1. The organization must comply with the periodicity obligations, technical conditions, and minimum parameters defined in this Annex for carrying out:
a) Chest X-rays (RXTP) in occupational health control programs for employees exposed to mineral dust, according to the criteria of the International Labour Organization (ILO);
b) Spirometry to evaluate respiratory function in employees exposed to mineral dust and to assess employees who need to use personal respiratory protection equipment.
2. CHEST X-RAYS TO SUPPORT THE DIAGNOSIS OF PNEUMOCONIOSES
2.1 The procedures for performing RXTP must comply with the guidelines of Resolution RDC No. 330, dated December 20, 2019, which regulates the use of diagnostic X-rays nationwide, or its most recent revisions.
2.2 The equipment used for performing RXTP must have the following characteristics:
a) Single-phase high-frequency generator, preferably, and/or three-phase with 6 to 12 pulses, at least 500 mA;
b) X-ray tube – 30/50;
c) Aluminum filter of 3 to 5 mm;
d) Fixed grid with a focal distance of 1.50 m;
e) Grid ratio of 10:1 with more than 100 lines;
f) Grid ratio of 12:1 with 100 lines.
2.2.1 Mobile X-ray units can use equipment with 300 mA (three hundred milliamps) as long as the generator has a minimum power of 30 kW (thirty kilowatts).
2.2.2 When using RXTP equipment in mobile units, the following conditions must be met, in addition to the above requirements:
a) Have a specific permit for the operation of the transportable X-ray unit;
b) Be operated by a legally qualified professional under the supervision of a technical supervisor as per the aforementioned RDC;
c) Have a Technical Report issued by a legally qualified professional proving that the equipment used meets the requirements of this Annex.
2.3 The radiographic technique for RXTP must observe the following standards:
a) Fine focus (0.6 to 1.2 mm);
b) 100 mA or 200 mA (high rotation tube);
c) Time – 0.01 to 0.02 or 0.03 seconds;
d) Constant – 40 or 50 kV (kilovolts).
2.4 Film processing must be done by an automatic processor that meets the requirements of the responsible environmental agencies.
2.5 The identification of radiographic films used in conventional radiology must include, in the upper right corner of the radiographic film, the date of the exam, the order number of the service or the employee’s record, and the employee’s full name or initials.
2.6 Radiological reading must be descriptive, and the interpretation and issuance of RXTP reports must mandatorily use the ILO criteria in its most recent revision and the ILO standard radiographic set.
2.6.1 In selected cases, at the clinical discretion, High-Resolution Chest Computed Tomography may be performed.
2.6.2 Radiological readings must be recorded on a Radiological Reading Sheet that includes the identification of the radiograph and the reader, information about the image quality, and classification items.
2.7 The radiological exam report must be signed by one or more professionals, in case of multiple readings, from the following:
a) Radiologist with a specialist title or specialty registration in the Regional Medical Council and with qualification and/or certification in Radiological Reading of Pneumoconioses – ILO Radiological Classification, through a specific course/module;
b) Physicians of other specialties who hold a title or specialty registration in the Regional Medical Council in Pulmonology, Occupational Medicine, or Clinical Medicine (or one of its subspecialties) and who have qualification and/or certification in Radiological Reading of Pneumoconioses – ILO Radiological Classification, through a specific course/module.
2.8 Certifications are granted by passing exams from the National Institute for Occupational Safety and Health (NIOSH) or the “AIR-Pneumo” exam, and in the case of certification granted by the NIOSH exam, the professional may also be referred to as a “B Reader.”
2.9 Digital radiology systems of the CR or DR type may be used to obtain chest radiographic images for ILO radiological interpretation purposes.
2.9.1 The physical parameters for obtaining RXTP with adequate technical quality using digital radiology equipment should be similar to those of conventional radiology.
2.9.2 The identification of digital films must include, at a minimum, the date of the exam, the order number of the service or the patient’s record, and the patient’s full name or initials.
2.10 The Radiological Interpretation of digital radiographs must follow ILO criteria.
2.10.1 Images generated in digital radiology systems (CR or DR) and transferred to monitors can only be interpreted with the standard radiographs on an adjacent monitor.
2.10.2 Monitors used for displaying the radiograph to be interpreted and the standard radiographs must be of diagnostic quality, with a minimum resolution of 3 megapixels and a 21” (54 cm) diagonal display per image.
2.10.3 Digital images printed on radiological films must be interpreted with the standard radiographs in printed format, on negatoscopes.
2.10.4 The interpretation of digital radiographs for ILO radiological classification purposes is not allowed under the following conditions:
a) Radiographs on monitors compared with standard radiographs on a negatoscope, or vice versa;
b) Digital radiographs printed on radiological films with reductions smaller than 2/3 of the original size;
c) Digital radiographs printed on photographic paper;
d) Images originating from conventional radiography systems that have been digitized by scanner and subsequently printed or displayed on a screen.
2.11 Services offering digital radiology must ensure the confidentiality of electronic files and data of workers undergoing pre-employment, periodic, and termination RXTP for ILO radiological classification purposes through appropriate technical and administrative procedures.
2.12 RXTP obtained by the conventional method must be stored in original format radiological films.
2.13 Images obtained by digital systems (CR or DR) must be stored in the following formats:
a) Printed on radiological films with a maximum reduction equivalent to 2/3 of the original size; or
b) In digital media, recorded in DICOM format and accompanied by a radiological image viewer.
2.14 The responsibility for storing the images must be defined and documented.
2.15 The responsibility for storage lies with the occupational physician responsible for the PCMSO or, in the case of the company having its own service, the person responsible for the radiology service.
2.15.1 The storage refers to occupational radiographs, pre-employment, periodic, and termination exams, as well as any radiographs with changes that are suspicious or attributable to occupational exposure.
2.16 The storage time for exams must comply with the criteria defined in NR-07.
2.17 The employer must, after the end of the employment contract involving asbestos exposure, provide periodic medical control exams for at least thirty years at no cost to the workers.
2.17.1 These exams, including chest X-rays, must be conducted with the following frequency:
a) Every three years for workers with exposure periods up to twelve years;
b) Every two years for workers with exposure periods of more than twelve to twenty years; and
c) Annually for workers with exposure periods exceeding twenty years.
2.17.2 The worker will receive, upon termination and subsequent returns, a notice of the date and location of the next medical evaluation.
TABLE 1 – PERIODICITY OF RADIOLOGICAL EXAMS FOR EMPLOYEES EXPOSED TO DUST CONTAINING SILICA, ASBESTOS, OR COAL
| Companies with periodic quantitative measurements | Chest X-ray |
| UCL* ≤ 10% OEL** | – Pre-employment; and – Termination, if the last exam was conducted more than 2 years ago. |
| UCL > 10% e ≤ 50% OEL | – Pre-employment; – Every 5 years until 15 years of exposure, then every 3 years; and – Termination, if the last exam was conducted more than 2 years ago. |
| UCL > 50% e ≤ 100% OEL | – Pre-employment; – Every 3 years until 15 years of exposure, then every 2 years; and – Termination, if the last exam was conducted more than 1 year ago. |
| UCL > 100% OEL | – Pre-employment; – Annually during exposure; and – Termination, if the last exam was conducted more than 1 year ago. |
| Companies without quantitative evaluations | – Pre-employment; – Every 2 years until 15 years of exposure, then annually; and – Termination, if the last exam was conducted more than 1 year ago. |
*UCL = Upper confidence limit of the arithmetic mean estimated for a lognormal distribution with 95% statistical confidence.
**OEL = Occupational Exposure Limit.
NOTES:
1. Workers who present a Radiological Reading of 0/1 or higher must be evaluated by specialized medical professionals.
2. For workers whose exposure has decreased but who were exposed to higher concentrations for one year or more, the same interval for radiological exams from the period of higher exposure must be maintained.
TABLE 2 – PERIODICITY OF RADIOLOGICAL EXAMS FOR EMPLOYEES EXPOSED TO DUST CONTAINING INSOLUBLE OR SLIGHTLY SOLUBLE PARTICLES OF LOW TOXICITY AND NOT OTHERWISE CLASSIFIED ***
| Companies with periodic quantitative measurements of respirable dust | Chest X-ray |
| UCL* ≤ 10% OEL** | – Pre-employment. |
| UCL > 10% e ≤ 100% OEL | – Pre-employment; – After 5 years of exposure; and – Repeat at clinical discretion. |
| UCL> 100% OEL | – Pre-employment; – Every 5 years. |
| Companies without quantitative evaluations | – Pre-employment; – Every 5 years. |
*UCL = Upper confidence limit of the arithmetic mean estimated for a lognormal distribution with 95% statistical confidence.
**OEL = Occupational Exposure Limit.
***To be classified as PNOS (particles not otherwise specified), the solid particulate material must have the following characteristics (ACGIH, 2017):
a) No defined OEL;
b) Insoluble or slightly soluble in water (or preferably in lung fluid if this information is available);
c) Low toxicity, meaning it is not cytotoxic, genotoxic, or chemically reactive with lung tissue, does not emit ionizing radiation, is not sensitizing, and does not cause toxic effects beyond inflammation or overload mechanism.
1. After the termination of the employment contract involving asbestos exposure, the employer must provide periodic medical control exams for at least 30 (thirty) years at no cost to the workers.
1.1 These exams, including Chest X-rays, must be performed with the following periodicity:
a) Every 3 (three) years for workers with exposure periods up to 12 (twelve) years;
b) Every 2 (two) years for workers with exposure periods of more than 12 (twelve) to 20 (twenty) years; and
c) Annually for workers with exposure periods exceeding 20 (twenty) years.
2. Upon termination and subsequent returns, the worker will receive a notice of the date and location of the next medical evaluation.
3. OCCUPATIONAL SPIROMETRY
3.1 Employees occupationally exposed to mineral dust indicated in the PGR risk inventory must undergo spirometry in pre-employment medical exams and every two years.
3.2 Employees occupationally exposed to other pulmonary aggressors* indicated in the PGR risk inventory, other than mineral dust, should undergo spirometry if they develop respiratory signs or symptoms.
3.3 In roles requiring the use of personal respiratory protection equipment, employees with a history of chronic respiratory disease or respiratory signs and symptoms must undergo spirometry in the pre-employment medical exam or risk change exam.
3.4 In the event of spirometric alteration, the occupational physician responsible for the PCMSO must:
a) Investigate possible relationships between the result and occupational exposures; and
b) Assess the need for referral for specialized medical evaluation.
3.5 In termination exams for employees exposed to asbestos, the spirometry periodicity should be the same as the radiological exam.
3.6 The organization must ensure that the execution and interpretation of spirometry follow the standardizations in the most recent version of the Brazilian Consensus Guidelines on Spirometry.
3.7 The interpretation of the exam and the spirometry report must be done by a physician.
* “Other pulmonary aggressors” refer to chemical agents that can be inhaled in the form of particles, fumes, mists, or vapors and are considered sensitizers and/or irritants according to the criteria in the Globally Harmonized System of Classification and Labeling of Chemicals (GHS).