Back at work the next day, it was my turn to cover the thyroid patient. When a patient has thyroid cancer, the thyroid gland is surgically removed. After removal, the patient is given a small dose of radioactive iodine and then passed under a nuclear medicine camera. The thyroid gland absorbs iodine. If the cancer had metastasized, spread, beyond the thyroid, the cancerous thyroid tissue will absorb the radioactive iodine and be visible to the camera. If there’s too much cancer spread, the patient is brought in for a 3 day hospital stay and given a much larger dose of Iodine-131 to zap the thyroid cancer with Beta and Gamma radiation. The radioactive iodine undergoes radioactive decay with a half-life of 8 days, or a decay constant almost 9% per day. Combined with the natural rate of elimination from the body (by urine, feces, breath, sweat, etc,) the effective half-life of the radioactive iodine in the patient is less than 24 hours. In 3 days the patient has about 12% of the radioactive iodine in their body and they can go home.
One good source of healthy, natural iodine is lobster. If you eat lobster, your thyroid will have plenty of good fresh iodine. Pierre had told me of a conspiracy theory he’d heard from Allan Johns that foods containing Bromine, such as bread made with brominated flour, can block iodine absorption. The thyroid may absorb the chemically similar bromine. Lack of iodine due to bromine absorption may have caused an increase in thyroid cancers. Is this on purpose or by accident? The Conspiracy Theorist may never know. In any case, it was Wednesday; the day to treat the thyroid patient.
I went to Nuclear Medicine (or “Nuke Med” for short) and there was Darryl Jones. Darryl Jones and Darryl Smith alternated by week who was in charge. They were both Nuclear Medicine Technicians. The physician in charge was Lawrence Chessmastre. We sometimes referred to them as Larry, Daryll and Daryll. On this particular day the thyroid patient was to be administered 125 millicuries of radioactive iodine 131. The dose was dependent on the weight of the patient, the relative amount of the cancer, and how much it had metastasized.
“Hey Daryll, how’s things?”
“Not bad, Justin. You? The patient is with Dr. Chessmastre. She’ll be here in a few minutes.”
“Here” was the Nuke Med Hot Lab. The patient would soon come in and drink the I-131 through a straw while the Dr. takes a squeezee bottle and squirts deionized water into the vial to make sure the patient sips up as much as possible and not waste any. The vial is sitting in what we call a “lead pig,” so we’re not all being exposed to the gamma rays. (This is one method of administering I-131; another method is simply a pill.) After the patient ingests the I-131 they walk up or are brought by wheelchair to their room to stay for the 3 days while their body processes the I-131. As the Radiation Safety Physicist/Technician, my job was to measure the radiation dose rate approximately 1 meter from the patient’s neck. This would be the baseline data, and I’d measure the level again on the day of discharge to ensure not too much was still in the body.
“You going to the hockey game this weekend?” I asked. Daryll held season tickets to the local NHL team.
“No, but I have the tickets sold. I have too much going on this weekend.”
Dr. Chessmastre and the patient came in.
“Have you verified the dose, Daryll?”
“Yes Dr C. It came in at 101% of prescribed dose.”
“OK, better high than low. We do have quite a bit of metastasization in this case. Hopefully this will be enough and we won’t have to go through this again, right Mrs. Needham?”
“Right!” she agreed.
Dr. C. (or the NMTs also called him LC) had a fine bedside manner, and the respect of his patients. One of his common lines was “We’re all going to die someday. My job is to make sure you don’t die from thyroid cancer.” It is considered a treatable disease, with a 5 year survival rate of 98%.
She drank the dose, and I took my readings. I’d take a few more readings once we got up to the room where she’d spend the next few days. Nuke Med had a few more administrative things to tend to first.
Once the patient was in the room, I asked her to lay down in the bed. I took note of the radiation dose rate on the side of the bed, the foot of the bed, the door to the room, and the walls of the adjoining rooms. The readings at the side of the bed were for the nurses, who would be coming in to monitor vitals and whatnot. The nurses had radiation badges to monitor their radiation dose. I calculated the nurses’ allowed “stay time” in the room. The readings at the walls were to see how much radiation might penetrate to expose other patients. If the readings were too high, I’d go into the adjoining rooms and check the levels there. Usually, they were adequate. I made a copy of my readings and taped it to the door of the room.
I always try to make the patient feel at ease. I would say something like “This is just for our records, this is not a big deal, blah blah blah.” They knew the score by now anyway. The additional instructions we gave the patients were a bit bizarre. We had them dump any soft foods they didn’t eat, like pudding or mashed potatoes, down the toilet. Anything that couldn’t go down the toilet was collected in trash cans marked “radioactive.” We had to save the food waste, and the bedding, until it decayed down to a radiation level that we could legally throw out in the regular trash, or send out to be laundered, respectively. (The thumb rule was 10 half-lives. One half to the tenth power is about 0.1%. 10 times 8 day half-life is 80 days, about three months.)
Three days later we would go back to the room and verify the patient wasn’t emitting too much residual radiation; that most of it had passed out of the body and/or decayed. If the patient was low enough, they would go back to Nuke Med, and then be discharged. Then it was our turn to really go to work.
We’d begin to clean the room. We’d collect the radioactive waste, then clean the radioactivity out of the room. It was everywhere. During the 3 days, radioactive iodine was in the patient’s breath, in their fingerprints, coming out of their pores. The shower was hot (radioactive,) the toilet was hot, the floors were hot, the tv remote, any handle anywhere in the room, everything. We’d wipe it down with whatever generic cleaner and we’d get most of it, but it wasn’t possible to get all of it. The bathroom was the worst. Every time they peed, naturally, radioactive urine contaminated the toilet. When they showered, they were showering away their radioactive sweat and dead skin cells, and it would be on the shower floors and the walls. We would decontaminate the walls and the floors. There was no way to decontaminate the bathroom toilet. The toilet ceramic seemed to absorb the radioactive iodine. We would decon the toilet as best as we could. We would get it down to what we called “no loose surface contamination” but it would still be emitting radiation. Loose surface contamination is contamination that can be removed by a dry filter paper wiped along the seat. The units were “counts per minute per 100 square centimeters” (which is about 16 square inches.) The limit was about half a nanocurie. We also took gamma radiation readings. The limit was approximately 0.1 millirem per hour. This was pretty much attainable. There is no zero in radiation safety. There is what we call “below minimum detectable activity.” However, minimum detectable activity varies with which radiation detector you’re using, what the background reading is, and other things.
Background radiation levels will be different on grass, tarmac, granite, first floor, second floor, 3rd floor et cetera ad infinitum. Everything has its own background level.I once worked a job checking the electrical insulators at a power grid. The electric insulators had some Naturally Occurring Radioactive Material (NORM), and we were getting certain readings. When we went back to the administrative building to give our readings and our report, I noticed that the steps were made of granite. Just for the hell of it, I checked the gamma reading on the on the granite, and it was higher than anything we had seen all day on the insulators. The New York Times once had an article about radiation levels in natural granite, the title of which was “Is Your Kitchen Radioactive?” The short answer is “yes.” Your Kitchen is Radioactive. Deal with it. OK, not every kitchen , but if you have a granite countertop then it may very well be.
This is what we deal with in radiation safety. The question is always “How good is your instrument? How low can you count?” There is no zero. There’s naturally occurring rad material, there’s cosmic radiation from every star being born millions of light years away. You may have heard bananas are radioactive from potassium 40 (K-40) which is about 1% abundance of potassium. Salt substitute is radioactive because it’s Potassium Chloride instead of Sodium Chloride. The Nuclear Regulatory Commission wanted to make a lower limit ruling called “Below Regulatory Concern” or BRC, but the anti-nuclear activists complained and BRC was never made law. So since then, nothing is below regulatory concern. Is this Regulatory Capture or is this the opposite of Regulatory Capture? The anti-nukes may have committed the Regulatory Capture is this case.
But I digress. And what do I know? I’m an accused Felon out on bail awaiting trial.
Shocked in the Suburbs 