http://informahealthcare.com/ebm
ISSN: 1536-8378 (print), 1536-8386 (electronic)
Electromagn Biol Med, Early Online: 1–5
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2015 Informa Healthcare USA, Inc. DOI: 10.3109/15368378.2014.999373
ORIGINAL ARTICLE
Dosimetry of electromagnetic field exposure of an active armlet and its
electromagnetic interference to the cardiac pacemakers using adult,
child and infant models
Hu Yang
1
, Yuduo Wang
1
, Jiangang Yang
2
, and Tongning Wu
3
1
School of Information and Communication Engineering, Beijing Information Science and Technology University, Beijing, China,
2
Tianjin Medical
Devices Quality Supervision and Testing Center, Tianjin, China, and
3
China Academy of Telecommunication Research of Ministry of Industry and
Information Technology, Beijing, China
Abstract
Wearable devices have been popularly used with people from different age groups. As a
consequence, the concerns of their electromagnetic field (EMF) exposure to the human body
and their electromagnetic interference (EMI) to the implanted medical devices have attracted
many studies. The aim of this study was to evaluate the human exposure to the EMF of an
active radiofrequency identification (RFID) armlet as well as its EMI to the cardiac pacemaker
(CP). Different human models from various age groups were applied to assess the result
variability. The scalar potential finite element method was utilized in the simulation. Local EMF
exposure and the exposure to the central nerve system tissues were evaluated using different
metrics. EMI to the CP was assessed in terms of the conducted voltage to the CP. The results
from all the models revealed that the studied RFID armlet would not produce the EMF exposure
exceeding the safety limits. The calculated interference voltage was highly dependent on the
distance between the RFID armlet and the CP (i.e. the physical dimension of the individual
model). The results proposed to evaluate the appropriateness of the current EMI measurement
protocol for this kind of devices used by the infants.
Keywords
Electromagnetic field exposure,
electromagnetic interference, infant
model, variability, wearable devices
History
Received 9 September 2014
Revised 10 December 2014
Accepted 14 December 2014
Published online 7 January 2015
Introduction
The rapid development of the wearable technology gave rise
to the ubiquitous electromagnetic field (EMF) emitters
surrounding the human body. Notably, besides the usage by
the adults, these wearable EMF emitters appeared more
frequently than ever before in nurseries and maternity wards.
For example, the active radiofrequency identification (RFID)
armlet, bracelets or anklets became popularly used to prevent
the unauthorized delivery of the neonates (Collins, 2005;
Szekendi et al., 2006; Xiao et al., 2007). When a baby was
born, the mother and child could wear a bracelet/armlet/anklet
which contained an active RFID tag. This tag emitted and
received the signals intermittently to ensure that the baby was
within a certainty distance to its mother. The RFID reader
could be deployed at the border of the secured and the
unsecured area. Any unauthorized displacement out of the
secured area would trigger the alarm.
Emitters of this kind functioned at around 10 MHz.
Although they were featured with low power consumption,
they introduced concerns not only for EMF safety
(Bernhardt et al., 2002) but also for the electromagnetic
interference (EMI) to the medical devices, particularly, with
the implantable medical devices (IMDs; Irnich, 2002;
Seidman et al., 2010).
Local EMF exposure should be assessed as the physical
separation between the devices and the human body could be
within several centimeters, which would possibly result in
significant local absorption. Furthermore, the distance
between the emitter and the neonate’s central nerve system
(CNS) tissues was smaller compared with that of an adult,
which theoretically associated with higher induced E-field
strength. Although no evident link between the long-term,
low-level EMF exposure and the health effect of human was
established, some animal studies suggested the possible
correlation with the adverse biological effects (Toler et al.,
1998). Thus, the dosimetric analysis was necessary to
characterize the realistic exposure dose.
On the other hand, the emission of this kind of devices can
lead to EMI to the IMDs including cardiac pacemakers (CP)
and implantable cardioverter defibrillators. If the external
E-field coupled with the metallic lead (which acted as a
receiving antenna; Wang et al., 2000) so as to produce a high
Address for correspondence to Tongning Wu, China Academy of
Telecommunication Research of Ministry of Industry and Information
Technology, No. 52, Huayuan bei Road, Beijing 100191, China. Tel/Fax:
+86-10-62304633-2084. E-mail: toniwoo@gmail.com
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