Saturday, February 11, 2012

Now I Really Am the Atomic Spud

A few months ago I started getting odd pains after eating. The symptoms weren't like those of the acid reflux I've had for most of my life (and can control most of the time with Prilosec), but they did seem similar to the pains my wife had been having off and on for a few years. We found out last year that she had a pyloric ulcer as well as gallbladder disease; the former was treated with expensive medications and the latter was taken care of through gallbladder removal surgery. Since we didn't know which of her symptoms was caused by what ailment, we really couldn't say if my problem was caused by an ulcer (pyloric ulcers are the result of bacterial infection and can be spread from person to person) or by a gallbladder problem.

A visit to the doctor a few weeks ago indicated that I don't have an ulcer. A simple blood test showed that I didn't have the bacterial infection and the description of my symptoms didn't seem to match up with those of an ulcer. According to the doctor, certain symptoms I've been having are characteristic of a malfunctioning gallbladder. The doctor explained to me that the first technique we could use to confirm his suspicions would be to look for gallstones using ultrasound. If that came up negative, we could monitor the gallbladder's function with a HIDA scan. He warned me that it's possible for both techniques to yield negative results and to still have gallbladder disease. Last week I had a sonogram that showed that I didn't have any gallstones. On Friday morning I went in for the HIDA scan. I came out of the scan radioactive.

Yep, that's me

Prior to a HIDA scan, the patient is injected with the radioactive isotope Technetium-99m (Tc-99m). The Tc-99m eventually ends up in the person's bile and can be seen passing through the gallbladder with a radiation-detecting scanner. In my case, I was also injected with a medicine near the end of the scan that exercises the gallbladder as if I had eaten a fatty meal. The function of the organ was monitored and I was instructed to tell the technician whether or not the injection recreated the pain.

Hours of gamma radiation-emitting fun
I have yet to receive the results of my scan, but the final injection caused a relatively mild form of the discomfort I've been having. As for the radioactivity, I was injected with 6 millicuries (mCi) of Tc-99m. Six thousandths of a curie seems like a lot to someone who typically works in units of picocuries (pCi), or trillionths of a curie. Of course, the isotopes I work with emit a lot more energy per curie than Tc-99m. The relatively low energy of the gamma photon emitted when Tc-99m transitions to Tc-99 is much of the reason why this form of Technetium is used for medical diagnostics.

Anyway, if my experience is anything like those of the people who received the diagnostic, happened to have a Geiger counter at home, and posted the results on the Internet (oddly enough, I'm not one of those people), I probably left the clinic with an on-contact radiation reading between 20 and 30 millirem/hr. (Objectively, this is not a very high level, but at work we would consider implementing certain controls when dealing with an item emitting that level of radiation.) Tc-99m has a half-life of 6 hours, meaning that the radiation level is halved every six hours. The effective levels may drop even faster since the radioisotope will also leave the body through the urine. Given my line of work and the caution with which we treat radiation and contamination, it's amusing to think that I am currently an unmarked, walking radiation source and that I'm simply dumping radioactivity into the sewers every time I flush the toilet.

Most sources suggest that I'll have received about 500 millirem of exposure by the time the Tc-99m is out of my system. Although this is not an insignificant level of exposure over such a short period of time, it is still far from being dangerous. It is also a lot higher than the amount I've received at my facility since I started there several years ago. Occupational radiation exposure is monitored separately from that of other sources (e.g., medical treatments). Thus, I won't be allowed to wear a dosimeter when I go back to work next week until I'm scanned by a radiological controls technician and am declared to have returned to background radiation levels. I look forward to finding out my radiation level on Monday so I can back-calculate the level I reached when I was first injected.

I wonder what super powers I'll get

UPDATE: 2/13/12
First thing this morning a radiological controls technician checked my radiation levels. Between Tc-99m's short half life and the soda and Powerade I was drinking to flush out my system, I had returned to background levels. And since I don't know when I got rid of most of the isotope, I can't even back-calculate my original levels. The worst part is that I don't have a single super power to show for it.

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