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. To understand the concept of non-ionizing imaging better, we need to explore non-ionizing radiation.
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Jetzt kostenlos anmeldenNon-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. To understand the concept of non-ionizing imaging better, we need to explore non-ionizing radiation.
Ionization is the process of giving an electron enough energy to break away from an atom. Non-ionizing radiation does not have sufficient energy to cause ionization. It is found in the long-wavelength end of the spectrum and has the potential to excite molecules and atoms, thus causing them to vibrate faster. Here are some examples of non-ionizing radiation:
Wavelengths shorter than 125 nm are considered to be ionizing radiation. 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.
Non-ionizing imaging is used in many different areas of medical physics for a variety of reasons. These areas include ultrasound imaging, magnetic resonance scanning, and fiber optics and endoscopy.
Ultrasound imaging (sonography) is a technique for seeing the interior of the body using high-frequency sound waves. Because ultrasound pictures are taken in real time, they can reveal internal organ movement as well as blood moving via blood vessels. When sound waves are transmitted into the body and then reflected back to a scanner, pictures are generated. Ultrasound imaging, unlike X-ray imaging, does not expose people to ionizing radiation.
In medical physics, ultrasound imaging can be used to identify the reasons for pain, swelling, and infection in the body's internal organs, as well as to inspect a baby in pregnant women or the brain and hips in infants. Abdominal scans often use a 7MHz frequency (f). On top of this, if you consider the fact that the speed of sound in tissue (vw) is approximately 1540m/s, then the wavelength (λ) of ultrasound would be:
\[\lambda = \frac{v_w}{f} = \frac{1540 m/s}{7 \cdot 10^6 Hz} = 0.22 [mm]\]
The general consensus is that you can successfully scan tissue to a depth of around 500 \(\lambda\). For 7 MHz, that is \(500 \cdot 0.22mm = 0.11m\).
There are no echoes when sound waves flow smoothly through uniform material. As a result, the ultrasound image on the screen is black, with no echoes. A wave is reflected back to the probe when sound waves strike tissue that absorbs or transmits the sound.
Depending on the strength of the reflection, the ultrasound picture is white or gray. Ultrasound, unlike x-rays or CAT scans, cannot identify tissue density. Instead, it looks for sonotransmission (the passage or reflection of sound).
On an ultrasound, very thick tissues, such as bone or kidney stones, rapidly reflect echoes and appear bright white. Echoes are also easily reflected in air, such as in the intestine. As a result, the bowel's border also looks white on an ultrasound. Therefore, things with vastly different densities (such as air and bone) may show on ultrasound as bright white.
Magnetic resonance imaging (MRI) is a radiological imaging method that creates images of the body's anatomy and physiological processes without using X-rays or ionizing radiation.
Strong magnetic fields, magnetic field gradients, and radio waves are used in MRI scanners to create pictures of the body's organs. The MRI equipment transmits magnetic and radio frequency waves into the patient's body to obtain a picture.
The atoms in the magnetic field produce energy that transmits a signal to a computer. The computer then converts the signal into an image using mathematical algorithms.
An MRI device picks up signals from the nuclei (centres) 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.
Endoscopy is a procedure that enables doctors to look into the body's pathways. The use of an endoscope to examine and check the interior of body organs, joints, or cavities is known as endoscopy.
An endoscope is a device that provides lighting and visibility into the interior of a joint using fibre optics and lens systems. Depending on the medical procedure, the part of the endoscope introduced into the body may be stiff or flexible. In endoscopy, the total internal reflection principle of optics is used. This is a phenomenon that happens at the border between two mediums, in which all light is reflected back into the first medium if the incidence angle in the first medium is larger than the critical angle.
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 anaemia, bleeding, inflammation, diarrhoea, or cancers of the digestive system.
The three types of non-ionizing imaging used in medical physics are ultrasound imaging, magnetic resonance scanning (MRI), and endoscopy.
Non-ionizing imaging is preferred in medical physics because non-ionizing radiation is much less harmful to the human body than ionizing radiation
Non-ionizing imaging is used to look into the interior of the body and help diagnose or monitor therapy for a number of diseases.
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.
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.
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.
Does non-ionizing radiation conserve enough energy to cause an electron to break away from the atom?
No, it doesn't.
Non-ionizing radiation waves have a long wavelength. True or false?
True.
What is another name for ultrasound imaging?
Sonography.
Which one of the techniques in non-ionizing imaging does not capture the interior of the human body in real time?
Magnetic resonance imaging (MRI).
An endoscope is a device that provides lighting and visibility into the interior of a joint. True or false?
True.
Radiation waves with which wavelength value are considered ionizing radiation?
λ <125nm.
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