Every day after work, Doug Abrams checks to see if he's radioactive.
It's simple, he says: you stand on this scale and stick your hands in the detector box, and, after a countdown, the computer tells you if you're clean or — "Contaminated!" it says, in a pleasant voice.
"Ooh!" Yeah, that doesn't happen that often, he says. He and the staff soon track the problem to a lead-lined chamber across the room that they'd left open for a photographer.
Nothing to worry about, he says. "We don't see it very often, thank goodness, and we watch it very closely and take it very seriously." As per procedure, he thoroughly washes his hands and scans his clothes with a Geiger counter before leaving the lab.
Some people drive trucks. Abrams smashes atoms. The St. Albert scientist makes radioactive medicines for a living, harnessing atomic power to treat cancer.
Radiation medication
Abrams strides down the clean white halls of the Edmonton Cross Cancer Institute and stops by a door with a big yellow radiation sign by it. "This is the cyclotron area," he says, as he swipes his card — the place he and his team do their work. Inside are robotic arms, thick lead shields, and steel benches crowded with beakers — oh, and a roaring particle accelerator the size of a truck. Photocopied pictures of Henri Becquerel and Marie Curie supervise from the walls.
This is the Edmonton Radiopharmaceutical Centre, and Abrams is its boss. It's his job to make most of the radioactive medicines used in the Capital region.
It's a career he got hooked on in university, he says. "Before I went to university, I liked chemistry and I liked biology," so he got into pharmacology. This was pharmacy one step over the edge — a challenging field that combined physics, chemistry, biology and more. He was hooked after his first course, and ended up at the Cross Cancer in 2001.
Radiation is everywhere, Abrams notes, caused by the decay of unstable elements into stable ones. Radiopharmacists use it to see and treat diseases inside the body.
Say you want to check on a patient's kidney functions, he says as an example. You can't see into the kidney normally, but if you make its inside glow with radiation, you can track blood as it moves through the organ using a special camera.
There are thousands of radioactive substances available, Abrams says, but only about five of them are safe to use in people. The most common is the technetium-99m, as it's powerful enough to send energy outside the body but not strong enough to kill you. "If God was going to make a radioisotope for human use, technetium would be as close as he could get." Fluorine-18, carbon-11, iodine-124 and nitrogen-13 isotopes are also used.
Isotopes tend to go everywhere on their own, Abrams says, so you have to hook them to tracer molecules to get them to stick to specific tissues. Link them to glucose, for example, and they'll seek out glucose-hungry cancer cells. Link them to diphosphonates, and they'll head for bones.
Spinners and doughnuts
Senior technologist Dacia Richmond is one of the people at the institute that uses radiopharmaceuticals. One of the more common uses is the Positron Emission Tomography, or PET, scan, she says. Done about 40 times a week, it uses fluorine-18 to track the spread of cancer through a body.
The process starts with the cyclotron — a truck-sized blue cube covered with copper tubes and wires. The number of protons in an atom determines its identity, Abrams says. Smash protons into them fast enough, and you can make them stick, transmuting them from one element to another.
The cyclotron has two circular copper magnets stood on edge in it, Abrams explains, and uses them to accelerate protons to about 20 per cent of the speed of light.
Once they're at speed, operators stick a charcoal strip in front of the protons that redirects them down a millimetre-wide tube and into whatever they want to transform — a vial of water, in this case. Billions of protons smack into the water's oxygen atoms every second, transforming them into radioactive fluorine-18.
That fluorine is several hundred times more radioactive than they need it to be in the patient, Abrams says — the radiation wears off fast, so they need to make more than they need — so they're extra-careful when handling it. The cyclotron itself is behind a 30-tonne concrete door, for example, while the experimentation chambers have about four inches of lead around them. To avoid handling the fluorine directly, they usually shunt it about with nitrogen gas.
The fluorine gets pumped into a shielded chamber called a hot cell for further transformation. Technicians use robot arms in the cell to pipette the amount of isotope they need into a vial, which is then sent to a mass of tubes and wires called an automatic synthesis unit. That computer-controlled unit performs the complex reactions needed to link the fluorine to glucose, creating a radioactive sugar called fluorodeoxyglucose.
The now finished — and much less radioactive — medicine is then sent to Richmond, who gives it to her patient through an IV drip. "It's only about the volume of a teaspoon," she says, and takes about an hour to spread through the body.
The patient then lies in a big doughnut called a PET scanner for about 30 minutes. Fluorine-18 is radioactive because it has too much positive charge, Abrams explains, making it unstable. It spits out that extra charge as positron — the antimatter equivalent to an electron — that explodes on contact with an electron, producing two gamma rays.
Using a ring of detectors (the doughnut), the PET scanner traces these rays to their point of origin, displaying it as a dot on a computer screen. Once the scan is complete, the screen has a bunch of black blobs on it representing concentrated radiation sources — possible tumours.
Doctors overlay those blobs with a 3-D X-ray of the patient called a CT-scan to match those tumours to organs and tissues, helping them determine the best course of treatment. The radioactive fluorine passes out of the body later.
Glowing future
These are exciting times for nuclear medicine, Abrams says. Doctors are developing new, easier ways to make isotopes, and discovering new uses for them. Other institutes are testing out radiotherapeutics, for example, which use targeted isotopes to treat tumours within a patient.
Abrams and his team got a $3-million grant this year to experiment with technetium production. Technetium-99m is one of the most commonly used isotopes in nuclear medicine, but right now the only way to get it is from places like the Chalk River nuclear reactor in Ontario. When that reactor shut down in 2009, it caused a global shortage that threatened many medical procedures.
Abrams and his team are building a powerful cyclotron that they believe could make the isotope. If they're successful, they will greatly reduce the risk of shortages, meaning more reliable tests for cancer patients.
"For a relatively small amount of money," he says, about $3.5 million per cyclotron, "you could locate these all around Canada," he says. Just one would make enough technetium to supply all of Edmonton.
"It's a very small field with a very large impact on patient care," Abrams says, when asked why he stays on the job. There aren't a lot of radiopharmacists out there, so there's still plenty for him to discover.
Sure there's the radiation, but he says he's comfortable with the risk. "People who are worried about radiation just don't take the job."
Oh, and for the record, he doesn't glow in the dark. "It's a very common joke," he says.
