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

Abstract

Purpose: The aim of the current attempt was quantitative investigation of the electromagnetic interference (EMI) of a mobile phone with 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 99m Tc. The experiment was performed for different distances of 10,12,14, 16, 18, 20, 25, and 30 cm between mobile 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.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 function of medical devices is an unfavorable event that may result in malfunctioning of this life-supporting equipment.1-6 Today, mobile phones have been translated from a just communication tool into can-not-live-without device, increasing the probability that it may come to the vulnerable medical devices.Although, up to now, number of reported significant medical errors that resulted from mobile phone interference with medical devices have been relatively rare, yet in the literature several cases of EMI and concomitant errors have been published. [7][8][9] Results of the studies have indicated that based on the factors such as type of medical device and mobile phone, and also separation distance between these two, different levels of EMI may occur.10 Gamma camera of a SPECT scanner is part of medical systems that may be susceptible to the electromagnetic field (EMF) generated by mobile phone. 7,11,12 SPECT is a routine imaging modality that provides images from bio-distribution of radioisotopes inside the body. The first clinical evidence of mobile phone EMI with SPECT scanner was a case report in which function of a gamma camera had been interrupted by ringing of a mobile phone, located in a patient's pocket, as light spots on frame 6 of the flow phase in the acquired image during the renal scintigraphy.7 This vulnerability is largely because of the photomultiplier tubes (PMTs) that are used to intensify acquired 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 SP...

Impact of Mobile Phone Interference on Gamma Camera Performance

“…Data suggest that the closer a device (eg. phone) is to the gamma camera, the more likely it will cause an effect, in particular, count reduction [1][2][3]. With the increasing popularity of mobile phones, the chance of a device being left in a patient's pocket during a scan is increased.…”

“…Some models had significant effects on count density, while others had none; however, the only effects noted were during ringing of the phone (not standby). Pashazadeh et al [3] tested a GSM 900 MHz mobile device at different distances from a gamma camera, as well as different angles during a SPECT rotation. The results suggested that when mobile phones were operated under ringing conditions, they demonstrated a decrease in the overall count rate, compared to standby mode.…”