What is radiation?
Radiation is best described as energy moving through space, and it can take many forms, including visible light, x-rays, gamma-rays, microwaves, and radio waves. Radiologists use low dose radiation in the form of x-rays to create images of different parts of your body. High doses of radiation can also be used to treat certain types of cancer.
Where does radiation come from?
Radiation is all around us. The two main sources of ionizing radiation are from natural background radiation and medical exposure (CT scans and x-rays). Natural background radiation comes from the Sun (cosmic radiation), the Earth (mostly Radon gas), and from naturally radioactive substances in our body. Natural background radiation exposure accounts for an average of 3.1 mSv/yr with variations depending on where you live. The average radiation exposure to individuals in thus is 6.2 mSv/yr which includes natural background and medical imaging.
What are x-rays?
X-rays are a type of radiation used in medical imaging much like a camera uses visible light to create an image. X-rays pass through the body and create an image on film based on how many x-rays get absorbed and how many pass-throughs. These films are commonly referred toes “x-rays,” but x-rays are actually the type of radiation that is used to produce the image. Studies that use x-rays include plain films, fluoroscopy, and computed tomography (CT scans).
It is important to realize that in a properly performed individual exam, the potential health benefits almost should always outweigh the potential risks of radiation exposure. However, there is data to suggest that high doses of radiation increase your future risk of cancer. This data is compiled from high dose exposures including survivors of atomic bombs and radiation spills.
You will hear a lot about x-radiation as the cause of increased cancer mortality. Some say minimum cause some say up to 10% and more increased cancer deaths. There is no definite proof, however, that the low doses of radiation used with common x-rays or CT scans cause cancer. But we know enough and should be prudent enough to attempt to use this technology carefully and only when needed.
Typical Radiation Doses Comparison
Exam Dose in mili-Severts as a measure of radiation (mSv).
Just being alive on earth exposes each human being to natural background radiation of 3.1 (mSv) per year with the average US Exposure being 6.2 mSv/ year;
Dental x-rays 0.01;
Airline Flight 0.02;
Chest x-ray 0.10;
Chest CT 7.0;
Abdominal CT 8.0
Keep in mind, the overall lifetime risk of developing an invasive cancer is 37.5% (1 in 3) for women and 44.9% (1 in 2) for men regardless of imaging and x-ray history.
These statistics are averages and do not predict what is going to happen to you. They do not take into consideration individual risk factors including lifestyle (smoking, diet, exercise, etc), family history (genetics) or radiation exposure. The majority of cancers occur later in life and the average lifetime risk of dying from cancer is 25% (1 in 4).
WHAT ABOUT CT SCANS?*
These sites aims to provide accurate information for patients and health care providers to facilitate well-informed discussions about the increased risk of cancer from low dose radiation exposure.
The American College of Radiology (ACR) and the
International Atomic Energy Agency (IAEA) both recommend hospitals
monitor radiation exposure. It may be some time before all hospitals
have the ability to track individual exposure. This site allows patients
to log-in, create their own imaging record and generate an X-ray Risk
Report with information about cancer risk.
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3. Lee CI, Haims AH, Monico EP, et al. Diagnostic CT Scans: Assessment of Patient, Physician, and Radiologist Awareness of Radiation Dose and Possible Risks. Radiology 231 (2): 393-398. (2004).
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10. NCRP Report No. 160, Ionizing Radiation Exposure of the Population of the United States. Available at www.ncrponline.org. Accessed April 2009.
11. Health Physics Society: Radiation Exposure During Commercial Airline Flights. Available at http://www.hps.org/publicinformation/ate/faqs/commercialflights.html. Accessed September 2009.
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14. ACR Statement on Airport Full-body Scanners and Radiation, January 2010.
15. Balon HR, Roff E, Freitas JE, et al: Society of Nuclear Medicine Procedure Guideline for C-14 Urea Breath Test. Version 3.0, June 23, 2001
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17. Platts D, Brown M, Javorsky G, et al: Comparison of fluoroscopic versus real-time three-dimensional transthoracic echocardiographic guidance of endomyocardial biopsies. Eur J of Echocardiography 11, 637-643, 2010.
18. Hendrick ER: Radiation Doses and Cancer Risks from Breast Imaging. Radiology, 257 (1), 246- 253, 2010."
• Don’t get any study you don’t need.
• Ask your physician whether & how the benefits of study outweigh potential risks.
• Keep a history of your studies in a diary form by date and type to avoid unnecessary repeat exams and so that the new exam can be compared to the previous exam.
For help along these lines use these two very valuable sources of information.
www.Xrayrisk.com ; www.acr.org/ac
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