Dose to sensitive organs due to scattered radiation during chest CT

The use of ionizing radiation for the treatment and diagnosis of diseases is more frequent. The technologies associated with diagnostic imaging are constantly evolving, allowing faster and cheaper diagnoses to benefit the patient. However, this has caused an increase in exposure to ionizing radiation for both patients and health professionals. One of the diagnostic techniques for obtaining high-resolution anatomical images of patients is computed tomography (CT). Due to the type, detail and quality of the images obtained with CT its use is becoming more frequent. The information provided by these images allows the specialist to make better diagnoses; however, exposure to X-rays deposits a dose in the patient. CT represents approximately 20% of all x-ray examinations; however, due to its characteristics, it is responsible for 70% of the medical dose accumulated by the patient. During the acquisition of the images, the highest dose is deposited in the area of the body whose image is to be obtained. During the incidence of X-rays there is dispersion of these that reach sensitive organs whose dose is not evaluated. The aim of this work was to estimate, using Monte Carlo methods, the dose to sensitive organs due to scattered radiation during chest CT. With the MCNP5 code the CT equipment and a hybrid anthropomorphic phantom, type BOMAB, with lenses, thyroid, mammary glands and reproductive organs were modeled. It was found that the absorbed dose in these organs depends on the size of the organ and the distance between the organ and the surface of the cut on the thorax where the X-rays are incident. (author)