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What is Radiation Protection?
The combination of Radiobiology and Applied Physics.

Defined as:
Effective measures employed by radiation workers to safeguard patients, personnel, and the general public from unecessary exposure to ionizing radiation.
What is your responsibility to the patient regarding radiation protection?
To limit the patient's exposure to ionizing radiation to the the smallest amount possible.
What is ALARA?
As Low As Reasonably Possible
What does ALARA assume?
That ANY amoount of radiation has the potential to cause harm!
Stochastic Effects - ie. Probability with no threshold
Give ways to keep exposures as low as possible.
Use the smallest dose possible.

Produce high quality radiographs with the 1st exposure.

Avoid repeats.

Shield patients when ever possible.

Be meticulous with Therapy setups.
Read the chart very carefully.
See Bushong Ch. 1 Page 11

1. Familiarity leads to false security.

2. Never stand in the Primary beam.

3. Always wear protective apparel.

4. Always wear a radiation monitor.

5. Never hold a patient. Use restraints, or a relative can hold.

6. The person holding the patient must ear protective apparel.

7. Use gonadal shields.

8. Do not examine pregnant women, especially in 1st trimester.

9. Collimate to the smallest field size.

10. The basics of radiation control – Time, Distance, Shielding.


What are the sources of natural background radiation?
1. Terrestrial, radioactive elements in the earth, such as uranium, radium, thorium.

2. Cosmic, radiation from outer space, the result of nuclear reactions in the sun and stars.

3. Radionuclides in the human body.
There are 3 forms of this radiation.
What are the exposure totals for natural background radiation?
1. 198 radon

2. 29 terrestrial

3. 29 cosmic

4. 39 internal.
Total exposure to natural background radiation in US is 295mrem per year.
What are the artificial sources of radiation and their levels?
1. Medical and 39mrem
dental x-rays

2. Nuclear medicine 14mrem

3. Consumer products 10mrem

4. Occupational exposure 2mrem
Four Items
Define Risk and Benefit.
Risk can be defined as any potential threat to the well being of a human.

Benefit is defined as improvement of the quality of life of a human.
What are Perceived Risk and Risk Comparison?
Perceived Risk - individuals or groups express their perception of risk.

Risk Comparison -makes correlations between two or more activities.
What is the BERT?
Background Equivalent Radiation Time

- used to explain to a patient how much their exposure would be, compared to natural background levels.
Dr John Cameron, has recommended the use of an actual unit called the BERT.
What are the shortcomongs of the BERT model?
Values tend to vary from one center to another. (kVp, mAs, time).

Diagnostic x-rays use a different type of radiation (for the most part) than is seen in natural background radiation.
X-ray versus gamma and particulate.
What does the phrase "no threshold to radiation risk" mean?
Any dose of radiation could have a potential effect.
Stochastic Effect
What is the significance of Figure 1-3 regarding the safe use of ionizing radiatrion?
The health of the population improves when radiation is well used, and declines when it is over or under-used.
Bell Curve
Explain how Figure 4, Risk Benefit for an individual is used.
Positive outcomes are associated with good risk benefit, increasing to a maximum of 6.

Negative outcomes, should involve patient and physician discussion of higher risk.
What are the three common goals for all radiologic technologists?
1. To promote diagnostic/therapeutic efficacy of all examinations. (highest quality x-rays and destroy malignant tissue in radiation therapy).

2. Provide radiation protection in balance with goal number 1. (imaging exams have maximum information at the lowest dose, radiation therapy spares normal healthy tissue).

3. To provide the highest level of patient care possible - both technical and nurturing.
How do Guidelines 6 & 7 in the ASRT Code of Ethics apply to our professional role as radiologic technologists?
1. Guideliune 6 - provides pertinent information to the physician for diagnosis BUT does NOT diagnose.

2. Duideline 7 uses techniques and procedures to minimise everyone's radiation exposure.
What should our professional attitude be toward radiation protection?
We are the individuals best able to limit the dose of the public ionizing radiation.

We are the publics first line of defense.
What is GSD?

What does it represent?
Genetically Significant Dose

The GSD is a measure of the genetic exposure to the population from diagnostic and other forms of radiation.
Why is the GSD rising?
1. There are ever increasing numbers of individuals who are undergoing diagnostic procedures including screening.

2. Defensive medicine (x-rays taken of areas other than what is necessary in case a law suite is filed).

3. An aging population resulting in increased exams.

4. Better diagnostic and therapeutic efficacy of examinations.
Why is it so easy to adopt the attitude that radiation causes no real harm?
Familiarity breeds contempt!

Ionizing radiation, in almost all cases today, does not produce immediate effects.
What are apathetic technologists and their role in radiation protection?
These technologists avoid unnecessary radiation only as much as they are compelled to.

1. By law.
2. Department rules.
What are actively motivated technologists and their role in radiation protection?
1. Recognizes professional responsibility.

2. Limits the size of the beam if possible to a smaller area than is possible with PBL(positive beam limitation or collimation).

3. Will go out of their way to find appropriate lead shielding for all their patients.

4. Is a contributing member of professional societies.

5. Engages in continuing education
5 items
What is the role of the Radiologic Technologist in Education?
Radiologic technologists must realize that one of their roles is as an educator.

The radiographer is able to provide patient/public education related to radiologic procedures and radiation protection and safety.
What are Ethics?
Ethics: the systematic study of rightness and wrongness of human conduct and character as known by natural reason. (Radiologic Sciences and Patient Care, Carlton & Adler)

They involve general guidelines that are translated into practice in the clinic.
What is thetechnologist's ethical obligation toward the patient?
A technologist has an ethical obligation to act in the best interest of the patient.
What does the 1991 safe medical devices act state?
The 1991 Safe Medical Devices Act authorized civil penalties to technologists who do not report defects and failures in medical devices.
What is Licensure?
Licensure - the process by which some competent authority, such as the state, grants Permission to a qualified individual to perform certain specified duties.
What is the goal of licensure?
The ONLY GOAL of licensure is to protect the public from excessive ionizing radiation.
Explain the process of possible legal action involved in an accidental radiation exposure.
The most likely charge that could be brought would be cancer induction.

Or, in the case of a pregnant patient a defect to the fetus.
What factors must be present for Negligence to have occurred?
Four items must be satisfied:

1. It must be shown that a DUTY on the part of the professional exists.

2. IF a duty is shown, a BREACH of duty must be shown.

3. The cause must be due to an ACTION on the part of the professional.

4. IF a cause is proven, an INJURY must be proven.
What impact does possible legal action have on us as health care workers?
1. A lawsuit against a technologist is close to impossible to bring to a court of law.

2. This may limit the legal liability of the technologist in the case of radiation injury.

3. This INCREASES the technologist's MORAL liability
UNIT 2

What are the physical properties associated with X-rays?
1. Are a form of electromagnetic radiation.

2. Have no mass and no charge.

3. Are sinusoidal, with electric and magnetic components traveling perpendicular to each other.

4. Behave like both a wave and particle.

5. Are the most penetrating of the electromagnetic waves.

6. Are heterogeneous. (many wavelengths).

7. Are polyenergetic (many energies).

8. Travel in a straight line at the speed of light.

9. Diverge from a source and are emitted isotropically.

10. Cannot be focused by a lens.

11. Do not reflect off surfaces.

12. Are electrically neutral.

13. Produce secondary and scatter radiation when interacting with matter.

14. Can cause certain crystals to fluoresce.

15. Affect photographic film.

16. Can ionize all matter including gasses.

17. Cause biologic changes.
Give the metric prefixes.
Giga G 10 9
Mega M 10 6
Kilo K 10 3
Deci d 10 -1
Centi c 10 -2
Milli m 10 -3
Micro u 10 -6
Nsno n 10 -9
What is “Skin Erythema Dose”?
The earliest unit of radiation measurement.

Defined as the dose of radiation which causes diffuse redness over the skin following irradiation.
What is Exposure?

What are its units?
When air or matter is irradiated with gamma or x-rays, ionization takes place.

Conventional SI Measurement
Roentgen (R) Gya Exposure in
air
What is a Roentgen?
The unit of exposure is the Roentgen, a measurement of coulombs per kilogram.

1R = 2.58 x 10 –4 c/Kg
What is a Coulomb?
The charge of electrons liberated by ionization.

1C = 6.3 x 10 18 electrons.
What is Absorbed Dose?

What are its units?
Absorbed dose equals the amount of energy absorbed by the irradiated object.

Conventional SI Measurement
Rad Gyt Absorbed
dose
What is a Rad?
1rad = energy transfer of 100 ergs per gram of tissue.

(Erg = dyne x centimeter)
What is Absorbed Dose Equivalent?

What are its units?
This is a method to calculate effective absorbed dose for ALL types of ionizing radiation.

ADE calculations use a quality factor assigned to each type of radiation to make the adjustment for biologic damage.

Conventional SI Measurement
Rem Seivert Absorbed
Dose Equivalent
What is a Rem?
Rem = Rad x QF
What is Radioactivity?

What are its units?
Radioactive decay of a material is measured with the conventional unit of the curie or the SI unit of becquerel.

Conventional SI Measurement
Curie Becquerel Amount of radioactivity
What is a Curie?
A curie is defined as the quantity of a radioactive nuclide in which the number of disintegrations per second is 3.7 x 10 Power10

The becquerel is defined as the quantity of a radionuclide in which the dps is 1.
Give the conversions of Roentgen, Rad, Rem and Curie to SI Units.
R x .01 = Gya Air Kerma
(Gray in Air)

Rad x .01 = Gyt Gray in Tissue

Rem x.01 = Sv Seivert

C x 3.7 x1010 = Bq Becquerel
Give the conversions from Absorbed Dose to Ansorbed Dose Equivalent.
Seivert = Gray x QF

or

Rem = Rad x QF
Give Z numbers of Bone, Soft Tissue, Fat, and Water.

How do these affect Absorption?
Bone Z = 13.8 to 20
Soft tissue Z = 7.4
Fat Z = 5.9
Water Z = 7.9

Absorption ~ Z cubed
Give the Quality Factors for the different types of Ionizing radiation.
X-rays 1
Gamma rays 1
Beta particles 1
Proton particles 2
Alpha particles 20
Thermal neutrons 5
Give the Half Lives for different radioactive nucleides.
Uranium – 4.5billion years
Radium – 1622years
Radon – 3.8days
Iodine131 – 8days
Cesium 137 – 30years
Cobalt60 – 5.27years
Strontium90 – 29.1years
Technetium99 – 212,000years (Tc99m – 6hours)
Plutonium – 87.7years to 24,100years (diff isotopes)
What is Kerma?
KERMA is kinetic energy released in matter.