The Essential Physics Of Medical Imaging May 2026

Unlike X-ray or MRI, uses mechanical energy rather than electromagnetic radiation. It relies on the piezoelectric effect , where crystals in a transducer convert electrical energy into high-frequency sound waves. These waves reflect off internal boundaries (acoustic impedance). By measuring the time-of-flight of the echoes and applying the Doppler Effect , physics allows us to visualize not just static anatomy, but the real-time velocity of blood flow. Nuclear Medicine: PET and SPECT

The oldest and most common form of imaging relies on the and Compton scattering . In traditional X-rays, high-energy photons are fired through the body; dense structures like bone absorb more photons (attenuation), while soft tissues allow more to pass through to the detector. The Essential Physics of Medical Imaging

weighted images) varies by tissue type, providing the most detailed soft-tissue contrast available in medicine today. Sound Waves: Ultrasound Unlike X-ray or MRI, uses mechanical energy rather