Radiation safety

Discovery of X rays

1895- Wilhelm Roentgen

becquerel

1896- first biological effects of x rays/gamma rays

first safety regulation

1921

types of radiation

• electromagnetic radiation

• particulate radiation

electromagnetic radiation

• energy having no mass

• ionizing and non-ionizing

• made of photons, acts like a wave

particulate radiation

has mass and energy

disintegration of an unstable atom

all types are ionizing

non-ionizing

Atoms or molecules that remain electrically neutral because their electrons stay bound in place.

ionizing

removes electrons from atoms, leads to biological damage

short wavelength

energy is high

frequency is high (short)

long wavelength

energy is low, frequency is low (long)

radiation exposure

amount of ionizing radiation you encounter in the air

Measured as Coulomb (C)/kg air

Traditional unit – Roentgen (R)

absorbed dose

how much ionizing radiation is absorbed into the object

equivalent dose

measure of how the absorbed dose differs with different types of ionizing radiation on tissue.

regulations of radiation exposure

-Required when radiation workers are likely to receive ≥ 10% of the annual dose limit (5 rem) in one year.

• MPD

• ALARA

• dosimeter

prodromal stage

occurs within hours of 1st dose

nausea, vomiting, diarrhea, fatigue

latent stage

last hours to weeks

no visible symptoms

manifest illness

last from hours to months

acute radiation syndrome

•Large and penetrating dose (≥ 1 Gy)

•External source

•Dose received by entire body

•Dose delivered in a short time (within minutes)

1. prodromal stage

2. latent stage

3. manifest illness

4. recovery or death

MPD

maximum permisible dose. -Dose equivalent that a person is allowed in a specific period of time resulting in minimal side effects.

ALARA

as low as reasonably achievable

Always minimize radiation dose when possible

safety fundamentals

reduce time

distance

shielding

collimation

minimize restraint and personel

Computed tomography

●Works like traditional x-rays, only 3D

●X-rays strike the patient from multiple angles, creating much larger amounts of radiation

●Each x-ray reaches a detector and gets converted to a Hounsfield Unit (HU), which correlates to different tissue types

MRI

●No radiation exposure

●Combination of magnetic field and application of radiofrequency pulses

●Danger lies in strength of magnetic field