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Revision Advanced Biomedical Imaging. Dr Mohamed el Safwany, MD. Types of electromagnetic waves. 10 -12 cm. X Rays are high-energy EM radiation and part of EM spectrum. X-Ray tube consists of: Evacuated tube Cathode (tungsten) Focusing cup Copper anode block
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Revision Advanced Biomedical Imaging Dr Mohamed el Safwany, MD.
Types of electromagnetic waves 10-12cm X Rays are high-energy EM radiation and part of EM spectrum
X-Ray tube consists of: Evacuated tube Cathode (tungsten) Focusing cup Copper anode block Tungsten target (high Z material) high melting point high thermal conductivity More efficient X-Ray production
X-Ray tube consists of: Evacuated tube Cathode (tungsten) Focusing cup Copper anode block Tungsten target (high Z material) high melting point high thermal conductivity More efficient X-Ray production
Computed Axial Tomography (CT) Probing patient from different directions during 360 rotations with x-ray beam of known intensity (I0) & measuring it after it has passed the pt (I). Attenuation depends thickness and density of tissues • Image displays on computer or multiple films New technologies are • Helical CT & • Multiple slice / detector arrays
Ultrasound (US) • Ultrasound machine transmits high-frequency sound into body using a probe. • Sound waves travel into body & hit a boundary between tissues (fluid & soft tissue). • Some waves reflected back to the probe and are detected by probe while some travel on further until they reach another boundary and then reflect back to the probe. • So image depends on transmission characteristics of the interfaces. • Image display on computer or films.
12cm Time between pulse emission and echo return determines depth Velocity =Distance/ Time Echo Reflection 160Us 20cm 260Us Reflection Echo DR Azza Helal
The Ultrasound Machine A basic ultrasound machine has the following parts: Transducer probe- probe that sends and receives the sound waves Central processing unit (CPU) - computer that does all of the calculations and contains the electrical power supplies for itself and the transducer probe Transducer pulse controls- changes the amplitude, frequency and duration of the pulses emitted from the transducer probe Display - displays the image from the ultrasound data processed by the CPU Keyboard/cursor - inputs data and takes measurements from the display Disk storage device(hard, floppy, CD) - stores the acquired images Printer - prints the image from the displayed data
Magnetic Resonance Imaging(MRI) • Image formed by transmitting and receiving radio waves inside a high magnetic field. • All routine MRI techniques are based on receiving and processing of the signals from protons of hydrogen atom. • The image is mainly related to Patient hydrogen density • MRI makes great pictures because of large no of protons in the body, primarily in water and fat. • Image display on computer or multiple films