NRSB RRS key terms

Principle of keeping radiation dose As Low As Reasonably Achievable, taking into account economic and social factors. It guides daily decisions about technique, shielding, and repeat imaging.

Maximum permitted radiation doses set for occupationally exposed workers, the public, and specific tissues such as the lens of the eye. Limits apply to planned exposures and exclude background and medical exposure of patients.

Device such as a film badge, thermoluminescent dosimeter, or optically stimulated luminescence badge worn to record a worker's cumulative radiation dose. Results are reviewed against dose limits and investigation levels.

Radiation intensity from a point source decreases in proportion to the square of the distance from that source. Doubling distance reduces intensity to one quarter, which is why standing back is a primary protection tool.

Radiation deflected from its original path by interaction with matter, especially the patient. It is the main source of occupational exposure and is reduced by collimation, beam restriction, and shielding.

Protective garment containing lead or lead-equivalent material worn by staff during fluoroscopy or mobile radiography. A typical apron provides 0.5 mm lead equivalent, attenuating most scattered photons reaching the torso.

Placement of lead shielding over reproductive organs during imaging when it does not obscure diagnostic information. It reduces gonadal dose and is documented in the patient record.

Restriction of the x-ray beam to the area of clinical interest using adjustable shutters. It reduces patient dose, improves contrast by limiting scatter, and is verified by checking the light field.

Number expressing how likely an area adjacent to an x-ray room is occupied, used when calculating shielding. Full occupancy is 1, partial is 1/4, and occasional is 1/16.

Product of tube current and exposure time, controlling the total number of x-ray photons produced. Increasing mAs raises receptor exposure and patient dose without changing the energy of the beam.

Maximum energy of the x-ray beam, controlling photon penetration and subject contrast. Higher kVp produces a more penetrating beam and fewer photoelectric interactions, lowering dose for a given receptor exposure.

Reduced x-ray output on the anode side of the beam because photons generated deeper in the anode target are absorbed. It is used to advantage by placing the thicker body part under the cathode side.

Small area on the anode where electrons strike and x-rays are produced. A smaller focal spot improves spatial resolution, while a larger one permits higher tube currents without overheating.

System that terminates the exposure when a preset amount of radiation reaches ionization chambers behind the receptor. It standardizes receptor exposure across patient sizes and reduces repeat images.

Numeric value reported by digital systems that estimates receptor exposure and allows comparison with a target range. It is a quality-control tool, not a measure of patient dose.

Ability of an imaging system to display small, closely spaced structures as distinct. It is tested with line-pair phantoms and is influenced by focal spot size, receptor pixel size, and motion.

Device of alternating radiopaque and radiolucent strips placed between patient and receptor to absorb scatter before it reaches the image. It improves contrast but requires higher exposure and precise alignment.

Loss of density across an image caused by improper grid alignment, tilt, or wrong source-to-image distance. It appears as uniform or asymmetric underexposure and typically requires a repeat.

Distance from the focal spot to the image receptor. Standard distances such as 100 cm or 180 cm control magnification, receptor exposure, and geometric sharpness.

Enlargement of the recorded image compared with the actual object, produced when the object lies farther from the receptor. It is reduced by increasing SID or decreasing object-to-receptor distance.

Blur or ghosting caused by patient, detector, or tube movement during exposure. It degrades spatial resolution and is minimized with short exposure times, immobilization, and clear breathing instructions.

Image taken again because the first exposure was unacceptable for positioning, exposure, motion, or artifacts. Repeats increase patient dose and should be tracked as a quality indicator.

Patient's voluntary agreement to a procedure after receiving an explanation of its purpose, risks, benefits, and alternatives. The radiographer confirms consent is documented and answers questions within scope.

Verification of a patient's identity using at least two identifiers, such as name and date of birth, before any procedure. It prevents wrong-patient imaging and is a required safety practice.

Brief pause before a procedure in which the team confirms patient identity, procedure, site, and any special requirements. It is standard practice for invasive or high-risk imaging procedures.

Infection-control practices applied to all patients, including hand hygiene, gloves, gowns, masks, and safe handling of sharps and body fluids. They assume every patient may carry a transmissible organism.

Adverse response to iodinated contrast media ranging from mild nausea or hives to severe anaphylactoid shock. Radiographers recognize early signs and initiate emergency response per protocol.

Position with the patient supine and the head lower than the feet. It is used in some hypotensive emergencies and in selected procedures, and requires care to prevent aspiration or sliding.

Position with the patient supine and the upper body elevated, often 45 to 90 degrees. It aids breathing and comfort in patients with dyspnea or suspected aspiration risk.

Reference stance with the body upright, face forward, arms at the sides, and palms facing anteriorly. Directional terms such as medial, lateral, proximal, and distal are defined relative to it.

Path of the central ray through the patient, described by the entrance and exit points, such as anteroposterior or posteroanterior. It determines how anatomy is superimposed on the image.

Overall body orientation and specific placement used for an image, described by the patient's position and the part examined. It is distinct from projection, which describes the beam path.

Central axis of the x-ray beam, directed to a specific landmark and aligned perpendicular to the part and receptor unless angling is required. Correct centering reduces distortion and repeat exposures.

Describing material or tissue that attenuates x-rays strongly and appears light on the image, such as bone or metal. The term contrasts with radiolucent structures that transmit x-rays.

Planned set of activities that monitor equipment performance, image quality, and radiation safety to ensure consistent diagnostic results. It includes scheduled tests, documentation, and corrective action.

Legally defined range of duties a radiologic technologist may perform, set by state law and regulation. Acting outside it can constitute unprofessional conduct regardless of employer request.

Principles guiding conduct toward patients, colleagues, and the public, including honesty, confidentiality, and accountability. Ethical breaches may also violate licensure rules and reporting obligations.

Obligation to protect patient health information from unauthorized disclosure. It covers images, reports, and conversations, and is governed by law and professional standards.