Technology plays an important role in modern medical centers, making healthcare increasingly complex, relying on complex technical equipment. This technical complexity is particularly noticeable in the nuclear medicine. Poorly design human–system interfaces can increase the risks for human error. The human-centered approach emphasizes the development of the equipment with a deep understanding of the users activities, current work practices, needs and abilities of the users. An important concept of human-centered design is that the ease-of-use of the equipment can be ensured only if users are actively incorporated in all phases of the life cycle of design process. Representative groups of users are exposed to the equipment at various stages in development, in a variety of testing, evaluation and interviewing situations. The users feedback obtained is then used to refine the design, with the result serving as input to the next interaction of design process. The limits of the approach are that the users cannot address any particular future needs without prior experience or knowledge about the equipment operation. The aim of this paper is to present a methodological framework that contributes to the design of the human-system interfaces, through an approach related to the users and their activities. A case study is described in which the methodological framework is being applied in development of new human-system interfaces of the thyroid uptake system

FARIAS, Marcos S.

MONTEIRO, Beany G.

MONTEIRO, Jonathan K. R.

SANTOS, Isaac J. A. Luquetti

Carpe dIEN

2013 International Nuclear Atlantic Conference - INAC 2013 
Recife, PE, Brazil, November 24-29, 2013 
ASSOCIAÇÃO BRASILEIRA DE ENERGIA NUCLEAR - ABEN 
ISBN: 978-85-99141-05-2 
 
 
HUMAN-CENTERED DESIGN OF THE HUMAN-SYSTEM 
INTERFACES OF MEDICAL EQUIPMENT: THYROID UPTAKE 
SYSTEM 
 
 
Jonathan K. R. Monteiro
1
, Marcos S. Farias
1
, Beany G. Monteiro
2 
, Isaac J. A. Luquetti 
Santos
1 
 
1
 Instituto de Engenharia Nuclear (IEN/CNEN-RJ) 
Laboratório de Usabilidade e Confiabilidade Humana (DENN/SEESC) 
Rua Hélio de Almeida, 75 
21945-906 Cidade Universitária, RJ 
luquetti@ien.gov.br 
 
2
 Universidade Federal do Rio Janeiro (UFRJ) 
Departamento de Desenho Industrial 
Cidade Universitária, Ilha do Fundão 
21941-590 Rio Janeiro, RJ 
 
 
 
ABSTRACT 
 
Technology plays an important role in modern medical centers, making healthcare increasingly complex, relying 
on complex technical equipment. This technical complexity is particularly noticeable in the nuclear medicine. 
Poorly design human–system interfaces can increase the risks for human error. The human-centered approach 
emphasizes the development of the equipment with a deep understanding of the users activities, current work 
practices, needs and abilities of the users. An important concept of human-centered design is that the ease-of-use 
of the equipment can be ensured only if users are actively incorporated in all phases of the life cycle of design 
process. Representative groups of users are exposed to the equipment at various stages in development, in a 
variety of testing, evaluation and interviewing situations. The users feedback obtained is then used to refine the 
design, with the result serving as input to the next interaction of design process. The limits of the approach are 
that the users cannot address any particular future needs without prior experience or knowledge about the 
equipment operation. The aim of this paper is to present a methodological framework that contributes to the 
design of the human-system interfaces, through an approach related to the users and their activities. A case study 
is described in which the methodological framework is being applied in development of new human-system 
interfaces of the thyroid uptake system. 
 
 
1. INTRODUCTION 
 
Human error has many causes such as performance shaping factors, organizational factors 
and user interface design [1]. The technical complexity and poorly design human–system 
interfaces may increase the risks for human error. Complex medical equipment can exhibit 
problems in man-machine interaction that could trigger a human error [2]. An interface can 
be defined as part of a system with which users carry out contact through the physical and 
cognitive plan. The user interface is composed of information, data, controls and commands 
in computer screens. Nuclear medical equipment designed using usability criteria can 
INAC 2013, Recife, PE, Brazil. 
 
improve operational reliability and time required to learn how to use the equipment can be 
reduced. The evaluation process of human-system interfaces has as objective to prove that the 
functions and tasks can be executed with safety by users. User interfaces must have high 
usability in order to create prerequisites for safe operation, installation, maintenance and 
increase the efficiency of the interaction.. 
  
Usability is the extent to which a product can be used by specified users to achieve specified 
goals with effectiveness, efficiency and satisfaction in a specified context of use [3]. An 
important concept of human-centered design is that usefulness and ease-of-use can be 
ensured only if users are actively incorporated in the equipment design cycle. The most 
accepted way of involving users in the design of equipment is through a process of iterative 
refinement [4]. Representative groups of users are exposed to the equipment at various stages 
in development, in a variety of tests. The users feedback obtained is then used to refine the 
design, with the result serving as input to the next interaction of design process.  
 
Participatory ergonomics involves users actively engaged in system development and 
analysis of ergonomics problems. It emphasizes system development with a deep 
understanding of the activities performed by users, of their current work practices, of their 
needs and skills. The goal is to encourage and support work force participation in the 
analysis, redesign and evaluation of their own tasks, workplaces and work practices by 
applying different methods and techniques [5]. 
 
The human-centered design requires design activities that should take place during the system 
development. These activities are: to understand and specify the context of use; to specify the 
users and organizational requirements; to produce design solutions and to evaluate designs 
against requirements. The human-centered design process should start at the earliest stage of 
the project (e.g. when the initial concept for the product or system is being formulated), and 
should be repeated iteratively until the system meets the requirements [3].  Human-centered 
design needs a variety of skills. A range of personnel is necessary to address the human 
aspects of the design. This means that a multi-disciplinary team should be involved in a 
human-centered design process.  
 
The aim of this paper is to present a methodological framework that contributes to the 
human-system interfaces design of the thyroid uptake system, through an approach related to 
the users and their activities. The methodology includes human factors standards, 
questionnaires and the participation of a multidisciplinary team. The research is based on 
field studies in the Clementino Fraga Hospital, UFRJ, in Rio de Janeiro and includes the 
thyroid uptake system developed in Nuclear Engineering Institute. 
 
 
 
2. THE THYROID UPTAKE SYSTEM  
 
The actual model of the thyroid uptake system is a nuclear pulse counting digital system 
compact, of easy operation and low power consumption, capable to assist mainly the 
activities related to nuclear medicine. The equipment is intended for measuring of counting of 
ionizing radiation in diagnosis exams “in - vivo” and radiotherapy in experiences "in-vitro". 
It is operated through one personal computer and specific software that comes together the 
equipment. The useful graphic interface developed for thyroid uptake exams makes possible 
INAC 2013, Recife, PE, Brazil. 
 
to the user the system operation. It allows the user to select the desired function, such as, 
verification and calibration of the system, and updating of the data of the exam. Once defined 
the function that the user has chosen, a corresponding window will appear in the screen. At 
the end of the procedure, the graphic interface informs to the user, through the main screen, 
the value of the percentile uptake of the iodine absorbed by the thyroid gland. The main 
screen is shown in figure 1. Figure 2 shows the screen of data entry. This screen is shown 
when the option selected  in the main screen is UP TO DATE.  
 
 
 
 
 
Figure 1. Main screen  
 
 
 
Figure 2. Data entry screen 
 
 
 
3. METHODOLOGICAL FRAMEWORK  
 
 
The principal objective of the methodological framework is to present a specific approach for 
the human-system interfaces development of the thyroid uptake system. It include the use of 
human factors and ergonomics standards, human factors guidelines and the participation of 
multidisciplinary team that actively participates in development of the system, bringing 
together different information sources, representations, perspectives and fundamental 
principles.  
 
 
INAC 2013, Recife, PE, Brazil. 
 
The first level concerns the definition of a multidisciplinary team. The composition of the 
team should reflect the relationship between the organization responsible for technical 
development and the users. It includes human factors experts, industrial designers and 
electronic and nuclear engineers.  
 
The second level concerns the assignment of the responsibilities and tasks to the 
multidisciplinary team. The tasks and responsibilities are assigned to each team member 
according to their technical capabilities. The human factors experts are required to coordinate 
the overall discussion related to human factors requirement and to carry out the methodology. 
Users provide information in response to questions related to their needs, work practices and 
the operation of similar equipment. All the necessary activities for the identification of system 
mission are carried out and safety aspects, technological restrictions and users performance 
are discussed. The second level summarizes various activities, such as choice of the human 
factors and ergonomics standards and guidelines. 
 
The third level concerns the identification of the conceptual design requirements. It is related 
to the following item such as definition of operational system; definition of visual identity of 
new interfaces; organization and information grouping and use of colors. 
 
 
3.1. Definition of operational system 
 
The choice of operational system influences directly on the layout of the interface, as well as 
their basic control commands. The operational system chosen is Microsoft operating system, 
Windows 8 .  
 
 
3.2. Definition of visual identity of new interfaces  
 
Windows 8 presents layout of straight lines and primary colors. This kind of visual identity is 
more practical and consistent with the development of an interface for nuclear medicine, 
except for the great variety of colors, which can confuse the user. Windows 8 presents the 
information organization through visible icons, aiding in navigation with little cognitive 
effort. The interface framework is designed using full screen. It enables the use of any control 
layout of the window, such as maximize, minimize and close. It occupies the entire active 
area of 1280 x 1024 pixels. The choice implies in the development of new window 
commands and the use of specific keys by users to control the Windows. Several studies were 
made in black and white color (maximum contrast and readability), so that there was no 
interference in the perception of color. Buttons and displays were applied to sketches and its 
contours and position were changed. The screens layout was designed in order to help the 
users to carry out of the tasks and tries to occupy the smallest space possible without 
compromising the reading. The use of the buttons and displays remains equal as the existing 
interfaces, using the standard rectangular format accepted on interfaces for nuclear area, and 
according to the recommendations of the ISO 9241 [3] and NUREG-0700 [6]. 
3.3. Organization and information grouping  
 
The organization of the information grouping was kept as close as possible to the original 
interfaces, in order to facilitate the learning and training. The information is grouped by 
INAC 2013, Recife, PE, Brazil. 
 
blocks, represented by icons that facilitate navigation and reduce the amount of information 
displayed, reducing visual fatigue and possible errors caused by navigation difficulty. The 
icons organization on the screen follows a order, closely linked to the tasks performed by 
users.  
 
 
3.4. Use of colors 
 
According to NUREG-0700 guideline [6], there are eight acceptable colors that can be used 
in the interfaces development. The colors are red, yellow, green, cyan, blue, magenta, white 
and black. Each one is represented by the level of attention and contrast relations among 
themselves. For good level of attention is necessary to use red and yellow. 
 
 
 
4. RESULTS 
 
 
In this item results of the methodological framework application are presented. The 
multidisciplinary team included two human factors experts, one industrial design, one 
electronic engineer and two users.  The tasks and responsibilities were assigned to each team 
member according to their technical capabilities. 
 
The multidisciplinary team decided to use the standard ISO 9241 and guideline NUREG 700 
[6] as references. The NUREG 700 provides one section dedicated to basic human system 
interface elements. The basic human system interfaces elements are: information display, 
user-interface interaction and controls.  
 
ISO9241 [3] series are the first HCI related ISO standards. It provides the definition of 
usability and explanations how to identify the information when specifying or evaluating 
usability. The principal information are: designing user-system dialogues and interface 
navigation; selecting displays; designing or selecting alphanumeric keyboard; keyboards and 
other input devices; designing workplaces for display screen users and recommendations for 
the design and evaluation of user guidance attributes of software user interfaces 
 
The multidisciplinary team decided to choose an old version of thyroid uptake system, as 
reference equipment to be analyzed. This analysis was used to discover salient features of the 
reference equipment that should be similar to those under development.  
 
The industrial design is responsible for the initial sketch of the interfaces framework layout 
and details about the information to be presented.  The following interfaces were developed: 
Initial screen; equipment calibration; general information of the patient, isotope and doctor; 
particular information of the patient; particular information of the doctor; particular 
information of the isotope; radiation counting results; background radiation counting;  results 
report. Figure 3 shows the initial screen. Figure 4 shows the calibration screen. Figure 5 
shows patient information. 
 
 
 
INAC 2013, Recife, PE, Brazil. 
 
 
 
 
 
Figure 3. Initial screen 
 
 
 
 
 
Figure 4. Calibration screen 
 
 
 
 
INAC 2013, Recife, PE, Brazil. 
 
 
 
Figure 5. Patient information 
 
 
 
5. CONCLUSIONS 
 
 
Human-centered design must actively involve the users in product development in all phases 
of the design process. Users are not simply consulted at the beginning and called in to 
evaluate the system at the end. They must be treated as partners throughout the design 
process. Receiving user feedback at each phase of the process also changes the nature of the 
final evaluation, which is used to refine the interface rather than discover major usability 
problems. The main purpose of this study is to investigate the use of usability and ergonomic 
criteria as powerful tool for nuclear medical equipment development. Design decisions made 
in the early phases, such as requisite functionality, choice of platform and software 
architecture, does affect the usability of the system. If effective evaluations are carried out 
during all design process, problems can be discovered before too much investment in the 
design has been made. The final objective of this paper was to present and apply a 
methodological framework that contributes to the design of the human-system interfaces, 
through an approach related to the users. The methodology includes human factors standards, 
questionnaires and the participation of a multidisciplinary team. The research is based on 
field studies and includes the development of new human-system interfaces of thyroid uptake 
system, developed in Nuclear Engineering Institute. 
 
ACKNOWLEDGEMENTS 
The authors gratefully acknowledge the support of National Advice of Scientific and 
Technological Development (CNPQ-Conselho Nacional de Desenvolvimento Científico e 
Tecnológico). The research was performed at Laboratory of Usability and Human Reliability 
(LABUCH), Rio de Janeiro, Brazil (SEESC / IEN). 
 
INAC 2013, Recife, PE, Brazil. 
 
 
REFERENCES 
 
1. J. Reason, “Human Error”, Cambridge University Press,  Cambridge (1990). 
2. W. A Hyman, “Errors in the Use of Medical Equipment”, Human Error in Medicine, 
Lawrence Erlbaum Associates, Inc. London (1994). 
3. International  Organization for Standardization, ISO 9241. Usability requirements (1994). 
4. C. M. Pancake, “A Collaborative Effort in Parallel Tool Design” in Environments and 
Tools for Parallel Scientific Computing, J. Dongarra and B. Tourancheau, eds. SIAM, 
pp.112-118 (1994). 
5. A. S. Imada, “Participatory Ergonomics”, Ergonomics Society of Australia, Sydney, Vol. 
88,  pp. 711–713 (1991). 
6. U. S. Nuclear Regulatory Commission NUREG 0700, Revision 2, Human System 
Interface Design Review Guideline (2002).  
 
 
 
 


HUMAN-CENTERED DESIGN OF THE HUMAN-SYSTEM INTERFACES OF MEDICAL EQUIPMENT: THYROID UPTAKE SYSTEM

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HUMAN-CENTERED DESIGN OF THE HUMAN-SYSTEM INTERFACES OF MEDICAL EQUIPMENT: THYROID UPTAKE SYSTEM

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