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Radiation Safety

July 10, 2012

What you need to know

Today, doctors have more tools than ever at their disposal to diagnose and treat patients. Perhaps one of the most useful - and therefore widely used-is medical imaging, including X-rays, as well as more recent advancements, such as computed tomography scanning.

"Medical radiation has increased over the last century as the number and type of examinations have increased," explains Mimi Lin, M.D., a radiologist and director of Washington Hospital's Mammography Program. "This is especially true in the last 25 years with the advent of computed tomography scanning, also known as CT or CAT
scanning. CT image quality is excellent with great visualization of anatomy and pathologic processes."

The effectiveness of CT scans to diagnose certain types of disease processes such as cancer, infection and trauma, as well as being a less invasive way to evaluate arteries of the body, has led to a dramatic rise in this type of medical imaging, according to Lin.

Increasing Use

"The number of CT examinations went from 3 million in 1980 to 62 million currently," Lin says. "CT scans accounts for 15 percent of imaging procedures but 75 percent of medical radiation dose. This has resulted in an increase in the
average personal radiation exposure in the United States."

With the average person in the United States being exposed to more radiation during medical imaging procedures, from routine to complex, Lin says it's in the public's best interest to understand the benefits of these tests, as well as the inherent risk associated with the radiation exposure they involve.

"The major concern about radiation exposure is related to possible cancer induction," Lin explains. "However, the increased risk of cancer development is generally regarded as small when compared to the natural incidence of cancer
and other everyday risks-such as flying in an airplane and driving a car.

"Additionally, when compared to other lifestyle factors, including smoking, alcohol consumption, diet, and sun exposure; environmental and occupational factors such as asbestos and pesticides; and infection agents such as viruses and bacteria, the risk associated with routine medical radiation exposure is insignificant."

Knowledge is Key

Unfortunately, Lin says, understanding of radiation and its use for diagnostic and treatment procedures is low, which can leave people feeling overconfident or fearful when their physician refers them for a procedure.

"I think most individuals don't understand radiation in general, let alone risk from radiation. Most people, including physicians, under-estimate or over-estimate the radiation dose for any given diagnostic procedure. In a recent survey of radiologists and emergency room physicians, about 75 percent of the entire group significantly underestimated the radiation dose from a CT scan."

A better awareness of radiation and its uses in the healthcare setting is essential to making sure that patients and their physicians are partnering to make the best use of a tool that should be used with discretion. Lin says that
radiation exposure used in medical imaging is best illustrated when compared to radiation that we are all exposed to from natural sources.

"The average person in the United States receives a dose of about three units of radiation-called millisieverts (mSv)-per year from naturally occurring, background
radiation. Mammography has an average dose of 0.7 mSv, or approximately three months equivalent of background radiation."

A CT of the chest, abdomen, or pelvis, she says, has a radiation dose of approximately eight to 10 mSv each, which is equivalent to approximately three years of background radiation, and in the end, Dr. Lin says it boils down to making an educated judgment call.

Questions to Ask Your Doctor

If any test or prescription is ordered for you or your family member, you should understand its purpose. Here are some questions to ask your doctor:

  • Why am I getting this test or medication?
  • What question will the test answer?
  • Is this the best test for the question?
  • Are there alternatives to the test being ordered?
  • What can happen if I don't take the test?
  • Is the risk of the test worth the benefit of the result?

Washington Hospital takes every precaution necessary to protect patients that are exposed to medical radiation through x-ray and CT scans. Mimi Lin, M.D., radiologist and director of Washington Hospital's Mammography Program says it's
important for patients to discuss the benefits and risks of radiation with their physicians.

"The question of the benefits versus the risks of radiation is important. And quite often the benefits do outweigh the potential risk. For example, finding an early breast cancer by screening mammography has been shown to outweigh the risk of the radiation exposure."