False triggering of an ultraviolet flame detector after 99mTc-MDP injection

We report a patient who set off a restroom’s ultraviolet-spectrum flame detector, occurring 2.5 h after administration of radioisotope 99mTc-MDP (740 MBq) for bone scintigraphy. The radiation dose rate emitted from the patient was estimated to be about 11.82 μSv/h at a distance of 100 cm. To date, many cases have been reported of radiation detector false alarms triggered by radioisotopes administered to patients, presumably due to strengthened security measures and increased radioisotope use. Only one other case of false flame detector triggering in relation to radioisotope administration has been reported, in that case due to therapeutic radioiodine; there have been no prior reports of diagnostic ^99mTc triggering flame detectors.