amir reza khorasanchi - Assistant Professor, Department of Nuclear Medicine, Shahrood University of Medical Sciences, Semnan, Iran
Esmat Ramezanzadeh - PhD Student of Medical Physics, Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
Azam eskandari - PhD Student of Medical Physics, Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
Erfan saatchian - PhD Student of Medical Physics, Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
mahmoodreza yahyaei - MSc Student in Nuclear Physics, Shahrood University of Technology, Semnan, Iran

Introduction: It is important that estimated doses from patients administered radiopharmaceuticals in nuclear medicine by hospital staff but other people in connection to patients need radiation protection. The purpose of this study was to measure the dose rate with increasing distance from patients to estimate the average effective dose in hospital staff and companions of patients. Material and Methods: Myocardial perfusion scanning was performed using Technetium ۹۹m-methoxy isobutyl isonitrile (۹۹mTc-MIBI) (in ۲ groups of stress and rest). We measured the external dose rate for ۴۸ patients (۲۳ men and ۲۵ women) at ۴ distances and ۵ times. Doses are estimated for a range of scenarios, in hospital staff, public transportation, and family contacts. Finally, the obtained data were compared to the trigger level introduced by the International Commission on Radiological Protection ۵۳ and ۶۲ (ICRP). Data analysis was performed using SPSS version ۲۴. Results: The distance of the times when patients need family or hospital staff to be with them was divided into ۴ categories (injection to scanning, using public transport, emergency patients during injection to scanning, and emergency patients after finishing medical procedures).  Conclusion: In all scenarios, effective doses were obtained at less than ۱۰۰ µSv according to ICRP guidelines. Due to the significant increase of the uptake in the heart and skeleton, after injection, the dose rate per MBq in the stress rate before ۱hr decreases more slowly than the rest test, and the effective dose of hospital staff in stress procedure is more than rest procedure.

Technetium Tc ۹۹m Sestamibi, Radiation Exposure, Radiation Dosage, Radiation Protection