EMF dose in patients and medical staff during hyperthermia treatment of cancer

At the Erasmus Medical Center, we apply hyperthermia treatments (HT) of cancer in the pelvic area using an electromagnetic applicator installed in a Faraday shielded treatment room. Consequently, medical staff and accompanying persons are exposed to electromagnetic fields (EMF) during treatment. In the past, procedures were defined based on measurements defining compliant areas where the fields are expected to be below the exposure guidelines. Today, advanced electromagnetic models enable more precise dose assessment in the human anatomy and better evaluation of the procedures. The objective of this study was to investigate theoretically if the exposure of medical staff and accompanying persons is compliant to the guidelines when adhering to the procedures. Therefore, the whole-body averaged (SAR_wb) and spatial-averaged (SAR_10g) specific absorption rate was assessed numerically in whole-body models of the patient, medical staff and an accompanying person. We found that predicted fields can exceed the exposure guidelines ten fold. However, the basic restrictions on SAR_wb and SAR_10g are not exceeded for workers, but SAR_wb can exceed the guideline by a factor of two for accompanying persons that are in close vicinity of the applicator. In conclusion, adhering to the procedures defined in the early nineties is effective in keeping the exposure in medical staff and accompanying persons compliant to the exposure guidelines.