Otimização de Protocolos usados na Rotina Clínica de um Tomógrafo em um Hospital Universitário

Abstract

Computed tomography (CT) is a technique that uses ionizing radiation to acquire images in slices. In order to guarantee the correct functioning of the equipment and the image quality for an adequate diagnosis, the optimization of medical exposures to radiation, as well as the quality control of the CT equipment are necessary, as recommended by Resolution RDC nº 330 in its annex IN nº 93. The radiation dose used in CT scans should be as low as possible to generate an image of diagnostic quality. The objective of the work is to suggest optimized protocols that can be used in clinical practice in routine exams. The contrast noise ratio (CNR) and the volume computed tomography dose index (CTDIvol) were used to calculate figures of merit (FOM). The manufacturer's phantom (TOS) was used to calculate the RCR and the CTDIvol indicated to equipment was registred. The criterion established to define the best protocol was based on FOM. For the optimization of skull exams, the protocol that stood out the most promoted an increase in FOM of 24.9% in relation to the protocol used in clinical practice. Among the chest and abdomen protocols, the one that stood out the most for the FOM value was the one that increased the voltage value from 120 kVp to 135 kVp. In this protocol, the FOM value increased by 8.4% compared to the routine protocol. Other protocols were tested and greater CTDIvol reductions were recorded, enabling an optimization process.