PRC RadTech flashcards

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

Bremsstrahlung

Continuous x-ray spectrum produced when electrons decelerate in the target nucleus field; maximum photon energy equals kVp.

Characteristic radiation

Discrete x-rays emitted when a projectile electron ejects an inner-shell electron and an outer-shell electron fills the vacancy.

Half-value layer

Thickness of material that reduces x-ray intensity to half; increases with kVp and filtration; measures beam quality.

Inverse square law

Intensity is inversely proportional to the square of distance: I1/I2 = (d2/d1)^2; doubling distance reduces intensity to one quarter.

Photoelectric effect

Complete absorption of an x-ray photon by an inner-shell electron; dominates at low kVp and high atomic number; produces high contrast.

Anode heel effect

X-ray intensity is lower toward the anode side of the beam; place thicker body parts toward the cathode for uniform exposure.

Focusing cup

Negatively charged metal cup around the filament that confines the electron beam to a small area on the anode.

Line-focus principle

Angled anode target creates a smaller effective focal spot than actual focal spot, improving resolution while spreading heat.

Automatic exposure control

Ionization chambers measure radiation reaching the receptor and terminate exposure at a preset level, controlling receptor exposure.

Tube rating chart

Graph showing maximum kVp, mA, and exposure time combinations for a focal spot; prevents anode overheating and tube damage.

PA chest radiograph

Upright projection at 72 inches with scapulae rotated clear of lungs; reduces heart magnification and thyroid dose.

KUB abdomen

Supine AP abdomen radiograph at 40 inches showing kidneys, ureters, and bladder; no contrast medium is used.

Odontoid view

Open-mouth AP projection of the upper cervical spine showing C1 and C2, including the dens and lateral masses.

Anatomic position

Upright, facing forward, arms at sides with palms forward; reference position for describing body planes and directions.

Epiphyseal plate

Cartilaginous growth plate between epiphysis and metaphysis in immature long bones; appears as a radiolucent line.

Barium sulfate

Positive oral contrast agent used for GI studies; contraindicated if bowel perforation is suspected because it causes peritonitis.

15 percent rule

Increase kVp by 15% to halve mAs, or decrease kVp by 15% to double mAs, maintaining receptor exposure.

Magnification

Size distortion calculated as SID divided by SOD; reduced by increasing SID or decreasing object-to-image receptor distance.

Grid ratio

Ratio of height to interspace width of grid strips; higher ratio removes more scatter and requires more mAs.

Quantum mottle

Noise from too few x-ray photons reaching the receptor; reduced by increasing mAs or using a faster receptor.

Exposure indicator

Digital value reflecting receptor exposure; deviates from manufacturer's target when technique is outside optimal range.

Modulation transfer function

Measure of how well an imaging system preserves spatial resolution at different spatial frequencies; higher MTF indicates sharper image detail.

ALARA

Principle of keeping radiation dose as low as reasonably achievable, considering economic and social factors.

Occupational dose limit

Effective dose limit for radiation workers is 50 mSv per year; lens limit 150 mSv and extremity limit 500 mSv.

Controlled area

Area where occupational exposure may occur, posted with radiation warning signs and access limited to authorized personnel.

Lead apron equivalence

Protective apron must be at least 0.25 mm lead equivalent; 0.5 mm is recommended for fluoroscopy and high-dose procedures.

Declared pregnant worker

Worker who voluntarily declares pregnancy; fetal dose limit is 0.5 mSv per month and 5 mSv over gestation.

Informed consent

Patient's voluntary agreement after receiving information about procedure, risks, benefits, and alternatives; must be documented.

Patient confidentiality

Duty to protect patient health information from unauthorized disclosure, consistent with privacy laws and professional codes.

Scope of practice

Legal boundaries of the radiologic technologist role: perform imaging and related procedures under supervision, not diagnose.

Beneficence

Ethical principle of acting for the patient's benefit and promoting good outcomes while minimizing harm.

Professional boundary

Limits that protect the therapeutic relationship; avoid personal, financial, or romantic involvement that could exploit patients.