Introduction to Radiation Protection Ch. 1-2 Terms

Radiation

the transfer of energy from one location to another; the emission of energy in the form of electromagnetic waves or as moving subatomic particles passing through space from one location to another

When was the discover of x-rays (first medical use)?

November 8, 1895

X-rays produce

ions

Ions

electrically charged particles

Properties of x-rays

invisible, penetrating, electrically neutral, cannot be focused with a lens, travel in straight lines at the speed of light (until they interact), produce ions and can cause fluorescence in certain crystals, affect film, polyenergetic

T/F x-rays can be focused with a lens

false

X-rays travel in __________ at the ______ until they ______

straight lines; speed of light; interact

Polyenergetic/heterogenous

photons with different energies within x-ray beam

Ionization

the process in which an atom loses or gains an electron

The production of ____ is responsible for biologic harm to human tissue

ions

List the consequences of ionization in human cells

Creates unstable atoms (1), free electrons (2), low-E XR photons (3), free radicals (4), new, detrimental biologic molecules (5), and causes injury to the cell that may manifest itself as abnormal/loss of function (6)

What are the technical factors

kVp and mAs

Kilovoltage peak (kVp)

controls quality of radiation (penetrability)

Milliampere-seconds (mAs)

controls amount of radiation

What’s considered unnecessary exposure

any exposure that doesn’t benefit a person in terms of diagnostic information, and any exposure that doesn’t enhance the quality of the study

Exposure

amount of ionization produced in air when ionizing radiation is present

Exposure units

coulomb per kilograms (C/kg) or roentgen

Absorbed Dose (D)

amount of energy deposited in a material per unit mass

Absorbed Dose (D) units

gray (Gy) or rad (radiation absorbed dose)

Effective Dose (EfD)

measures the absorbed dose received, the exact type of radiation, and the specific organ systems irradiated (location, amount, and type)… most beneficial to know

Effective Dose (EfD) units

sievert (Sv) or rem

ALARA

as low as reasonably achievable

ORP

optimization for radiation protection

Diagnostic Efficacy

the degree to which the diagnostic study accurately reveals the presence or absence of disease in the patient; provides the basis for determining whether an imaging procedure is justified

Flow of responsibility

ordering physician  radiologic technologist  radiologist

RSO

radiation safety officer

What does the RSO do?

responsible for executing, enforcing, and maintaining an ALARA-based radiation safety program

Cardinal Principle TIME (for patient)

reduce the amount of “beam on” time

Cardinal Principle TIME (for tech)

reduce time spent in room where x-rays are produced

Cardinal Principle DISTANCE (for patient)

use as much distance as warranted between x-ray tube and patient (SID {source to image receptor})

Cardinal Principle DISTANCE (for tech)

stand at the greatest distance possible from the patient

Cardinal Principle SHIELDING (for patient)

shield the patient when it won’t interfere with the anatomy of interest

Cardinal Principle SHIELDING (for tech)

place a shield between you and the patient

____ is the most important cardinal principle for the patient

time

____ is the most important cardinal principle for the tech

distance

_ is the most effective means of protection

communication

Patients must be aware of…

what a specific procedure involves, what type of cooperation is required, and follow-up instructions, if any

General

the probability of injury, ailment, or death resulting from an activity

Medical Imaging

the possibility of inducing radiogenic cancer or a genetic defect after irradiation (stochastic effects)

BERT

background equivalent radiation time; compares the amount of radiation received during an exam with the natural background radiation received over a period of time

T/F BERT does not imply radiation risk

True (ch. 1)

Image Gently Campaign

goal to reduce pediatric dose especially during CT exams

The risk of radiation is for pediatrics than adults

3x greater

Risk

in the medical industry, with reference to the radiation sciences, the possibility of inducing adverse biologic effects, such as injury to the skin or induction of cancer or a genetic defect after irradiation

The Alliance for Radiation Safety in Pediatric Imaging

A partnership of medical societies whose overall common purpose is to reduce the radiation dose for pediatric patients

Image Wisely Campaign

concerned with the large increase of general public exposure to ionizing radiation; goal is to lower the amount of radiation used in medically necessary imaging studies and eliminate unnecessary procedures; annual pledge

Currently, dose recording is the norm in only ____ and _____

interventional radiography (IR); CT

Who requires monitoring of patient dose in CT and in interventional procedures?

the Joint Commission

NEXT program meaning

national evaluation of x-ray trends

The NEXT program’s purpose

Conducted to provide data on systems as they exist in the U.S. on the date of the latest survey

Radiation exposure received by persons not employed in the medical imaging profession (e.g., patients, the general public)

nonoccupational dosage

An electromagnetic wave is a type of energy that travels through space as a combination of

electric and magnetic fields

Wave-particle duality

this form of radiation travels through space as a wave but can interact with matter as a particle of energy called a photon

Ionizing portion of the EM spectrum

Has sufficient kinetic energy to eject an electron from its orbit around an atom’s nucleus

Non-ionizing portion of the EM spectrum

Lacks sufficient energy to eject an electron from orbit

Ionizing ex.

gamma rays (naturally occurring), x-rays (human-made), UV (> 10 eV)

Non-ionizing ex.

Ex: UV(< 10 eV), Visible light, Infrared, Microwaves, Radio

Particulate radiation is a type of energy that comes from __ moving at high speeds

subatomic particles (protons, neutrons, electrons)

T/F particulate radiation is considered to be ionizing

True (ch. 2)

Alpha Particles

Emitted from nuclei of very heavy elements (ex: uranium and plutonium) via a process called radioactive decay; consists of 2 protons and 2 neutrons

Alpha particles have ____ penetrability

low

Alpha particles can be stopped by a

piece of paper

Beta Particles

Identical to high-speed electrons except for their origin (within the nucleus)

Beta particles have ____ penetrability

higher

Beta particles can be stopped by a

lead or wood

Beta particles are _ lighter than alpha particles

8,000x

What radiographic procedures use electrons

oncology treatments (treat superficial skin lesions)

What radiographic procedures use protons

cancer treatments

What radiographic procedures use neutrons

cancer treatments and nuclear fission

Equivalent Dose (EqD)

takes into account the type of ionizing radiation that was absorbed (how much and what type)

Equivalent Dose (EqD) unit

sievert (Sv)

Cellular damage

leads to abnormal cell function or complete loss of cell function (ex. mutations, cataracts, leukemia); injury on the cellular level caused by sufficient exposure to ionizing radiation at the molecular level

Changes in blood count (organic damage and substantial decrease in WBCs) at…

an EqD of 250 mSv / 0.25 Sv

Natural source of radiation accounts for…

3.1 mSv of average annual EfD

Medical/human-made sources of radiation accounts for…

2.4 mSv of average annual EfD

Name the three types of natural radiation

terrestrial, cosmic, and internal

Terrestrial

radioactive materials in the Earth’s crust

Cosmic

radiation from the sun and solar system

Internal

due to inhaled or ingested/injected radionuclides

____% of natural background radiation is from radon and thoron

42

Radon’s half-life is about

4 day

Thoron’s half-life is around

55 seconds

Radon is a decay element of ____

radium

Radon emits _ particles which can attach to dust particles and be inhaled

alpha

What is the second-leading cause of lung cancer in the U.S.

radon

Who is at high risk when it comes to ingesting radon?

smokers

EPA radon limits

5pCi/L (results in 0.05 mSv EqD to the lung yearly)

Cosmic radiation has the greatest intensity at

higher altitudes

The average person receives _____ of cosmic radiation

0.3 mSv/year

The most prominent radioactive isotope found in the human body is

potassium-40

Name the five types of human-made radiation

consumer products, nuclear fuel, atmospheric fallout, nuclear plant accidents, and medical radiation

On the electromagnetic spectrum _ has the longest wavelength

radio waves

Ionization-type smoke detector

Consumer product containing radioactive material

Radionuclides

Internal radiation from radioactive atoms which make up a small percentage of the body's tissues

Organic damage

Genetic or somatic changes in a living organism (e.g., mutations) caused by excessive multicellular damage from exposure to ionizing radiation

How is actual radiation dose to the global population from atmospheric fallout from nuclear weapons testing received?

It is not received all at once but instead is delivered over a period of years at changing dose rates

As of 2016, which of the following is the total average annual radiation equivalent dose from medical, human-made, and natural radiation?

5.5 mSv/year

The Russian liquidators who worked during 1986 and 1987 at the Chernobyl power complex demonstrated a statistically significant rise in the number of

mainly leukemia cases (but also, thyroid and breast cancer)

Medical radiation accounts for of the average annual EfD

2.3mSv

What are the two largest sources of medical radiation

diagnostic (CT, XR, IR, fluoroscopy) and nuclear medicine