Exposição ocupacional em cardiologia intervencionista por meio de dosimetria computacional – uma análise do IMC do paciente

Abstract

With the growing number of obese people around the world, the incidence of obesity-related diseases, such as cardiovascular diseases, is also increasing. An alternative for treating some of these diseases is through interventional cardiology (IC), which uses ionizing radiation to visualize and treat these conditions in a minimally invasive manner. Therefore, the treatment of obese patients through IC procedures has been very common. One of these procedures is coronary angiography (CA), discussed in this work. As X-rays are activated in real time during these procedures, the doses received by workers present in the room are of great concern. Since occupational exposures are proportional to the doses received by the patient and these tend to be higher in obese patients due to the need of more energetic radiation, it is assumed that professionals receive higher doses the larger the patient's size. The goal of this work is to analyze the influence of patient’s body mass index (BMI) on occupational doses. Thus, effective and equivalent doses were obtained for two professionals, a main physician and an assistant, for three different patient sizes, from computer simulations using the Monte Carlo method. A common IC room was simulated with PA, LAO45, RAO30 and RLAT projections. The voltages used were 80 kV and 100 kV, with the spectra generated by the SpekCalc software with additional filtration of 1.5 mmAl, anode angle of 12º and tungsten target. It was observed that the doses in the professionals were very close for the different sizes of patients when dealing with the same tube voltage, in all projections. Higher occupational doses were associated with obese patients only when they were examined at higher tube voltage than leaner patients. The projection considered most critical was RLAT. In it, the two professionals received the highest effective doses, that is 3.04 μSv for the main physician and 2.85 μSv for the assistant. Considering the different parameters studied, professionals were more exposed in the situation in which the smaller patient was examined at 100 kV in the RLAT projection, a situation in which workers receive both scattered and primary radiation. It was possible to conclude that the main parameter affecting occupational doses, when analyzing different patients, was tube voltage. As for equivalent doses, it was found that the eye lens was one of the organs that received the highest dose, in both professionals, even with the use of lead glasses. The results found emphasize the need for the use of individual and collective protective equipment by all professionals working in CA procedures.