Detailed information on acceptance and constancy test
In order to meet the high requirements of the diagnostic findings, some basic principles have been developed in Germany to ensure that the image reproduction systems used (BWS) meet these high-quality standards. At the same time, supervisory authorities were appointed to ensure that the quality assurance frameworks created are also implemented.
ACCEPTANCE AND CONSTANCY TEST
To ensure the correct installation and configuration of the image reproduction systems used (BWS), an acceptance test of the image reproduction systems used (BWS) by the manufacturer or supplier must be carried out, in accordance with §16 of the X-ray Ordinance (RöV). It must thereby among others be cross-checked whether the image display device (BWG) is activated in the correct resolution and whether the required guideline values according to the declared spatial class and the findings method are adhered to.
The following are visual and metrological tests, so-called constancy tests, which must be carried out at regular, defined intervals. These are carried out by expert personnel of the operator or by a service provider such as Rein Medical GmbH.
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STANDARDS, GUIDELINES ETC.
There are varying catalogues of requirement, which are placed on the image reproduction systems used (BWS). The following regulations must be taken into account in the context of quality assurance:
The DIN 6868-157: 2014-11, which regulates the execution of the acceptance test of the image reproduction systems used (BWS), is a German standard from November 2014 which replaces the DIN-V 6868-57: 2001-02, in the case of initial commissioning and new acceptance of findings monitors, by supplementing the requirements of the constancy test and the adaptation of the State-of-the-Art.
An important constituent part of quality assurance is the consideration of environmental conditions. In this case, attention must not only be paid to direct and indirect light sources during the acceptance test.
In contrast to DIN-V 6868-57, which is no longer permitted for new acceptances with effect from 1 May 2015, there is no distinction according to categories (category A / category B. / mammography) but rather a classification according to spatial classes with corresponding requirements (see table)
These spatial classes (RK 1-6) are subdivided into
- The image reproduction systems used (BWS) with diagnostic quality
- The image reproduction systems used (BWS) with viewing quality
An image reproduction system used (BWS) consists of several components (hardware and software), which are documented during the acceptance test. When replacing any of these components or changing the software version of PACS or operating system, a partial acceptance / comparison measurement must be performed to ensure that the change does not affect the image quality.
In addition, the field of application of dentistry is now regulated in DIN 6868-157.
In the case of the acceptance test, it is among others necessary that the under DIN 6868-157 test images specified from the application software (in most cases your PACS software) can be displayed in the native resolution of the image display device (BWG). Since a negative influence on the representation of the test images when using different software cannot generally be ruled out, the manufacturer or supplier during the acceptance test must either carry out the tests in the application software, or e.g. ensure identical representation by means of a comparison measurement between application and QA software. This serves the uniform approach of the DIN 6868-157, pursuant to which all components which a quality-relevant influence on the quality of diagnostics in the quality assurance can have, are taken into account.
The quality assurance guideline (QS-RL) is currently being revised due to the new features of DIN 6868-157. It regulates the practical implementation of the constancy test in accordance with DIN-V 6868-57, which applies to monitors, with acceptance prior to 1 May 2015, as well as the constancy test in accordance with DIN 6868-157 in the revised version.
VIEW OF OTHER COUNTRIES
Although Germany plays a leading role in the implementation and design of quality assurance at national level in Europe, there are other countries that also demand the implementation of quality assurance of image display devices (BWG). One of the most important quality assurance pioneers is the American Association of Physicians in Medicine (AAPM) and the report of the AAPM Task Group 18 (TG18). The quality assurance guideline for medical imaging display systems of the Japan Industries Association of Radiological Systems Standards (JESRA) is also strongly inspired by this description of quality assurance. Other countries that have also implemented quality assurance are usually based on the AAPM or the DIN V 6868-57 template, such as the Swiss "Directive R - 08 - 06" of the Federal Office of Public Health.
MINIMUM REQUIREMENTS PLACED ON IMAGE DISPLAY DEVICES (BWG) PURSUNT TO DIN 6868-157
| Body region / method | Max. display luminance in cd/m2 | Min. luminance in cd/m2 *1 | Maximum luminance ratio | Matrix of the image display device (BWG) Pixel (w) x Pixel (h) | Luminance characteristic | Homogeneity within image display devices (BWG) (among several image display devices (BWG) | Pixel error (per 1024 × 1024 pixels) | adequate device from JVC |
|---|---|---|---|---|---|---|---|---|
| Projection radiography (thorax, skeleton, abdomen) | ≥ 250 | ≥ 250 | ≥ 1 600 × ≥ 1 200 | GSDF ± 10 % | < 25 % (< 20 %) |
CCL214, CCL258i2, CCL358i2, CCL650i2, ME205, MS25i2, MS35i2, CL-S200, |
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| Fluoroscopy, all applications | ≥ 150 | ≥ 100 | ≥ 1 024 × ≥ 1 024 | GSDF ± 15 % | < 25 % (< 20 %) | CCL214 CCL258i2, MS25i2, ME205, CL-S200, CL-S300 |
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| Computer tomography | ≥ 150 | ≥ 100 | ≥ 1 024 × ≥ 1 024 | GSDF ± 15 % | < 25 % (< 20 %) | CCL214, CCL258i2, MS25i2, ME205, CL-S200 | ||
| In the case of spatial class RK 5: Dental digital volume tomography, intraoral X-ray with dental tube devices, panoramic radiographs, cephalometric radiographs of the skull, dental skull overview images, hand images for skeletal growth determination | ≥ 200 | ≥ 1,1 × Lamb | ≥ 100 | ≥ 1 024 × ≥ 768 | Not applicable *2 | < 30 % (< 30 %) | A ≤ 1, B ≤ 5, C ≤ 5, D ≤ 1 | CCL214, CCL258i2, MS25i2, ME205, CL-S200 |
| In the case of spatial class RK 6: Intraoral X-ray diagnostics with dental tube devices, panoramic layer shots, cephalometric radiographs of the skull, dental skull overview images, hand surveys for skeletal growth determination | ≥ 300 | ≥ 100 | ≥ 1 024 × ≥ 768 | Not applicable *2 | < 30 % (< 30 %) | CCL214, CCL258i2, MS25i2, ME205, CL-S200 | ||
| Mammography | ≥ 250 | ≥ 250 | ≥ 2 048 × ≥ 2 048 | GSDF ± 10 % | < 25 % (< 10 %) | MS55i2plus, CCL550i2 | ||
| Mammographic stereotaxis | ≥ 200 | ≥ 100 | ≥ 1 024 × ≥ 1 024 | GSDF ± 15 % | < 25 % (< 20 %) |
CCL214, CCL258i2, MS25i2, ME205, |