NIOSH Safety and Health Topic:

Chest Radiography

B Reader Information for Medical Professionals

If you are visiting this Web Page, you may be interested in the NIOSH B Reader Program or you may be curious about becoming a B Reader.

--Do you live in a coal mining area and expect to classify chest radiographs for the Coal Workers' X-Ray Surveillance Program as mandated by the Federal Mine Safety and Health Act of 1977 (external link)?

--Have you been asked to classify chest radiographs of asbestos- exposed workers as governed by the U.S. Department of Labor regulations?

--Are you involved in classifying chest radiographs for medical screening, surveillance, research, or compensation programs?

The B Reader Examination

B Reader approval is granted to physicians with a valid U.S. state medical license who demonstrate proficiency in the classification of chest radiographs for the pneumoconioses using the International Labour Office (ILO) Classification System.

Proficiency is evaluated via the B Reader Examination, which was developed in response to the mandates of the Federal Mine Safety and Health Act. Since the examination was first administered in 1974, more than 1000 physicians have passed it. Currently, there are about 300 B Readers (Current B Reader List).

Examinations are offered monthly at the Appalachian Laboratory for Occupational Safety and Health (ALOSH) located in Morgantown, West Virginia. A passing score results in approval as a B Reader. Each B Reader is required to be re-examined every four years. Most B Readers renew for an additional term.

Regulations mandate that all physicians who participate in the examination and/or classify chest radiographs under the Act must utilize the ILO System and Standard Films. These standard films are necessary when participating in the B Reader Examination or utilizing the NIOSH Self-Study Syllabus, and are an important resource at the American College of Radiology (ACR) Symposium on Radiology of the Pneumoconioses.

For more information:
Wagner GR, Attfield MD, Parker JE. Chest Radiography in Dust-Exposed Miners: Promise and Problems, Potential and Imperfections. OCCUPATIONAL MEDICINE: State of the Art Reviews. Philadelphia, Hanley & Belfus, Inc. 1993; 8(1):127-141.

For additional information, you may wish to refer to:
Wagner GR, Attfield MD, Kennedy RD, Parker JE. The NIOSH B Reader Certification Program--An Update Report. JOURNAL OF OCCUPATIONAL MEDICINE. 1992; 34:879-884.

2000 ILO Revisions

The revised edition (2000) of the Guidelines for the Use of the ILO International Classification of Radiographs of Pneumoconioses has been released. NIOSH has updated the entire B Reader Program to reflect these changes. Potential B Reader candidates should keep the following in mind:

B Reader certifications under the previous ILO system will continue to be valid until their date of expiration.
NIOSH has revised both the B Reader certification and recertification examinations to make them consistent with the ILO revision.
A revised Roentogenographic Interpretation Form, consistent with the ILO revision, is now available from NIOSH and is being used in all components of the CWXSP. You may download a copy of the form from this site by clicking on the link above.
NIOSH now tests all B Reader candidates according to the revised ILO system. Upon the expiration of their certification, current B Readers will be required to recertify under the revised system.

To order copies of the revised edition of the International Classification of Radiographs of Pneumoconioses, use the ILO Web site:

Visit the ILO Web site External Link: http://www.ilo.org/
Under Highlights (right side of the page), click Publications
Select New Books
Select Titles Alphabetically
Select the letter "I"
Select "ILO Standards-Related Activities in the Area of Occupational Safety and Health"
Then scroll down to “International Classification of Radiographs of the Pneumoconioses” to order

During the transition from the 1980 to the 2000 edition of the ILO Classification, readers have asked about the use of different available sets of standard radiographs in classifying films under the current 2000 revision of the Classification.

Two issues have arisen:

1) The ILO now offers two distinct sets of the standard films: the "Complete Set" consisting of 22 radiographs, and the "Quad Set" consisting of 14 radiographs. Although the two sets are generally comparable, international trials have demonstrated some tendency for film classifications to vary, depending on the set of radiographs used. Thus, for the purposes of classifications under the NIOSH Coal Workers' X-ray Surveillance Program, use of the "Complete Set" is preferred. Readers should consult with the responsible parties regarding this issue when they perform classifications for other purposes, such as research studies, medical surveillance programs, or clinical or medical-legal evaluations.

2) In order to preserve continuity and consistency in the classifications, the images used in reproducing the 2000 version of the standard radiographs are identical to those used for the 1980 set of standard radiographs, aside from one image which demonstrates pleural abnormalities. The ILO did endeavor to improve image quality in the 2000 set by utilizing advanced computer image techniques. The NIOSH Coal Workers' X-ray Surveillance Program requires that readers submit classifications adhering to the 2000 Revised Edition of the Guidelines for the Use of the ILO International Classification of Radiographs of Pneumoconiosis. The sets of standard images used in the 2000 and 1980 Classifications are nearly identical, and thus it is the individual reader's choice which of these two sets of standard radiographs to use after that time. However, because the quality of the 2000 standard radiographs has been enhanced by the ILO, NIOSH recommends that readers consider using these current standard radiographs for classifying films for NIOSH programs and studies.

Pre-Examination Preparation

NIOSH strongly recommends some pre-test preparation for examination participants to assure familiarity with the ILO Classification System and associated Roentgenographic Interpretation Form. Pre-test preparation is extremely important because anyone who fails the examination must wait six months before re-testing. The examination is difficult: only about half of the examinees pass.

Pre-test preparation is offered in the form of (1) the NIOSH Self-Study Syllabus which is available through ALOSH and developed specifically for this purpose; and/or (2) attendance at the American College of Radiology (ACR) Symposium on Radiology of the Pneumoconioses.

The Syllabus is available by mail in the United States on a first-come, first-served basis from ALOSH prior to scheduled testing. Additionally, the Syllabus may be used on-site by anyone interested in coming to Morgantown to study prior to taking the examination. The Syllabus can also be utilized at certain other locations in the U.S. and internationally. To increase the availability of these materials, NIOSH is working to make the Syllabus Set available on CD or DVD. To request the Syllabus, call (888) 480-4042 or email CWXSP@cdc.gov.

The American College of Radiology (ACR) Symposium on Radiology of the Pneumoconioses is usually held every 2-3 years. You can contact the ACR for further details (800) 227-5463 ext. 4245.

Digital Radiography

In light of the recent technological advances in radiology, particularly in the area of digital radiology, many B Readers have inquired about the use of digital radiography in the classification of pneumoconioses. Questions have focused on the use of either 'soft copy' images that can be read on a monitor or 'hard copy' digital images that can be printed on film like traditional film-screen radiography. To comply with regulatory requirements under 42CFR Part 37, B Readers must continue to use standard film-screen radiographs when classifying chest radiographs for the Coal Workers' X-Ray Surveillance Program. The regulation specifies the use of film no less than 14 by 17 inches, and the use of a diagnostic radiograph machine having a rotating anode tube with a maximum of a 2 mm. source.

In addition, the guidelines for use of the ILO International Classification of Radiographs of Pneumoconioses prescribe side-by-side viewing of subject and standard radiographs, and state that the standard films take precedence in defining profusion categories. Thus, until provisions for use of digital images have been specified, readers using the ILO Classification for all purposes should continue to use traditional film screen radiographs and standards.

In March 2008, NIOSH conducted a workshop on Application of the ILO International Classification of Radiographs of Pneumoconioses to Digital Chest Radiographic Images (DHHS (NIOSH) Publication No. 2008-139).

NIOSH is conducting research to assess the equivalency of traditional radiography and digital radiography in pneumoconiosis classification. It is essential to understand the performance of digital systems in ILO classification before digital radiography can be recommended for use by B Readers. NIOSH is requesting miners who participate in the Enhanced CWHSP to undergo an additional digitally-acquired chest radiograph, and then is comparing the classifications of digital images to those obtained using the traditional film screen system. Digital images are being classified using ILO standard film images that were digitized by Alfred Franzblau, M.D., Professor, Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan (permission for use provided to NIOSH by the ILO). Based upon the results of relevant completed and ongoing research, as well as consultation with experts in the field, NIOSH is working to develop recommendations for digital radiographic imaging in the recognition and classification of pneumoconiosis.

Roentgenographic Interpretation Form

Roentgenographic Interpretation Form
PDF only 460 KB (2 pages) En español
(OMB 0920-0020) (CDC/NIOSH 2.8) (July 2007)
This form must be completed by the A or B Reader that interprets a chest radiograph for NIOSH as part of the Coal Workers' X-ray Surveillance Program. Print/Copy as a double-sided form.