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American Journal of Biomedical Engineering 2013, 3(6A): 15-21

DOI: 10.5923/s.ajbe.201310.03

Quality in Computorized Tomography – From Image Acquisition to Dose, Concepts, Myths and Definitions

António Fernando Lagem Abrantes1, Luís Pedro Vieira Ribeiro2,*, Rui Pedro Pereira Almeida3, João Pedro Pinheiro4, Kevin Barros Azevedo5, Carlos Alberto da Silva6 1PhD, Member of the Research Center of Sociologic Studies of Lisbon´s Nova University (Cesnova), Professor and Member of the Center for Health Studies (CES) of Algarve´s University Health School (ESSUAlg), Director of the Radiology Department and professor at ESSUAlg, Algarve, Portugal 2PhD, Member of the Research Center of Sports and Physical Activity (CIDAF) of Coimbra University, Professor and Member of the Center for Health Studies (CES) of Algarve´s University Health School (ESSUAlg), Algarve, Portugal 3Post-graduate, Member of the Center for Health Studies (CES), PhD Student at Beira Interior University, Professor and Member of the Center for Health Studies (CES) of Algarve´s University Health School (ESSUAlg), Algarve, Portugal 4Post-graduate, MSc student at the National Public Health School, Professor of the Radiology Department at Algarve´s University Health School (ESSUAlg), Algarve, Portugal 5Post-graduate, Member of the Center for Health Studies (CES), PhD Student at Cranfield University, Professor of the Radiology Department at Algarve´s University Health School (ESSUAlg), Algarve, Portugal 6PhD, Member of the Research Center of Sociologic Studies of Lisbon´s Nova University (Cesnova), Professor and Director of the School of Social Sciences of Évora´s University Abstract With this review article, we intend to demonstrate the importance of Computerized Tomography (CT) in healthcare quality and safety. The concept of safety in CT is wider than for general healthcare. Safe healthcare provided using CT must include diagnostic image quality and reliability, as this is the only way to ensure diagnostic accuracy. The images must be acquired with the most adequate protocols available and with the lowest achievable radiation dose. In this article we will focus primarily on the concepts of dose, since this variable strongly affects the image quality and the consequent diagnostic accuracy. In methodological terms, 73 papers and 6 catalogues issued by the manufacturers of CT equipment, that included the keywords low dose, ultra-low dose and dose reduction were analysed. After review of these articles we found that about 82% are chest exams, namely the lungs. The remaining were subdivided mainly by studies of the sinuses, heart and bone segments. After this review we selected the only 10 articles that present the keywords and simultaneously quantify the dose reduction. Given the lack of precision associated with these terms, introduced mainly by commercial catalogues of different equipment brands, we intend to demonstrate that the concepts low dose and ultra-low dose are wrapped in unclear marketing strategies, without a strict and unambiguous definition of what is the effective dose. We propose that these concepts should be clearly defined and a precise indication of the effective dose reduction value should be compared to the default value (standard diagnostic dose) by exam region. Therefore, it is demonstrated that there is no concrete definition of what low dose or ultra-low dose are. These slogans cannot be used until they are not holistically defined, as well as the correspondent dose reduction value. Keywords Dose, Low-Dose, Ultra-Low-Dose, Computed Tomography, Image Quality

1. Introduction

The preoccupation of healthcare institutions about quality, as led to a progressive implementation of management systems and procedures focused on achieving higher quality standards. A healthcare quality service is one that proves able to meet customer expectations[1]. In healthcare, quality intends to be a possible target of measurement and * Corresponding author: [e-mail] (Luís Pedro Vieira Ribeiro) Published online at http://journal.sapub.org/ajbe Copyright © 2013 Scientific & Academic Publishing. All Rights Reserved

not just a definition of good. It is more of an ongoing effort to improve, than a degree of pre-defined excellence. In relation to healthcare services, there were major changes in recent years. The increasing demand, particularly in the case of CT, meant that radiology departments had to invest effectively in their quality and not focus only on the quality of image acquisition and interpretation. This "holistic department quality" gives greater relevance to the mood and atmosphere perceived by the patient, than to the processes within the department. This concept of quality can be perverse when analyzed by the actual competitive perspective, especially focused in increasing profits through increasing the number of exams, the volume size of the

16 António Fernando Lagem Abrantes et al.: Quality in Computorized Tomography – From

Image Acquisition to Dose, Concepts, Myths and Definitions

acquisition or the reduction of collimation, since these are the factors that most influence negatively the dose in CT. When we discuss radiology, especially CT, we are referring to a diagnostic tool that is responsible for much of the artificial irradiation of populations. CT corresponds to about 25% of the annual average exposure in the U.S. (2006) and 50% of the exposure in terms of medical exams[2]. For this reason, CT is subject to strict monitoring of radiological protection, existing legislation to limit and reduce dose levels resulting from CT examinations[3]. Surveillance and safety measures, as well as the diagnostic reference levels (DRL´s), relate to amounts of radiation by examination or procedure. However, the introduction of concepts such as ultra-low-dose and low-dose are abstract and turn out to be purely qualitative, serving above all, in most cases, as marketing strategies. Such concepts do not effectively materialize the quantitative aspects of radiological exposure, fundamental to account for irradiation and absorbed dose. After reviewing 73 articles that address the concepts of reduction in dose, low dose and ultra-low dose, only 4 of them (Neroladaki et al[4], Bacher et al[5], Schuncke et al[6] and Bulla et al[7], although differing between them, point in fact an effective value of dose reduction. In this context and according to the available literature, some questions remain unanswered as we move forward. So what are we talking about when we refer to procedures, tests and equipment using ultra low-dose or low-dose? A CT equipment built under the concept of low-dose; uses this feature on all procedures or just part of them?