X-Rays

Overview

X-rays are a form of electromagnetic radiation, just like ordinary light. Unlike light, X-rays have higher energy and can pass through most objects, including the body. Medical X-rays create images of tissues and structures inside the body. When X-rays travel through the body and reach a sensor on the other side, they form images that represent the “shadows” of objects inside the body.

Doctors use X-rays to screen for disease, make diagnoses, and even treat certain conditions. X-rays are one of the most common and useful tools in modern medicine. But like all medical procedures, they carry some risks that patients should understand.

Related Health Effects

X-rays are a form of ionizing radiation, that can harm living tissue. Exposure to ionizing radiation is known to increase the risk of cancer. The risk increases with the number of exposures over a person’s lifetime. Discuss with your doctor about your specific levels of risk for X-ray procedures.

However, the risks of cancer from medical X-rays are very small, and the benefit from having these tests is usually greater than the risks. When used properly, the diagnostic benefits of X-ray scans significantly outweigh the risks.

Risk Factors

Risks During Pregnancy

An X-ray in a pregnant woman poses no known risks to the baby if the area of the body being imaged is not near the abdomen or pelvis. If imaging of the abdomen and pelvis is needed, doctors prefer to use exams that do not use ionizing radiation, such as magnetic resonance imaging (MRI) or ultrasound.

Risks for Children

Children are more sensitive to ionizing radiation, which puts them at greater risk of developing cancer from such radiation over their lifetime. Children’s bodies are growing, and the cells in their bodies divide rapidly, making them more sensitive to radiation. Parents may want to ask the X-ray technologist or doctor if their machine settings have been adjusted for children, which helps reduce their risks.

Diagnostic Uses

X-rays and related technologies help diagnose a wide range of conditions.

Standard X-rays scans detect:

• Broken teeth and bones
• Bone changes or abnormalities
• Herniated discs in the spine
• Scoliosis and other spine curvature conditions
• Osteoarthritis
• Infections such as pneumonia or other lung infections
• Certain tumors and other abnormal masses
• Kidney stones and calcifications
• Foreign objects in the body
• Other dental problems

Mammography (a type of digital X-ray) screens for:

• Breast cancer and other breast diseases
• Tumors that appear as regular or irregular-shaped masses
• Tiny bits of calcium called microcalcifications, which in specific patterns could indicate cancer

Computed tomography (CT) is a medical imaging procedure that uses X-rays and computers to create detailed pictures of the inside of your body. CT identifies:

• Possible tumors or lesions in the abdomen
• Heart disease and abnormalities
• Brain injuries, tumors, clots leading to stroke, and hemorrhage
• Lung tumors, pulmonary embolisms (blood clots), excess fluid, emphysema, and pneumonia
• Complex bone fractures, severely eroded joints, and bone tumors
• Circulatory diseases such as coronary artery disease, blood vessel aneurysms, and blood clots
• Spinal conditions
• Kidney and bladder stones
• Abscesses and inflammatory diseases such as ulcerative colitis and sinusitis
• Injuries to the head, skeletal system, and internal organs
• Brain bleeds and abnormal brain function in patients being evaluated for Alzheimer’s disease and other causes of cognitive decline

Bone mineral density (using Dual Energy X-ray Absorptiometry, DEXA or DXA) tests measure:

• Calcium and other minerals in bone to identify and diagnose osteoporosis
• Risk of fractures
• Effectiveness of osteoporosis treatment

DXA usually measures bone mineral density in the hip and spine, key areas for assessing bone health.

Treatment and Management

Using X-rays to Treat Cancer

X-rays and other types of ionizing radiation given at high levels can destroy cancerous tumors and cells by damaging their DNA. The radiation dose used for treating cancer is much higher than the radiation dose used for diagnostic imaging. Therapeutic radiation can come from a machine outside of the body or from a solid, liquid, or gaseous radioactive material that is placed into the body, inhaled, or injected into the bloodstream.

Using X-rays to Guide Medical Procedures

Healthcare professionals use real-time X-ray imaging — a series of X-rays using a continuously monitoring digital detector, like a video camera for the x-rays — to help guide medical procedures such as stent or catheter placement.

Find Clinical Trials

Clinical trials uncover better ways to prevent, diagnose, treat, and understand diseases and conditions. To ensure results apply to everyone, volunteers of all ages, sexes, and backgrounds, including both healthy individuals and those with specific medical conditions, are needed. Find clinical trials on X-rays.

Community Support

Discuss with your doctor about your specific levels of risk for X-ray procedures, including risk of multiple procedures over time.

Several organizations have developed guidelines to reduce unnecessary radiation exposure:

• The U.S. Food and Drug Administration (FDA)'s Initiative to Reduce Unnecessary Radiation Exposure from Medical Imaging offers information to raise patients’ awareness of their radiation exposure. The site focuses on the safe use of medical imaging devices and informed decision-making about when to use specific imaging procedures.
• The Image Gently campaign seeks to raise awareness about methods to reduce radiation doses during pediatric medical imaging examinations.
• The American College of Radiology (ACR) has developed the ACR Appropriateness Criteria®, evidence-based guidelines to help providers make appropriate imaging and treatment decisions.
• Scanner manufacturers are developing newer detector systems and image reconstruction algorithms that can provide higher quality images at much lower radiation doses.

Some organizations recommend that people keep a record of the imaging examinations they have received. A sample form called My Medical Imaging History includes questions to ask the doctor before undergoing an X-ray.

For more information on medical X-rays, visit:

• RadiologyInfo.org: The public information website of the Radiological Society of North America (RSNA) and the American College of Radiology (ACR); provides information about diagnostic radiology, including X-ray and CT imaging.
• NCI Cancer Imaging Program (CIP): Part of the Division of Cancer Treatment and Diagnosis; funds cancer-related research in imaging sciences and technology.
• ECOG-ACRIN Cancer Research Group: One of the groups in NCI’s National Clinical Trials Network that runs clinical trials testing ways to improve X-rays and CT or new uses of those imaging technologies.
• ACR Appropriateness Criteria®: Evidence-based guidelines developed by the American College of Radiology to help providers make appropriate imaging and treatment decisions.

Note: This resource list is for informational purposes only. It is not comprehensive, and an organization’s inclusion does not constitute an endorsement by NIH. 

Research Information

The National Institutes of Health (NIH) is the largest public funder of biomedical research in the world. NIH invests most of its budget in medical research seeking to enhance life and to reduce illness and disability. NIH-funded research has led to breakthroughs and new treatments helping people live longer, healthier lives, and building the research foundation that drives discovery.

NIH supports research to develop new X-ray and CT technologies and reduce their risk to health.

Find NIH-funded research projects using NIH RePORTER, a searchable database of current and past research projects supported by NIH and other federal agencies.