The exact location of this sighting has been omitted (not as specific as my other sightings, since this one was at my place of work) as you may recall since July there have been two other radioactive people found there!
I was getting a cup of coffee in the area called the Cafe, when my PM1703M started to vibrate. Background prior to the event was 8 uR/hr. When it started alarming I noted roughly 13 uR/hr, and it rose to roughly to double the rate when one of the women on my team was within 5 feet of me putting sweetener in her coffee. I slowly added coffee and cream to my coffee and continued to measure.
She was telling another co worker about some stomach problems she was having, and how she had to go to several Doctors about it, and eventually went to one who prescribed a diagnostic nuclear test called a HIDA Scan (Hepatobiliari Imuno-Diacetic Scan, or sometimes called cholescintigraphy). In many instances I just know that someone has been injected with or has had radioactive materials implanted in them, this time I know several things:
The procedure: It is relatively simple, from a purely technical standpoint. An individual is injected with a radioactive tracer while lying on a table. Using a camera only sensitive to Gamma radiation, the technician will film the liver producing bile, filling the gallbladder, and then the bile draining into the small intestine via the bile ducts. The patient needs to lie still for about one hour to one and one-half hours.
The Isotope: In most cases it is Technetium 99m (Tc 99m), a gamma emitter.
The Half life of the Isotope: Tc 99m has a half life of roughly 6.01 hours. However, Tc 99m decays to Technetium 99 (Tc 99), which has a half life of 21,110 years. Fortunately Technetium does not stay in the human body a long time, it is excreted in urine. This characteristic makes it a very useful element for medical diagnostic imaging.
Where does all the Technetium 99 go? Into our sewer system! Fortunately only small amounts are used in medical tests, so it is diluted and spread out quite rapidly.
Since I know her she also was quite open about what the technician told her, which was wise, “it is only a small dose received by the patient, and that one may receive higher doses while a passenger in an airplane” (which on a coast to coast flight is 3 to 5 millirem, in addition to the 3 millirem the average person receives every day). The technician also advised her to be careful around her child. As for the maximum reading, the PM1703M displayed 792 uR/hour at six inches from her.
What have we learned from this? You never know when you may be silently irradiated by the co-worker, boss or client that may be sitting across from you, getting coffee in the lounge, or sitting in the office or cubical next to you. Gamma rays have no respect for steel, drywall or several feet of air. Radiation above background may be found anywhere, anytime, and anyplace, even the workplace.