View to the West

Lost in the debate over whether or not to pursue nuclear power generation are the everyday miracles that radiation performs. In medicine, in nuclear imaging and therapy, the promise of Marie Curie's discovery is being realized.

A cousin of mine – not Jay, the physicist, or David the waste manager, another cousin – had a tumor on her eye, too close to the optic nerve to risk surgery. Not long ago, she would have gone blind in that eye. But last year, doctors attached a tiny bead of radioactive material to the tumor. The bead had a known half-life; it would only emit radiation for a certain number of days. And it had a very small effective radius – two millimeters – so the decay activity would not affect other tissues nearby.

It's called brachiotherapy, and it is being hailed as a more precise and far less damaging alternative to external beam radiation. The comic-book beam has been around for decades and has effectively treated breast, prostate, head, and neck cancers. But the beam, as narrow and focused as it is, is a relatively blunt instrument. It can scar, and it inevitably "burns" healthy tissue on its way to the disease.

My med-student daughter Cloe tells me that in the world of nuclear medicine, the big excitement is targeted nuclear therapy. One form involves the surgical insertion of radioactive "seeds" into a problem prostate, say, or directly into a breast tumor site. Even more astonishingly, they can now craft artificial antibodies that travel through the bloodstream to attack a specific cancer.

Say you've got lymphoma. Doctors biopsy the tumor and identify the external markers on the tumor cells. They can then design a molecule that will target only those cancerous cells. The antibodies are attached to a radioactive isotope – iodine has been used effectively – and injected into the patient. Unlike chemotherapy, where the drugs kill all dividing cells, healthy or diseased, these antibodies seek out only the tumors, attach to them, and zap them.

And it gets better. Nuclear imaging is going inside the body. The PET scan (positron emission tomography) will soon take its place alongside the CAT (computer assisted tomography) scan and the MRI (magnetic resonance imaging) in "seeing" inside the body. A CAT scan looking for lung cancer, for example, will show you all of the nodules (scars, anomalies, etc.) but will not distinguish the benign ones from the malignant. With a PET scan, the patient takes a small dose of radioactive glucose internally. These molecules are absorbed by metabolically active nodules and show up as "hot spots" on the scan. The cancer is pinpointed quickly.

In the near future, internal radioactive imaging, using PET, will help us identify disease. And radioactive targeted antibodies will kill it. All without a scalpel. In fact, radiologists foresee a day when surgery as we know it ("A chance to cut is a chance to cure.") will be rendered obsolete. The lines between the disciplines are already blurring.

Radiation's power for good has a long way to go to eclipsing its reputation for harm. But the promise, in the medical world at least, is coming to fruition. My cousin traveled from California to Cloe's wedding here in October. Along with the rest of the family, she watched the sunset light wash over the new bride and groom, and cried for joy.