RAD PROTECTION

PRELIM HAHA

An area where radiation exposure is safe for the general public.

→ Uncontrolled area

An area where radiation levels are safe for trained staff (occupational).

→ Control area

Protective barrier against scatter or leakage.

→ Secondary protective barrier

Required thickness of primary protective barrier.

→ 1/16 inch lead

One of the cardinal principles: using protective barriers like lead aprons.

→ Shielding

One of the cardinal principles: increase space between patient and source.

→ Distance

One of the cardinal principles: reduce exposure duration.

→ Time

Radiography done with mobile x-ray units.

→ Portable radiographic equipment

Imaging procedure with the highest dose due to continuous exposure. → Fluoroscopic exam

→ Fluoroscopic exam

Device housing that must keep leakage radiation below 1 mGy/hr at 1 m.

→ X-ray tube housing

Lead-lined structure that absorbs radiation.

→ Protective barrier

Two main sources of radiation exposure.

→ Natural and man-made

Three main rules of radiation protection.

→ Cardinal principles (Time, Distance, Shielding)

Group requiring special care to avoid unnecessary exposure.

→ Pregnant patients

Patients needing special care because of small body size and radiosensitivity.

→ Pediatrics

Device that automatically sets exposure based on detected radiation.

→ AEC (Automatic Exposure Control)

Shield type: attached to tube, casts a protective shadow.

→ Shadow shield

Shield type: lead piece placed directly in contact with patient.

→ Flat contact shield

Gonad shielding effectiveness:

female = 50%, male = 95%

Sum of inherent and added filtration.

→ Total filtration

Filtration added between tube and patient (aluminum plates).

→ Added filtration

Filtration that is built into x-ray tube (glass, oil, housing).

→ Inherent filtration

Cone often used in os calcis (heel) projection.

→ Cones

Typical length of radiographic cones.

→ 10–12 inches

Automatic adjustment of collimator to film size.

→ PBL (Positive Beam Limitation)

Simplest beam restrictor, flat lead opening.

→ Aperture diaphragm

Beam restrictor shaped like a long tube for small areas.

→ Cylinder cone

Device with adjustable shutters to limit the beam.

→ Collimator

Any image taken again due to error.

→ Repeat exposure

Device used to reduce scatter and improve image contrast.

→ Grid

System that combines x-ray film with intensifying screens.

→ Film-screen combination

Darkroom or digital processing of images.

→ Processing

Technique factors that control patient dose (kVp, mA, time).

→ Exposure factors

Device used to protect reproductive organs.

→ Gonad shielding

Removal of low-energy photons from the x-ray beam.

→ Filtration

Method of restricting x-ray beam to reduce patient dose.

→ Beam limitation

Principle meaning “As Low As Reasonably Achievable.”

→ ALARA

Embryo-fetus total dose limit for entire gestation.

→ 5 mSv

Embryo-fetus monthly dose limit.

→ 0.5 mSv

Annual radiation limit for the general public (infrequent exposure).

→ 5 mSv

Annual radiation limit for the general public (frequent exposure).

→ 1 mSv

Maximum annual radiation dose for students under 18.

→ 1 mSv/year

Formula for lifetime radiation limit based on age.

→ Cumulative effective dose = 10 mSv × age (years)

Maximum occupational exposure for the eye lens, skin, and extremities.

→ 150 mSv (eye lens), 500 mSv (skin/extremities)

U.S. regulatory agency that enforces radiation safety laws.

→ NCR (Nuclear Regulatory Commission)

Organization that gives U.S. radiation protection recommendations.

→ NCRP (National Council on Radiation Protection and Measurements)

Organization that gives international recommendations on radiation protection.

→ ICRP (International Commission on Radiological Protection)