RADIATION PROTECTION

Gondal shielding

• use on patients of reproductive age

• Use when gonads lie in with in/near beam (5cm)

• Use when it won’t compromise required diagnostic info

Beam restricting device

• measures dose and energy of radiation

• MUST BE WORN AT ALL TIMES

Optically Stimulated Luminescence (OSL)

• measures radiation quantity

• Consists of aluminum oxide, copper filter, a tin filter, and an imagin filter

• Aluminum oxide is exposed to laser light which stimulated after use, cause to become luminescent in proportion of the amount of radiation exposure which determines occupational workers exposure

10 commandments of radiation

• understand and apply cardinal principles

• Don’t allow familiarity to result to false security

• Never stand in primary beam

• Always wear protective apparels when not behind barrier

• Always wear radiation monitor and position it outside lead apron at collar

• Never hold a patient

• Person holding patient must wear protective apron/gloves if possible

• Use gonadal shielding on child age if not interfering with exam

• Avoid x-ray pregnant women patients

• Always collimate to smallest field size appropriate for exam

Technical factor selection

• requires kVp and mAs

• High kVp + low mAs = low patient dose

• Decides how much radiation

Filtration

• remove or absorb low energy photons with a low atomic # metal

• Decrease patient dose Decides

• Total filtration = 2.5mm Al

Radiation units

• exposure

• Absorbed dose

• Dose equivalent

• Kerma

Exposure

• exposure in air

• Columb/ kilogram (C/kg)

• Old term roetgen

Absorbed dose

Gray (Gy)

Patient exposure

Old term- rad

Dose equivalent

• occupational exposure

• Sievert (Sv)

• Old term- rem

• Dose per year = 5rem or 5000mrem

• .05sv or 50mSv

Kerma

Kinetic Energy Released in Matter

• joule/kg (Gray)(Gy)= absorbed dose

Radiation

Energy that comes from a source and travels through some material or through space

Leakage

Doesn’t hit patient

Useful beam

Has a divergent look

Scatter

Comes off patient, is never good. Makes image look foggy

Ionization

Removal of electron from atom

Other names for x-ray

• radiation

• Photons

• Useful beam

• EM energy

• Quantum

• Bundle of energy

• Primary x-ray beam

ALARA

As low as reasonably achievable

kVp

KiloVoltsPeak

mA(s)

milli amperes x seconds

cardinal rules of radiation protection

1. time- minimize time

2. distance- maximize distance

3. shielding- use when it will not obscure important diagnostic information

shielding devices

lead aprons = .50mm Pb

thyroid shield= .25mm Pb

lead glasses= .35mm Pb

ionizing radiation

high-energy radiation capable of producing ionization in substances through white it passes

• can be harmful to humans

x-rays

forms of electromagnetic radiation

• travel at speed of light

• no mass

• no charge

remnant radiation

what made it through

image receptor

what catches the image

collamation

• close beam

• decreases tissue exposure to radiation

• makes image look nice