Radiation Safety and Operations

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Direct Ionization Caused By:

Protons

Alpha Particles

Beta Particles

Positron Particles

Slide 22

Indirect Ionization Caused By:

Neutrons

Gamma Rays

X-Rays

Slide 23

DNA and Radiation

Slide 24

Ionizing Radiation at the Cellular Level

Causes breaks in one or both DNA strands or;

Causes Free Radical formation

Slide 25

Cellular Effects

Slide 26

Cellular Effects

Cell death

Cell repair

Cell change

Is this change good or bad?

Slide 27

Our Bodies Are Resilient

DNA damage is most important and can lead to cell malfunction or death.

Our body has ~ 60 trillion cells

Each cell takes “a hit” about every 10 seconds, resulting in tens of millions of DNA breaks per cell each year.

BACKGROUND RADIATION causes only a very small fraction of these breaks (~ 5 DNA breaks per cell each year).

Our bodies have a highly efficient DNA repair mechanisms

Slide 28

Dividing Cells are the Most Radiosensitive

Rapidly dividing cells are more susceptible to radiation damage.

Examples of radiosensitive cells are;

Blood forming Cells

The intestinal lining

Hair follicles

A fetus

This is why the fetus has a exposure limit (over gestation period) of 500 mrem (or 1/10th of the annual adult limit)

Slide 29

At HIGH Doses, We KNOW Radiation Causes Harm

High Dose effects seen in:

Radium dial painters

Early radiologists

Atomic bomb survivors

Populations near Chernobyl

Medical treatments

Criticality Accidents

In addition to radiation sickness, increased cancer rates were also evident from high level exposures.

Slide 30

Effects of ACUTE Exposures

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Slide 31

Old Terms

Roentgen-Based on the quantity of electrical charges produced in air by X or Gamma photons 1R=2 billion pr

RAD-Radiation Absorbed Dose is the work energy resulting from the absorption of one ROENTGEN or 6.24 E5 Mev