Reader Questions on X-rays
About 5 min read
The following questions on x-rays were sent in by readers:
- Harm from airport x-rays
- Do TV tubes accumulate x-rays?
Absorption of x-rays in soft tissues
Harm from airport x-rays
I would like to know about the airport x-ray machines that scans our bodies and “beeps” when it detects metal objects. Does it has the same effect as a normal x-ray? How much harm will we get, if we go through that scan everyday?
Zirino
Malaysia, Oct. 2001Answer
The metal detector you walk through uses magnetic fields and not x-rays. It does not harm you, even if you use it every day. That is the device that beeps if it detects metal.
The power of the x-ray used in airport scanners is very low. Usually, only luggage is scanned with x-rays. Some airports are planning on using a special x-ray device to scan some suspicious passengers, but that is not generally used.
Do TV tubes accumulate x-rays?
I found Your X-ray article very interesting and did get some new ideas concerning the problem. But I still miss answers to these questions:
1. Do the X-Rays accumulate in a Tube or TV-Tubes material during TV-Watching?, and after Turn Off, do they send these accumulated x-rays?. Are the ‘no more used’ old TV or PC tubes dangerous because of accumulated x-rays.? Are X-Rays accumulable?
2. How dangerous live the people (e.g. programmers) staring 8 hours daily at Computer-Monitors, this from a much shorter distance than normally in case of TV-Set. Are the PC-Monitors less dangerous.?
3. How great and dangerous is the X-Ray coming out from the back side of the X-Ray tube? There are many people in offices working behind the X-Ray-Tubes-Devices (stock exchange staffs).
4. How dangerous are X-Ray-Tubes (TV-Sets) when used while/after having been strong shuttled while being transported long time? The same for TV-Sets in buses and airplanes ?
5. How dangerous are the airport x-ray baggage check machines? When we use these x-rayed objects and clothes afterwards, does it influence our health.? Do the objects stay X-ray contaminated?
6. What about the danger from X-Ray-Tubes having a leak, especially TV-Tubes?
> >From a scientific press release:
“X-rays and other classes of ionizing radiation have been, for decades, a proven cause of virtually all types of mutations — especially structural chromosomal mutations (such as deletions, translocations, and rings)….. Additionally, x-rays are an established cause of genomic instability, often a characteristic of the most aggressive Cancers.
Not surprisingly, a host of epidemiological studies have firmly established that x-rays and other classes of ionizing radiation are a cause of most varieties of human Cancer. We have a high level of confidence that our findings, about the important causal role of medical radiation in both Cancer and IHD, are correct.”
Kind regards, Leszek
February 2002Answer
The answers to your questions are:
1. X-rays are formed when electrons in the TV tube hits the surface, making light and images you see. X-rays are just like light, and they radiate from the source. Once an x-ray is formed it travels away from its source, just like the visible light does. It is a ray and cannot accumulate.
2. The x-rays that come from a PC monitor are very low-level. Several years ago people could purchase a window with lead material to put over the monitor screen to eliminate any x-rays. Manufactures have reduced the level of x-rays substantially, but I think you still can get such a protective screen if you are worried. Certainly there has not been much concern about it, but it may be an issue.
3. I don’t think x-rays coming out the back or side is as much of a program as the magnetic field that comes out the back and sides. It is unknown if high-level magnetic fields can cause harm in people.
4. The main danger in x-ray tubes in transportation is that they break and shatter. Also the material on the screen may be poisonous.
5. X-ray go right through materials and they are gone. The danger in humans is that the high-energy ray can damage some molecules, resulting in cancer. Also high-energy radiation can burn the skin, but you never get that much radiation from a machine. X-ray machines at the airport are fairly low level.
Absorption of x-rays in soft tissues
I am an Engineering graduate doing my final year in Electronics and Communication in Kamaraj University in the Tamil Nadu, a state in India
I have a question about x-ray imaging.
Due to non-linear absorption of tissues, we need to insert contrast agents in the body before x-ray is taken. What we want is the response of the tissues to x-rays and how non-linear it is. Basically, we want the model of x-ray imaging curve. We also want to know how much contrast variations will make the doctor to decide wrong conclusion?
Jagadeeswaran
March 2002Answer
The absorption of x-rays is generally proportional to the density of the material. There are also some materials that selectively absorb certain wavelengths of radiation.
Usually physicians use x-rays to determine if there is an area of greater or less density than the surrounding tissue. This goes under the assumption that a diseased or injured area has a noticeably different density. Obviously, x-rays don’t work very well with studying soft tissue, which is certainly not as dense as bone.
In some tests, a heavy material is ingested or put in a soft tissue to help in the diagnosis. A drink of Thorium will coat the stomach, allowing a study for tumors or problems in the soft tissue.
To do an exact study of the absorption, where you may be concerned about linearity, is not easy in the body. Care must be taken on injecting contract agents into the tissue. There are some x-ray devices that use false colors in the output to increase the contrast and to avoid injecting invasive material into the body.
In general, ultra-sound is better suited to study soft tissues.
What do you think?
Feel free to establish a link from your web site to pages in this site.
Students and researchers
The URL of this page is www.school-for-champions.com/science/xrays2.htm. Please include it as a reference in your report, document, or thesis.
If you would like to contribute a report, short article, lesson material or helpful tips on physical science, please check contributor information for details on what to do and the benefits you can receive.
Also, tell a friend about this material.
Where can you go from here?
- School for Champions
- Curriculum Outline
- Physical Science Topics
- X-rays
- Reader Questions on X-rays
- Other good stuff:
- Wave Motion
- Electromagnetic Waves
- Light
- Succeed in Writing
Search
Enter one or more keywords to search the School for Champions site and find related lessons:
Click Science Definitions for definitions of science words.