Things you may want to know

Transcription

1 Things you may want to know 1 / 9 Last updated 18-Nov-05

2 Why medical monitors are special? Unlike commercial displays, Medical displays are used in the hospital and they are displaying contain life critical information. When you are in an airplane, you are not allowed to use any electronic devices during a take or a landing because these moments are critical. A piece of wrong information caused by an interference with other electronic devices can give a wrong data to the pilot resulting may be a crash. With the same token, medical devices have tighter specifications on EMI/EMC as well as higher image quality standard. Medical monitors fall into one of two categories: One is Clinical display, the other is Diagnostic Display. To make it short, Clinical display has tighter control on EMI and electric current regulation. For Diagnostic Display, it should also meet DICOM standard for grayscale reproduction for Digital Radiology. DIN is also required in German market and is supposed to be a pan-european standard for Diagnostic Medical Display. What is DIN ? Simply put, DIN is a criterion for White Uniformity. White uniformity is a brightness variation from the center of the screen to the four corners of the screen. Current DIN requires having this brightness variation less than 15% and there is a discussion to increase this level to 10%. As of October 2005, DIN conformance is a mandatory requirement for a display to be sold in German market as a medical equipment. Just for your information, White Uniformity for a commercial display is 25%. 1 2 Measurement is done with 50% gray pattern, and the measured brightness variation from the center to each corner should not exceed more than 15%. C / 9 Last updated 18-Nov-05

3 What is DICOM? DICOM stands for Digital Imaging and Communication in Medicine. As it says literally, it defines all specifications from medical picture acquisition to archiving of those pictures. As the advancement of high performance computers and higher resolution displays, the conventional X-ray radiology using Film has been taken over by a new Digital Radiology using higher resolution LCD. DICOM defines the format of pictures acquired digitally, and PACS, Picture Archiving and Communication System is responsible for picture archiving and distribution. Why DICOM Calibration is necessary? Human eyes are non-linear devices and there is a threshold for them to distinguish brightness change of an object. DICOM defines JND, Just Noticeable Difference which shows the relationship between brightness increase in a physical world and the response of human eyes for that change. Basic idea of DICOM calibration is to give a capability to LCD display so that it can generate correct brightness levels for incoming pixel so that human eyes can recognize the information correctly. Since LCD display's performance is not linear and is not designed to take human factor into consideration, DICOM calibration is a must process for all Diagnostic Medical Display. Before DICOM Calibration After DICOM Calibration As you can clearly see from the figures above, gray scale transition after DICOM calibration is much smoother than without it meaning that you can see more image details from an X-ray image which is critical for doctors to make a correct diagnosis. 3 / 9 Last updated 18-Nov-05

4 How often DICOM calibration should be performed? DICOM and JND are a function of Brightness. As long as the brightness does not change, you do not need to re-calibrate a display. SBC, Stable Brightness Control is always checking the brightness change, and when the brightness change exceed a tolerance, then Lumical generates a warning so that a system administrator can take corrective actions. Actual number of re-calibration varies depending on the maintenance policy of a hospital. Why medical monitors use a special graphics adaptor? High-resolution Monochrome Medical Displays are using a special format to achieve grayscale performance standard: Packed Pixel Format. One pixel of a color LCD display is composed of three sub-pixels: Red, Green, and Blue. Since monochrome display does not need this individual color information, the display is using all these color data channels to generate high quality grayscale images. Graphics adaptors provided with these highresolution monochrome displays generate Packed Pixel Format image data and the monochrome display decode this data to reproduce DICOM compliant medical images. The fact is that each manufacturer has its own Packed Pixel Format. Thus a graphics adaptor for 5MP display from company A does not work with a 5MP display from company B. for 3MP and 5MP monochrome displays, a dedicated graphics adaptor should be used with the displays. When you use a commercial graphics adaptor for a monochrome medical display, then you can see either no pictures or a mirror image like the one shown above. 4 / 9 Last updated 18-Nov-05

5 Two different terminologies: VGA vs. Mega Pixels Unlike commercial display market, "MP", Mega Pixel is a commonly used terminology in a medical display market. Interestingly enough, the terminology itself reflects the application area of a display: Pixel Counts Major Application Comment 1MP Modality / Patient Chart or Viewing Station Color 2MP Patient Chart or Viewing Station Color / Monochrome 3MP General Digital Radiology Monochrome 5MP Mammography Monochrome When you look at the medical display, you will find that there are only four screen sizes available in the market: 18", 19", 20.3", and 21.3". Since the viewable size is almost same, more pixels naturally means more details. This is the reason of using the terminology Mega Pixel instead of QXGA or QSXGA. What is Lumical? Lumical is a S/W that can control WIDE displays. Lumical has two different versions: Lumical Client and Lumical Server. Lumical Client is a standalone S/W that should be installed on a Workstation. Lumical Server is a Network Management S/W that can control and manage all Lumical Clients that are connected through a network. Lumical Client and Lumical Server provide numerous benefits and flexibility including hands-free remote maintenance. For the details, please refer to the manual attached. Lumical Client Lumical Client Lumical Client Lumical Client Lumical Server Lumical Client Lumical Client Lumical Client Lumical Client is installed in each computer, and Lumical Server is installed in one computer that controls the whole network. 5 / 9 Last updated 18-Nov-05

6 Why do we need Lumical USB version? Lumical is designed to work with graphics adaptor manufactured by Realvision. Lumical is communicating with a monitor via DDC and graphics adaptors from Realvision have DDC capability. But Graphics adaptors from Matrox does not support DDC thus can not communicate with the monitor. Lumical USB version is designed for cases like this. The program communicates with monitors via USB still providing all functionality as DDC version of Lumical does. As long as communication concerns, Lumical USB version works with any graphics adaptors available in the market as long as a computer supports USB connection. DVI DVI USB RealVision Graphics Adaptor Matrox/Other Graphics Adaptor 6 / 9 Last updated 18-Nov-05

7 Why WIDE monitor is special? 7 / 9 Last updated 18-Nov-05

8 Along with the wide spread of digital radiography, monochrome displays are getting more and more popular taking over conventional X-ray films. Since the performance of the monochrome displays is critical for diagnostic medical imaging devices, it is mandatory that all displays designed for diagnostic image viewing to be compliant with DICOM14 standard. In 2004 WIDE introduced an industry first three-sensor configuration for grayscale viewing system, M- series. In this new configuration, two of three sensors are fully dedicated to DICOM calibration. The benefit of Dual Sensor configuration, I-Q Sensor, is the accuracy or the calibration reliability. Conventional monochrome displays for digital radiography have been using single sensor for 1,024 different grayscale reproductions. With two sensors instead of one, the sensor electronics is capable of handling twice more grayscale dynamic range than other medical displays do providing more reliable and accurate calibration. Securing an enough dynamic range in a low brightness region is especially important because it is directly related to a correct JND generation specified in DICOM 14 standard. Dual sensor configuration secures enough dynamic ranges not only for low brightness region but also for high brightness region. The performance of this new configuration is already proven in the field and M-series has been the choice of most major hospitals and OEM customers. In addition to the number of sensor is increased, the light pick up area of M-series is three times larger than the one used with other competitors products. Since the sensor is picking up light from a limited area, and the measurement should be reliable enough to represent the characteristics of the whole panel. Clearly, the larger a light pick up area, the more accurate the measurements are. Dual Sensor unit has a special driving mechanism with which the sensor unit is only visible when the calibration is performed. After calibration, the sensor unit is stored in a bezel reserving 100% of viewable area to viewers. For the reliability of the sensor driving mechanism, engineers from Rugged and Industrial Division of WIDE Co. used its know-how to make it maintenance free. For an accurate calibration, a sensor should be placed to LCD panel as close as possible. WIDE retractable sensor does this discarding the possible interference with ambient lighting meaning ambient lighting interference proof DICOM calibration. Some manufacturers came up with a similar solution that has a drop down arm like sensor unit, but the distance from the sensor to LCD panel is 8 / 9

9 quite far. For this type of calibration system, it is recommended to turn the ambient lightings off or at least it should be lowered. There are additional benefits of having M-series. M-series comes with Lumical Client software which allows users to calibrate and adjust all display parameters without any hardware interruptions. Calibration results are visually illustrated by graphs. In conjunction with Lumical Client, Lumical Administrator/Server is also available with which users can do remote maintenance and calibration. Lumical Administration/Server software communicates with Lumical Client and monitors the status and quality changes of individual display. When Lumical Client detects abnormal measurements, then Lumical Administrator receives the information and generates automatic alert so that System Engineers can check the status of the display at the site. WIDE introduced the industry first three-sensor configuration for grayscale viewing display system: M- series. WIDE engineers are challenging to new technologies that can benefit our customers. With WIDE display, you will see something that have been there to been seen for a long time. WIDE Korea, HQ WIDE EU WIDE USA WIDE Japan Chungbuk, Korea Amsterdam, The Netherlands Tempe, AZ, USA Tokyo, Japan Tel Tel Tel Tel Fax Fax Fax Fax / 9