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What does one particle of radiation do?
In the first studies, researchers aimed a single particle at the nucleus of the cell-where DNA is located. Eighty percent of the cells shot through the nucleus survived. This contradicts the belief that if radiation slams through the nucleus, the cell will die. But the bad news is that the surviving cells contained mutations. Cells have a great capacity to repair DNA, but they cannot do it perfectly. The damage left behind in these studies from a single particle of alpha radiation doubled what damage was already there. This proved, beyond a shadow of a doubt, that there is no such thing as a safe dose of radiation. If one particle of radiation leaves damage behind-damage that can lead to cancer-then no amount of radiation is "safe". That doesn't mean that every mutation leads to cancer. The vast majority do not. But every mutation has the potential to become an abnormally growing cell, and the effects are cumulative over time.
They did more studies, hitting cells with more particles. If the cells are hit with 8 particles, about 10% of them survive, but with more damage. Twenty particles of radiation shot through one cell kills it with very few exceptions. The interesting thing about this is that a high dose of radiation that kills cells outright may be less dangerous than a lower dose that merely cripples them. Lethal hits leave no imperfectly repaired (mutated) survivors. Cells that are completely destroyed can't multiply with mutations. On the other hand, killing too many cells will kill the entire organism.
The radiation from x rays is less energetic than that from radon. But it is not less dangerous. Joint research between scientists at Brookhaven National Laboratory and the National Center for Scientific Research in France demonstrates that low LET radiation, including x rays, cause a type of damage similar to the serious double-strand breaks where radiation blasts through both strands of DNA, leaving it completely broken. The radiation from x rays causes similar damage by hitting each strand individually, but close together. The result is similar to a double strand break.
What happens when an alpha particle whizzes through the cell, but misses DNA? In this case, it hits cytoplasm, the body of the cell. In 1999, Hei's group at Columbia did experiments, again shooting predetermined numbers of alpha particles through each cell. They came up with a very surprising finding. Hitting cytoplasm causes mutations in DNA. That seems odd; how could radiation damage something it doesn't touch? The answer is that radiation creates secondary free radicals. These are the types of radicals health-conscious people are familiar with. They have lower energy than radiation and they don't cause the same type of damage or as much of it. However, they can actually be worse because again, this is sublethal damage the body will attempt to repair, and mutations will inevitably result.
The body has evolved an "antioxidant defense system" to help stop these kinds of free radicals. Dietary antioxidants also help protect against them. Hei's group demonstrated that glutathione was effective, and other studies show that N-acetylcysteine, SAMe, MSM and other sulfur-containing antioxidants also protect against secondary free radicals created by radiation.
A mysterious finding
In the late '90s, it was discovered that ionizing radiation causes damage a different way. Previous research showed that adding the growth liquid from irradiated cells to non-irradiated cells could kill them. It wasn't because of free radicals or radiation damage. This is strange. Researchers at Harvard and the Los Alamos National Laboratory looked into and found that the irradiated cells might be communicating somehow with non-irradiated cells.
Meanwhile, Hei's group came up with convincing proof that irradiated cells could cause mutations in their nonirradiated neighbors. And further, that the phenomenon could be blocked by a chemical that interferes with communication between cells (lindane).
The Harvard/Los Alamos researchers also found that interfering with cellular communication stopped the damage, and this year they published proof that "bystander" cells that get no radiation at all nonetheless have changes in the expression of tumor suppressor gene p53 and a related gene that controls the cell cycle known as p21. These genes play roles in cancer. This means that radiation affects crucial genes.
Researcher Hei and colleague Gloria Calaf have begun studying how breast cells respond to estrogen after being hit with alpha radiation. So far they've shown that changes occur in BRCA, the "breast cancer susceptibility gene". Researchers at Loma Linda have speeded up and worsened prostate cancer with one low-dose whole body irradiation and a growth factor. These kinds of "real world" experiments will lead to a greater understanding of radiation's contribution to cancer.
We now know that radiation damages cells in at least three different ways: directly, through free radicals and through cellular communication. The idea that there is such a thing as a "safe" dose of radiation has been disproved. Where does that leave Gofman's observation that radiation is a significant cause of heart disease and cancer? Gofman acknowledges that radiation is not the only cause of heart disease and cancer, and he's quick to point out that multiple factors contribute. Poor diet, chemicals, viruses and a lack of exercise have proven connections to heart disease and cancer, which is a multi-stage process. But far from being disproved, Gofman's observations have gained even greater support by recent radiation research. Whether we like it or not, the very thing we use for diagnosing and treating heart disease and cancer is helping cause it.
Every dose of radiation we get is cumulative. It's very important that we realize and understand that medical radiation, and indeed all radiation, is not benign. It damages tissues even though we can't feel it or see it. It can come back to haunt us years after exposure, with very serious and devastating effects. The acceptance of radiation as safe by us as individuals and by us as a society has to be challenged. Radiation is a business, an industry, not a natural part of our lives-even though we grew up believing it was. The blind acceptance of our doctor's assurances that radiation is safe-is dangerous. The blind acceptance of radiation in our society is short-sighted and potentially self-destructive.
Informed consent should become routine for radiation procedures, just as it is for other medical procedures. For this to occur, the truth about radiation has to be available to everyone-the risks as well as the benefits. No longer can we pretend that a body scan here-and-there, a chest x ray now-and-then or a quick-look-at-our-colon has no lasting effect. They do. And until we accept that, high rates of cancer and heart disease will continue, and we, ourselves, may become one of the statistics.
John W. Gofman. 1996. Preventing Breast Cancer: the Story of a Major, Proven, Preventable Cause of this Disease. San Francisco: CNR Book Division.
Azzam EI, et al. 2001. Direct evidence for the participation of gap junction-mediated intercellular communication inthe transmission of damage signals from alpha-particle irradiated to nonirradiated cells. Proc Natl Acad Sci USA 98:473-78.