Understanding the Risks and Benefits of Different Imaging Modalities
Imaging modalities are different procedures that create images of the bones and tissues inside the body. As with almost everything, there are benefits and risks to undergoing the different imaging modalities. Understanding these benefits and risks can help you get the most out of your medical imaging.
Overview of Diagnostic Imaging
Definition and Purpose of Diagnostic Imaging
Diagnostic imaging allows your doctors to look inside your body for clues about your health. More specifically, diagnostic imaging creates images that your doctor can use to diagnose a condition, plan treatment, and monitor how well your body is responding to that treatment.
Importance of Imaging in Modern Medicine
Doctors rely on medical imaging to diagnose almost all major medical problems, such as trauma, heart disease, cancer, and neurological disorders.
Medical imaging is essential for:
- Detecting diseases early, when they are most responsive to treatment
- Accurate diagnoses
- Guiding certain procedures, such as ultrasound-guided biopsies
- Monitoring treatment
- Enabling personalized treatment
- Improving patient outcomes
Types of Diagnostic Imaging Modalities
Doctors can choose from a number of diagnostic imaging techniques, known as modalities.
These modalities include:
X-rays: Common Uses and Safety Considerations
First used in 1895, X-rays are the original modality. Because they are good for visualizing bones and joints, it is most commonly used to visualize broken bones and dislocated joints. However, doctors still rely on X-rays to quickly diagnose pneumonia (fluid in the lungs). Mammograms use X-ray technology to help doctors diagnose breast cancer.
X-rays are beneficial in that they are:
- Quick
- Inexpensive
- Readily available
X-rays do have drawbacks, though, in that they:
- Use ionizing radiation to create the images
- Are poor at imaging details in soft tissues
Computed Tomography (CT): When Is It the Best Choice?
Computed tomography combines X-rays with a powerful computer to create three-dimensional (3D) images of internal organs. These 3D images can be seen as “slices,” or cross-sectional images that allow a doctor to see inside an organ. CTs sometimes involve the use of contrast, which is a type of dye that makes certain features more visible.
CTs are beneficial in that they offer:
- Detailed anatomical images of virtually any organ or body system
- Fast exams and quick results
- Visualization of blood vessels and other features inside organs
Risks of CT scans:
- Greater exposure to ionizing radiation in X-rays
- Allergic reaction to the contrast dye
CTs are often the best choice when:
- Patients are in a lot of pain or cannot stay still for long periods
- Doctors need imaging quickly during medical emergencies
- Patients have bone fractures
Magnetic Resonance Imaging (MRI): Benefits and Limitations
MRI uses strong magnets, radio waves, and a computer to create diagnostic images. In the most basic terms, the magnets align the protons in water molecules, and then the radio waves knock the protons out of alignment. When the MRI technician turns off the radio waves, the protons release energy as they realign with the magnetic field. The MRI machine detects this energy and uses the information to create images.
MRI is beneficial in that it:
- Is exceptional for creating images of soft tissues and organs
- Does not use ionizing radiation to create images
- Creates images at various angles and in 3D
MRI does have its downsides. For example, MRI may be:
- Expensive
- Time-consuming
- Noisy
- Hazardous for patients with certain metal implants or objects
Ultrasound: Safe and Effective for Various Conditions
Also known as sonography, ultrasound uses sound waves to create diagnostic images.
Ultrasound is safe, in that it does not expose the patient to any radiation. It is highly effective in creating diagnostic images, and especially for creating real-time images of soft tissues and vessels. What’s more, ultrasound machines are portable, so technicians can take them anywhere patients and doctors may need them.
The imaging technology does have its downsides, but they are minimal. Ultrasound is not as good as other modalities for visualizing structures deep within the body, for example. What’s more, the patients’ specific anatomy and the skill of the ultrasound technician can affect the quality of the images, which is why it is important to choose an imaging center with highly skilled personnel.
Understanding Radiation Risks in Medical Imaging
Radiation is the primary risk when it comes to medical imaging. To create images, X-rays emit ionizing radiation, which is a type of radiation that atoms release. This radiation has enough energy to ionize an atom, which means it removes an electron (negative particle) from it. Removing the electrons from atoms can alter molecules in the human body, and eventually harm skin or other tissues. Excessive exposure to ionizing radiation can damage DNA to cause cancer, skin burns, and other health issues.
Special Considerations for Vulnerable Populations
Some people have a higher risk for health problems associated with ionizing radiation. Vulnerable populations include fetuses, infants and children, pregnant women, the elderly, and people who have compromised immune systems.
Imaging Risks for Pregnant Individuals
Exposure to ionizing radiation during pregnancy can potentially damage the fetus’s body cells and DNA, which may lead to birth defects, developmental delays, and cancer later in life.
Considerations for Pediatric Imaging
Because they are still growing, the cells inside the bodies of children and fetuses are dividing and growing rapidly, which makes the cells more vulnerable to the effects of ionizing radiation. Children with weakened immune systems are at special risk.
Safety Measures and Guidelines in Diagnostic Imaging
Regulatory agencies have developed safety measures, protocols, and guidelines to reduce risk to both patients and healthcare providers during diagnostic imaging.
Protocols for Healthcare Providers to Minimize Risk
Healthcare providers who perform diagnostic imaging are at great risk for exposure to ionizing radiation. They adhere to principles known as ALARA (as low as reasonably achievable) to stay safe. These principles focus on time, distance, and shielding.
- Time: Minimize their time around the imaging device when it is emitting ionizing radiation
- Distance: Maximize their distance from the device when it is in operation
- Shielding: Use lead or other shielding devices to block ionizing radiation
Patient Guidelines for Informed Decision-Making
More than ever, patients are taking control of their healthcare. Information is essential for making any important decision, of course, but especially when it comes to medical decisions.
The Balance of Risks and Benefits in Imaging
To make an informed decision, patients must balance the risks and benefits of imaging.
The benefits of diagnostic imaging include:
- Early detection of diseases
- Improving the accuracy of a diagnosis
- Informed treatment planning
- Enhanced monitoring of a disease or the effectiveness of treatment
Risks include:
- Exposure to ionizing radiation
- Allergic reactions to the contrast used in MRIs
- False positives – can lead to unnecessary anxiety and further testing
- Incidental findings – the imaging could reveal abnormalities that are unrelated to the original reason for the test
Importance of Diagnostic Imaging in Diagnosis and Treatment
Diagnostic imaging can give patients and doctors the information they need for accurate diagnoses and effective treatment plans without invasive procedures.
Weighing the Benefits Against the Risks
In most cases, the benefits of diagnostic imaging greatly outweigh the risks. Exposure to ionizing radiation is the primary risk of many modalities, and most of these imaging tests emit radiation at far lower levels than we receive from the world around us.
Scientists often use the term millisievert (mSv) to describe doses of radiation. The average American receives about 3 mSv per year from natural radiation, such as cosmic radiation from outer space; people living at high altitudes receive more than those living at sea level. Traveling on an airplane also exposes you to radiation: you’ll receive about 0.03 mSv when you fly from coast to coast. Radon gas in our homes is the largest source of radiation, at about 2 mSv per year.
A chest x-ray exposes you to about 0.1 mSv, which is about the same as the radiation you’d receive from 10 days of natural background radiation.
Considering the very small amount of radiation required to create a diagnostic image, the benefits significantly outweigh the risks in most cases.
How to Make an Informed Choice with Your Doctor
Your doctor can help you make decisions about your diagnostic imaging by outlining the benefits of imaging, reviewing your risks, discussing ways to minimize your risks, and discussing alternatives.
Empowering Patients with Knowledge
Knowledgeable patients have better outcomes because patients who understand their healthcare are more likely to adhere to treatment plans.
At NVRA, we know that our patients are curious about their health. We are also confident that our patients are able to understand the intricacies of the imaging care they receive.
Schedule Your Imaging Test with Confidence
When it comes to healthcare, confidence in your providers is essential – especially when it comes to diagnostic imaging. After all, your health depends on high-quality imaging performed by professionals.
Staffed with 14 highly trained and board-certified radiologists, NVRA uses prime diagnostic imaging at our four locations conveniently located in Southbury, Waterbury, and Prospect, Connecticut. Our patients rely on us for high-quality 3D Mammography, CT scan, Ultrasound, Open/High field MRI, General Radiology, Arthrography, and Bone Density imaging.
