Digital Chest Radiography

Digital Imaging Updates

NIOSH is currently researching the use of digital chest images for the evaluation of the pneumoconioses. Current guidance and information pertinent to the acquisition, viewing, and evaluation of digital chest images based on this research and other knowledge is summarized on our Update Page. The page also includes a summary of research needs and other developments relating to enhancing the evaluation of digital chest images for the purpose of improving the sensitivity, accuracy, and reliability of detecting occupational lung disease.

The world is in process of transition from film screen radiology to the use of digital imaging. In many places, the transition is virtually complete. While digital methodology brings with it certain benefits and potential opportunities for enhancing the recognition and classification of pneumoconioses and other occupational lung diseases, it also creates certain challenges. Being aware of this trend, the National Institute for Occupational Safety and Health (NIOSH) has been pursuing means to facilitate and standardize the evaluation of chest images, with the object of enhancing the accuracy and precision of determinations and making modern digital imaging technologies accessible and practical for use in classification.

These efforts have been focused in three areas:

  1. The development of guidelines and recommendations for the use of digital radiography and images in recognition and classification of the pneumoconioses.
  2. The development of free software (NIOSH BViewer©) for the evaluation and classification of digital images of the chest for pneumoconioses, using the International Labour Office (ILO) reference chest images. Please note that the NIOSH BViewer is not required and NIOSH is aware of several B Readers that are able to use a commercial DICOM Viewer or PACS to display the ILO reference chest images along side of patient chest images. Contact your software vendor or PACS administrator for technical assistance.
  3. The creation of an image repository. In this, individuals and organizations can submit anonymized, deidentified chest images that may be of interest to the medical and scientific community for a range of applications, such as education, training, quality control, research, and surveillance.

Guidelines for the use of digital imaging in the recognition and classification of pneumoconioses

The application of any technology requires ongoing attention to personnel, equipment, and procedures to maximize the likelihood of acceptable performance. To assist radiographic facilities, physician readers, governmental agencies, and other interested organizations in assuring that the recognition and classification of pneumoconiosis using digitally-acquired chest radiographs is at least as safe and effective as traditional film screen radiography, NIOSH has prepared Guidelines, based upon accepted contemporary professional recommendations. As the field of digital radiology evolves, users are encouraged to maintain familiarity with new findings, approaches, and equipment.

NIOSH has prepared the NIOSH Guideline: Application of Digital Radiography for the Detection and Classification of Pneumoconiosis (DHHS (NIOSH) Publication No. 2011-198) to provide information and recommendations to individuals and organizations who wish to acquire and use digital images for the recognition and classification of pneumoconioses.

NIOSH BViewer© software

Using film radiography, standardization of the viewing environment was relatively easy to achieve, simply requiring a dimly lit room, a viewing light box having the correct luminosity and radiographic films taken according to conventional methods. In contrast, vendors of modern digital radiographic equipment, in the interest of achieving better diagnostic success, now provide the means to manipulate radiographic images. Such techniques not only include variation of brightness and contrast parameters, but often include enhancement techniques such as edge enhancement and noise reduction. The ability of the reader to vary these parameters clearly complicates efforts to standardize the viewing process across readers and reading sessions, both for the test image and the standard images. Since readers may differ in their selection and setting of these viewing tools, the ultimate result, therefore, is that unfettered access to these tools would likely result in unfortunate increases in between- and within-reader variation.

Digital radiography, with its attendant opportunity for image manipulation, thus brings with it unique challenges for the classification of pneumoconioses. Image manipulation runs counter to the fundamental principles of pneumoconiosis classification, where the underlying principle has been the standardization of images and the reading environment. The International Labor Office (ILO) promulgated a standard approach for assessing x-ray films in 1930. This not only defined uniform means for obtaining the images but used reference comparison images and a clearly-defined nomenclature and associated categorical grading schemes for derivation of scores reflecting the type, extent, and severity of the various chest abnormalities associated with pneumoconioses ILO Classification.

In order to minimize the variability resulting from different approaches to the display of digital radiographs, NIOSH funded the development of computer software that strictly controls the display of the chest images used during performance of classifications. This program has been named the NIOSH BViewer©, and is available free of charge for downloading. The ILO has published the Guidelines for the Use of the ILO International Classification of Radiographs of Pneumoconioses, Revised Edition 2011. At the current time, NIOSH is inviting the physicians to test out the NIOSH BViewer© to determine whether there are any problems in its installation and operation. We request that those who test the program provide us feedback, in terms of its success, problems, and with respect to enhancements that might be made.

In the process of developing this software, NIOSH has become aware that installation on commercial Picture Archiving and Communication System (PACS) and similar systems may be problematic. It appears that vendors are reluctant to permit other software, regardless of origin, to be installed along with their own because of potential liability concerns. To our knowledge, the NIOSH BViewer© should not create any untoward effects; however, it may be that only those users with standalone workstations and systems paired with diagnostic-quality grayscale display function (GSDF)-compliant displays may be able to install and try out the software. Refer to the BViewer system requirements for more information.

Those wishing to use the NIOSH BViewer© must note the following disclaimer:

The NIOSH BViewer© software is provided to support health care practitioners in their management of digital posterior-anterior radiographic chest images used in occupational medical monitoring programs. The software is only intended to assist the user in assembling and organizing the information required to make medical decisions, and cannot be substituted for competent and informed professional judgment. To assure appropriate utilization of this software, users need to adhere to accepted professional standards and applicable federal, state and local laws and regulations regarding the collection, display, storage, transfer, and interpretation of medical images. Adherence to the NIOSH Guidelines is also very desirable. NIOSH does not warrant the reliability or accuracy of the software, graphics, or text.

Download NIOSH BViewer© Software

NIOSH BViewer Software version 1.2n (February 2020) (System Requirements)

NIOSH would be pleased to receive feedback on any aspect of the NIOSH BViewer , including its performance, utility, problems, potential enhancements, installation assistance, etc. Please send an email to