An assessment of hazards caused by electromagnetic interaction on humans present near short-wave physiotherapeutic devices of various types including hazards for users of electronic active implantable medical devices (AIMD)

Lightweight polyurethane composite foam for electromagnetic interference shielding with high absorption characteristic

Due to the rapid growth of electronic equipment technology, efficient electromagnetic shielding materials are needed for equipment and human protection. Among them, foam shielding materials with absorption as the primary mechanism have higher application value than highly reflective materials. Highly absorbing shielding materials can reduce the secondary pollution caused by electromagnetic wave reflection. In this study, we added Fe3O4@Polyvinyl alcohol (Fe3O4@PVA) and graphene oxide@silver (GO@Ag) into the polyurethane (PU) matrix and constructed Fe3O4@PVA and GO@Ag/PU composite foam by foaming. Fe3O4@PVA and GO@Ag form an excellent network structure in the PU foam skeleton, significantly improving its electromagnetic shielding effectiveness (EMI SE) and mechanical properties. The shielding effectiveness reached 30.9 dB with a specific EMI SE (SSE) of 274.9 dB × cm3 × g-1 at a Fe3O4@PVA filling of 7 wt%, where the electromagnetic wave absorption accounted for more than 80 % of the total EMI SE, proving absorption as the primary shielding mechanism. The results show that Fe3O4, as a ferromagnet, has both the dielectric loss of ferroelectric materials and the hysteresis loss of ferromagnetic materials in electromagnetic shielding, effectively improving the wave absorption performance of composite shielding materials. Therefore, this work provides a promising idea for efficient and lightweight wave-absorbing shielding materials in aerospace, portable electronic devices and lightweight wearable devices.

Physiotherapists' Understanding of Shortwave Diathermy Contraindications: A Questionnaire Survey

Purpose

It is known that electromagnetic fields and heat generated by shortwave diathermy (SWD) can have adverse effects on living tissue. The purpose of this research is to evaluate Jordanian physiotherapists' knowledge of pulsed and continuous SWD contraindications. And investigate the potential contraindications about which Jordanian physiotherapists may have limited knowledge.

Subjects and Methods

This cross-sectional study investigates Jordanian physiotherapists' knowledge of SWD contraindications. In 38 private and public hospitals, a self-administered questionnaire survey was carried out. Participants were asked to classify 32 conditions as "always, sometime, or never" contraindicated or "I do not know". Participants are physiotherapists with two or more years of postgraduate experience. Two forms comprised the survey. The first consisted of assessing their reaction to the contraindications of pulsed shortwave diathermy (PSWD), while the second consisted of continuous shortwave diathermy (CSWD).

Results

Approximately 270 physiotherapists were eligible to participate in this investigation. Only 150 questionnaires were distributed to the therapists who agreed to the study. One hundred twenty-eight were returned for an average response rate of 85.3% (128/150). Respondents had good agreement about using SWD for cardiovascular condition, however, 24 respondents (19%) thought PSWD can be used over venous thrombosis. Only 64% of the respondents was aware that pacemakers are contraindicated for PSWD. Approximately 14% to 32% seem unaware that tuberculosis and osteomyelitis are contraindicated for both CSWD and PSWD. About 21% to 28% have been unaware that the use of PSWD is contraindicated for specialized tissues (eg, eyes, gonads, or malignant tissues) and 29% during pregnancy.

Conclusion

Jordanian physiotherapists generally agreed on the widely acknowledged contraindications of CSWD for specific conditions. However, there was considerable uncertainty among Jordanian physical therapists about the contraindications of PSWD. This discrepancy highlights the need to improve physiotherapist awareness and for more fact-based research to the contraindication of SWD modality.

MICROWAVE DIATHERMY IN PHYSIOTHERAPY: INTRODUCTION AND EVALUATION OF A QUALITY CONTROL PROCEDURE

Microwave diathermies (MWDs) are electromagnetic (EM) radiation emitting systems that are used by physiotherapists for thermotherapy treatment. Although this form of therapy is widely available in most physiotherapy units worldwide, management of the equipment is not obligatory addressed either by clinical engineers or medical physicists. A novel quality control (QC) protocol for MWD equipment, examining mechanical, electrical and electronic condition, the power output and EM radiation distribution in the electrotherapy room, was used during a national QC survey. The results of the survey revealed serious concerns about the safety of users and coexisting patients. The proposed approach could result in the introduction of EM-screened rooms, ensuring that MWD users and other persons in the vicinity will not be exposed to EM radiation over reference levels. International bodies could develop specific directives for EM radiation exposure in Physiotherapy Units, to conform to the proposed acceptance and functioning criteria for MDWs.

In silico modelling of influence from low or intermediate frequency magnetic fields on users of wearable insulin pumps

PURPOSE

The aim was to model the effects of exposure to a low or intermediate frequency electromagnetic field (LIF-EMF), characterized by the electric field induced in the body, in order to evaluate how the type of insulin needle and the way it is injected influences the exposed user of a wearable insulin pump.

MATERIAL AND METHODS

Numerical models of exposure scenarios (sources of LIF-EMF, with a dominant magnetic component: 50Hz-1MHz; the insulin needle type; the way it is injected and insulin pump user) were worked out. The influence of the insulin needle on the user's safety (the ratio of the induced electric field in tissues surrounding the needle and tissues of a person without an injection, both exposed identically) were calculated.

RESULTS

The effects of LIF-EMF exposure in insulin pump users were found to be up to approximately 7-times higher, varying with statistically significance (p < .05) with the material of the needle, the way it is injected and the polarization of the affecting magnetic field.

CONCLUSIONS

When steel insulin needles is used, the assessment of user's EMF exposure should be carried out using magnetic field limits at least 5-times lower than given in general international requirements.