Answer to Question #10451 Submitted to "Ask the Experts"

Category: Radiation Workers

The following question was answered by an expert in the appropriate field:


I read about something called the "bystander effect" in which fish exposed to radiation were placed in the same tank as fish that were not exposed to radiation. By placing the radiation-exposed fish in the same tank, it actually affected the cells of other fish that were not exposed to radiation.

Such a finding indicates that radiation exposure is contagious. Is this the case in human beings? If not, what is the reason that such a result could occur in fish, but not in human beings?

I am in a romantic relationship with a radiation worker. Can his exposure be transferred to me and affect my cells?


Great question! The short answer is, "I don't think you should worry about being involved with a radiation worker." Let me explain.

The bystander effect loosely describes the situation where something directly hit by radiation sends some sort of signal to its neighbors (who weren't directly hit by radiation), and the neighbors show a biological effect. We have known about this effect in cells for several years. We see that cells that are directly hit by radiation send a signal to neighboring cells and those cells check themselves for DNA damage, and if they find it, they start repairing it or if the damage is too serious, the damaged cells commit suicide (which is what you want damaged cells to do so they don't go on and cause cancer). There is a lot of debate about what this phenomenon means in terms of radiation risk. Some scientists think that this means that low doses of radiation carry more risk than we thought because the effects aren't limited to those cells that were directly hit. Other scientists (including me) think this shows that low doses of radiation turn on our biological defense mechanisms that protect us not only against the radiation damage, but also against the background damage we all carry around with us.

The really interesting thing about the recent experiments you mentioned is that they suggest that this bystander effect acts not only between irradiated cells and their neighbors, but also between whole organisms exposed to radiation and their neighbors. I personally know the scientists who did this research, and I have a lot of confidence in their work. But as with any scientific study, it needs to be replicated before we jump to any general conclusions. Furthermore, these studies involved fish, and we don't know if the same thing happens in other organisms, like humans. Good studies (like this one) almost always raise a lot of new questions.

So, the take-home message is that this research is very exciting to those of us who study low-dose radiation effects, but I certainly wouldn't make any decisions about my social life based on it.

Brant Ulsh, CHP, PhD

Ask the Experts is posting answers using only SI (the International System of Units) in accordance with international practice. To convert these to traditional units we have prepared a conversion table. You can also view a diagram to help put the radiation information presented in this question and answer in perspective. Explanations of radiation terms can be found here.
Answer posted on 1 October 2012. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.