ANAT30007 Lecture 10: [H1/91 notes] Principles of Imaging the Musculoskeletal System A
10 Jun 2018
School
Department
Course
Professor
Speciality of medical imaging
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Originally using Rotgen's "new" rays (X-rays 1895)
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Radiographs thus radiology
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No longer reliant on X-rays
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Expanded dramatically over last 20-40 years to include many different modalities
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Radiology
2 aspects to medical imaging
Structure: Anatomy
Function: How is that structure working? Increasingly important
Plain radiography
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CT
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US
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MRI
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Gamma imaging
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PET
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NM (nuclear medicine)
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Modern medical imaging
Usually electromagnetic radiation
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Acoustic
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Energy source
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Interaction of that energy with the body
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Detection device for that energy
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Image display
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Basis of all medical imaging
Energy sources
4.1 Principles of Imaging the Musculoskeletal System
Monday, 23 March 2015
12:27 am
Locomotor Page 1
X-rays (radiographs, CT)
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γrays (NM)
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positrons (PET) decay →γrays
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Ionising - detach electrons from atoms (thus can cause injury to body)
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sound (US)
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FM radio/magnetism (MRI)
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non-ionising
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Energy sources
Digital image
pixels
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vacuum tube with electric current between a filament and target (cathode and anode),
current releases energy, forming X-rays
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Crookes tube - X-rays
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transmission of X-rays
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e-density of tissues i.e.atomic number& []
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more recently “x-ray detector”
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Photo graphic film(negative)
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more recently computer monitor
Light box
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Plain radiography
Locomotor Page 2
more recently computer monitor
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photoelectric interaction: atom is ionised; compton interaction: X-ray is deflected and
becomes noise
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Bone: dense and contains Ca (high atomic number)
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Soft tissue
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Locomotor Page 3
Document Summary
Expanded dramatically over last 20-40 years to include many different modalities. Ionising - detach electrons from atoms (thus can cause injury to body) Rays (nm) positrons (pet) decay rays non-ionising sound (us) Crookes tube - x-rays vacuum tube with electric current between a filament and target (cathode and anode), current releases energy, forming x-rays e-density of tissues i. e. atomic number& [] transmission of x-rays. Locomotor page 2 more recently computer monitor photoelectric interaction: atom is ionised; compton interaction: x-ray is deflected and becomes noise. Bone: dense and contains ca (high atomic number) Right: lung replaced by consolidation/fluid denser than air. Locomotor page 4 energy source, multiple detectors - rotate around each slice. Crookes tube - x-rays e-density of tissues transmission of x-rays. X-ray detector solid-state scintillation crystal gas ionization chamber. Transmission of high frequency sounds acoustic differences between different tissues; sound is reflected back when there is a difference. Piezoelectric crystal - converts sounds to an electric signal.
