The document provides an overview of medical imaging, detailing various techniques such as x-rays, CT scans, MRI, ultrasound, and nuclear medicine, which are essential for diagnosing and treating medical conditions. It discusses specific modalities like projection radiography, highlighting its use, limitations, and the effects of magnification on image quality. Additionally, the document explains the advantages and applications of imaging technologies like nuclear medicine and digital radiography, emphasizing their roles in modern healthcare.

1. MEDICAL IMAGING
MANJUCHETHAN N
RESERCH SCOLOR,DEPARTMENT OF STUDIES IN COMPUTER
SCIENCE,MGM, UNIVERSITY OF MYSORE.
05-03-2023 DoS in CS, MGM 1

2. What is Medical imaging?
• Medical imaging refers to the use of various techniques to create
images of the inside of the body for the purpose of diagnosing and
treating medical conditions.
• These techniques may include x-rays, computed tomography (CT),
magnetic resonance imaging (MRI), ultrasound, and nuclear medicine
imaging.
• Medical imaging is an important tool in modern medicine, as it allows
doctors to non-invasively visualize the inside of the body and diagnose
a wide range of conditions, from broken bones to cancer.
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3. Projection radiography
• Projection radiography is a type of medical imaging that uses x-rays to create images of the inside of the
body. It is also known as plain film radiography or conventional radiography.
• In projection radiography, x-rays are produced by an x-ray tube and directed through the body onto a film or
detector plate. Different parts of the body absorb x-rays differently, so the resulting image shows the different
structures inside the body in varying shades of black and white.
• Projection radiography is a widely used and relatively inexpensive imaging modality, and it is particularly
useful for examining the bones and joints. It is also commonly used to diagnose problems in the chest, such as
lung infections or pneumonia. However, it has some limitations, as it does not provide as much detail as some
other medical imaging techniques, such as CT or MRI.
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4. Projection radiography (X-ray)
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5. Projection radiography (X-ray)
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6. Projection radiography (X-ray)
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7. Projection radiography (X-ray) Covid 19
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8. Projection radiography (X-ray)
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9. Projection radiography (X-ray) - Devices
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10. Projection radiography (X-ray) - Devices
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11. Magnification in Projection radiography (X-ray)
• The beam divergence is an important component of projection X-ray imaging as it
causes the magnification of the projection X-ray image.
• The magnification creates three major constraints on the image acquisition.
• First, if the image is overly magnified, the organs of interest may not fall within the
imaging field of view and therefore will not be captured by the detector.
• Second, the higher magnification can lead to increased blurring because of
geometrical factors, e.g. focal spot size.
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12. Magnification in Projection radiography (X-ray)
• Finally, for sensors that require a certain amount of signal to achieve sufficient
image quality, higher magnification may necessitate increased radiation dose
to the patient in order to achieve the required signal at the detector.
• These constraints, in conjunction with the desired field of view, the minimum
achievable focal spot size, and expected radiation dose, dictate the proper
geometry for any given acquisition in terms of focal spot to detector distance,
field of view, and body part to detector distance
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13. Magnification in Projection radiography (X-ray)
• If X-rays are assumed to originate from a single point on the target of the X-ray
tube, then the magnification of the radiographic image is calculated as
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14. Magnification in Projection radiography (X-ray)
• If the distance between the target of the X-ray tube and the X-ray detector is constant,
• The ratio of the image size to the object size may be increased by moving the object toward the
X-ray tube. This is called object shift enlargement.
• In contrast, image shift enlargement maintains a constant distance between the target and the object
but moves the detector farther from the object to increase the ratio of image size to object size.
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Magnification in projection X-ray imaging: f is the
apparent focal spot of the X-ray tube, SID is source to
image representing the distance between the image
receptor and the target of the X-ray tube.

15. Magnification in Projection radiography (X-ray)
• The amount of enlargement possible without significant loss of image detail is an important consideration in projection X-ray
imaging.
• With the image receptor close to the patient, the blurring of the detector (termed unsharpness in radiographic imaging) is the primary
determinant of the visibility of image detail.
• As the distance between the detector and the patient is increased by object shift or image shift enlargement, the effect of detector
unsharpness on the image detail is unchanged.
• However, the contribution of geometric unsharpness increases steadily with an increasing distance between the patient and the
image receptor, i.e. increasing magnification,
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16. Computed tomography (CT)
• Computed tomography (CT) is a diagnostic imaging technique that
uses X-rays to produce detailed cross-sectional images of the body.
• The images can be manipulated to show different levels of tissue
density and can be used to diagnose and monitor a wide range of
medical conditions, including cancer, cardiovascular disease, and
neurological disorders.
• CT scans are fast, non-invasive, and highly accurate. However, they do
expose the patient to a relatively high dose of radiation, so they should
only be used when the potential benefits outweigh the risks.
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17. CT images of Abdomen, Pelvis & Brain
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18. Nuclear medicine
• Nuclear medicine is a medical specialty that uses small amounts of radioactive material to diagnose
and treat diseases. The radioactive material, called a radiopharmaceutical, is usually injected into
the body, swallowed, or inhaled.
• The radiopharmaceuticals used in nuclear medicine emit gamma rays, which can be detected by
special cameras that create images of the inside of the body. Nuclear medicine can be used to
diagnose conditions such as cancer, heart disease, and thyroid disorders, and to treat conditions
such as thyroid cancer and some types of pain.
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19. Nuclear medicine
• Nuclear medicine differs from other exams, such as x-ray, CT or MRI,
because it images organ function, rather than just the anatomy. This means
that it can show how an organ functions, not simply what it looks like. This
allows us to not only monitor cancer, but also indicates the activity of many
organs including the thyroid, heart, stomach and kidneys. Nuclear medicine
is also well known for imaging the bones and joints to detect a number of
abnormalities including trauma, fractures, arthritis or tumors.
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20. Nuclear medicine images
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21. Ultrasound imaging
• Ultrasound imaging, also known as sonography, is a medical imaging
technique that uses high-frequency sound waves to create images of internal
organs and structures in the body.
• These images are used to diagnose and monitor a wide range of medical
conditions, including pregnancy, heart and blood vessel diseases, and
certain types of cancer. Ultrasound is a non-invasive and relatively
inexpensive imaging technique that does not use ionizing radiation, making
it a safe option for many patients.
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22. Ultrasound imaging
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23. Magnetic Resonance Imaging
• Magnetic Resonance Imaging (MRI) is a non-invasive medical
imaging technique that uses a magnetic field, radio waves, and a
computer to produce detailed images of the organs and tissues within
the body.
• MRI is a useful tool for diagnosing and monitoring a wide range of
medical conditions, including cancer, heart and vascular disease, and
injuries to the brain and spine. Unlike X-ray and CT (computed
tomography) scans, MRI does not use ionizing radiation, making it a
safer option for certain patients, such as pregnant women.
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24. Magnetic Resonance Imaging
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25. Fluoroscopy
• Fluoroscopy is a medical imaging technique that uses X-rays to create
real-time, moving images of the body.
• It is often used to guide procedures such as catheterizations, biopsies,
and joint injections.
• Fluoroscopy can also be used to monitor the movement of organs and
to diagnose certain conditions such as stomach ulcers or blockages in
the intestines.
• However, because it uses ionizing radiation, fluoroscopy exposes the
patient to a relatively high dose of radiation and should be used only
when necessary.
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26. Fluoroscopy
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27. Fluoroscopy
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28. Angiography
• Angiography is a medical imaging technique used to visualize the
inside of blood vessels, including the arteries and veins.
• It is typically done using X-ray technology, and involves injecting a
contrast dye into the blood vessels so that they can be more easily seen
on the X-ray images.
• Angiography can be used to diagnose and treat a wide range of
conditions, including blockages in the Angiography, aneurysms, and
other abnormalities.
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29. Angiography
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30. Digital radiography
• Digital radiography is a type of X-ray imaging that uses digital
technology to capture and store X-ray images.
• Instead of using film to capture the images, digital radiography uses a
digital detector, such as a flat panel detector, to convert the X-ray
energy into a digital signal that is then stored on a computer.
• This allows for faster image acquisition, improved image quality, and
easier image storage and retrieval. Additionally, digital radiography
also allows for the use of computer-aided detection and diagnosis
(CAD) tools, which can help radiologists interpret images more
accurately.
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31. Digital radiography
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32. Digital radiography
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33. Mammography
• Mammography is a type of imaging test that uses low-dose X-rays to
create detailed images of the breasts.
• It is used as a diagnostic tool to detect breast cancer and other
abnormalities in the breast tissue.
• It is typically recommended for women over the age of 50 and for
those with a higher risk of breast cancer.
• The procedure is usually performed by a radiologic technologist and
interpreted by a radiologist.
• Some common side effects of mammography include breast
discomfort, tenderness, and compression during the test.
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34. Mammography
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35. Outcome:
• Introduction to Medical Imaging: Basic imaging principle, Imaging
Modalities-Projection radiography, Computed Tomography, Nuclear
medicine, Ultrasound imaging, Magnetic Resonance Imaging,
Fluoroscopy, Angiography, Digital radiography, Mammography.
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36. What do you feel?
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