Should I ask for the thyroid guard?


Thyroid gland

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The thyroid is a small butterfly-shaped master gland, just below your Adam’s apple. It is called the master gland because it governs your metabolism. It decides the rate at which you will burn calories or your heart will beat. It produces two main hormones: T4 (also called thyroxine) and T3 (also called triiodothyronine), which have an enormous impact on your health.

Other than hypothyroidism (less than the optimal function of the thyroid gland) a disease which affects 10 percent of women worldwide, the thyroid gland has come under the scanner recently because there have been a whopping 121 percent increase in the episodes of thyroid cancer in women <30 years.

In industrialized countries, thyroid cancer is the fastest growing cancer in women, especially in high-income countries.

In the US there has been a tripling of thyroid cancer incidence over 35 years. In Korea, the numbers of thyroid cancer have increased by 15 times from 1993 to 2011. In India, Kerala has reported a high incidence of thyroid cancer.

Causes of thyroid cancer

In 2011 Dr. Mehmet Oz in his show held responsible radiation caused by mammography and dental x-rays for the increase in thyroid cancer in women.  In a way, Dr. Mehmet was right when he said this. American Thyroid Association writes on its website that exposure of the thyroid to radiation at a young age is a well-established risk factor for the development of thyroid cancer.

Undeniably, the larger chunk of the radiation is coming currently from diagnostic X-ray procedures and dental X-rays tops the list. It is the most common source of radiation to the thyroid.

In his program, Dr. Oz warned that people who have more than five X-rays a year have a fourfold greater risk of developing this cancer, and recommended the use of a lead thyroid shield when getting dental X-rays or mammograms.

Thyroid Guard
Thyroid Guard


What is a thyroid guard and how does it help?

A thyroid guard or thyroid shield is a lead collar that wraps around your neck to block the radiation that’s generated in making X-ray images. During an X-ray, the majority of radiation needed to create the images goes exactly where it’s aimed. However, the rest of the body is exposed to small amounts of scatter radiation, including your thyroid. Understandably, direct hits of radiation to the thyroid carry greater risk than indirect, so-called “scatter” hits.

The key issue in using the thyroid guard in X-rays is risk versus benefit.

Studies like coronary angiography esophageal swallow studies expose the thyroid to far more radiation than a simple two-view chest x-ray or mammogram.

However, using a thyroid guard during these X-rays fraught with risks, as it might interfere with the value of the diagnostic study. For example, if the thyroid guard blocks the upper edges of your lung tissue on the x-ray picture, your doctors won’t be able to see a small abnormality (such as a tumor) hiding up there.

Should you use a thyroid guard during a mammogram?

During a mammogram, there are two X-rays per breast. However, most radiation exposure occurs in your breast. But the rest of your body is exposed to small amounts of scatter radiation (known as background radiation) which is equivalent to a fraction of the natural radiation you’d receive in one day.  

With the use of thyroid guard, there is a risk that it might block the tail end of breast tissue near the axilla (armpit) or deep breast tissue abutting the chest wall and your mammogram could not show small cancer.

Thyroid collar during xrays

Should you use thyroid guard during a dental X-ray?

Dental X-ray is a source of radiation. Yet, they are a necessary evil because the only way to treat and detect an abscess, tumor or some cavities are by taking x-rays. The American Dental Association recommends Dental X-Rays only when it is necessary for treatment.

Since dental  X-rays continue to remain under the suspicion needle and have received a lot of flak, it is better to ask for a thyroid guard if you are getting dental X-rays done and do ask your dentist if the X-ray is really necessary before you undergo the radiation?

In the Indian context, the judgment is still divided on the increased episodes of thyroid cancer. While the western studies attribute it to the effects of radiation, Indian research studies hold overdiagnosis responsible for the higher episodes, which means that the disease was present before, only it wasn’t getting diagnosed.  

Eventually, we’ve to admit that we are bombarded with radiation, which comes from sources like airport scanners, dental x-rays or CT scan, yet saying a NO to a CT scan or mammogram doesn’t sound like a sensible thought! Asking for a thyroid collar before a dental X-ray is a wise decision. Do it, and if you’r wondering how does a thyroid collar look like click here to have the first glimpse of it.




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