Radiology Technology Qualification (China) - independent subject foundations key terms

Reduction of a beam through interaction with matter, interpreted using the energy spectrum, material and geometry rather than treated as an image-display adjustment.

The thickness that reduces beam intensity by one half under the specified measurement conditions, related to beam quality and the relevant attenuation model.

Energy deposited per unit mass, expressed in gray, distinct from weighted dose quantities, an exposure index or an individual probability of disease.

A weighted protection quantity used for specified comparisons and assessments, not an exact direct measurement of one patient’s biological injury.

Radiation redirected through interaction, which can reduce image contrast and contribute to occupational exposure in a way that depends on the geometry.

Restriction of the useful beam field to appropriate anatomy, requiring a balance between task coverage, exposure and avoiding unnecessary irradiated areas.

Loss of useful radiation reaching the receptor because of grid misuse or geometry, which can degrade an image and require proper cause investigation.

A detector-related indicator of acquisition exposure under its defined convention, distinct from image brightness and exact absorbed dose to the patient.

Statistical variation related to detected photon numbers, which must be distinguished from motion, detector, grid and processing artifacts.

Description of how an imaging system transfers contrast at different spatial frequencies under defined conditions, rather than one universal clinical quality score.

In helical CT, table travel per rotation divided by nominal total beam width, with dose effects depending on other parameters and output control.

The center of the displayed CT attenuation range in the specified window setting, which changes presentation rather than the acquired tissue attenuation.

The span of attenuation values allocated across the displayed grayscale in a CT window, interpreted together with its level and display convention.

Recovery of longitudinal magnetization after excitation in MRI, described by T1 under the specified model and not interchangeable with transverse signal decay.

An imaging-derived description of diffusion behavior that helps interpret diffusion-weighted signal within the relevant acquisition and clinical context.

Conversion between mechanical and electrical behavior in suitable materials, used for generation and reception of diagnostic ultrasound signals.

Misrepresentation arising when sampling is insufficient for the relevant signal variation, with particular acquisition-dependent forms in MRI and pulsed Doppler.

A labeling category identifying defined conditions for use in the MR environment, requiring verification rather than an assumption of unrestricted safety.

Assessment of whether an imaging procedure is appropriate for its intended clinical purpose and person, considering expected benefits, risks and relevant alternatives.

Adjustment of an appropriate examination to obtain necessary information while managing exposure and other risks, rather than simply minimizing all signals or all tests.