X-Rays | Delmarva Dental Services


Radiation Exposure Radiographs (X-rays) have a huge impact upon our lives from airport scanners to cancer treatment but in many ways they are a mystery to most people. Xrays have always been present but weren’t discovered until 1895 by Wilhelm Roentgen. Since that time they have been used for diagnosis and treatment of injury and disease. An x-ray is a wave of electromagnetic energy. There are two types of electromagnetic energy (waves), nonionizing (low frequency) and ionizing (high frequency) energy. Examples of nonionizing waves are UV light, visible light, microwaves and radio waves. Xrays are ionizing radiation which can damage cells including the DNA by removing an electron (ionizing) from the atoms in molecules. The higher the x-ray dose the greater the damage. Low doses spread out over time are thought to be harmless because the body repairs any damage. However, we know high doses cause cancer from studies of atom bomb survivors in Japan. Radiation doses can be measured in many ways. The more common ways to measure is the biological effect on the body. The older unit of measure was the Rem, and millirem. The newer international measure is the Sievert, millisievert or microsievert. The measurements are similar to the meter and millimeter for distance. Different parts of the body absorb and therefore, are affected differently by radiation. The salivary glands are more affected by an xray scan of the head than the jaw bone. Parts of the body that grow faster are affected more than slower growing areas. Cancer cells grow very fast and are more affected by radiation. This is why radiation is used to treat cancer tumors. The whole body absorbed doses listed in the table are an average of all the body parts Ionizing radiation (x-rays) can come from many sources such as cosmic radiation from our solar system, radioactive elements in the soil, and radon from the air. The average person receives about 620 millirems (6,200uSv) per year, half from the environment and half from medical procedures. The following table shows the amount of radiation received to the whole body from various x-rays sources.Whole Body Absorbed Dose
SOURCE microSieverts (uSv) millirems (mrems)
Air in a year 2280 228
Cosmic rays in a year 260 26
Ground in a year 160-630 16-63
Computer screen in a year 10 1
TV Screen in a year 10 1
Living in a brick house a yr 80 8
Sleeping next to someone a yr 20 2
½ pack of cigarettes per day (1yr) 180 body (160,000 to lungs) 18 body (16,000 to lungs)
One hr of airplane travel 5 .5
Airport body scanner .05 to .25 .005 to .025
1 dental x-ray film .3 .03
Full set of dental film xrays 18 1.8
Full set dental digital xrays 6 .6
Dental Cone Beam Computer Tomography (CBCT) 5 to 206 .5 to 20.6
Chest xray 100 10
Mammogram 420 42
CAT scan of head 2000 200
CAT scan of upper GI 6000 600
CAT scan of chest 7000 700
Radiation Treatment for cancer 20,000,000 to 80 ,000,000 2,000,000 to 8,000,000
Amount of Short term xray exposure thought to cause cancer (EPA) 4,000,000 400,000
Two very important computer enhanced developments have lessened the effect of xrays to our bodies. The first is the use of digital sensors rather than film. Digital sensors are more sensitive than film and much less radiation is needed. For example dental film xray exposure is three times digital xray. The second development is the ability to focus the xray beam in a more precise way which concentrates the radiation to the smaller area of interest. This minimizes the effect of the radiation to the body. For example, a medical CAT scan of the head is 10 times more radiation than a “cone beam computerized tomograph “(CBCT) of the head. Highly focused radiation is also used for cancer radiation treatment. Delmarva Dental Services takes it responsibility to your health seriously. We will be more than happy to discuss the risks versus the benefits of any diagnostic or treatment procedure.