Kuwait MOH Radiographer flashcards

33 cards. Read the term and the definition here. The deck at the top of this page is optional.

Bremsstrahlung radiation

Continuous x-ray spectrum produced when projectile electrons decelerate in the anode target; the maximum photon energy equals the tube voltage in keV.

Inverse square law

Radiation intensity is inversely proportional to the square of the distance from the source; doubling distance reduces dose to one quarter.

Anode heel effect

Reduced beam intensity on the anode side of the field; thicker patient parts are placed toward the cathode side to compensate.

Half-value layer

Absorber thickness that reduces beam intensity by half; minimum total filtration is 2.5 mm Al equivalent above 70 kVp.

Atlas and axis

C1 (atlas) lacks a body and supports the skull; C2 (axis) provides the dens for head rotation.

Right main bronchus

Wider and more vertical than the left, making it the more likely path for aspirated material.

Diaphragm level

At full inspiration the domes lie near the 10th posterior or 6th anterior rib; the right hemidiaphragm is normally higher.

AP versus PA projection

AP enters anterior and exits posterior; PA enters posterior and exits anterior; projection is defined by the part-to-image relationship.

PA chest positioning

Patient stands with chest against receptor, shoulders rolled forward, chin elevated, and exposure at full inspiration.

AP pelvis rotation

Feet internally rotated 15 degrees to bring the femoral necks into profile; beam centered between ASIS and pubic symphysis.

Spatial resolution

Ability to distinguish small, closely spaced objects; described in line pairs per millimeter and limited by pixel and focal spot size.

Deviation index

Digital measure of receptor exposure relative to the reference; a value within plus or minus 1 indicates acceptable exposure.

Detective quantum efficiency

Combined measure of resolution and noise performance; higher DQE indicates better image quality per unit dose.

Collimator alignment test

Daily QC check that the light field aligns with the radiation field within 2 percent of the source-to-image distance on each side.

kVp accuracy test

Measured tube voltage must be within plus or minus 5 percent of the indicated value for acceptable performance.

ALARA principle

All exposures should be kept as low as reasonably achievable, considering economic and social factors.

Occupational dose limits

20 mSv per year averaged over 5 years for whole body; 150 mSv for lens; 500 mSv for extremities and skin.

Lead apron attenuation

A 0.5 mm lead-equivalent apron attenuates about 90 percent of scattered radiation at diagnostic energies.

Gray and sievert

Gray measures absorbed dose (J/kg); sievert measures equivalent dose, equal to absorbed dose times the radiation weighting factor.

Linear-quadratic model

Cell survival equals exp(-alpha D minus beta D squared); the alpha/beta ratio indicates tissue repair capacity.

Deterministic versus stochastic

Deterministic effects have a threshold and increase in severity; stochastic effects have no threshold and increase in probability.

Informed consent

Patient agreement after explanation of procedure, benefits, risks, and alternatives, required for contrast and significant-risk procedures.

Anaphylaxis management

Stop injection, call for help, give intramuscular epinephrine, provide oxygen, and monitor vital signs.

Scope of practice

Procedures a radiographer is licensed to perform under Kuwait MOH regulations; practicing beyond it is prohibited.

Hounsfield unit scale

CT attenuation scale with water at 0 HU, air at -1000 HU, and bone above +1000 HU.

MRI safety zones

Zone I public, zone II reception, zone III restricted, zone IV magnet room; ferromagnetic objects must never enter zone IV.

Doppler effect

Frequency shift of reflected sound from moving blood; color Doppler shows direction and velocity, spectral Doppler quantifies flow.

Technetium-99m half-life

Six hours; widely used for bone and cardiac imaging because of favorable energy and short half-life.

Therapeutic ratio

Tumor control probability divided by normal tissue complication probability; fractionation improves it by exploiting repair differences.

Hand hygiene

Single most effective measure to prevent healthcare-associated infection; alcohol rub for routine use, soap and water when soiled.

Airborne precautions

Required for tuberculosis and measles; use an N95 respirator and a negative-pressure room.

PDSA cycle

Plan-do-study-act framework for continuous quality improvement; tests changes on a small scale before full implementation.

DICOM and PACS

DICOM is the standard for image storage and transmission; PACS stores and retrieves images across the enterprise.