Unit 21:
Medical Physics Applications.
by:Areej Rashid 12N
,Learning aim A:
Intro (non ionising radiation):
Non-ionizing radiation withinside the scientific placing refers to types of
electromagnetic radiation that don't have sufficient strength to ionise atoms or
molecules This means they cannot remove electrons from atoms or molecules and
create charged particles that can damage living tissue.
Justification of the use of non-ionising radiation in medical settings.
MRI scans:-
What do they do?
A strong magnetic field, radio waves, and a computer are used in MRI (Magnetic
Resonance Imaging), a type of medical imaging, to produce precise images of the
inside of the body. Numerous medical conditions, such as injuries, tumours,
infections, and neurological disorders, can be detected and tracked using MRI
scans.
The patient is placed on a table that slides into a sizable tube-shaped machine
during an MRI scan. As a result of the machine's creation of a potent magnetic field
all around the patient's body, the hydrogen atoms in the body's tissues are
compelled to align themselves with the field. Then, after stimulating the atoms with
radio waves, the machine uses the signals those atoms produce to create detailed
images of the interior of the body.
The brain, spinal cord, bones, and joints are just a few of the organs and tissues that
can be studied in detail using an MRI scan. They can also aid in the discovery of
anomalies that might not be picked up by other imaging techniques, like X-rays or
CT scans.
Unlike X-rays and CT scans, MRI scans are generally thought to be safe and don't
use ionising radiation. They are not, however, suggested for everyone, especially for
those who have specific medical implants or devices, like pacemakers or cochlear
implants. The use of contrast agents, which has some risks and may not be suitable
for all patients, is sometimes used to make certain tissues more visible during an
MRI scan.
In general, MRI scans are a useful diagnostic tool that can offer crucial details about
a variety of medical conditions. Your healthcare provider will give you comprehensive
,instructions on how to get ready for the procedure and what to expect during and
after the scan if you are scheduled for an MRI.
reference:https://www.nhsinform.scot/tests-and-treatments/scans-and-x-rays/mri-sca
n#:~:text=Magnetic%20resonance%20imaging%20(MRI)%20is,any%20part%20of%
20the%20body.
Examples of what MRI scans can be used for:
-breast cancer
-brain and spinal cord
-injuries on joints; back or knees etc.
-cysts and tumours
-heart problems
-diseases of body organs such as the liver
-bone fractures
-internal bleeding
reference:https://www.medicalnewstoday.com/articles/146309#uses
Types of MRI scans:
-closed bore=these usually look at enormous tubes and this is where the patient
tends to enter by lying down and entering the tube.
-wide bore=The tubular area is usually bigger (about 70 cm or more).
-short bore=The tubular part of this machine tends to be shorter which is less
triggering for the patient.
-open MRI=these are usually in different shapes and they can either be closed or
opened at the ends.
How are MRI scans produced?
, Radio waves, powerful magnetic fields, and computers are all used to create MRI
(Magnetic Resonance Imaging) scans.
The patient is placed inside a sizable tube-like device that houses a powerful magnet
during the MRI scan. The patient's body's protons, which are primarily present in
water molecules, are aligned by the magnetic field. The patient's body receives radio
waves from a radiofrequency coil, which causes the protons to absorb energy and
then release it as they realign themselves.
The radiofrequency coil detects the protons' energy, which a computer then
interprets as an image. The MRI machine can produce extremely detailed images of
the patient's internal structures by examining the patterns of energy released by the
protons in various parts of the body.
The resulting MRI images are able to differentiate between various tissues, such as
muscles, organs, and bones, because different types of tissue in the body emit
different patterns of energy. Contrast agents, which are injected into the patient's
bloodstream to highlight specific structures or abnormalities, can also be used to
improve MRI.
reference:https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/ma
gnetic-resonance-imaging-mri
What are MRI instrumentations?
The devices used to produce MRI scans are known as MRI (Magnetic Resonance
Imaging) devices. They are made up of the following main elements:.
-Magnet: The heart of an MRI machine is a magnet. In the patient's body, the protons
are aligned by a powerful magnetic field produced by the device.
-Gradient Coils: The gradient coils are little coils of wire that generate various
magnetic fields. The spatial gradient produced by these coils enables the MRI
machine to identify and differentiate between various body parts.
-Radiowaves are delivered into the patient's body using radiofrequency coils. The
energy that the body's protons absorb and release as a result of these waves is
picked up by the coils to produce the MRI image.
-Computer: The radiofrequency coil signals are processed by the computer to
produce the final MRI image.
-Operator Console: At the operator console, the MRI technician regulates the
scanner and tweaks the imaging settings to improve scan quality.
