1. Radiological Awareness
Introductory slide.

2. Objectives Identify types of radiation
Identify terminology and risks associated with radiation
Identify self aid procedures for protection against radiation exposure
Sets the stage for understanding the what/why about your radiation detection equipment
OBJECTIVES
Upon completion of this block of instruction, you will be able to accomplish these learning objectives.
a. Identify the types of radiation.
b. Identify the terminology and risks associated with radiation.
c. Identify appropriate self-aid procedures for protection against exposure to radiation.
This class provides a common background for new equipment training at both the basic and advanced level.

3. Pretest Check your knowledge about radiation Fill in your answers now
Keep until class is done, compare your answers
PRETEST
This pretest will check your knowledge about radiation. Take a few minutes to fill in the information, then keep the test and correct it as you go through the lesson. At the end, we will review the answers.

4. Do not print this slide. Chart only used for Note page.
PRETEST
Radiological Awareness
Circle the letter of the one best answer to each question.
Student name: __________________________
1. What type of hazard is present with alpha radiation?
a. External only. c. Both internal and external.
b. Internal only. d. No hazard at all.
2. What makes up gamma radiation?
a. High energy photons. c. High speed charged particles.
b. Low energy photons. d. Low speed charged particles.
3. What does the term “half-life” mean with respect to radiation?
a. Time to recover halfway from radiation sickness.
b. Maximum time allowed near a radioactive material before having to evacuate the area.
c. Amount of radiation dose that would kill half of the people who were exposed to that level.
d. Time for a radioactive substance to lose half of its radioactivity.
4. What is the difference between a curie (becquerel) and a rad (gray)?
a. Rads measure absorbed dose and curies measure the amount of material present.
b. Rads measure dose equivalent and curies measure absorbed dose.
c. Rads measure the amount of material present and curies measure absorbed dose.
d. Rads measure absorbed dose and curies measure dose equivalent.
5. What is the average background radiation?
a. 10 rem per exposure. c. 360 mrem per year.
b. 100 mrem per exposure. d. 5 rem per year.
6. As a result of exposure to radiation or contact with radioactive materials, which condition has the higher risk?
a. Irradiation. c. Internal contamination.
b. External contamination. d. Incorporation.
Do not print this slide. Chart only used for Note page.

5. Do not print this slide. Chart only used for Note page.
PRETEST (continued)
Radiological Awareness
Circle the letter of the one best answer to each question.
7. In addition to wearing Personal Protective Equipment (PPE), what are three simple and effective methods of radiation protection?
a. Time, distance, and shielding.
b. Time, half-life, and turn back dose rate.
c. Increase exposure, evacuation, and lead aprons.
d. Union rules, state laws, and local regulations.
8. When using distance as a form of radiation protection, what does the “four times” rule mean?
a. Dose rate is reduced by four times (one quarter) when the distance is halved.
b. Dose rate is reduced by four times (one quarter) when the distance is doubled.
c. Distance is multiplied by four times when the dose rate is doubled.
d. Distance is multiplied by four times when the dose rate is halved.
9. What is the purpose of a radiation survey meter?
a. Track personal exposures. c. Find radioactive contamination.
b. Entryway monitor. d. Identify radionuclides.
10. During self-decontamination, what is the best method of removing radioactive materials from your hands?
a. Thorough scrubbing. c. Ice cold water, no soap.
b. Soap and tepid water. d. Amputation.
Grading instructions: This test is self graded.
Keep this test with you throughout the class.
Correct any mistakes as the information is covered in class.
At the end of the class, review the correct answers.
Hand in the completed test to the instructor.
Do not print this slide. Chart only used for Note page.

6. Ionizing Radiation
Ionizing radiation is electromagnetic energy or energetic particles emitted from a source
Electromagnetic energy: radio waves, light, x-rays, etc.
Source: unstable atoms of any material
Ionize: To strip electrons from other atoms causing chemical changes in molecules
IONIZING RADIATION
Ionizing radiation can occur naturally, such as from radioactive atoms, or can be machine generated (e.g., x-rays).
a. The basic building block of all matter is the atom. The atom consists of a central nucleus made up of neutrons and protons with electrons orbiting around it. Each element has a specific number of protons. There is an average ratio of protons to neutrons (1 to 1.2) in a stable atom. When an atom is radioactive, usually there is an excess of neutrons causing an imbalance of this ratio of protons to neutrons.
b. A radioactive atom can become stable by ejecting particles of matter or excess energy to reach a more stable configuration. The ejection of a particle of matter (such as an alpha or a beta particle) changes this ratio toward a more stable state. Since the number of protons changes as an atom ejects particles, the resultant element, called the “daughter” product, will be different than the original one. Excess energy is given off as electromagnetic energy of very short wavelength, called gamma radiation. When all the excess energy and mass is given off, the daughter product finally becomes stable.
c. This type of radiation will cause ionization of a target material. Ionization is the stripping off of electrons, which are used for chemical bonding. In other words, ionization will cause unwanted chemical changes in the molecules that are irradiated.

7. Alpha Radiation Heavy charged particles Highly ionizing
Not penetrating
Travel several centimeters in air or a few microns in tissue
Stopped by paper or clothing
Internal hazard
ALPHA RADIATION
Alpha particles are heavy charged particles ejected from the nucleus of a radioactive atom. They are composed of two neutrons and two protons.
a. Because of their relatively large mass and charge, alpha particles are more highly ionizing than other forms of radiation.
b. Alpha particles do not penetrate the skin and can be shielded by a thin layer of paper or clothing. Because the outer layer of skin is dead and several microns thick, the alpha particle is unable to penetrate through the dead layers of skin to reach the lower layers of living cells and generally will not cause any skin damage.
c. If an alpha emitter gets inside the body through inhalation, ingestion, or via a wound, the alpha emissions are near live tissue, and localized damage will occur.
d. Alpha radiation is therefore an internal hazard only.

8. Beta Radiation High energy small particle Moderately penetrating
Up to a few meters in air
Several millimeters in tissue
Primarily internal hazard, some external
BETA RADIATION
A beta particle, although it comes from the nucleus, has the mass and charge of an electron travelling at high speed.
a. Beta particles travel up to a few meters in air and are moderately penetrating. Beta radiation can penetrate human skin to where new skin cells are produced.
b. If beta emitting contaminants are allowed to remain on the skin for a prolonged period of time, they may cause skin injury. Materials emitting beta particles may be harmful if deposited internally.
c. Beta radiation is primarily an internal hazard and to a lesser extent, an external hazard (i.e., to the skin and lens of the eye).

9. Gamma Radiation or X-rays
High energy rays
Very penetrating
Difficult to shield
Protective clothing will not protect against photon radiation
External and internal hazard
GAMMA RADIATION OR X-RAYS
Gamma radiation is high energy photons that frequently accompany the emission of alpha and beta particles. To a lesser extent, some radioactive materials also give off x-radiation.
a. Gamma and x-radiation are able to travel long distance in air and through many centimeters of human tissue. Both readily penetrate most materials.
b. Dense materials are needed for shielding from gamma radiation. Chemical protective clothing provides little shielding from gamma radiation but will prevent contamination of the skin by the radioactive materials.
c. Materials that emit gamma radiation and x-rays constitute both an external and internal hazard to humans. X-rays that are machine produced are only external hazards.

10. Neutron Radiation Uncharged high speed particle
Can be very penetrating
Requires special consideration for shielding
External and internal hazard – but – not likely to encounter neutron radiation
NEUTRON RADIATION
Neutrons are neutral particles emitted from the nucleus of certain radioactive atoms.
a. Neutrons lose most of their energy through collisions with other atomic nuclei, much like when one billiard ball strikes another.
b. Under certain circumstances, neutrons can be captured by a stable nucleus, making the bombarded nucleus radioactive. This process is called activation.
c. Neutron radiation is an external hazard since neutrons are very penetrating.
d. It is not very likely to encounter neutron radiation sources outside of a nuclear reactor or a nuclear detonation. The neutron sources used for industrial purposes normally create neutron radiation through the process of bombarding a target material with another radiation source. For example, an americium/beryllium source uses the alpha radiation from radioactive americium to bombard the beryllium target, producing neutrons from within the target.

11. Examples of Radioactive Materials
Substance Emit Use
Americium 241 a, g Smoke detectors
Cobalt 60 b, g Medical therapy
Cesium 137 b, g Many industrial uses
Radium 226 a Medical therapy
Uranium 238 a, b, g Reactors and weapons
Iridium 192 b, g Industrial radiography
EXAMPLES OF RADIOACTIVE MATERIALS
These are examples of materials that emit ionizing radiation and are used in nuclear medicine, cancer therapy, industry, or research.
a. Radioactive materials are chemically identical to their nonradioactive counterparts. Radioactive materials behave in the body the same as their nonradioactive counterparts (for example, radioactive iodine behaves the same as stable iodine).
b. Generally, most commercially produced items containing radioactive materials isolate the material in one component and the radioactive material is in elemental form or in a salt solution.

12. Radiation Half-life
Time required for a radioactive substance to lose half of its radioactivity
Each radionuclide has a unique half-life
From a fraction of a second to millions of years
Examples:
Tc-99m 6.0 hrs
I days
Co yrs
Sr yrs
Pu ,400 yrs
U-238 4,150,000,000 yrs
RADIATION HALF-LIFE
The radiation half-life is the measure of time required for a radioactive substance to lose one-half its radioactivity through natural radioactive decay. For practical purposes, after 10 half-lives, most of the radioactivity in a quantity of a radioactive material is gone.
Each unique radioactive material, called a radionuclide, has its own half-life. Some are very short and some are extremely long. Radionuclides used in nuclear medicine often have a short half-life to limit the amount of radiation given to the patient. The opposite extreme, such as uranium and other naturally occurring radionuclides have half-lives measured in millions of years.

13. Units of Measure Rad (Gray) = absorbed dose Roentgen (R) = energy
Dose rate expressed in R/h, mR/h, μR/h
Counts per minute (cpm) - measure of energy from surface contamination (not the same as R/hr)
For gamma and x-ray, 1 R ~ 1 rad
UNITS OF MEASURE
The basic unit for measuring radiation dose is the gray. The older unit, the rad (radiation absorbed dose) is still commonly used. Present units of measurement and international units include the gray (Gy) which is equivalent to 100 rads, and the sievert (Sv) which is equivalent to 100 rem.
a. The gray is defined as the deposition of one joule of energy per kilogram (kg) of tissue. Compare that to the original unit of radiation energy, the roentgen, which for our purposes, equals about one rad of gamma energy. The rad is a measure of absorbed dose while the roentgen is a measure of ionization potential in air. That’s why we are concerned with the rad.
b. Radiation instruments actually measure in roentgen, or R, and fractional units like milli roentgen (mR) or micro roentgen (μR). Dose rate is measured in R/hour (R/h) and the same fractional units. Dose rate is to dose as the speedometer of a car is to the odometer. That is, dose (odometer) measures how much radiation is already received, while dose rate (speedometer) measures how fast the radiation is coming at you.
c. Another unit of measure for dose rate is counts per minute (cpm). This applies to surface contamination and is not the same as R/h, although it can be compared under some conditions. Conversion between cpm and R/h is not described in this course, but the RSO can describe this once the radionuclide, measuring instrument, and calibration parameters are known.

14. Units of Measure (Cont.)
Rem (sievert) - amount of damage suspected from a particular type of radiation dose
(1R = 1 rad = 1 rem) gamma = 20 rem alpha
Curie (becquerel) - amount of material in terms of its radioactivity
Compare 1 Ci = 37 billion Bq
UNITS OF MEASURE (continued)
d. To quantify the amount of damage that is suspected from a radiation exposure, gray (rads) are converted into sievert (rems, which at one time stood for Roentgen Equivalent Man). The sievert (rem) is adjusted to reflect the type of radiation absorbed and the likelihood of damage. In most cases, the gray and sievert will be equivalent (1 Gy = 1 Sv = 1,000 milliGy = 1,000 milliSv). When expressing dose rate of gamma radiation, it is common to use rads or gray. When expressing doses to humans, these are usually expressed in rems or sievert in order to account for all types of radiation equally.
e. For example, a standard x-ray machine was used to deliver 1 gray (100 rads) of radiation for comparison of the biological endpoint with other types of radiation. It was found that 1 gray of gamma and beta radiation produced the same effect as 1 gray of x-rays. However, only 0.2 gray (20 rads) of neutrons and 0.05 gray (5 rads) of alpha were found to produce the same effect as 1 gray of x-ray. Therefore, neutron and alpha radiations were more potent and required fewer gray to produce the same effect.
f. The last unit is the becquerel (Bq). The older unit is the curie (Ci) . This is a measure of the amount of radioactive material in terms of its radioactivity, or how many disintegrations per second of radiation are coming from the material. One curie was originally defined as the amount of radioactivity of 1 gram of radium. Now it is redefined as 37 billion disintegrations per second (dps); 1 Bq is 1 dps.

15. Background Radiation Natural sources of radiation (~ 260 mrem/yr)
Cosmic radiation
Radioactive material in the environment
Radon is largest contributor
Radioactive material in the body
Manmade sources (~ 100 mrem/yr)
Medical and dental procedures
Releases to the environment
Commercial / industrial sources
BACKGROUND RADIATION
There are two primary sources of radiation exposure from the environment that we live in: those of natural origin and those that were added by manmade sources.
a. Natural sources make up an average estimated exposure of about 260 mrem/yr. This is from a combination of cosmic radiation, some of which is filtered out by the atmosphere, and radioactive materials in the soil, water, air, and even in our own bodies. Of this category, radon gas from the natural decay of Uranium (and its daughter products) in the soil is the largest single contributor to the overall background exposure.
b. Manmade sources have added some additional burden to the environment, estimated to be about 100 mrem/yr. One of the principal manmade sources are medical and dental procedures, such as x-rays, nuclear medicine diagnostics, and other procedures involving radiation exposure (e.g., fluoroscope). Another is from nuclear testing and reactor accidents, such as the disaster at Chernobyl, that have released tons of radioactive material into the environment over the years. The most common (and often least recognized) sources of radiation come from the everyday consumer items that are commercially produced and used in the home, workplace, or in industry. For example, smoke detectors in every home contain a small piece of radioactive material in the detector. ,

16. Radiation Doses In Perspective
Natural background and manmade radiation 360 mrem/yr (~20 +/- μR/h is background)
Diagnostic chest x-ray 10 mrem
Flight from LA to Paris 4.8 mrem
Barium enema 800 mrem
Smoking 1.5 packs per day 16,000 mrem/yr
Heart catheterization 45,000 mrem
Mild acute radiation sickness 200,000 mrem
LD50/60 for radiation 450,000 mrem
RADIATION DOSES IN PERSPECTIVE
Radioactivity has existed for as long as we know in the crust of the earth, in building materials, in the food we eat, in the air we breathe, and in everything else.
a. Radiation from these materials, as well as cosmic radiation from the sun and universe, make up the natural background radiation to which we are constantly exposed.
b. Most individuals are exposed to about 360 millirems (3.6 milli Sv) per year from natural (80%) and manmade (20%) sources.
c. If an individual is exposed to more than 100 rems (1 Sv) at one time, predictable signs and symptoms will develop within a few hours, days, or weeks depending on the dose.

17. ALARA Goal of exposure management: keep radiation exposures to a level
As Low As Reasonably Achievable
(ALARA)
ALARA
The goal of radiation safety managers is to limit personal exposures in themselves and al others to a level that is As Low As Reasonably Achievable (ALARA). This does not mean taking extreme measures in a futile attempt to eliminate all radiation exposure. This is impossible, since there is always some natural background radiation both on Earth and in space. Rather, the concept of ALARA means to minimize unnecessary exposures whenever practical. The emphasis is on the word “reasonably.”

18. Radiation Exposure Risks
Increasing risk s
Thyroid
Lung
Liver
Bone
RADIATION EXPOSURE RISKS
Regardless of where or how an accident involving radiation happens, several types of radiation-induced injury can occur. These are, from lowest to highest risk to the person: external irradiation; external or internal contamination with radioactive materials; and incorporation of radioactive material into the body.
a. External irradiation occurs when all or part of the body is exposed to penetrating radiation from an external source. During exposure, some of this radiation can be absorbed by the body and some can pass completely through. A similar thing occurs during an ordinary chest x-ray. After external exposure, an individual is not radioactive and can be treated like any other patient. Note, after high neutron exposure, some materials in the body can become activated, but this is an extreme case.
b. Contamination occurs when radioactive materials are released into the environment. People who have radioactive materials on or in their bodies are contaminated. An external surface of the body, such as the skin, can become contaminated. Most radioactive materials can be easily removed from the skin. If radioactive materials get inside the body through the lungs, gastrointestinal tract, or wounds, the contaminant can become deposited internally and is not easily decontaminated.
c. Incorporation refers to the uptake of radioactive materials by body cells, tissues, and target organs such as bone, liver, thyroid, or kidney. In general, radioactive materials are distributed throughout the body based upon their solubility and other chemical properties. Incorporation is not possible unless internal contamination has occurred.
Irradiation
External contamination
Internal contamination
Incorporation

19. Self Protection Measures
1st Avoid exposure and contamination
Detect radiation exposure
Back away when too high
2nd Use Personal Protective Equipment (PPE)
3rd Decontaminate yourself
SELF PROTECTION MEASURES
The concepts of avoidance, protection, and decontamination are key to self defense against any hazardous material, including radioactive materials (and their ionizing radiation).
a. The first priority in protecting yourself from radiation exposure is to avoid the exposure and contamination whenever possible. When in doubt, back away. The use of radiation detection equipment is part of the recognition and avoidance process.
b. When it is not possible to avoid the radioactive material, avoid the spread of contamination onto yourself through the use of Personal Protective Equipment (PPE).
c. If contaminated, decontaminate yourself before the material finds its way into your body.

20. Radiation Protection Basics
Time
Distance
Shielding
PPE
RADIATION PROTECTION BASICS
There are several ways of reducing your exposure to radiation. These are explained in detail on the next several slides.

21. 100 mrem per hour x 15 minutes (.25 hour) = 25 mrem
Time
Source
Dose
25 mrem
Result
TIME
The shorter the time in a radiation field, the less the radiation exposure.
a. The radiation dose is reduced in proportion to reduction of exposure time. An example is as follows: If exposed to a radioactive source emitting a dose rate of 100 mrem per hour, an exposure time of 15 minutes will produce a total radiation dose of 25 mrem.
D = (d)(t)
Where D = Dose
d = dose rate
t = length of time of exposure
b. Work quickly and efficiently. A rotating team approach can be used to keep individual radiation exposures to a minimum.
100 mrem per hour x 15 minutes (.25 hour) = 25 mrem

22. Distance The “four times” rule Source 1 meter 1 meter
Dose rate is ¼ when distance is doubled
DISTANCE
The farther a person is from a source of radiation, the lower the radiation dose.
a. While alpha particles only travel a little over an inch in air, and beta particles will travel only a few yards in air, gamma rays can travel extensive distances. As a result, gamma rays pose the greatest threat of external exposure.
b. Do not touch radioactive materials. Use shovels, brooms, etc. to move materials, to avoid physical contact. Backing off a few meters from radioactive materials can drastically reduce the exposure to the person.
c. In the case of gamma rays from an unshielded point source, the intensity increases or decreases in proportion to the square of the distance from the source.
d. An easy way to remember this is the “four-times” rule. As a rule of thumb, every time you double the distance away from a gamma point source, you reduce the exposure rate by four times. Technically, the dose rate (D) is equal to the source strength (S) at one meter divided by the distance away squared (d2), or D=S/d2.
100 mrem/hr
25 mrem/hr

23. Shielding Alpha Beta Gamma paper lead SHIELDING
Although not always practical in emergency situations, shielding offered by barriers can reduce radiation exposure. Radiation can be blocked or reduced by various materials.
a. Alpha particles travel approximately 1 to 2 inches in air and cannot penetrate unbroken skin or paper. Therefore, no shielding of alpha radiation is necessary for self protection. No shielding of alpha is necessary, but prevention of inhalation (of alpha emitting substances) with respiratory protection is important.
b. Beta particles travel up to 10 feet in air and can penetrate a few millimeters of tissue. They can be stopped by light layers of clothing, aluminum foil, or an average book. If shielding is needed from a strong beta source, use wood or dense plastic rather than lead or other heavy metal, since metals emit x-rays if bombarded by beta radiation.
c. Shielding is only practical for gamma or x-ray sources. One example is a lead apron used for x-ray patients. Gamma radiation is reduced by heavy, dense materials such as steel, concrete, earth, or lead.
d. Neutrons can travel several hundred feet in air and are very damaging to cells. They can be slowed or stopped by water, paraffin, or plastic. Do not shield neutron producing sources with lead or dense metals. Neutrons will produce gamma rays in reactions with these materials.
e. When in doubt about which material to use for shielding, consult a health physicist or other qualified radiation safety expert.
paper
lead

24. Simplified Radiation PPE
Protect your respiratory tract
Respirator, surgical mask, etc.
Protect your skin
Gloves!
Outer clothing
Chemical suit is not always needed
SIMPLIFIED RADIATION PPE
Keeping the radioactive material off of and out of your body will reduce your exposure from the material.
a. Foremost is the protection of the respiratory tract. Wearing any type of mask or respirator will limit the intake of radioactive particles. Preferably, a particulate mask that uses N-95 or better filtration will keep out particles greater than 1 micron. It is not likely to be exposed to smoke or fumes of radioactive materials in smaller particle size at the hospital.
b. Protect the skin using normal gloves, scrubs, or other protective clothing. It is not necessary to wear chemical protective clothing unless involved in decontamination operations.

25. Detect Ionizing Radiation
Not detected by human senses
Requires use of detection instruments
No single instrument can detect or measure all types of radiation
DETECT IONIZING RADIATION
Radiation cannot be detected by our senses. It can only be detected and identified with instrumentation.
a. Radiation detection instruments measure radiation in amounts of contamination and in exposure rates. When the possibility of the presence of radiation exists, checking for radiation is always recommended.
b. No single instrument will detect all types of radiation. Since gamma radiation is the most dangerous form from external sources, all dosimeters, survey instruments, and area monitors check for gamma.
can't smell it
can't see it

26. Radiation Detection Instruments
Dosimeter measures dose received (odometer)
Track personal exposure
Survey instrument detects and measures dose rate (speedometer)
Find source of radiation
Find surface contamination
Area monitor is a fixed site survey meter
Entry alert
RADIOLOGICAL SURVEY INSTRUMENTS
We will look more closely at some specific radiation detection instruments in the next lesson. A general overview of detection instruments:
a. A dosimeter measures radiation dose received. Like the odometer of a car, it measures how far down the road you have already gone. Dosimeters are used as a passive device to track and record doses for legal and medical reasons. Many dosimeters have alarms to alert the wearer before dangerous amounts of radiation are received.
b. A survey instrument measures the dose rate of varying types of radiation, depending on which probe (detector) is used. Like the speedometer of a car, it shows real-time how fast you are going down the road. Survey meters have alarms to alert the user that the rate is too high. A survey meter is an active device used to search for radiation levels or surface contamination by radioactive materials.
c. An area monitor is a passive version of a survey meter, which is usually mounted to a wall near the door or other designated location. Like an immobile survey meter, it monitors the area and alarms when the radiation is too high. The most common use of an area monitor is to alert those nearby when some radioactive material is brought into the hospital through the entrance that is monitored.

27. Self Decontamination Wash it off If showering, use shampoo
Hand washing
Tepid water, mild soap
No scrubbing
If showering, use shampoo
Remove and launder clothing
Monitor after decon
SELF DECONTAMINATION
No matter how careful we are around radioactive materials, there is some chance of becoming contaminated. If wearing PPE, remove it as part of assisted decontamination procedures. If your skin and clothing become contaminated for any reason, there are several self-decon measures to reduce personal exposure risk.
a. Wash off the radioactive material from the skin as soon as practical. The hands are the most likely place for contamination while doing normal duties in the hospital. Use warm water and mild soap to remove the material from the skin. Too hot will open the pores while too cold will motivate the person to scrub faster and finish too soon. Do not scrub the skin, as this will drive in the material rather than remove it.
b. If showering, the same rules apply. Use a mild shampoo all over, especially in the hair.
c. Remove the clothes and launder them to remove any radioactive materials that might have rested on the outer surfaces. It is not likely that you will become so contaminated that you will have to use special laundering procedures. In extreme cases, the clothes may have to be checked for contamination levels to determine whether or not special laundering procedures will be required.
d. Monitor for residual contamination after decon is done, and repeat as needed. Monitoring procedures will be discussed in the next lesson.

28. Radiation Summary
Recognize types, terms, and risks of ionizing radiation
Understand self protection measures
Time, distance, shielding
PPE
Detecting radiation
Self decon
Review answers to pretest
RADIATION/SUMMARY
Recognize the types of ionizing radiation and the terms associated with them.
a. Types: alpha, beta, gamma, and x-ray.
b. Terms: half-life, dose, and dose rate.
c. Units of measure: rad (gray), rem (sievert), curie (becquerel), and cpm.
Understand how to implement radiation self protection measures, including time, distance, shielding, PPE, and self decontamination.
Answers to the Pretest: Refer to appendix A.

29. Pretest Review 1. (alpha hazard) B, internal only
Appendix A: Pretest Answers
Radiological Awareness
Circle the letter of the one best answer to each question.
Student name: __________________________
1. What type of hazard is present with alpha radiation?
a. External only. c. Both internal and external.
b. Internal only. d. No hazard at all.
2. What makes up gamma radiation?
a. High energy photons. c. High speed charged particles.
b. Low energy photons. d. Low speed charged particles.
3. What does the term “half-life” mean with respect to radiation?
a. Time to recover half-way from radiation sickness.
b. Maximum time allowed near a radioactive material before having to evacuate the area.
c. Amount of radiation dose that would kill half of the people who were exposed to that level.
d. Time for a radioactive substance to lose half of its radioactivity.
4. What is the difference between a curie (becquerel) and a rad (gray)?
a. Rads measure absorbed dose and curies measure the amount of material present.
b. Rads measure dose equivalent and curies measure absorbed dose.
c. Rads measure the amount of material present and curies measure absorbed dose.
d. Rads measure absorbed dose and curies measure dose equivalent.
5. What is the average background radiation?
a. 10 rem per exposure. c. 360 mrem per year.
b. 100 mrem per exposure. d. 5 rem per year.
6. As a result of exposure to radiation or contact with radioactive materials, which condition has the higher risk?
a. Irradiation. c. Internal contamination.
b. External contamination. d. Incorporation.
1. (alpha hazard) B, internal only
2. (gamma radiation) A, high energy photons
3. (half-life) D, time for a radioactive substance to lose half its radioactivity
4. (curie vs. rad) A, rads measure absorbed dose and curies measure the amount of material present
5. (avg. background) C, 360 mrem per year
6. (highest risk) D, incorporation
7. (simple protection) A, time, distance, and shielding
8. (four times rule) B, dose rate is reduced by four times (one quarter) when the distance is doubled
9. (survey meter) C, find radioactive contamination
10. (self decon of hands) B, soap and tepid water

30. Do not print this slide. Chart only used for Note page.
Appendix A: Pretest Answers (continued)
Radiological Awareness
Circle the letter of the one best answer to each question.
7. In addition to wearing Personal Protective Equipment (PPE), what are three simple and effective methods of radiation protection?
a. Time, distance, and shielding.
b. Time, half-life, and turn back dose rate.
c. Increase exposure, evacuation, and lead aprons.
d. Union rules, state laws, and local regulations.
8. When using distance as a form of radiation protection, what does the “four times” rule mean?
a. Dose rate is reduced by four times (one quarter) when the distance is halved.
b. Dose rate is reduced by four times (one quarter) when the distance is doubled.
c. Distance is multiplied by four times when the dose rate is doubled.
d. Distance is multiplied by four times when the dose rate is halved.
9. What is the purpose of a radiation survey meter?
a. Track personal exposures. c. Find radioactive contamination.
b. Entryway monitor. d. Identify radionuclides.
10. During self-decontamination, what is the best method of removing radioactive materials from your hands?
a. Thorough scrubbing. c. Ice cold water, no soap.
b. Soap and tepid water. d. Amputation.
Grading instructions: This test is self graded.
Keep this test with you throughout the class.
Correct any mistakes as the information is covered in class.
At the end of the class, review the correct answers.
Hand in the completed test to the instructor.
Do not print this slide. Chart only used for Note page.