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More than 100 years ago, German physicist William Conrad Roentgen was fiddling around with a black box and cathode ray tubes in his laboratory when he made a discovery that would dramatically influence a health care profession that was born in the same year.

Chiropractic and X-rays both began in 1895 and have been joined at the hip (pun intended) ever since.

There was no scientific reason attached to the name X-ray. Roentgen simply didn't know what else to call it because he had no clues as to what the images he saw were made of. Hence the name X-rays or unknown rays.

This article is to give readers an overview of how an X-ray is made, why we use X-rays medically, and some safety and public protection issues.

We are all familiar with the process of creating a shadow. The first shadows I remember were on the sidewalks of Meadville on East Henry Street where I grew up.

There were three elements required for this shadow: 1) energy source(sun); 2) object to block the light(a body); and 3) platform to cast the shadow upon(sidewalk).

The reason a shadow was cast on the sidewalk is that the sun's rays could not pass through a human body and it was the contrast between the light from the sun shining on the sidewalk and the lack of light the body blocked that caused this shadow.

In a similar way with an X-ray, there is: 1) an energy source(an X-ray tube); 2) object(again, a body) only instead of the body blocking all of the rays it only blocks the ones that come in contact with bone and denser tissue; and 3) platform(X-ray film).

This X-ray film is placed in a cassette. Within the cassette are chemicals that are "excited" when they are hit by the X-ray beam and give off a small amount of light. This light exposes the film - where a lot of X-rays come through, if it is dark; and where little X-rays come through to the cassette to exit the chemicals, the film appears white, as in the instance of bone. Based on the nature of a patient's condition as well as a number of other factors, X-ray studies of a spine, for example, may be indicated.

Doctors of chiropractic receive more than 300 hours of X-ray studies in college and are fully trained to take radiographs (X-rays) and identify subtle abnormalities of alignment as wellas identifying a condition that should be addressed by another health care practitioner.

X-rays are a relatively safe and cost-effective way to view the structure and general condition of the spine, X-rays are also useful in assessing the appropriateness of chiropractic care as they can help to rule out the existence of a more serious problem such as spinal fractures, tumors and infections, which require immediate medical intervention. In the arena of safety, there are some common sense practices and procedures that we follow.

In 1986, Russell introduced the "10-day rule" to prevent effect of radiation in pregnancy. The guideline states X-ray procedures in women of childbearing age that involve the abdomen or pelvis should only be carried out during the first 10 days after a menstrual period of normal duration and intensity. This rule means X-ray procedures on fertile women who enter our offices during the later half of the menstrual cycle should be deferred to after the start of the menstrual cycle to avoid the risk of irradiating an unsuspected embryo.

In addition to the 10-day rule, there are steps used to further reduce the amount of X-ray exposure that a responsible practitioner will use:

  • Only necessary X-ray views are taken.
  • A shield of filtration block to reduce the X-ray beam from affecting sensitive tissue.
  • Rare earth intensity screens can ct X-ray exposure by 50 percent.
  • Grids to reduce scatter radiation and improve X-ray quality.
  • High speed film to exposure by up to 1/12th.
  • Minimal exposure times.
  • Regular changing of processor chemicals to give high quality diagnostic films.
  • Using a collimator that is installed on all modern X-ray tubes to limit exposure.

This information can be useful when you are in a doctor of chiropractic's office or in the office of another health care provider.

As in all diagnostic tests, one should weigh the risk/benefit ratio and be comfortable with the information you receive from your health care provider.

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