[en] With the discovery of x-rays and radioactive isotopes with applications in medicine, several techniques have been and have been developed for the purpose of use in therapy and diagnosis. In the early days of the use of ionizing radiation from x-rays and radioisotopes, deleterious effects in occupationally exposed individuals (IOE) were already observed. Actions aimed at minimization and protection were adopted, among them the use of plumbiferous shields. However, a new technology, PET (Positron Emission Tomography) was developed; this technique makes use of a positron emitting radioisotope, ¹⁸F with energy of 511 keV. The interaction with heavy nuclei, lead for example, emits characteristic X-ray. This paper presents conclusive results that the OEI's use of lead protection is more damaging to the organism because it allows more deleterious effects as a function of the characteristic x-rays. Objective: This study analyzes the levels of radiation doses absorbed by X-rays and gamma rays in occupationally exposed individuals in PET-CT services. Methodology: The method developed in the research was divided in two moments: in the first the acquisitions were carried out without the plumbiferous protection apron and in the second with the apron, for comparison effect. This procedure was performed in two steps, the first step was a source of ¹⁸F-FDG, with 10 mCi, and in the second of ¹³⁷Cs, with 194 μC. Results: In the first stage, the means were: 0.044 ± 0.017 without the apron and 0.054 ± 0.017 with the use of the protective apron. The average radiation presented is 95 ± 3% for radiation μ and 5 ± 3% for x-ray. In the second stage the averages were: 2.7 ± 0.8 without the use of the apron and 2.8 ± 0.8 with the use of the protective coat apron. The average radiation has a value of 65 ± 8% for radiation μ and 35 ± 8% for X-ray. Conclusion: Despite the high levels of radiation involved during the manipulation and administration of ¹⁸F-FDG for PET/CT imaging studies, it is not recommended to wear a protective coat of IOE, due to the production of X-rays characteristic of photoelectric effect that occurs due to the interactions of the high energy gamma rays with the lead atoms. (author)