Non Ionising Imaging

Non Ionising Imaging

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Non-ionizing imaging is a type of medical physics that involves using ultrasound, MRI, and optical imaging. These methods are safer for medical purposes because they don't involve ionization. To get a better understanding of non-ionizing imaging, we need to look at non-ionizing radiation. This type of imaging is becoming more popular in the medical field because it doesn't pose as many health risks as other types of imaging. So, if you're ever in need of medical imaging, you might want to ask your doctor about non-ionizing options.

Non-ionizing radiation

Radiofrequency (RF) radiation as used by broadcast and telecommunication applications. Infrared radiation as used in heat lamps. Ultraviolet (UV) radiation from the sun and used in tanning beds.

Take a look at the diagram below. Wavelengths shorter than 125 nm are considered to be ionizing radiation.

Electromagnetic Spectrum

Now that you have learned about non-ionizing radiation, you can understand better which methods in the medical world include non-ionizing imaging and why they are used.

What does non-ionizing imaging include?

Non-ionizing imaging is a popular technique used in medical physics, and it has many applications. Some examples include ultrasound imaging, magnetic resonance scanning (MRI), and fiber optics and endoscopy. These methods are preferred because they don't use ionizing radiation, which can be harmful to the body. So, if you're ever in need of medical imaging, it's worth considering non-ionizing options like these.

Ultrasound imaging

Ultrasound imaging is a technique that uses high-frequency sound waves to see inside the body without exposing people to ionizing radiation. The pictures generated by ultrasound are taken in real-time, which means they can show internal organ movement and blood flow through vessels. This technology is often used to identify the source of pain, swelling, and infection in internal organs, as well as to inspect babies in pregnant women or the brain and hips in infants.

Abdominal scans typically use a 7MHz frequency, and the wavelength of ultrasound is determined by the speed of sound in tissue, which is approximately 1540m/s. The ultrasound image on the screen appears black when sound waves pass through uniform material with no echoes. When sound waves strike tissue that absorbs or transmits the sound, a wave is reflected back to the probe. Depending on the strength of the reflection, the ultrasound picture appears white or gray. While ultrasound cannot identify tissue density like x-rays or CAT scans, it does look for sonotransmission, which is the passage or reflection of sound.

Magnetic resonance scanning

Magnetic resonance imaging (MRI) is a radiological imaging technique that generates images of the body's anatomy and physiological processes without using X-rays or ionizing radiation. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to create pictures of the body's organs.

During an MRI scan, the patient is placed in a magnetic field and exposed to radio frequency waves. The atoms in the patient's body respond to the magnetic and radio frequency waves by producing energy that is detected by the MRI equipment. The equipment then transmits this energy to a computer, which converts it into an image using mathematical algorithms.

MRI is a non-invasive diagnostic tool that can be used to detect a wide range of conditions, including cancer, infections, injuries, and neurological disorders. MRI images provide a detailed view of the body's internal structures, allowing healthcare professionals to make accurate diagnoses and develop effective treatment plans. Unlike X-rays and other imaging techniques that expose patients to ionizing radiation, MRI is considered safe for most people. However, patients with certain medical devices or conditions may not be able to undergo an MRI scan.

Example of an MRI result
Example of an MRI result

An MRI (magnetic resonance imaging) scan is a test that creates clear images of the structures inside your body using a large magnet, radio waves and a computer. The MRI device picks up signals from the nuclei (centers) of hydrogen atoms in your body using a strong magnetic field and a burst of radio frequency waves. Because they contain few hydrogen atoms, air and hard bone do not produce an MRI signal. As a result, these regions appear in black. The quantity of fat and water present in each tissue, as well as the machine settings utilized for the scan, affect the intensity of bone marrow, spinal fluid, blood, and soft tissues, which range from black to white.

A chest, abdominal, or pelvic MRI can be used to help diagnose or monitor therapy for a number of diseases.

Fiber optics and endoscopy

Endoscopy is a medical procedure that allows doctors to examine the body's pathways by using an endoscope to check the interior of body organs, joints, or cavities. An endoscope is a device that uses fiber optics and lens systems to provide lighting and visibility into the interior of a joint. Depending on the medical procedure, the part of the endoscope introduced into the body may be stiff or flexible.

Endoscopy uses the total internal reflection principle of optics, which is a phenomenon that occurs at the border between two mediums, where all light is reflected back into the first medium if the incidence angle in the first medium is larger than the critical angle. This principle allows the endoscope to transmit the image of the body's interior to a monitor, enabling the doctor to see and examine the area being investigated in real-time.

Endoscopy is a minimally invasive procedure that is used to diagnose and treat a wide range of medical conditions, including digestive disorders, respiratory issues, joint problems, and cancer. It is a safe and effective method of examining the body's pathways and can often be performed on an outpatient basis, allowing patients to return home the same day.

This is how the principle works in endoscopy step by step:


An endoscopy may be used to obtain tissue samples (biopsy) to screen for illnesses and disorders, including anemia, bleeding, inflammation, diarrhea, or cancers of the digestive system.

Non-ionizing imaging - key takeaways

Non-ionizing imaging is a critical tool used in medical physics to visualize the interior of the body, including internal organs and joints, without using ionizing radiation. Non-ionizing imaging methods include ultrasound imaging, magnetic resonance imaging (MRI), and endoscopy.

Ultrasound imaging uses high-frequency sound waves to create real-time images of internal organs and tissues. This method is particularly useful for examining fetal development during pregnancy, detecting abnormalities in the liver and gallbladder, and visualizing blood flow through blood vessels.

Endoscopy is a procedure in which an instrument, called an endoscope, is introduced into the body to provide a visual inspection of internal organs, joints, or cavities. It is commonly used to diagnose and treat conditions of the digestive system, such as ulcers and tumors.

Magnetic resonance imaging (MRI) uses strong magnetic fields, magnetic field gradients, and radio waves to produce detailed images of the body's anatomy and physiological processes. MRI is particularly useful for diagnosing soft tissue injuries and abnormalities in the brain and spinal cord.

Overall, non-ionizing imaging techniques are critical tools for medical professionals to diagnose and treat a wide range of medical conditions without exposing patients to harmful ionizing radiation.

Non Ionising Imaging

What are the three types of non-ionizing imaging used in medical physics?

The three types of non-ionizing imaging used in medical physics are ultrasound imaging, magnetic resonance scanning (MRI), and endoscopy.

Why is non-ionizing imaging preferred in medical physics?

Non-ionizing imaging is preferred in medical physics because non-ionizing radiation is much less harmful to the human body than ionizing radiation

What is non-ionizing imaging used for in medical physics?

Non-ionizing imaging is used to look into the interior of the body and help diagnose or monitor therapy for a number of diseases.

Is MRI non Ionising radiation?

The radiation used in the MRI procedure is non-ionising radiation and the X-rays are not involved either. Instead, Strong magnetic fields, magnetic field gradients, and radio waves are used in MRI scanners to create pictures of the body's organs.

Is ultrasound Ionising or non Ionising?

Ultrasound imaging, unlike X-ray imaging, does not expose people to ionizing radiation. It is a technique for seeing the interior of the body using high-frequency sound waves. 

What is Non-Ionising Imaging?

Non-ionizing imaging is an area of medical physics that includes ultrasound, magnetic resonance imaging, also known as MRI, and optical imaging. These methods are preferred in medical areas because they are less harmful than imaging using ionization.

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