X - rays & Ultrasound

What are X-rays a form of?

Electromagnetic radiation with wavelengths ranging from 0.01 to 10 nm.

What are the key properties of X-rays?

Ionization, fluorescence, diffraction, and they can penetrate most materials.

How are X-rays produced?

When high-energy electrons decelerate upon collision with a metal target.

What are the two components of X-ray spectra?

Continuous spectrum (Bremsstrahlung radiation) and characteristic spectrum.

What controls the beam intensity and photon energy in X-rays?

Tube current (mA), tube voltage (kV), filtration, and collimation.

What is the primary use of high-energy X-rays in medicine?

To destroy cancerous tissues in radiotherapy.

What is the primary use of low-energy X-rays?

For diagnostic imaging of bones and soft tissues.

What does the attenuation equation I = I0 exp(μ−x) represent?

It describes the intensity of X-rays after passing through a material.

What is required for better visualization of soft tissues in X-ray imaging?

Contrast agents like barium or iodine.

What is fluoroscopy used for?

To provide real-time X-ray imaging.

What are the three types of digital image receptors in radiography?

Flat-panel detectors, computed radiography (CR) plates, digital radiography (DR) systems.

What does a rotating beam X-ray CT scanner do?

Creates cross-sectional images and provides 3D reconstructions of internal structures.

What materials are used in piezoelectric transducers for ultrasound generation?

Materials like quartz or lead zirconate titanate (PZT).

What is an A-scan in ultrasound imaging?

A one-dimensional representation of echoes used to measure eye structure dimensions.

What is the purpose of a coupling medium like gel in ultrasound?

To minimize reflection losses at tissue boundaries.

What is the Doppler shift equation used for?

To measure blood flow velocity in Doppler ultrasound.

What is acoustic impedance defined as?

Z = cρ, where c is the speed of sound in tissue and ρ is tissue density.