»Medical

»Medical X-Rays

This page describes how x-rays are used to diagnose medical conditions.

Overview

From broken bones to life threatening illnesses, x-ray machines help diagnose and treat numerous medical conditions. In fact, seven out of ten people receive either a medical or dental x-ray every year.

Literally thousands of x-ray machines are used daily in medicine and industry for examinations, inspections, and process controls. Because of their many uses, x-rays are the single largest source of man-made radiation exposure.

In a clinic setting you are most likely to encounter radiation from a diagnostic x-ray. X-rays pass more easily through the soft tissues of our bodies than through our bones and organs. After passing through our body, x-rays strike a special x-ray film, creating an image showing shadows where our bones, organs and other dense masses have absorbed x-rays.

Like microwaves, radio waves, and visible light, the x-rays produced by an x-ray machine are a form of electromagnetic radiation. Unlike microwaves, radio waves, and visible light, x-rays are ionizing radiation, which is capable of removing electrons from atoms and damaging living cells and the DNA of those cells. However, since x-ray machines only produce radiation during operation and the amount of radiation used is small, resulting medical problems are unlikely.

»Mammography

This page describes how x-rays are used during a mammography.

Overview

A high-quality mammogram is an effective tool for early detection of breast cancer. Mammography machines produce x-rays, which pass through the soft parts of bodies and capture a two-dimensional image of the dense parts, including tumors and cysts.

Like microwaves, radio waves, and visible light, the x-rays produced by a mammography machine are a form of electromagnetic radiation. Unlike microwaves, radio waves, and visible light, x-rays are ionizing radiation, which is capable of removing electrons from atoms and damaging living cells and the DNA of those cells. However, since mammography machines only produce radiation during operation and the amount of radiation used is small, resulting medical problems are unlikely.

Who is protecting you

The States

State radiation programs, in cooperation with the Food and Drug Administration (FDA), manage the inspection of mammography equipment and facilities.

U.S. Food and Drug Administration (FDA)

Congress enacted the Mammography Quality Standards Act (MQSA) in 1992 to ensure that all women have access to the high-quality mammogram necessary to detect breast cancer in its earliest, most treatable stages. As a result of MQSA, FDA developed and implemented mammography quality standards regulations. In addition, MQSA mandates that facilities ask about breast implants prior to performing mammogram, deliver the mammogram results directly to the patients, transfer mammograms to other facilities upon request, and limit discussions with patients to any concerns a patient may have about the procedure. Technicians may only discuss the procedure with patients; only a certified radiologist may interpret the results.)

FDA regulates mammography facilities, equipment and personnel. All mammography facilities are required to be certified by the American College of Radiology; have qualified personnel with the necessary credentials; and adhere to quality control measures, patient dose maximums, and image quality standards.

What you can do to protect yourself

Typically, people's exposure to x-rays is almost entirely from dental and medical x-rays, including a mammogram. The best way to protect yourself from excessive exposure to x-rays is to make sure the technician performing the procedure has the proper qualifications and receive assurance the x-ray machine has been inspected recently and is properly calibrated. You can also talk with your healthcare providers about when to schedule x-rays, how often you should have x-rays, and whether other procedures can provide equivalent information.

»Radiation Therapy - External Beam

This page provides information on the medical treatments that involve focused beams of radiation to treat cancerous tumors.

Overview

Approximately 50% of all cancer patients will receive some type of radiation treatment. Radiation therapy is external radiation treatment in which doctors use focused beams of radiation to treat cancerous tumors. It is just one of the many different methods of radiation treatment administered in hospitals. There are different types of radiation therapy: external beam therapy, three-dimensional conformal radiation therapy, and stereo tactic radio surgery.

External Beam Therapy delivers a single beam of high-energy x-rays to the location of the patient’s tumor. The beam is generated outside the patient, by a machine called a linear accelerator, and is targeted at the tumor site. These treatments are usually performed in multiple sessions over the course of several weeks.

Intensity-Modulated Radiation Therapy uses a computer simulation to produce an accurate image of the tumor and surrounding organs so that multiple radiation beams can be shaped exactly to the contour of the treatment area. Because the radiation beams are precisely focused, nearby healthy tissue is spared.

Stereotactic Radiosurgery is not, as the name suggests, a form of surgery. It is usually a one-day treatment of a single high-dose—or sometimes smaller, multiple doses—of radiation beams that converge on the specific area of the brain where the tumor or other abnormality resides. Using a helmet-like device that keeps the head completely still and three-dimensional computer-aided planning software, stereotactic radiosurgery minimizes the amount of radiation to healthy brain tissue.

These methods are painless, treat various types of cancer, and often work in conjunction with other forms of treatment (e.g., chemotherapy or surgery). The linear accelerators used in these treatments emit high-energy x-rays,a form of electromagnetic ionizing radiation. Ionizing radiation is high-energy radiation capable of stripping electrons from atoms. The free electrons have the ability to damage living cells, such as in tumors. This is how radiation therapy stops cancer cells from dividing and growing, thus slowing tumor growth. In many cases, radiation therapy is capable of killing cancer cells, thus shrinking or eliminating tumors.

The machine sits in a room with lead and concrete walls so that the high-energy x-rays do not escape. The radiation therapist must turn on the accelerator from outside the treatment room. One of the benefits of accelerators is that, unlike radioactive sources, they only produce radiation when they are operated.

»Diagnostic Nuclear Medicine

This page describes how diagnostic nuclear medicine is used to diagnose certain medical conditions.

Overview

Nuclear medicine is a subspecialty within radiology that helps evaluate different organ systems, including kidneys, liver, heart, lungs, thyroid, and bones. For many diseases, nuclear medicine is the most reliable method for making diagnoses and determining appropriate treatments.

While therapeutic nuclear medicine may use large amounts of radioactive materials, diagnostic nuclear medicine generally uses small amounts of radioisotopes, typically technetium-99m, given intravenously or orally. However certain tests such as heart scans use much higher doses. In order to target a specific organ system, the radioisotope, or "tracer", is combined with a chemical known to accumulate in that system. This compound is called a "radio pharmaceutical agent." When it collects in the organ being evaluated, a gamma camera detects gamma rays emitted by the tracer. This data is fed into a computer where it is used to produce images and other information about the organ system.

Nuclear medicine has been used for more than half a century to diagnose and treat many diseases.

Use of Radioactive Materials

Industrial uses of radiation in equipment such as moisture and density gauges and consumer products such as ionizing smoke detectors are sources of radiation that if improperly handled can result in environmental contamination or personal exposure.