The main purpose of this study was to investigate dose rate emanating from patients treated with 131I to evaluate which of the theoretical formulas, inverse-square law (ISL) and International Atomic Energy Agency-International Commission on Radiological Protection (IAEA-ICRP) suggested equation, can provide a sufficiently close approximation of the measured dose rate. Measurements were performed based on the IAEA safety report No. 63 method at 0, 12, 24, and 48 h after administration of radioiodine at a distance of 1 m for 69 patients and for the rest of 67 patients, dose rate was measured at 2, 4, 24, and 48 h at a distance of 2 m. Results revealed that the ISL formula gained better approximation of measured dose rates than the IAEA-ICRP equation with the lesser error. The ISL formula is still more reliable than the novel method of dose calculation in the vicinity of patients. This finding reminded us the prime importance of distance as a radiation protection principle.

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...

Ultrasound irradiation to a certain site of the body affects the efficacy of drug delivery through changes in the permeability of cell membrane. Temperature increase in irradiated area may be affected by frequency, intensity, period of ultrasound, and blood perfusion. The aim of present study is to use computer simulation and offer an appropriate model for thermal distribution profile in prostate tumor. Moreover, computer model was validated by in vivo experiments.Method. Computer simulation was performed with COMSOL software. Experiments were carried out on prostate tumor induced in nude mice (DU145 cell line originated from human prostate cancer) at frequency of 3 MHz and intensities of 0.3, 0.5, and 1 w/cm2for 300 seconds.Results. Computer simulations showed a temperature rise of the tumor for the applied intensities of 0.3, 0.5 and 1 w/cm2of 0.8, 0.9, and 1.1°C, respectively. The experimental data carried out at the same frequency demonstrated that temperature increase was 0.5, 0.9, and 1.4°C for the above intensities. It was noticed that temperature rise was very sharp for the first few seconds of ultrasound irradiation and then increased moderately.Conclusion. Obtained data holds great promise to develop a model which is able to predict temperature distribution profile in vivo condition.