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.
evolves this concept by rotating the X-ray source around the patient. This uses the Radon transform , a mathematical principle that reconstructs 2D projections into 3D cross-sectional slices, allowing for much higher spatial resolution and the ability to distinguish between varying densities of soft tissue. Nuclear Magnetic Resonance: MRI The Essential Physics of Medical Imaging
While other methods image anatomy, nuclear medicine images . In Positron Emission Tomography (PET) , a radioactive tracer is injected into the patient. As the tracer decays, it emits a positron, which quickly meets an electron. This results in an annihilation event , producing two gamma rays traveling in opposite directions. Sensors detect these coincident photons to pinpoint metabolic "hotspots," such as tumors or brain activity. Conclusion The oldest and most common form of imaging