Radiation exposure from PET-patients in other hospital settings

Introduction
PET/CT scans involve the administration of a radioactive tracer, emitting 511 keV gamma photons. Accordingly, the waiting areas at the department of nuclear medicine are designed to minimize radiation exposure from radioactive PET patients. However, when continuing to other departments right after the scan, PET patients are referred to common waiting rooms. As a result, it is possible for patients, relatives and caretakers, here under pregnant women and children, to unknowingly spend prolonged periods of time adjacent radiation emitting patients.The aim of this study is to examine the radiation dose to patients or accompanying persons from radiation emitting PET patients in hospital waiting rooms.

Methods
Dose rates of twenty-four patients were measured directly after micturition following PET scan at distances equivalent to distances between seats in a waiting room at a radiological department. Cumulative doses for a patient sitting close to up to four PET patients at increasing time periods were calculated.

Results
Measured dose rates varied from 33.39 to 74.39 μSv/h, with a median of 52.34 μSv/h. Thirty minutes at 30 cm from the lowest measured dose resulted in a cumulative dose of 16.92 μSv. However, 1 h at 30–85 cm from four high emitting patients resulted in an accumulated dose of 134.6 μSv.

Conclusion
Patients or accompanying people waiting for prolonged periods of time in waiting rooms with an influx of PET patients may repeatedly unknowingly be subjected to radiation.

Implications for practice
This study highlights the need to reassess waiting area protocols to minimize radiation exposure from PET patients. Directing PET patients to specialized waiting areas may protect groups like pregnant women and children. Educating healthcare staff on this will ensure a safer environment.