We might be closer to reaching the final frontier in space. After all, we sent the Perseverance to Mars in 2020. But there are other “final frontiers” to conquer here on Earth. And we are not talking about the depth of the oceans. Catheter and surgery robots go to places inside our bodies where we could not otherwise. The only way to achieve this safely is through reliable, custom displays.
In short, displays in medical applications can be a medical professional’s second pair of eyes. Display precision and accuracy is the difference between a correct diagnosis or terrible malpractices. Since displays are critical for pain relieving, for diagnosing, and for saving lives, when you are developing solutions in this field, you should review features, like the ones included below, to determine which screen adapts best to your application.
In hospitals and clinics, light varies greatly from patient rooms to operating rooms or specialized labs. Patient rooms commonly offer a lot more sunlight than operating rooms, for example. Also, patient monitoring applications usually require displays with letters or numbers for specific parameters. Being able to read big black numbers from a distance is a priority. Let’s think of medical cart displays. The most important feature would be to offer great readability in a room with variable light. In contrast, on an operating room with controlled lightning, medical professionals need to see 3D graphics of organs or bodies to perform critical procedures. They would probably have a closer access to those screens than in patient rooms. In this case, brightness is less of a priority than on patient monitoring. Consequently, lighting conditions in the place in which you expect users to leverage the machine will determine brightness and sunlight readability capabilities.
How many details do you need to see on a medical display? In other words, how high of a resolution do you need? It varies depending on the application. For diagnostic machines, like X-Rays, you need high quality images. This means that displays require a higher pixel count to accurately provide a diagnosis. In applications such as ultrasound, mammography and PACS, minimum 3MP (Mega Pixels) resolution is required. Finally, patient monitoring displays will require lower resolutions. If a nurse needs to take a quick look from a distance to check parameters in patient rooms, you won’t probably need that many pixels.
Grayscale and Colors
The general trend in medical imaging today is to replace direct viewing such as X-Ray film, photographic print, etc. with digital images on a display. Grayscale images are used mainly in applications such as X-Ray, computerized tomography (CT), and nuclear Magnetic Resonance Imaging (nMRI) scan.
In X-Ray applications, grayscale consistency is fundamental to achieve correct diagnosis. Grayscale must be consistent and repeatable from machine to machine and across medical facilities. To ensure the consistency on the display system performance indicators, The American College of Radiology (ACR) and the National Electrical Manufacturers Association (NEMA) formed a joint committee to develop a standard for Digital Imaging and Communication in Medicine (DICOM). In particular, the Grayscale Standard Display Function (GSDF) defines the luminance response of a display to ensure that the contrast is consistent throughout the pixel value range of a displayed image. Other parts of the DICOM Standard specify how digital image data can be moved from system to system.
Nowadays, medical imaging has been moving from exclusively grayscale modalities toward increasing use of color. Mapping from grayscale intensity to color is specified by a look-up table (LUT) and DICOM specifies a selection of color palettes for specific applications, such as Positron Emission Tomography (PET) images. When selecting a display for a medical imaging application, the user would want to see one with minimal color inversion, with a LUT, and is compliant with DICOM grayscale calibration features.
As a result, the same committee mentioned above is working towards a standard for color since color inversion and density can affect the quality of medical images, which in turn affects diagnosing and procedure accuracy. This is particularly important as we move towards 3D modelling of humans to diagnose and perform catheter or surgical procedures.
One of the frequent questions when sourcing displays, relates to whether implement a monitor working at 50Hz or 60Hz. For some applications, like a nurse workstation, 50Hz would probably provide the required refresh speed and enough cost savings. For catheters, for example, a 60Hz display can be more appropriate because you want the monitor to always show the most recent information to guarantee the instrument is exactly where you see it on the screen.
VGA vs. HDMI port
The main difference here is the amount of data that can be transmitted with a VGA cable in comparison to the HDMI cable. The HDMI cable functions more like a highway and the VGA more like a regular two-way street. In other words, VGA is an analog interface and HDMI is a digital one. HDMI can transfer more data, and offer higher resolutions, and higher frame rates than VGA. HDMI can also carry over audio while VGA can only transfer visuals. For cutting edge applications in which life is a stake, like in surgical robots, you would probably prefer to use HDMI ports. But you could source monitors with VGA ports for nurse workstations. Nevertheless, new applications in general are moving away from VGA ports which means that eventually most monitors will not have a VGA port. If your application is new, your will probably want to implement an HDMI port right away, or at least include both options. For legacy applications, you need to start gradually replacing old units with VGA ports with newer versions with HDMI ports.
Custom Size and Mounting Options
Ergonomics is key in the medical industry. Unlike regular office applications when users can be expected to sit down at a certain angle and distance from the monitor, medical staff can sit or stand away from medical machines or monitors, for example. Mounting options cam range from a standard VESA to some level of customization in the mechanical design to fit within a specialized chassis. This level of customization may also require specific sizes. In certain surgical robotic applications, the display mounted on the surgeon’s module needs to feel almost like a VR headset and the doctor must sit close to it. For applications such as on patient monitoring devices, displays must fit in limited spaces which requires displays in smaller and more compact sizes or form factors.
To summarize, there are several features to consider before sourcing a display for a particular medical application. If you work with an experienced hardware manufacturer to gather the required technical specifications to successfully achieve safety certifications, industry standards, user experience expectations, while helping you save costs.
If you want to continue reading about the hardware for the medical industry, you can visit this page.