Medical Imaging is a revolutionary in medical diagnosis. With the advent of micro-electronics and computer science, there is a lot of ease in identifying and treating the diseases as never before.
Medical imaging is a technique helpful in idenfying the possible diseases and disorders. Using different radio spectrums, different images of an organ can be captured. It comes under a medical test, these days depend on the type of the disease patient undergo this test. After image analysis is done, medical practitioner treats the patient. For example, Sonography, CT, MRI, and PET come under different medical imaging models. Each model serves some purpose, and has its own advantages and disadvantages.
Processing Techniques
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Monochrome image as 2-D function
Imaging models
We look at various imaging models available in field of medicine from Radiography to Echocardiography, their advantages and disadvantages, and applications.
Radiography
After the discovery of X-rays, Radiography came into limelight. Earlier to the discovery of X-rays also Radiography was available, but electromagnetic spectrum utilised for imaging. Using X-rays as source of illumination imaging is done, it exposes the internal architecture of non-transparent object of high density and composition. It is helpful in identifying bone fractures. It also serves other purposes too. Cost of equipment is low, and high mobility of setup makes high usage.
Working Principle
X-ray generator is used to generate x-rays, focus on the object. Some amount of the x-rays is absorbed by the object, and rest of them are passed through it. Passed through x-rays are captured by a detector behind the object. The detector is helpful in extracting the information of object internal structure in 2-D plane.
In figure 3, radiography using X-rays is shown.
Advantages
Cost of equipment is low, and high mobility of setup makes high …show more content…
Radiography using X-rays. Figure 4. X-ray imaging of a bone.
Magnetic Resonance Imaging(MRI)
Magnetic resonance scanner is costlier than Radiography. Image quality of the MRI varies significantly from X-ray imaging. Both the imaging techniques are highly sensitive to the tissue properties. MRI uses magnets to polarise and excite the hydrogen nuclei present in the water molecules of the human tissues, provides the detectable signal. MRI release the RF pulse that is helpful in binding hydrogen atom.
Working principle
MRI equipment sends the RF pulse to the are needs to examined. Pulse helps the protons pesent in the exposed area to energise, and make them spin in different directions. Some of the tissues of the exposed area only excite and tune to the RF pulse, that frequency is called as Larmour frequency. MRI uses three types of electromagnetic fields for imaging, very strong, gradient field and weak RF field.
MRI equipments are capable of producing images in 3D blocks. It does not have any side effects because of no ionisation mechanisms as in CT scan. Any individual can be subjected to any number of MRI scans.
Figure 5. MRI scanning equipment.