Computed Tomography (CT)
- Used technology: X-ray radiation
- Good contrast: Bones
- Advantages: Fast
- Disadvantages: Radiation exposure!
- Functionality: Electrons are emitted from a cathode in the X-ray tube and then collide with an anode in the form of a metal plate. Upon impact, X-rays are emitted, which then move through different tissues of the body. After leaving the body, the now weakened rays are received by the detector ring and their data is transmitted to a computer for processing. For a complete model, additional X-ray images are iteratively captured in a spiral motion.
- Examples of applications: Stroke and complex bone fracture
Magnetic Resonance Imaging (MRI)
- Used technology: Magnetic field
- Good contrast: Soft tissues
- Advantages: Safe, Also for tissues behind bones
- Disadvantages: Expensive, Slow, Noisy, Not possible with metal implants
- Functionality: A constant magnetic field aligns the nuclear spin axis of hydrogen atom nuclei. Electromagnetic pulses, orthogonal to the magnetic field, repeatedly tilt these axes. The energy absorbed during this process, which varies depending on the tissue, is emitted as an electromagnetic impulse when realigning. These impulses are then measured by antennas, in the form of coils, and then processed by a computer.
- Examples of applications: Brain tumor and meniscus tear
Sonography
- Used technology: Ultrasound
- Good contrast: Soft tissues
- Advantages: Inexpensive, Safe, Can show flow (Doppler sonography)
- Disadvantages: Does not penetrate bones or air, Not suitable for deep-seated organs
- Functionality: The ultrasound transducer emits ultrasound waves into the body. At the boundaries between different tissues and organs, the waves are reflected to varying degrees. The reflected waves are received again by the transducer and then processed by a computer. The calculated data is then directly output live on a screen.
- Examples of applications: Heartbeat and embryo