Non-ionising imaging key terms

ultrasound generation

The process of producing ultrasound waves by converting electrical energy into mechanical vibrations using a transducer.

ultrasound detection

The process of receiving ultrasound waves reflected from tissues and converting them back into electrical signals for imaging.

acoustic impedance

The product of the density of a medium and the speed of sound in that medium, influencing reflection at tissue boundaries.

reflection

The change in direction of an ultrasound wave when it encounters a boundary between two different media, determined by acoustic impedance.

pulse return time

The time taken for an ultrasound pulse to travel to a boundary and back, used to calculate depth.

depth calculation

The process of determining the depth of a boundary using the formula: depth = (speed of sound in tissue x pulse return time) / 2.

ultrasound imaging

A medical imaging technique that uses high-frequency sound waves to create images of organs and structures inside the body.

acoustic impedance

A property of a medium that affects the reflection and transmission of ultrasound waves, defined as the product of the medium's density and the speed of sound within it.

Total Internal Reflection

The phenomenon that occurs when a wave traveling through a medium hits the boundary with a less dense medium at an angle greater than the critical angle, causing the wave to be completely reflected back into the denser medium.

Critical Angle

The minimum angle of incidence at which total internal reflection occurs, defined by the relationship between the refractive indices of the two media.

endoscope

A medical instrument that uses fibre optics to transmit light and images from inside the body for diagnostic purposes.

fibre optics

Technology that uses thin strands of glass or plastic to transmit light signals, enabling high-quality image and data transmission.

image transmission

The process of transferring visual information from one point to another, often through optical fibers in endoscopy.

illumination transmission

The method by which light is conveyed through optical fibers to illuminate internal structures during endoscopic procedures.

Endoscopy

A medical procedure that uses an endoscope to examine the interior of a hollow organ or cavity.

Diagnosis

The process of identifying a disease or condition based on the signs, symptoms, and results of diagnostic tests.

Magnetic Field Strength

The force per unit charge experienced by a charged particle in a magnetic field, measured in teslas (T).

Resonance

The phenomenon that occurs when a system is driven at its natural frequency, leading to maximum energy absorption and signal enhancement in MRI.

resonance

The phenomenon where a system oscillates at maximum amplitude at specific frequencies, known as resonant frequencies.

radio-frequency pulses

Electromagnetic waves used in MRI to excite nuclei in a magnetic field, causing them to emit signals that are detected to form images.

Signal Detection

The process of identifying and measuring the signals produced by tissues in response to magnetic resonance imaging.

Image Formation

The creation of visual representations of internal structures based on the signals detected during MRI.

Magnetic Resonance Imaging (MRI)

A medical imaging technique that uses strong magnetic fields and radio waves to generate detailed images of organs and tissues inside the body.

Advantages of MRI

MRI provides high-resolution images without the use of ionizing radiation, making it safer for patients, and is particularly effective for imaging soft tissues.