An x-ray is a painless test that provides images of the interior of the body. These images are created by using low doses of electromagnetic radiation reflected on film paper or fluorescent screens. Chest, skull or spinal x-rays are often used to diagnosis certain neurological conditions, including Alzheimer’s disease, dementia, epilepsy and head injuries.
X-rays work by passing small amounts of electromagnetic radiation through the body to produce images of bones, teeth and internal organs. The type of x-ray administered depends on which part of the body needs to be examined.
In some cases, standard x-rays are not enough for diagnosing a patient’s neurological condition. In these instances, there are a number of specialized x-rays available, including: CAT scan (computed axial tomography), fluoroscopy and angiography.
X-rays may be taken in a laboratory, physician’s office or hospital. In general, no special preparation is needed before an x-ray is taken. However, sometimes a special dye called a contrast medium is used, in which case a physician may advise the patient how to prepare for the x-ray. Depending on the procedure, the patient will sit, stand or lie down between the x-ray machine and x-ray film.
X-rays usually do not cause any side effects when administered correctly. The levels of radiation used in x-ray procedures are so low that they pose only minimal risk to patients. However, x-rays may be harmful to developing fetuses. Therefore, women who are or may be pregnant should inform their physician or x-ray technologist of their condition.
About x-rays
An x-ray is a painless test in which part of the body is imaged by using low doses of electromagnetic radiation. This radiation is then reflected on film paper or fluorescent screens. These images, also known as radiographs or roentgenograms, are used to diagnose and monitor the treatment of various diseases.
Medical professionals often perform chest or skull x-rays as part of a neurological examination. X-rays of the spine also may be useful in diagnosing some neurological conditions.
X-rays are also used to diagnose specific neurological conditions. For example, x-rays may reveal the relative shortening of certain bones that is consistent with Rett syndrome. Other neurological conditions that may be diagnosed with x-rays include:
Alzheimer’s disease
Dementia
Epilepsy
Head injuries
Hydrocephalus
Meningitis
Neurocutaneous syndromes
Neuropathy
Spinal cord injury
X-rays also may be used to diagnose any of the following:
Determining if bones are broken, fractured, or chipped
X-rays are noninvasive, relatively inexpensive and fast. They are generally safe for people of all ages when used correctly. Other medical tests that combine computer and x-ray technology (e.g., fluoroscopy, CAT scan) may also be used to confirm the source of some types of neurological disorders. In some cases, a series of x-rays over a period of time may be needed to assess the progression of a condition or compare changes that may have occurred after treatment.
How x-rays work
X-rays work by passing small amounts of electromagnetic radiation through the body to produce images of bones, teeth and internal organs. The type of x-rays administered depends on which part of the body needs to be examined.
The x-ray is the oldest imaging technology still in use today. It was discovered almost by accident in the 1890s by a German scientist named Wilhelm Conrad Roentgen. Because no one understood the rays that were at work in forming these images, the rays were initially called x-rays. Much more is now known about this form of radiation.
Bones and cartilage (tissue that connects bones and joints) tend to be dense and absorb x-rays better than do soft tissues (e.g., skin, fat, internal organs). As a result, bones appear white on x-rays whereas tissues often are gray. Organs or structures containing mostly air, such as the lungs, appear black. Generally, the denser the bone or organ, the more clearly it will show up with an x-ray. The results may first be viewed by a physician with special training in interpreting x-ray results (radiologist) before they are explained to the patient.
An x-ray machine produces a beam of radiation that is pointed by a tube at the part of the body being examined. The area to be examined is placed between the metal film cassette and the x-ray tube, which is surrounded in lead casing except for a small opening through which the rays are beamed. Within the x-ray tube, a beam of electrons is fired into a target made of a chemical element known as tungsten, emitting photons that travel straight and outward from a point on the target to the area being x-rayed. The resulting images are recorded on either film or a fluorescent screen.
The energy contained in the photons may cause some cell damage. Most of this cell damage is repaired quickly, but some may be permanent. Considering the low doses of radiation involved in modern x-rays, most physicians feel the benefits of x-rays outweigh the very small risks associated with them. However, young children and developing fetuses are more sensitive to radiation. Women should advise their physician if they are pregnant before getting an x-ray.
Additional techniques may be necessary to get a clear view of softer tissues, hollow areas or fluid–filled body parts. For example, a physician may administer a special dye known as a contrast medium to produce sharper contrasts in light and dark areas on the x-ray. These contrasts give the physician a clearer image of areas such as the spinal cord, blood vessels, urinary tract and the gallbladder.
Types and differences of x-rays
In some cases, standard x-rays are not enough for diagnosing a patient’s neurological condition. In these instances, there are a number of specialized x-rays available, including:
CAT scan (computed axial tomography). This noninvasive or minimally invasive test uses multiple x-rays images, taken from different angles, to create three-dimensional images of body structures. It may be performed alone or with the use of a special dye (called a contrast medium). A CAT scan is used when an area inside the body needs to be viewed from multiple angles and in greater detail.
When diagnosing neurological disease, a CAT scan is used to view the brain and spine. Conditions that can be revealed include bone and vascular abnormalities, certain brain tumors and cysts, herniated discs, encephalitis, epilepsy, intracranial bleeding in stroke patients and spinal stenosis (narrowing of the spinal canal). An intrathecal contrast-enhanced CT scan is used to detect problems with the spine and spinal nerve roots. A discography (CAT scan of the back) can identify damage to the discs of the spine.
Fluoroscopy. This type of test uses x–rays to image internal body organs while they are in motion. A continuous x–ray beam is focused on the part of the patient being examined to create a detailed, moving image that appears on a monitor. This technique is sometimes used to guide the needle during injection therapy.
Cerebral angiography. Produces x-ray images of blood vessels in the brain, head or neck. A cerebral angiogram may be able to detect narrowing or obstruction of blood vessels. In this test, a catheter is inserted into the leg near the groin and threaded through the body and into an artery in the neck. Once the catheter is in place, a guide wire is inserted and contrast medium is released to travel through the bloodstream. When x-rays are taken, the dye helps reveal any obstructions. Angiography is most often used to diagnose stroke and to help find the size and location of a brain tumor, aneurysm or vascular malformation.
Myelography. Procedure in which a water- or oil-based dye is injected into the spinal canal to help highlight potential trouble spots in the spine during x-rays. It is used to diagnosed back or leg pain, fractures, herniated discs, spinal nerve injury and spinal tumors.
Before the x-ray
X-rays may be taken in a laboratory, physician’s office or hospital. In general, no special preparation is needed before an x-ray is taken, unless a special dye called a contrast medium is going to be used. Contrast mediums outline a specific body area internally. They can be swallowed, injected into a vein or inserted rectally, and have a dull, opaque appearance on film.
If a contrast medium will be used, patients may be asked not to eat or drink after midnight before the x-rays, and the physician may make minor changes in how the patient takes his or her medication. The physician will also ask about the patient’s history of allergies to screen for a potential allergic reaction to the dye.
A radiology technician or specially trained nurse generally takes x-ray films. At the time of the x-rays, he or she will ask the patient to remove any objects that may show up on the image (e.g., clothing, jewelry, wigs, watches and/or dentures). Splints or prosthetic limbs may also be removed in some cases.
Patients should inform the examiner if they have had an x–ray using a contrast dye or barium in the past few days. They should also make sure the examiner is aware of all medications that have been taken recently, including over-the-counter medications.
Female patients should be sure to inform the examiner if they are or may be pregnant, because x-rays can be harmful to fetuses in very rare cases. In cases where the benefits of the x-ray outweigh the potential risks, pregnant women may wear a lead apron over their abdomen during the x-rays.
A lead apron is also often worn by patients to help protect sex organs from x-rays. In high doses, women’s eggs and men’s sperm can be affected by radiation. However, the risk of this occurring as a result of an x-ray is extremely low. Women should also inform the examiner if they currently have an IUD (a form of birth control) implanted.
During and after the x-ray
Depending on the procedure, the patient will sit, stand or lie down between the x-ray machine and x-ray film. Pillows or soft weights may be used to hold the patient in position if necessary. For example, sponges and other supports may be used to keep the head still during a skull x-ray. Momentary compression of the body area being examined is occasionally needed for some x-rays.
The x-ray machine is then pointed at the area being examined. While exposed to x-rays, the patients may be encouraged to hold their breath to help remain still. Movement during x-rays can cause images to blur on film. Multiple x-rays may be taken from different angles if necessary.
X-rays can be as short as a few seconds or minutes, or take as long as an hour in cases where a contrast medium has been administered. Occasional swelling, pain or redness may be experienced at the injection site if a contrast medium is administered this way.
The x-ray film is usually developed within a few minutes. A physician who specializes in interpreting x-rays (radiologist) may first view the results before they are explained to the patient. Additional x-rays may be taken if necessary.
Patients can resume normal activities immediately following the x-ray(s). The radiologist or the patient’s physician will interpret the findings and review them with the patient either that same day or at a follow-up visit. Additional tests (e.g., MRI) may be necessary if the x–rays do not provide enough information on the tissues or structures being studied.
Potential risks with x-rays
The levels of radiation used in x-ray procedures are so low that they pose only minimal risk to patients. As a precaution, some patients may be asked to wear a lead apron to shield sex organs from exposure to radiation. At very high doses, radiation can damage a woman’s eggs or a man’s sperm.
High doses of radiation can also be harmful to a developing fetus. Therefore, women who are or may be pregnant should be sure to inform their physician or x-ray technologist of their condition. It may be necessary to take certain precautions to protect the fetus.
Some precautions that can be taken in an x-ray procedure include:
Ask the physician how an x-ray will help. Patients have a right to understand why a physician believes an x-ray is necessary. If it is medically necessary, it should not be refused, as the small risk of radiation is much lower than the risk of not having a condition properly diagnosed. Patients should not insist on having an x-ray if it is not medically necessary.
Ask for gonad shields for x-rays of the lower back, abdomen or area near the sex organs. These lead shields can protect a man’s testicles or a woman’s ovaries from radiation, which protects reproductive cells. This shield should be considered for any patient who may have children in the future. In some cases – such as in x-rays of the gonads – these shields are not an option.
Keep track of x-rays with an x-ray record card. Patients who have x-rays taken should record the date, type of exam and where the x-ray is kept. In some cases, these old x-rays can be used instead of taking new x-rays. Each family member should have an x-ray card.
Some x-ray procedures require the patient to swallow or be injected with a contrast medium. In rare cases, patients experience an allergic reaction to this dye. Patients with a history of such reactions should inform their physician or x-ray technologist.
Questions for your doctor regarding x-rays
Preparing questions in advance can help patients to have more meaningful discussions with healthcare professionalsregarding their condition or test. Patients may wish to ask their doctor the following questions related to x-rays:
Why do you recommend an x-ray for diagnosing my neurological condition?
What type of x-ray do you recommend?
How long will these particular x–rays take?
Will these x-rays require the use of a contrast medium?
Does it require any preparation on my part?
I think I’m pregnant. Should I wait to have x-rays?
How much radiation will I be exposed to?
What is the margin of error for x-rays in detecting diseases, broken bones, etc.?
Will I receive other tests in addition to the x-rays?
I recently had x-rays. Am I at risk for being exposed to too much radiation if I have more x-rays?
