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Introduction to Biomedical Engineering and Medical Imaging

Learn about the application of engineering principles to healthcare, including medical imaging techniques such as X-ray radiography, CT scans, and ultrasonography. Understand the basic principles and components of these imaging techniques and their advantages and disadvantages.

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Introduction to Biomedical Engineering and Medical Imaging

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  1. BTY100-Lec# 6.1 Biomedical Engineering Medical Imaging

  2. OUTLINE • Introduction to Biomedical Engineering • Medical Imaging: • X-Ray Radiography • CAT Scan • Ultrasonography

  3. Biomedical Engineering • is the application of engineering principles and design concepts to medicine and biology for healthcare purposes • It combines the design and problem solving skills of engineering with medical and biological sciences to advance: • healthcare treatment, including diagnosis, monitoring, and therapy

  4. Biomedical Engineering • Includes: • Medical imaging • Implants • Bionics

  5. Medical Imaging • is the technique of creating visual representations of the interior of a body for clinical analysis and medical intervention. • seeks to reveal internal structures hidden by the skin and bones, to diagnose and treat disease. • Commonly used techniques: • X-ray radiography, CT Scan, Medical ultrasound etc.

  6. X-ray Radiography is an imaging technique that uses electromagnetic radiation other than visible light, especially X-rays, to view the internal structure of the human body. Lung: Less dense, more x-rays pass through-Black image. Femur: Thick bone, lesser X-rays pass through: Whiter image • Basic Principle: • an x-ray beam is passed through a patient to a piece of film or a radiation detector, producing an image. • Different soft tissues allow different penetration of x-rays: depending on tissue density; the denser the tissue, the whiter the image

  7. X-ray Radiography • To create the image, a heterogeneous beam of X-rays is produced by an X-ray generator and is projected toward the object. • A certain amount of X-ray is absorbed by the object, which is dependent on the particular density and composition of that object. • The X-rays that pass through the object are captured behind the object by a detector. • The detector can then provide a superimposed 2D representation of all the object's internal structures.

  8. COMPONENTS • X-ray generator : • X-rays are produced by an electron beam (emitted from heated cathode filament) that is accelerated to a high speed and strikes a target. • The electrons are then focused and accelerated by an electrical field towards an angled anode target. • The point where the electron beam strikes the target is called the focal spot. • Most of the kinetic energy contained in the electron beam is converted to heat, but around 1% of the energy is converted into X-ray photons.

  9. COMPONENTS • Image detection system: a range of detectors have been used to collect images including: • Photographic film

  10. Image detection system • Scintillator Detector: • X-rays not absorbed by the target strike, a layer of scintillating material that converts them into visible light photons. • These photons then strike an array of photodiodes which converts them into electrons that can activate the pixels in a layer of amorphous silicon. • The activated pixels generate electronic data that a computer can convert into a high-quality image of the target, which is then displayed on a computer monitor

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  12. Two forms of radiographic images • Projection radiography : are often used to determine the type and extent of a fracture. • With the use of radio-opaque contrast media, such as barium, they can also be used to visualize the structure of the stomach and intestines

  13. Two forms of radiographic images • Fluoroscopy: produces real-time images of internal structures of the body in a similar fashion to radiography. • employs a constant input of x-rays, at a lower dose rateand real time image is produced using TV camera. • used in image-guided procedures when constant feedback during a procedure is required.

  14. Tomography • refers to imaging by sections or sectioning, through the use of any kind of penetrating wave.

  15. Computed Tomography Scanning • Basic Principle: uses computer-processed x-rays to produce tomographic images (virtual 'slices') of specific areas of the scanned object.

  16. Working CT Scan A CT scanner looks like a big, square doughnut. Inside the covers of the CT scanner is a rotating frame which has an x-ray tube mounted on one side and the detector mounted on the opposite side. A fan beam of x-ray is created as the rotating frame spins the x-ray tube and detector around the patient. As the x-ray tube and detector make this 360° rotation, the detector takes numerous snapshots. Typically, in one 360° lap, about 1,000 profiles are sampled. Profiles are then superimposed to generate a 3-D images.

  17. CT Scan Advantages: • High-contrast resolution: differences between tissues that differ in physical density by less than 1% can be distinguished • Data from a single CT imaging procedure can be viewed as images in different axial planes. This is referred to as multi-planar reformatted imaging Disadvantage: Uses high ionizing radiations hence dosage must be properly monitored.

  18. ULTRASONOGRAPHY • Ultrasound is an oscillating sound wave with a frequency greater than the upper limit of the human hearing range(20 kilohertz). • Ultrasound devices operate with frequencies from 20 kHz up to several gigahertz. • These sound waves are reflected by tissue to varying degrees to produce images

  19. ULTRASONOGRAPHY • commonly associated with imaging the fetus in pregnant women. • Other important uses include imaging the abdominal organs, heart, breast, muscles, tendons, arteries and veins.

  20. Working • Ultrasound images (sonograms) are made: • by sending a pulse of ultrasound into tissue using an ultrasound transducer (probe). • The sound reflects and echoes off parts of the tissue • this echo is recorded and displayed as an image to the operator.

  21. COMPONENTS • 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

  22. Ultrasonography • Advantages: • It is very safe to use and does not cause any adverse effects. • It is also relatively inexpensive and quick to perform. • The real time moving image obtained can be used to guide drainage and biopsy procedures. • Disadvantage • that it can not capture detailed images.

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