EHPLE Medical Radiology Technology - independent subject foundations flashcards
EHPLE Medical Radiology Technology - independent subject foundations · Build recall with a focused review session.
20 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Attenuation
- Reduction of a beam through interaction with matter, interpreted using the energy spectrum, material and geometry rather than treated as an image-display adjustment.
- Half-value layer
- The thickness that reduces beam intensity by one half under the specified measurement conditions, related to beam quality and the relevant attenuation model.
- Absorbed dose
- Energy deposited per unit mass, expressed in gray, distinct from weighted dose quantities, an exposure index or an individual probability of disease.
- Effective dose
- A weighted protection quantity used for specified comparisons and assessments, not an exact direct measurement of one patient’s biological injury.
- Scatter
- Radiation redirected through interaction, which can reduce image contrast and contribute to occupational exposure in a way that depends on the geometry.
- Collimation
- Restriction of the useful beam field to appropriate anatomy, requiring a balance between task coverage, exposure and avoiding unnecessary irradiated areas.
- Grid cutoff
- Loss of useful radiation reaching the receptor because of grid misuse or geometry, which can degrade an image and require proper cause investigation.
- Exposure index
- A detector-related indicator of acquisition exposure under its defined convention, distinct from image brightness and exact absorbed dose to the patient.
- Quantum noise
- Statistical variation related to detected photon numbers, which must be distinguished from motion, detector, grid and processing artifacts.
- Modulation transfer
- Description of how an imaging system transfers contrast at different spatial frequencies under defined conditions, rather than one universal clinical quality score.
- Pitch
- In helical CT, table travel per rotation divided by nominal total beam width, with dose effects depending on other parameters and output control.
- Window level
- The center of the displayed CT attenuation range in the specified window setting, which changes presentation rather than the acquired tissue attenuation.
- Window width
- The span of attenuation values allocated across the displayed grayscale in a CT window, interpreted together with its level and display convention.
- Longitudinal relaxation
- Recovery of longitudinal magnetization after excitation in MRI, described by T1 under the specified model and not interchangeable with transverse signal decay.
- Apparent diffusion coefficient
- An imaging-derived description of diffusion behavior that helps interpret diffusion-weighted signal within the relevant acquisition and clinical context.
- Piezoelectric effect
- Conversion between mechanical and electrical behavior in suitable materials, used for generation and reception of diagnostic ultrasound signals.
- Aliasing
- Misrepresentation arising when sampling is insufficient for the relevant signal variation, with particular acquisition-dependent forms in MRI and pulsed Doppler.
- MR Conditional
- A labeling category identifying defined conditions for use in the MR environment, requiring verification rather than an assumption of unrestricted safety.
- Justification
- Assessment of whether an imaging procedure is appropriate for its intended clinical purpose and person, considering expected benefits, risks and relevant alternatives.
- Optimization
- Adjustment of an appropriate examination to obtain necessary information while managing exposure and other risks, rather than simply minimizing all signals or all tests.