XRays
(Inappropriate Use)
Introduction
An X ray, also called roentgen ray, is electromagnetic radiation of shorter wavelength than visible light that has been used for over 100 years to see view structures hidden from the eye. X rays are produced when electrons (very small negatively charged particles that make up part of an atom) strike certain metals (particularly heavy metals). X rays, which can penetrate most substances, can be focused and aimed at specific targets such as part of the body.
X rays pass through organs and structures of the body onto a photographic plate. The difference in X ray penetration, and thus exposure of the photographic plate, depends on the density and thickness of the tissue the X ray passes through. For instance, the density of body structures is as follows:
bone greater than water/muscle/solid organs greater than fat greater than air
Less radiation will pass through bone than other tissues. Areas of the photogrphic plate with less exposure are lighter in color. Thus bones will appear white while the lungs normally appear darker.
Appropriate uses of X rays
It is known by most people that Xrays can be used to diagnose broken bones and that chest Xrays can be used to diagnose pneumonia. Most people (at least persons surfing the web) know that too much radiation from Xrays can be bad for you.
However, Xrays are not useful for visualizing many tissues in much detail, including the brain, muscles and most other non-bone tissues. Newer imaging techniques such as magnetic resonance imaging (MRI), computed tomography (CT), and ultrasound are superior to Xray in evaluating and detecting both healthy and diseased body tissues and organs.
X rays are commonly used to evaluate the integrity of bones, including vertebra of the spine.
Inappropriate use of X rays
It is not appropriate to perform screening X rays (ie.. those done to detect possible abnormalities in a person without any symptoms) in the vast majority of people. Periodic routine X rays to detect possible problems in the future are never indicated with the exception of mamograms.
Chiropractic practitioners still perform whole body X rays on a frequent basis. Such X rays consist of a single exposure of the head, neck, chest, abdomen, and pelvis in the front to back position.
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Whole body X rays do not show any particular body part very well. Such X rays are often of poor quality (poor patient position, improper X ray exposure, metal grid markings superimposed on the X ray).
- Such X rays are
taken in a single position. Complete examination a body part usually
require X rays be taken from at least 2 (and often 3) different angles.
A front to back (anterior to posterior) X ray of a vertebral body is
usually the least useful view.
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The only indication for whole body X ray screening is in young children whom physical child abuse is suspected.
Chiropractic Xrays, when taken for specific complaints such as neck or back pain, are frequently not properly performed in that technique is often not optimal and the appropriate number of views are often not done. Xrays performed in a medical setting are usually performed by licensed X ray techicians under the direct supervision of a radiologist.
The elusive subluxation
It has long been recognized that there is a moderate amount of variabilty in the appearance of X rays of the neck and lower back vertebra. Factors affecting noraml appearance can include proper positioning / posture, breathing, and body physique.
Chiropractors claim to detect subluxations by use of X rays. In medical terms a subluxation is the slippage in position of one veretebral body with respect to an adjacent vertebral body that can be clearly seen on X ray.
The only problem is that most subluxations that are claimed to exist by chiropractic analysis can not be found when examined by radiologists or other chiropractors. In blinded studies chiropractors have not been able to find subluxations claimed by other chiropractors.
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