Purpose: The aim of the current attempt was quantitative investigation of the

electromagnetic interference (EMI) of amobile phonewith the function of a SPECT

gamma camera during data acquisition.

Materials and Methods:We tested the effect of a mobile phone, in both ringing

mode and standby mode, on one SPECT gamma camera during scanning a cylindrical

phantom containing 5.4 mCi 99mTc. The experiment was performed for

different distances of 10, 12, 14, 16, 18, 20, 25, and 30 cm betweenmobile phone

and head of the scanner, and for different head angles of 0, 30, 60, 90, 120, 150,

and 180 degrees. A RF-EMF meter measured strength of electromagnetic field

throughout the study. Statistically significant decrease in count number was considered

to be electromagnetic interference.

Results: There was significant reduction in the recorded counts during ringing of

the mobile phone in all studied distances. For gamma camera, fixed at a distance,

there was no uniform pattern of reduction of the counts at different angles between

two operation modes of the mobile phone.

Conclusions: A mobile phone, at close distance, can be a sensible source of electromagnetic

field, disturbing the normal function of a gamma camera

Assadi, Majid

Jafarian Dehkordi, Forough

Pashazadeh, AliMahmoud

Tanha, Kaveh

Bushehr University of Medical Sciences Repository

ORIGINAL ARTICLEThe Effect of Electromagnetic Field Generated by a Mobile Phoneon the Performance of a SPECT ScannerA Quantitative StudyAli Mahmoud Pashazadeh, MSc, Forough Jafarian Dehkordi, MSc, Kaveh Tanha,MSC, andMajid Assadi, MDPurpose: The aim of the current attempt was quantitative investigation of theelectromagnetic interference (EMI) of amobile phonewith the function of a SPECTgamma camera during data acquisition.Materials andMethods:We tested the effect of a mobile phone, in both ringingmode and standby mode, on one SPECT gamma camera during scanning a cylin-drical phantom containing 5.4 mCi 99mTc. The experiment was performed fordifferent distances of 10, 12, 14, 16, 18, 20, 25, and 30 cm between mobile phoneand head of the scanner, and for different head angles of 0, 30, 60, 90, 120, 150,and 180 degrees. A RF-EMF meter measured strength of electromagnetic fieldthroughout the study. Statistically significant decrease in count number was con-sidered to be electromagnetic interference.Results: There was significant reduction in the recorded counts during ringing ofthe mobile phone in all studied distances. For gamma camera, fixed at a distance,there was no uniform pattern of reduction of the counts at different angles be-tween two operation modes of the mobile phone.Conclusions:Amobile phone, at close distance, can be a sensible source of elec-tromagnetic field, disturbing the normal function of a gamma camera.Key Words: quantitative, electromagnetic interference, mobile phone,SPECT, gamma camera(Clin Nucl Med 2015;40: 545–547)E lectromagnetic interference (EMI) of mobile phones with the func-tion of medical devices is an unfavorable event that may result inmalfunctioning of this life-supporting equipment.1–6 Today, mobilephones have been translated from a just communication tool intocan-not-live-without device, increasing the probability that it may cometo the vulnerable medical devices.Although, up to now, number of reported significant medicalerrors that resulted from mobile phone interference with medical deviceshave been relatively rare, yet in the literature several cases of EMI andconcomitant errors have been published.7–9 Results of the studies haveindicated that based on the factors such as type of medical device andmobile phone, and also separation distance between these two, differentlevels of EMI may occur.10 Gamma camera of a SPECT scanner is partof medical systems that may be susceptible to the electromagnetic field(EMF) generated by mobile phone.7,11,12 SPECT is a routine imagingmodality that provides images from bio-distribution of radioisotopesinside the body. The first clinical evidence of mobile phone EMI withSPECT scanner was a case report in which function of a gamma camerahad been interrupted by ringing of a mobile phone, located in a patient’spocket, as light spots on frame 6 of the flow phase in the acquired imageduring the renal scintigraphy.7 This vulnerability is largely because ofthe photomultiplier tubes (PMTs) that are used to intensify acquiredReceived for publication August 25, 2014; revision accepted February 12, 2015.From the Persian Gulf Nuclear Medicine Research Center, Bushehr University ofMedical Sciences, Bushehr, Iran.This study was financially supported by Bushehr University of Medical Sciences.Conflicts of interest and sources of funding: none declared.Reprints: Ali Mahmoud Pashazadeh, MSc, The Persian Gulf Nuclear Medicine Re-search Center, The Persian Gulf Biomedical Sciences Institute, Boostan 19 Alley,Sangi St, Bushehr, Iran. E-mail: a.pashazadeh@bpums.ac.ir.Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.ISSN: 0363-9762/15/4007–0545Clinical Nuclear Medicine • Volume 40, Number 7, July 2015Copyright © 2015 Wolters Kluwer Hsignal of the detected photons.13 Electromagnetic interference with thefunction of photomultiplier tubes, and consequently with the operationof gamma camera, dates back before the 1980s in which former modelsof SPECT scanners were being affected by the earth’s magnetic fieldduring rotation of head gantry.14 Whereas from those observations on-wards, magnetic shielding has been applied in PMT designing to provideprotection and stability necessary for acceptable function of gammacameras in the presence of the earth’s magnetic field, yet this shieldingseems not to be well enough to avoid interference by mobile phone’sgenerated field. In the former study, we qualitatively investigated suchinterference based on visual interpretation of a nuclear medicine physi-cian.11 Results of that evaluation, performed by 7 different models ofmobile phones, indicated that some types of mobile phones have the ca-pability to induce interruption on the function of the gamma camera,leading to a decrease in the recorded counts of the 99mTc activity.11As our previous attempt1 was a qualitative rather than a quantitativestudy, which has its limitations, therefore in this study we were goingto study EMI of a mobile phone on the function of a gamma camerain a quantitative way.METHODSTechnical EquipmentThe study was performed on a rotating dual-head digital gammacamera (ADACPegasys; model SHGenesys Epic,Milpitas, CA), locatedin our nuclear medicine clinic, that was equipped with a low-energy all-purpose parallel whole collimator.To generate an electromagnetic field, one Nokia 3350 (Nokia,Finland) mobile phone, operated with GSM communication system inthe frequency of 900 MHz, was chosen for the study and placed in thecenter of rotation of the scanner.Measurements of the EMF strength throughout the study weredone using a RF-EMF meter (EXTECH, USA).Source of activity consisted of 5.4 mCi 99mTc that was diluted inabout 17 cm2 of water. Then the solution was poured inside a cylindricalphantom with the dimension of 27(diameter)mm  142 (length)mmand was placed near the mobile phone.To assess the effects of distance on induced EMI, we used one ofthe camera’s head. Head of the camera was fixed at a 90-degree angle,then the study was performed at 8 different distances of 10, 12, 14, 16,18, 20, 25, and 30 cm.Also, to evaluate the effect of head angle, SPECT camerawas setat the radius of rotation (ROR) of 30 cm, then phantom was scanned atdifferent angles of 0, 30, 60, 90, 120, 150, and 180 degrees by bothheads. For each angle, recorded counts of 2 heads were averaged to cal-culate the average of the counts of that particular angle.In each scenario, the function of the gamma camerawas tested instandby and ringing modes of mobile phone, and for each mode, activitywas scanned for 10 s. The criterion that was considered as interferenceof the mobile phone with the function of the camera was significantreduction in the recorded counts of radioactivity in each scan.To do statistical evaluation of the data, all steps of the study wererepeated three times and SD of the measurements was calculated.www.nuclearmed.com 545ealth, Inc. All rights reserved.TABLE 1. Recorded Counts of 99mTc by Gamma Camera During 10 s in Standby and Ringing Modes of the Mobile Phone at DifferentAngles of Camera HeadAngle of the Camera (Degrees) 0 30 60 90 120 150 180Recorded counts (±SD) Standby mode 67,500 ± 228 69,701 ± 633 64,837 ± 222 63,064 ± 666 65,487 ± 117 67,825 ± 134 67,465 ± 231Ringing mode 65,325 ± 702 68,305 ± 208 62,951 ± 38 62,765 ± 152 63,256 ± 123 67,456 ± 200 64,987 ± 787TABLE 2. Recorded Counts of 99mTc by Gamma Camera During 10 s in Standby and Ringing Modes of the Mobile Phone at DifferentDistances From Camera HeadDistance of the Camera Head FromPhantom/Mobile Phone (cm) 10 12 14 16 18 20 25 30Recorded count (±SD) Standby mode 78,892 ± 250 77,402 ± 82 76,408 ± 98 75,670 ± 226 74,848 ± 184 74,323 ± 123 73,751 ± 335 73,165 ± 53Ringing mode 77,922 ± 185 76,879 ± 67 76,115 ± 27 75,452 ± 180 74,286 ± 226 73,747 ± 158 73,040 ± 125 72,550 ± 84Pashazadeh et al Clinical Nuclear Medicine • Volume 40, Number 7, July 2015Comparison of the data was done with statistical test of two-wayrepeated measures.RESULTSIn this study, to quantitatively assess mobile phone EMI with thefunction of a SPECT gamma camera, the operation of the scanner wastested at different RORs and different rotation angles when one mobilephone was being placed at the center of the rotation. Results of thestudy including rotation angles, RORs, and corresponding recordedcounts in standby and ringing modes in each scenario are summarizedin Tables 1 and 2.Measurements of the electromagnetic field of mobile phonewithRF-EMF meter revealed that this quantity decreased exponentially asthe distance frommobile phone increased (Fig. 1). A similar falling trendwas observed in recorded counts of 99mTc activity by gamma camera forboth standby and ringing modes of mobile phone, when distance ofgamma camera from center of rotation increased. Also for each dis-tance, recorded counts of activity were significantly lower when mobilephone was operating in ringing mode than in standby mode (Fig. 2)FIGURE 1. Electromagnetic field of mobile phone at differentdistances when operated in ringing mode.546 www.nuclearmed.comCopyright © 2015 Wolters Kluwer H(P < 0.05). The only exception for this observation was at a distanceof 16 cm in which the difference was insignificant.Analysis of the data of the rotation test revealed that recordedcount by gamma camera, fixed at ROR of 30 cm, has different values atdifferent angles, and in some angles this difference is statistically signif-icant (Fig. 3).DISCUSSIONThe aim of the present attempt was quantitative investigation ofelectromagnetic interference of mobile phone with the function of aSPECT scanner. In fact, we considered a hypothetical situation in whichmobile phone may come in close distance of a gamma camera. Inter-ruption in normal operation of a gamma camera, as visual reduction inthe recorded counts of the 99mTc that resulted from mobile phone field,in our previous study encouraged us to set an experiment to quantitativelystudy the phenomenon. The criterion for interferencewas statistically sig-nificant difference in the counts of the 99mTc recorded by the scanner.Based on the RF-EMF meter measurements, electromagneticfield generated by mobile phone, when it was in standby mode, wasFIGURE 2. Recorded counts of 99mTc activity by gamma cameraat different distances from center of rotation when mobilephone is operated in standby and ringing modes.© 2015 Wolters Kluwer Health, Inc. All rights reserved.ealth, Inc. All rights reserved.FIGURE 3. Recorded counts of 99mTc activity by gamma camera at different rotation angles whenmobile phone is operated in standbyand ringing modes.Clinical Nuclear Medicine • Volume 40, Number 7, July 2015 Mobile Phone Effect on SPECTof the order of background level, and there was no significant changein this quantity before and after the presence of mobile phone in itsposition in the center of the SPECT scanner in this mode. But, when-ever its operation status changed into ringing mode, RF-EMF metershowed remarkable increase in the electromagnetic field, indicatingpotential of mobile phone to remarkably enhance EMF of the environ-ment in its vicinity.We observed that at close distance, less than 30 cm, ringing ofmobile phone is able to adversely affect function of a gamma camera,although there was an exception in distance of 16 cm. Therefore, wecan conclude that ringing of mobile phone carried by the patient underscan may have unfavorable effect on acquired data during gamma scan.This can be more highlighted in cases when the head of the camera is inclose contact with the patient, a situation that may take place duringrenal scintigraphy.According to measurements, strength of EMF generated by mo-bile phone at a distance of 10 cm was four times more than that at30 cm. This observation highlights the importance of distance on thestrength of EMF field. Perhaps, one-meter policy, recommended by someresearches, provides a fairly secure zone to avoid such interference. In asimilar study by Stegmayr et al to assess potential of mobile phone anddigitally enhanced cordless telecommunication (DECT) device to in-duce adverse impact on SPECT, they found that while at distances of0, 30, and 42 cm, interference may occur, but at greater than 2 m, anyeffect was not observed.12After SPECTwas set at ROR of 30 cm and operated at step andshoot mode with interval angles of 30 degrees, we observed that whilefor some angles the differences in the recorded counts were significant,for other angles such change was not observed. On the other hand, thepattern of malfunctioning of device in both standby and dialing modesof the mobile phonewas non-uniform. The reason behind such observa-tion perhaps lay in the spatial distribution of the electromagnetic field.Situations such as variable noise in the room, room geometry, materialsused in the room walls, and reflexing factors in the environment of thestudy may affect distribution pattern and hence strength of the field, thesituations that were not under our control to avoid.Based on the results of the present study, we conclude that thereis a certain level of EMF as background that SPECT is well protectedagainst such amount of EMF. But mobile phone as a portable sourceof electromagnetic field may change this level when ringing. It wasthe reason that the presence of mobile phone operating in standby modenear the SPECT gamma camera had no sensible effect on the function© 2015 Wolters Kluwer Health, Inc. All rights reserved.Copyright © 2015 Wolters Kluwer Hof the camera, but in ringing mode it leads to malfunctioning of thescanner as a significant decrease in the recorded counts by the camera.ACKNOWLEDGMENTSThe authors would like to thankDr. Mohammad Seyedabadi for his kindhelp during statistical analysis of the data. We also thank Mrs NargesJamili who helped us to collect data.REFERENCES1. Mahmoud Pashazadeh A, Aghajani M, Nabipour I, et al. An update on mobilephones interference with medical devices. Radiat Prot Dosimetry. 2013;156:401–406.2. Ang G, Lian P, NgW, et al. Digital mobile telephones and interference of ophthal-mic equipment. Eye. 2005;21:29–32.3. Dang BP, Nel PR, Gjevre JA.Mobile communication devices causing interferencein invasive and noninvasive ventilators. J Crit Care. 2007;22:137–141.4. Fernández-Chimeno M, Silva F, eds. Mobile phones electromagnetic interferencein medical environments: a review. IEEE International Symposiumon Electro-magnetic Compatibility (EMC). 2010:311–316.5. Tandogan I, Temizhan A, Yetkin E, et al. The effects of mobile phones on pace-maker function. Int J Cardiol. 2005;103:51–58.6. Hekmat K, Salemink B, Lauterbach G, et al. Interference by cellular phones withpermanent implanted pacemakers: an update. Europace. 2004;6:363–369.7. Azizmohammadi Z, Baharfar N, Javadi H, et al. Effect of mobile cell phone ring-ing on function of gamma camera. Clin Nucl Med. 2011;36:1131.8. Tri JL, Hayes DL, Smith TT, et al., eds. Cellular phone interference with externalcardiopulmonary monitoring devices. Mayo Clinic Proceedings; 2001: Elsevier.9. Van Lieshout EJ, Van Der Veer SN, Hensbroek R, et al. Interference by new-generation mobile phones on critical care medical equipment. Crit Care. 2007;11:165.10. Cohen T, Ellis WS,Morrissey JJ, et al. Safe use of cellular telephones in hospitals:fundamental principles and case studies. J Healthc Inf Manag. 2005;19:39.11. Javadi H, Azizmohammadi Z, Mahmoud Pashazadeh A, et al. The electromag-netic interference ofmobile phones on the function of a gamma-camera.Clin NuclMed. 2014;39:232–236.12. Stegmayr A, Fessl B, Hortnagl R, et al. Interference ofmobile phones and digitallyenhanced cordless telecommunications mobile phones in renal scintigraphy. ClinNucl Med. 2013;38:597–603.13. Leonora E, Aiello S, Leotta G, eds. Influence of the Earth’s magnetic field onlarge area photomultipliers. Advancements in Nuclear Instrumentation Measure-ment Methods and their Applications (ANIMMA). IEEE 2nd International Con-ference. 2011;1259–1267.14. Rogers WL, Clinthorne NH, Harkness BA, et al. Field-flood requirements foremission computed tomography with an Anger camera. J Nucl Med. 1982;23:162–168.www.nuclearmed.com 547ealth, Inc. All rights reserved.

The Effect of Electromagnetic Field Generated by a Mobile Phone

on the Performance of a SPECT Scanner

The aim of the current attempt was quantitative investigation of the

electromagnetic interference (EMI) of amobile phonewith the function of a SPECT

gamma camera during data acquisition.

Materials and Methods:We tested the effect of a mobile phone, in both ringing

mode and standby mode, on one SPECT gamma camera during scanning a cylindrical

phantom containing 5.4 mCi 99mTc. The experiment was performed for

different distances of 10, 12, 14, 16, 18, 20, 25, and 30 cm betweenmobile phone

and head of the scanner, and for different head angles of 0, 30, 60, 90, 120, 150,

and 180 degrees. A RF-EMF meter measured strength of electromagnetic field

throughout the study. Statistically significant decrease in count number was considered

to be electromagnetic interference.

Results: There was significant reduction in the recorded counts during ringing of

the mobile phone in all studied distances. For gamma camera, fixed at a distance,

there was no uniform pattern of reduction of the counts at different angles between

two operation modes of the mobile phone.

Conclusions: A mobile phone, at close distance, can be a sensible source of electromagnetic

field, disturbing the normal function of a gamma camera.signal of the detected photons.13 Electromagnetic interference with the

function of photomultiplier tubes, and consequently with the operation

of gamma camera, dates back before the 1980s in which former models

of SPECT scanners were being affected by the earth’s magnetic field

during rotation of head gantry.14 Whereas from those observations onwards,

magnetic shielding has been applied in PMT designing to provide

protection and stability necessary for acceptable function of gamma

cameras in the presence of the earth’s magnetic field, yet this shielding

seems not to be well enough to avoid interference by mobile phone’s

generated field. In the former study, we qualitatively investigated such

interference based on visual interpretation of a nuclear medicine physician.

11 Results of that evaluation, performed by 7 different models of

mobile phones, indicated that some types of mobile phones have the capability

to induce interruption on the function of the gamma camera,

leading to a decrease in the recorded counts of the 99mTc activity.11

As our previous attempt1 was a qualitative rather than a quantitative

study, which has its limitations, therefore in this study we were going

to study EMI of a mobile phone on the function of a gamma camera

in a quantitative way

http://eprints.bpums.ac.ir/6277/1/pashazadeh2015.pdf

The Effect of Electromagnetic Field Generated by a Mobile Phone on the Performance of a SPECT Scanner

Abstract

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Bushehr University of Medical Sciences Repository

Bushehr University of Medical Sciences Repository