Radiation 

Safety Principles

O k Rid A i t d O

a

k Ridge 

Associa

t

e

d

Universities
Objectives

 Review the basic principles of radiat

safety.

 Discuss the application of these prin

Discuss the application of these prin

to various situations.
Introduction

 The principles of radiation safety are 

simple and easy to learn and remem

 However, it is fundamental that the

However, it is fundamental that the

application of these principles be basome knowledge or estimate of the radiological conditions.
Introduction

 Many people have learned radiation 

safety as:

 Time (minimize).

( )

 Distance (maximize). Shielding (utilize).

 These principles work for many 

circumstances, but other principles should be considered.
Introduction

 One of the best summaries of radiat

safety principles are the “Ten Principand Ten Commandments of RadiatioProtection” by Daniel Strom.

 This presentation is based on Strom

principles and commandments.
Goals of Radiation Safety

 Keep it safe

 Prevent deterministic effects Limit probability of stochastic effects

 Keep it legal

 Keep it affordable Be able to prove it

 Help people feel safe
#1. Time

 Minimizing the 

amount of time in a radiation field reduces the dose.

 Hurry, but do

hasty.
Time Reduction Methods

 Plan and discuss the task prior to en

the area.

 Use only the number of workers act

Use only the number of workers act

required to do the job.

 Have all necessary tools present bef

entering the area.
Time Reduction Methods

 Use mock-ups and practice runs tha

duplicate work conditions.

 Take the most direct route to the jo

Take the most direct route to the jo

if possible and practical.

 Never loiter in an area controlled for 

radiological purposes.
Time Reduction Methods

 Work efficiently and swiftly. Perform as much work outside the area as 

possible or, when practical, remove parts components to areas with lower dose ratecomponents to areas with lower dose rate

perform work.

 In some cases, the radiological control pe

may limit the amount of time a worker main an area due to various reasons (stay tim
Time Reduction Methods

 If you have been assigned a stay tim

not exceed this time.

 Do it right the first time, in the least 

amount of time necessary.
#2. Distance

 The distance principle 

has a purely geometric component.

 For physically small

 Stay away fro Stay upwind.

 For physically small

(point) sources, the dose rate is inversely proportional to the square of the distance away.
Inverse Square Law
Inverse Square Law

2

2

2

2

1

1

I

d

=

I

d

If the dose rate is 100 mrem/hr at from a point source, what is the dorate at 2 m?
Using the Inverse Square Law

I

d

I

I

d

I

d

2

1

1

2

2

2

2

1

1

=

=

hr

mrem

hr

mrem

I

m

m

I

d

I

25

(

2

)

(100 )(

1

)

2

2

2

2

2

2

2

===
Maximizing Distance Methods

 Stay as far away as possible from 

source of radiation.

 Be familiar with radiological conditi

in the areain the area.

 During work delays, move to lower 

rate areas or exit the area completduring long delays.

 Use remote handling devices when 

possible.

 At a minimum, use arm's length. 
Maximizing Distance Methods
#3. Source Barrier

 For radiation 

sources such as xray machines and photon-emitting radionuclides

, a 

 Keep it in.

barrier that attenuates the radiation is called a shield.
Typical Photon Shields

 Lead Concrete

 Depleted ura Leaded glass

 Iron
Neutron Shields

 Fast Neutrons:

 Polyethylene

Paraffin

 Slow Neutrons

 Boron Cadmium

 Paraffin Water Other proton rich 

materials

 Indium
Beta Shields

 Lucite Plastics Low atomic number material Shields are generally not required 

alpha-emitting radionuclides.
Source Barrier Methods

 Containment of radioactive material 

 Bagging contaminated items. Covering clean surfaces. Covering contaminated surfaces.

 Minimizing releases of radioactive m

to the environment by:

 Encapsulation of sources. Containments. Filtration.
#4. Personal Barrier

 This principle involves 

isolating the person from the radiation or radioactive material.

 Keep it out.

 Protective clothing Lead aprons and gloves Respirators
#4. Personal Barrier
#5. Dispersal

 Dispersal is the way 

humans have historically managed many waste problems.

 Disperse it and 

it.

 Be cautious in 

applying this principle....check with regulatory authorities.
#6. Source Reduction

 Simply using the 

smallest amount of radioactive material possible for a given pur

pose will reduce 

 Use as little a

possible

 Clean it up

p pdose.

 Managing decay is 

another example of source reduction.

 Clean it up Keep it clean Delay for dec
#6. Source Reduction

Storing waste for decay. 
#7. Decorporation

 Decorporation is the 

removal of radioactive material from the interior or surface of the body, or the 

 Get it out or 

you.

y,

blocking of uptakes from systemic circulation by specific tissues or organs.
Decorporation Methods

 Washing Debridement (cleaning a wound) Chelating agents Forcing fluids for tritium intakes

Forcing fluids for tritium intakes

 Blocking tissue uptake (KI for 

iodine intakes)

 Surgery
#8. Effect Mitigation

 An antidote for radiation exposure is 

known to exist, and is unlikely to be given the current state of understan(Strom pg.392).

 Some possible effect mitigators are 

radical scavengers and agents that roxidative damage.
Mitigation Methods

 Avoidance of acute 

effects may be obtained by spreading the dose out over timeto allow for re

pair.

 Limit the dam

 Spreading dose out 

over a group of people instead of a few may also mitigate effects to individuals.
#9. Optimal Technology

 Using or modifying a 

radiation technology to produce a lower dose.

 Choose the b

technology.

 Optimizing an existing 

technology.
#10. Limitation of Other Expo

 This principle involves 

limiting exposures to other agents that may work in concert with ionizing radiation.

 Don’t compo

risks.

 Examples of these 

would be agents that could cause tumor:

 Initiation. Promotion. Progression. 
Summary of Principles and Command

Principle CommandmentTime Hurry, but don’t be Distance Stay away/upwindSource Barrier Keep it inP lB i K iPersonal Barrier

Keep it out

Source Reduction Use as little as posDispersal Disperse and diluteDecorporation Get it out/offEffect Mitigation Limit damageOptimal Technology Choose best technoLimit Other Exposures Don’t compound ris
References

 Strom, Daniel J. “Ten Principles and 

Commandments of Radiation ProtecHealth Physics 70(3):388-393, 1996