as you are comfortable working in.
Eliminate Reflections & Other Sources of Glare
To check for reflections simply turn the display off and look for them on the display surface from a normal reading position. Eliminate as many reflections as possible e.g. by facing the display away from windows or moving the offending light source. Other computer displays with bright colour themes can contribute to reflections and high ambient luminance. Similarly, bright light sources in your peripheral vision can reduce visibility and should be minimised. e.g. switching off, replacing light bulbs with low output variants etc
- Turn the display off, or view a black image and look for and eliminate visible reflections from the display that are seen while viewing at a normal reading position. Eliminate extraneous sources of glare.
Display Selection
This is often the most problematic part of establishing a professional setup, and advice from your colleagues, PACS support, PACS vendor and medical physicist will be helpful in identifying a suitable choice.
Different professional groups have outlined performance specification for radiology displays. Some of the key specification from the ACR/RANZCR/RCR recommendations are summarised below.
Professional Display Specifications
| Specification | ACR | RANZCR | RCR | Highest Spec |
|---|---|---|---|---|
| Source | ACR–AAPM–SIIM TECHNICAL STANDARD FOR ELECTRONIC PRACTICE | Standards of Practice for Clinical Radiology | Standards for interpretation and reporting of imaging investigations | - |
| Published | 2017 | 2020 | 2018 | - |
| Matriz Size | - | >= 3MP | 1600x1200 (2MP) min | >=3MP |
| Pixel Pitch | approx 0.2 (<0.21) | - | 0.25 | approx 0.2 (<0.21) |
| Modes | - | - | Colour | Colour |
| Orientation | - | - | Landscape or Portrait | - |
| Max Lumiance | 350 cd/m2 | >=350 cd/m2 | 250 | 350 cd/m2 |
| Min Lumiance | 1.0 cd/m2 | 1.0 cd/m2 | 1 | 1.0 cd/m2 |
| Luminance Ratio | 350 | >250:1 | 250 | 350 |
| Grey Scale Calibration | DICOM GSDF (+/-10%) | DICOM GSDF (+/-10%) | DICOM GSDF (+/-10%) | |
| Luminance uniformity | - | <30% | - | <30% |
| Ambient Reflection (Lamb) | 1/4 Lmin | - | - | 1/4 Lmin |
| Bit Depth | 8 bit | 8 bit | - | 8 bit |
| Modalities | US/CR/DR/CT/MRI | US/CR/DR/CT/MRI | US/CR/DR/CT/MRI | All except Mam |
| Aspect Ratio | 3:4 or 4:5 | - | - | 3:4 or 4:5 |
Table 1: Key performance requirements from 3 different professional standards
Other Display Selection Considerations
- Compatability with the image display software you use when reporting.
- Different display panel technology has significant viewing angle performance differences and can have a marked influence on observer contrast sensitivity. IPS panel types generally perform adequately.
- Be aware the stated brightness and the actual out of the box brightness can vary significantly.
- 8 bit or 10 bit colour modes are generally both ok.
- Ignore the"Peak Brightness" specification quoted in some specifications and use the "Average Brightness". The peak brightness typically relates to a cinematic mode and is of no relevance to radiology.
Ergonomic Considerations
- A thin bevel around a display panel is less distracting if you want to use dual displays side by side.
- The lower the display panel reflective index the better, although this often isn't published in the specification.
- Shrouds for reducing light scatter are available and may be of use for a single display setup.
- Rather than using the stand packaged with the display, a desk mounted single or duel VESA mounting arm may allow for more flexibility in positioning and improved ergonomic configuration.
- Consider power consumption and energy efficiency rating.
- Use a backlit keyboard to make it easy to type in low lighting conditions e.g Logitech MX Keys
- Add bias lighting to the back side of the display to illuminate the room with the ligh source hidden from direct view e.g MediaLight Mk2 Eclipse, there are plenty of others
- Add a dark themed wallpaper to reduce glear from secondary displays e.g MyXrayDose Resource Page
The computer display market is fast-moving and there are offerings from most manufacturers that will meet the requirements in the highest specifications column in table 1 above. The list includes but is not limited to LG, Dell, HP, Samsung, EIZO, Barco, BenQ, Asus.
A search of my local computer retailer revealed a number of possible suitable choices, for example, the Dell U3219Q and the LG 32UL950-W.
Discussing the selection with your IT support can save a lot of post-purchase pain.
Display Calibration
To achieve a consistent presentation of greyscale images the displays need to have the same luminance characteristics. This is performed by calibrating the display to the standard DICOM Part 14 Greyscale Display Function while taking into account the ambient luminance, minimum luminance and maximum luminance. This requires software combined with a suitable photometer to measure the display characteristics, calculate a correction table and apply the table to correct the display to the DICOM Standard. We have developed a downloadable application called ViewIQ which works with an X-Rrite photometer (OEM version only) that we are able to supply for performing this calibration.
Tips for improving performance
Tip: The graphics card should be set to drive the display in its native resolution to get best resolution performance from the display.
Tip: Only use digital outputs and connections between the graphics card and the display. i.e A Display Port, or DVI-D to prevent the signal distortion possible with analogue connections.
Tip: Apply Dark Themes to other displays in the reporting area.
Set the display of other nearby displays to a Dark theme to reduce glare and reflections on adjacent image displays
Windows 10: To Change to a Dark Colour Theme
Right Click on the screen. Click Personalise, then Colours, then in the “Choose your colour” dropdown select Dark.
Tip: Apply Dark Background to other displays in the reporting area.
Windows 10: To Change to a darker Background image
Right Click on the screen. Click Personalise, then Background and then either choose a dark themed image or darker colour background.
Note: Some experimenting with this may be needed as may not work with colours of menus on some of your applications.
Final Checks
Run some final checks of performance. Either download the free test image generation application from here, or click on these links to the web versions of the test images below:
- Display black image and then look for reflections;
- Check the greyscale calibration and room lighting;
- Set the optimal viewing angle by adjusting the image sequence until the first letter visible appears. The tilt the display until the letters are best displayed over the diagnostically useful area of the display;
- Display A Very Simple Test final overall check of performance.
For more information on this service please visit the ViewIQ Display calibration page.
Parting Comments
- Room Lighting & reflections
- The display black level being too dark
- Display calibration not meeting the DICOM standard
- Display maximum brightness
We are able to supply display calibration software for any sized organisation from large distributed radiology providers to the sole radiology practitioners. Please send us a message if you would like to know more.
4 thoughts on “Setting up a Radiologist’s Home Reporting Display”
Thanks a very helpful article. Any chance you could do a detailed review and quick setup guides for a couple of the reporting monitors you’ve mentioned?
I am a veterinary radiologist and really appreciate that you posted this article. Super helpful. Thank you.
Are the new imacs sufficient for reporting xrays, CT and MRI images?
Ans:
Hi – iMacs are reported to have high brightness high resolution displays so can likely be made suitable for reporting. They will need to be calibrated to the DICOM Part 14 standard and also meet the local professional requirements for minimum and maximum luminance, viewing angle etc. These requirements all need to be checked against the display being offered.
Thank you for the concise and helpful review!
Radiologist
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