Dental X-rays (radiographs) are images of your teeth that your dentist uses to evaluate your oral health. These X-rays are used with low levels of radiation to capture images of the interior of your teeth and gums. This can help your dentist to identify problems, like cavities, tooth decay, and impacted teeth.
Dental X-rays may seem complex, but they're actually very common tools that are just as important as your teeth cleanings.
Why dental X-rays are performed
Dental X-rays are typically performed yearly. They can happen more often if your dentist is tracking the progress of a dental problem or treatment.
Factors affecting how often you get dental X-rays may include:
your age
your current oral health
any symptoms of oral disease
a history of gum disease (gingivitis) or tooth decay
If you're a new patient, you'll probably undergo dental X-rays so that your new dentist can get a clear picture of your dental health. This is especially important if you don't have any X-rays from your previous dentist.
Children may need to have dental X-rays more often than adults because their dentists might need to monitor the growth of their adult teeth. This is important because it can help the dentist determine if baby teeth need to be pulled to prevent complications, such as adult teeth growing in behind baby teeth.
Risks of dental X-rays
While dental X-rays do involve radiation, the exposed levels are so low that they're considered safe for children and adults. If your dentist uses digital X-rays instead of developing them on film, your risks from radiation exposure are even lower.
Your dentist will also place a lead bib over your chest, abdomen, and pelvic region to prevent any unnecessary radiation exposure to your vital organs. A thyroid collar may be used in the case of thyroid conditions. Children and women of childbearing age may also wear them along with the lead bib.
Pregnancy is an exception to the rule. Women who are pregnant or believe they may be pregnant should avoid all types of X-rays. Tell your dentist if you believe you are pregnant, because radiation is not considered safe for developing fetuses.
Preparing for dental X-rays
Dental X-rays require no special preparation. The only thing you'll want to do is brush your teeth before your appointment. That creates a more hygienic environment for those working inside your mouth. X-rays are usually done before cleanings.
At the dentist's office, you'll sit in a chair with a lead vest across your chest and lap. The X-ray machine is positioned alongside your head to record images of your mouth. Some dental practices have a separate room for X-rays, while others perform them in the same room as cleanings and other procedures.
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Types of X-rays
There are several types of dental X-rays, which record slightly different views of your mouth. The most common are intraoral X-rays, such as:
Bitewing. This technique involves biting down on a special piece of paper so that your dentist can see how well the crowns of your teeth match up. This is commonly used to check for cavities between teeth (interdental).
Occlusal. This X-ray is done when your jaw is closed to see how your upper and bottom teeth line up. It can also detect anatomical abnormalities with the floor of the mouth or the palate.
Occlusal. This technique captures all of your teeth in one shot.
Panoramic. For this type of X-ray, the machine rotates around the head. Your dentist may use this technique to check your wisdom teeth, plan for implanted dental devices, or investigate jaw problems.
Periapical. This technique focuses on two complete teeth from root to crown.
ExtraoralX-rays may be used when your dentist suspects there might be problems in areas outside of the gums and teeth, such as the jaw.
A dental hygienist will guide you through each step of the X-ray process. They might step outside of the room briefly while the images are being taken. You'll be instructed to hold still while the pictures are recorded. Spacers (film holders), if they're used, will be moved and adjusted in your mouth to obtain the proper images.
After dental X-rays
When the images are ready instantly in the case of digital X-rays your dentist will review them and check for abnormalities. If a dental hygienist is cleaning your teeth, the dentist may go over the results of the X-rays with you after your cleaning is done. The exception is if the hygienist discovers any significant problems during the X-rays.
If your dentist finds problems, such as cavities or tooth decay, they'll discuss your treatment options. If your dentist finds no problems, keep up the good work!
The outlook
Like brushing and flossing, getting regular dental X-rays is an integral part of your overall oral health.
Having a good checkup can be a relief, but this doesn't mean you shouldn't keep getting X-rays.
Depending on your age, health, and insurance coverage, X-rays may be performed every one to two years. Be sure to commit to your appointments and see your dentist sooner if you experience any pain or other changes in your mouth.
Thyroid scan
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A thyroid scan uses a radioactive iodine tracer to examine the structure and function of the thyroid gland. This test is often done together with a radioactive iodine uptake test.
How the Test is Performed
The test is done in this way:
You are given a pill that contains a tiny amount of radioactive iodine. After swallowing it, you wait as the iodine collects in your thyroid.
The first scan is usually done 4 to 6 hours after you take the iodine pill. Another scan is usually done 24 hours later. During the scan, you lie on your back on a movable table. Your neck and chest are positioned under the scanner. You must lie still so that the scanner gets a clear image.
The scanner detects the location and intensity of the rays given off by the radioactive material. A computer displays images of the thyroid gland. Other scans use a substance called technetium instead of radioactive iodine.
How to Prepare for the Test
Follow instructions about not eating before the test. You may be told not to eat after the midnight before your scan.
Tell your health care provider if you are taking anything that contains iodine because it may affect your test results. This includes some medicines, including thyroid drugs. Supplements such as kelp also contain iodine.
Also tell your provider if you have:
Diarrhea (may decrease absorption of the radioactive iodine)
Had recent CT scans using intravenous or oral iodine-based contrast (within the past 2 weeks)
Too little or too much iodine in your diet
Remove jewelry, dentures, or other metals because they may interfere with the image.
How the Test will Feel
Some people find it uncomfortable to stay still during the test.
Why the Test is Performed
This test is done to:
Evaluate thyroid nodules or goiter
Find the cause of an overactive thyroid gland
Check for thyroid cancer (rarely, since other tests are more accurate for this)
Normal Results
Normal test results will show that the thyroid appears to be the correct size, shape, and in the proper location. It is an even gray color on the computer image without darker or lighter areas.
What Abnormal Results Mean
A thyroid that is enlarged or pushed off to one side could be a sign of a tumor.
Nodules absorb more or less iodine and this will make them look darker or lighter on the scan. A nodule is usually lighter if it has not taken up the iodine. If part of the thyroid appears lighter, it could be a thyroid problem. Nodules that are darker have taken up more iodine. They can be overactive and may be the cause of an overactive thyroid.
The computer will also show the percentage of iodine that has collected in your thyroid gland (radioiodine uptake). If your gland collects too much iodine, it may be due to an overactive thyroid. If your gland collects too little iodine, it may be due to an inflammation or other damage to the thyroid.
Risks
All radiation has possible side effects. The amount of radioactivity is very small, and there have been no documented side effects.
Women who are pregnant or breastfeeding should not have this test.
Talk to your provider if you have concerns about this test.
Thyroxine (T4) Test
What is a thyroxine (T4) test?
A thyroxine test helps diagnose disorders of the thyroid. The thyroid is a small, butterfly-shaped gland located near the throat. Your thyroid makes hormones that regulate the way your body uses energy. It also plays an important role in regulating your weight, body temperature, muscle strength, and even your mood. Thyroxine, also known as T4, is a type of thyroid hormone. This test measures the level of T4 in your blood. Too much or too little T4 can indicate thyroid disease.
The T4 hormone comes in two forms:
Free T4, which enters the body tissues where it's needed
Bound T4, which attaches to proteins, preventing it from entering body tissues
A test that measures both free and bound T4 is called a total T4 test. Other tests measure just free T4. A free T4 test is considered more accurate than a total T4 test for checking thyroid function.
Other names: free thyroxine, free T4, total T4 concentration, thyroxine screen, free T4 concentration
What is it used for?
A T4 test is used to evaluate thyroid function and diagnose thyroid disease.
Why do I need a thyroxine test?
Thyroid disease is much more common in women and most often occurs under the age of 40. It also tend to run in families. You may need a thyroxine test if a family member has ever had thyroid disease or if you have symptoms of having too much thyroid hormone in your blood, a condition called hyperthyroidism, or symptoms of having too little thyroid hormone, a condition called hypothyroidism.
Symptoms of hyperthyroidism, also known as overactive thyroid, include:
Anxiety
Weight loss
Tremors in the hands
Increased heart rate
Puffiness
Bulging of the eyes
Trouble sleeping
Symptoms of hypothyroidism, also known as underactive thyroid, include:
Weight gain
Fatigue
Hair loss
Low tolerance for cold temperatures
Irregular menstrual periods
Constipation
What happens during a thyroxine test?
A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.
Will I need to do anything to prepare for the test?
You don't need any special preparations for a thyroxine blood test. If your health care provider has ordered more tests on your blood sample, you may need to fast (not eat or drink) for several hours before the test. Your health care provider will let you know if there are any special instructions to follow.
Are there any risks to the test?
There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
What do the results mean?
Your results may come in the form of total T4, free T4, or a free T4 index.
The free T4 index includes a formula that compares free and bound T4.
High levels of any of these tests (total T4, free T4, or free T4 index) may indicate an overactive thyroid, also known as hyperthyroidism.
Low levels of any of these tests (total T4, free T4, or free T4 index) may indicate an underactive thyroid, also known as hypothyroidism.
If your T4 test results are not normal, your health care provider will likely order more thyroid tests to help make a diagnosis. These may include:
T3 thyroid hormone tests. T3 is another hormone made by the thyroid.
A TSH (thyroid stimulating hormone) test. TSH is a hormone made by the pituitary gland. It stimulates the thyroid to produce T4 and T3 hormones.
Tests to diagnose Graves' disease, an autoimmune disease that causes hyperthyroidism
Tests to diagnose Hashimoto's thyroiditis, an autoimmune disease that causes hypothyroidism
Is there anything else I need to know about a thyroxine test?
Thyroid changes can happen during pregnancy. These changes are usually not significant, but some women can develop thyroid disease during pregnancy. Hyperthyroidism happens in about one in every 500 pregnancies, while hypothyroidism happens in approximately one in every 250 pregnancies. Hyperthyroidism, and less often, hypothyroidism, may remain after pregnancy. If you develop a thyroid condition during pregnancy, your health care provider will monitor your condition after your baby is born. Also, if you have a history of thyroid disease, be sure to talk with your health care provider if you are pregnant or are thinking of becoming pregnant.
What is a T3 (triiodothyronine) Test?
Definition:
The T3 test measures the amount of T3 hormone in the blood.
Alternative Names: Triiodothyronine; T3 radioimmunoassay
How the test is performed:
Blood is drawn from a vein on the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and an elastic band is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the band to swell with blood.
A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.
For an infant or young child, the area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.
How to prepare for the test:
The health care provider may advise you to stop taking drugs that may affect the test (see "special considerations").
For infants and children:
The preparation you can provide for this test depends on your child's age and experience. For specific information regarding how you can prepare your child, see the following topics:
infant test or procedure preparation (birth to 1 year)
toddler test or procedure preparation (1 to 3 years)
preschooler test or procedure preparation (3 to 6 years)
schoolage test or procedure preparation (6 to 12 years)
adolescent test or procedure preparation (12 to 18 years)
How the test will feel:
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the test is performed:
T3 is measured as part of a thyroid function evaluation. Most of the thyroid hormone made in the thyroid is in the form of T4. The body's cells convert the T4 to T3, which is the more active hormone.
Sometimes it can be useful to measure both T4 and T3 when looking at thyroid function. For example, in some cases of hyperthyroidism, T4 may be normal but T3 will be elevated.
Most of the T4 and T3 in the body is attached to proteins in the blood. These proteins serve as carriers. The T3 test measures both the T3 that is bound to the proteins and the T3 that is "free" floating in the blood. The free fraction is the hormone that is active.
Conditions that increase the levels of the carrier proteins -- such as pregnancy and liver disease -- will falsely raise the T3 level. In these cases, it is useful to measure either the free T3 level or to perform the RT3U test, which gives a measure of the amount of carrier protein.
T4 and T3 are important hormones in the regulation of metabolism. The exact mechanisms are not understood, but it is known that T4 increases the concentrations of numerous enzymes involved in the production of energy in the body.
Normal Values:
100 to 200 ng/dL (nanograms per deciliter)
What abnormal results mean:
Greater-than-normal levels may indicate:
hyperthyroidism (for example, Graves' disease)
T3 thyrotoxicosis (rare)
thyroid cancer (rare)
Lower-than-normal levels may indicate:
chronic illness
hypothyroidism (for example, Hashimoto's disease)
starvation
Additional conditions under which the test may be performed:
painless (silent) thyroiditis
thyrotoxic periodic paralysis
toxic nodular goiter
What the risks are:
The only risks of the test is those minor risks associated with having blood drawn.
Special considerations:
Drugs that can increase T3 measurements include clofibrate, estrogens, methadone, and oral contraceptives.
Drugs that can decrease T3 measurements include anabolic steroids, androgens, antithyroid drugs (for example, propylthiouracil), lithium, phenytoin, and propranolol.
What is a T cell count?
A T cell count is a blood test that measures the number of T cells in your body. A T cell is a type of white blood cell (WBC). WBCs are also called lymphocytes.
These cells fight off diseases. The two categories of lymphocytes are T cells and B cells. The T cells respond to viral infections and boost immune function of other cells, while the B cells fight bacterial infections.
Your body sometimes has too many or too few T cells. This may be a sign that your immune system isn't functioning properly.
A T cell count may also be known as a thymus-derived lymphocyte count or a T lymphocyte count. If you're being treated for HIV, this test may be known as a CD4 cell count. Some T cells contain a CD4 receptor. This receptor is where HIV attaches to the T cell.
Why do I need a T cell count?
Your doctor may order a T cell count if you're having symptoms of an immunodeficiency disorder, such as HIV. Symptoms associated with other conditions, such as leukemia or other cancers, may also prompt a T cell count.
The symptoms of an immunodeficiency disorder include:
frequently recurring infections
severe infections from bacteria or other organisms that don't usually cause severe infections
trouble recovering from illnesses
infections that don't respond to treatments
recurring fungal infections, such as yeast infections
recurring parasitic infections
How do I prepare for a T cell count?
A T cell count requires only a small sample of your blood. There's little you need to do to prepare for it.
Before your test, be sure to tell your doctor about all the medications you're taking. This includes any over-the-counter (OTC) and prescription medications or herbal supplements.
Certain medications can impact your T cell count, which will alter the results of your test. Your doctor may ask you to stop taking your medications for a little while, or they may change the dosage before your test.
Medications that may affect your T cell count include:
chemotherapy drugs
radiation therapy
corticosteroids
immunosuppressive drugs, such as anti-rejection drugs
Recent surgery or highly stressful experiences can also affect your T cell count. You should tell your doctor if any of these situations apply to you.
How is a T cell count determined?
Remember, your doctor only needs a small sample of your blood to get a T cell count. This procedure is also known as a blood draw or venipuncture. You may have the test in a medical laboratory or a doctors office.
A healthcare provider will begin by cleaning an area of skin on your arm or hand with antiseptic to help prevent infection.
They'll tie an elastic band around your upper arm so that blood collects in your vein.
Next, they'll insert a sterile needle into your vein and draw blood into a tube. The amount of blood drawn depends on the number of tests that your doctor ordered. It should take no longer than a couple of minutes to collect the blood sample needed.
You may feel some pain while having your blood drawn. This usually feels like a pricking or stinging sensation. You can help ease this pain by relaxing your arm.
When the technician finishes drawing blood, they'll remove the elastic band and the needle and apply a bandage to the puncture wound. You should apply pressure to the wound to stop bleeding and prevent bruising.
You'll be free to go about your day following the blood draw. Your sample will go to a laboratory, where technicians will count the number and type of white blood cells present.
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What are the risks associated with a T cell count?
There are very few risks associated with a T cell count. However, people with compromised immune systems often have this test. They may be at greater risk for developing an infection than the rest of the population.
Other possible risks of a T cell test include:
multiple puncture wounds if the technician has trouble finding a vein
excessive bleeding
lightheadedness or fainting
hematoma, which is a collection of blood under the skin
an infection at the puncture site
What do the results mean?
According to HIV.gov, a healthy T cell count should be between 500 and 1,600 T cells per cubic millimeter of blood (cells/mm3).
Low T cell count
A low T cell count is more common than a high T cell count. Low T cell counts usually indicate problems with your immune system or lymph nodes. Low T cell counts may be due to:
viral infections, such as influenza
aging
immunodeficiency disorders
exposure to radiation
HIV and AIDS
cancers that affect the blood or lymph nodes, such as Waldenstroms macroglobulinemia, leukemia, and Hodgkin's disease
congenital T cell deficiency, in some rare cases
High T cell count
Less often, you might have a T cell count that's higher than normal. A high T cell count can be due to:
infectious mononucleosis, also known as mono or the kissing disease
acute lymphocytic leukemia (ALL), a type of cancer that affects the WBCs
multiple myeloma, a type of cancer that affects the plasma cells in bone marrow
genetic disorders, such as in autoimmune lymphoproliferative syndrome
What happens after I receive my T cell count?
Your doctor will discuss any further tests you need for a diagnosis. They'll also provide you with treatment options if your results are above or below this range.
Medications may be prescribed to increase your T cell count. No specific foods have been shown to increase the number of WBCs or T cells in the body. However, a healthy diet can help to boost the immune system overall.