Radiation & Radioactivity

As a general rule, what distance should you maintain between you and the radiation source?

*A 3 to 6 foot distance*

What is the primary source of radiation exposure for anesthesia personnel?

*Scatter radiation*

What are 3 considerations when using radiation safe practices?

*Time, distance, and shielding*

What is the relative penetration power of alpha radiation?

1

What two ways are x-ray waves/beams generated?

1. Below the table and through the patients back (supine) to the front 2. Lateral view (x-ray rotated 90 degrees) to allow beam to enter from the ipsilateral side and exit from the contralateral side

What are some natural sources of ionized radiation? (3)

1. Cosmic rays 2. Terrestrial radiation (from deposits of radioactive elements such as uranium and radon) in the earth 3. Potassium (in your body)

What are some manufactured sources of ionized radiation? (4)

1. Smoke detectors 2. Watch dials that glow 3. TVs 4. Computer screens

When shielding yourself from radiation, what are some effective safety practices to use?

1. Wear shielding between you and the source 2. Wear a lead apron/wrap with 0.5 mm of lead (reduces exposure to 25% original dose) 3. Choose wrap apparel vs apron 4. Ensure proper storage and inspection of aprons (don't want defects)

What can pregnant women do to minimize radiation risk?

1. Wear wrap around lead that is 1 mm thick 2. Avoid > 500 mrem throughout gestation 3. Wear 2 radiation film badges (1 outside at collar, 1 inside at waist level). Total dose under lead should be 10% of collar/outside level.

What is the relative penetration power of gamma radiation?

10,000

What is the relative penetration power of beta radiation?

100

Medical imaging makes up roughly what % of the collective radiation dose to the population?

50%

Which form of radiation is the most dangerous, but easy to stop?

Alpha - easy to stop because of it's weight factor (20)

What is ALARA?

As Low As Reasonably Achievable (Use lowest output possible)

How did ionizing radiation get its name?

Because it is capable of removing an outer-shell electron from matter. Remember ionization refers to the removal of an electron from an atom

What specific form of ionized radiation can be stopped by relatively thin lead or wood?

Beta particles

Which particle consists of 1 electron?

Beta particles (much less mass compared to alpha)

In what areas may we encounter radiation?

CT Nuclear medicine Interventional radiology Cardiac catheterization lab Electrophysiology lab Orthopedic and urologic procedures

What type of cells are particularly vulnerable to ionized radiation?

Cells that divide quickly (bone marrow, embryos, tumors) and organs/tissues that have cells that are not replaced quickly (ovaries, central nervous system).

Does a chest x-ray or chest CT produce more radiation exposure?

Chest CT

What is worn by personnel working in high risk radiation exposure areas that monitors degree of exposure?

Dosimeters

When is exposure risk the greatest for pregnant women?

Early on in gestation

What type of radiation is a form of energy?

Electromagnetic radiation (EMR)

What kind of radiation is all around us and has the ability to take on several forms?

Electromagnetic radiation (radio waves, visible light, non-visible light, gamma rays, x-rays)

Describe the inverse square law.

Exposure is exponential. Doubling the distance from the x-ray source cuts the exposure to 1/4 the original dose; tripling the distance cuts the exposure to 1/9th the original dose.

T/F: Standing behind someone that is wearing lead does not minimize that amount of radiation exposure.

False. Ionized radiation travels in a straight line (not around corners).

What is considered the biggest element of exposure for CRNAs?

Fluoroscopy

What is highly reactive and has the ability to destroy good and bad bacteria?

Free radicals (i.e. peroxide)

What form of ionized radiation has no mass?

Gamma waves (no neutrons or protons) because it is a wave. If stopped at all, it may be stopped by thick lead or concrete.

Which form of radiation produces minimal damage, but gets through everything?

Gamma waves - more difficult to stop (weight factor is 1)

What is non-ionizing radiation? Examples in medicine?

Harmless radiation that comes from visible light, infrared radiation, microwaves, and radio waves (i.e. ultrasound and MRI)

What is the difference between gamma rays and x-rays?

How they are generated

Why is ionizing radiation harmful?

It can cause cellular injury

What is injected into the body when using nuclear medicine?

Low levels of radio nucleotides, radio pharmaceuticals, or radio tracers

What is created when electrons move?

Magnetism

Are reproductive radiation effects seen more in men or women?

Men. Exposure does not seem to impact ovaries.

After understanding relative radiation damage, which type of radiation do we consider most and least dangerous?

Most dangerous - gamma Least dangerous - alpha Because of penetrating power

What are the 2 categories of EMR?

Non-ionizing radiation and ionizing radiation

What are the 2 classes of ionized radiation?

Particulate (alpha and beta) and wavelength (EMR)

What does REM refer to?

Radiation Equivalent Man - unit of occupational radiation exposure Allows us to compare the degree of damage that radiation sources produce

What does RAD refer to?

Radiation absorbed dose - the quantity of radiation received by an individual (used for all types of ionizing radiation).

EMR: As energy waves travel through space, they are characterized by ___ electrical and ___ fields. Wavelength is measured from ___ to ___ and ___ is the number of waves per second.

Sinusoidal perpendicular, magnetic, peak, peak, frequency

In regard to penetrating power, which particle is the largest? What does it contain?

The alpha particle - contains 2 protons and 2 neutrons.

Which particle has little degree of exposure unless ingested?

The alpha particle because it is so large. It stops once it collides with other matter (i.e. paper, skin).

What is radiation?

The energy given off by matter in the form of rays or high speed particles.

Using nuclear medicine, how is a signal detected?

The injection is taken up by a body organ which then emits a faint and measurable gamma ray signal. These signals are then converted to images.

When thicker tissue is transversed on x-ray, what must be increased in order to obtain a quality image?

The miliamps (power) of the beam

What is a Roentgen (R)?

The unit of radiation exposure or intensity in air (only applicable for gamma and x-rays).

T/F: A large patient, large body part, or extreme angle of approach increases the risk of radiation exposure.

True. As energy level increases, there is an increased risk of radiation dosing/exposure for the patient.

What can you do to protect your thyroid?

Wear a thyroid shield with 0.25 mm of lead (thyroid is highly radiosensitive d/t high metabolic rate).

What can you do to protect your eyes from radiation?

Wear glasses with 0.5 mm of lead (offers 4x protection of regular eye glasses; plastic = no protection). Lens of the eye is sensitive. Lead glasses important if working in EP or cardiac cath lab.

What causes scatter?

When rays encounter other objects such as the patient. This causes beams to scatter.

What causes the release of energy in the form of radiation?

When unstable atoms "decay" and release their energy

How are free radicals formed?

When water and ionized radiation come together to produce a reactive species with an UNPAIRED electron.

What types of radiation falls under the ionizing radiation category? Examples in medicine?

X-rays, gamma rays, alpha and beta particles from nuclear decay. Examples include x-ray, CT, fluoroscopy, and nuclear medicine.