In recent years, computed tomography (CT) has become increasingly important in diagnostic radiology worldwide. The introduction of dual-energy CT and photon-counting computed tomography (PCCT) in clinical use has further expanded diagnostic possibilities with improved image quality without increasing patient dose (1). Iterative algorithms and deep learning reconstructions also enhance image quality by reducing noise (2, 7). Efforts to optimize CT procedures are still necessary, as per findings by UNSCEAR 2020. Despite accounting for only 10% of all examinations, CT scans contribute the highest percentage (62.6%) to the overall collective dose. The estimated annual number of CT scans is about 400 million, with an 80% increase in frequency and a 70% increase in collective dose (3).Currently, Brazil has not established diagnostic reference levels. The limited number of studies conducted in the country does not accurately reflect the situation.

According World Health Organization (WHO), the two main causes of death are associated with the following diseases: cardiovascular (ischemic disease) cardiac, stroke), respiratory (obstructive pulmonary disease). is one of the main causes of death in the world. Between 2000 and 2019, registration 77.5% increase in the number of deaths from Heart ischemic disease. Stroke and chronic obstructive pulmonary disease are 2nd and 3rd causes of death, responsible for approximately 11% and 6% of total deaths, respectively [4]. In Brazil, similar behavior was observed. Ischemic heart disease was the main cause of death between 2000 and 2017 for both sexes, Although there has been a reduction in mortality rates of 31.8% for people between 60-64 years old and 24.9% for the elderly (80+ years old) (5).

The aim is this work is to evaluate routine angiographic procedures that have potential for high dose on patients but are crucial for diagnostic of severe conditions such as CT brain perfusion, coronary computed tomography angiography CCTA, CT pulmonary angiography (CTPA), and brain angiography, using the anthropomorphic phantom Alderson-rando and TLD-100 LiF dosimeters. Estimate the doses absorbed in different organs, the effective dose and corresponding CTDIvol and DLP values ​​applying different protocols used in chest and head angiographic procedures.

1. Materials

TLD dosimeters (LiF:Mg,Ti TLD100) will be individually calibrated for the appropriate beam energy according to the methodology described by Yoshizumi (16). Alderson-Rando adult male anthropomorphic simulator (CIRS ATOM ®), available at IRD. The simulator features 25 mm thick sections and allows you to position the TLDs in 21internal organs

2. Methodology

The study was carried out in one hospital in Rio de Janeiro. The simulator anthropomorphic was scanned with routine protocols to obtain absorbed doses in organs and effective doses and one protocol elaborated using cientific literature and international recommendations. CT beam dosimetry was carried out for control of CT scanner dose.

            Results

            Most of procedures are in according with the reference levels of administered dose. Although some procedures could have optimized protocols, for dose reduction without compromising diagnostic practice.