Chapter 2 Radiation Types Sources Doses Flashcards
Dose from annual natural background radiation is approximately?
3.1 mSv
Annual dose from medical radiation is approximately?
2.3 mSv
Annual dose from human made radiation is approximately?
0.1 mSv
Annual dose from all natural, medical, human made radiation is approximately?
5.5 mSv
What are alpha particles?
Emitted from the nuclei of very heavy elements such as uranium and plutonium during radioactive decay
Contain 2 protons and 2 neutrons
Has a mass 4 times the mass of a hydrogen atom and a positive charge twice that of an electron (+2)
What are beta particles?
Identical to high speed electrons except for origin.
Are 8000 times lighter than alpha particles and have an electrical charge of (-1)
What is beta decay?
Occurs when a nucleus relieves instability by a neutron transforming itself into a combination of a proton and an energetic electron (beta particle).
What particle is able to penetrate biological matter to a much greater depth than alpha, with far less ionization along their paths?
Beta particles.
What is neutrino?
Has a negligible mass and no electric charge, but carries away any excess energy.
What is linear accelerator?
High speed (high energy) electrons are commonly produced in a radiation oncology treatment machine.
Use nonnuclear electrons that are most often used to treat superficial lesions in small areas or to deliver radiation boost treatments to breast tumors at tissue depths not exceeding 7 to 8 cm.
What are protons?
Positive charge, significantly less penetrating than high energy electrons.
What’s an isolated proton?
Identical to an ionized hydrogen atom, has a mass that exceeds the mass of an electron by a factor of 1800.
What’s a neutron?
Neutral charge and has same mass as a proton
What’s an isotope?
Two atoms that have the same number of protons, but different number of neutrons in their nuclei.
What’s a Radioisotope?
Is a combination of z protons and some of neutrons that leads to an unstable nucleus.
Z number?
Refers to the number of protons in the nucleus of an atom.
What’s absorbed dose?
The amount of energy per unit mass that has been absorbed into a material due to its interaction with ionizing radiation.
Measured in gray (Gy) or fractions of gray centigray (cGy)
What’s equivalent dose (EqD)?
Takes into account the type of ionizing radiation that was absorbed.
Provides an overall dose value that includes different degrees of tissue interaction that could be caused by different types of ionizing radiation
Measured in millisievert (mSv)
1 mSv is equal to how many sievert?
1/1000th
What’s effective dose (EfD)?
Best estimate of overall harm that might be produced by a given absorbed dose of radiation in human tissue.
Takes into account both the type of radiation and part of the body irradiated.
Measured in millisievert (mSv)
Biologic damage
Happens by ejecting electrons from the atoms composing the tissue, destructive radiation interaction at the atomic level results in molecular change, and this, in turn, causes molecular damage
What’s organic damage?
Changes in blood count that results from non negligible exposure to ionizing radiation
Whole body exposure of .25 mSv?
Effects: blood changes
Whole body exposure of 1.5 mSv?
Effects: nausea, diarrhea
Whole body exposure 2.0 mSv?
Effects: erythema (diffuse redness over skin)
Whole body exposure of 3 mSv?
Effects: if to gonads temporary infertility and 50% of death
Whole body exposure of 6.0 mSv?
Effects: Death
Three components of natural background radiation:
Terrestrial radiation
Cosmic radiation
Internal radiation
What’s terrestrial radiation definition?
From radioactive materials in the crust of the Earth.
What’s cosmic radiation definition?
From the sun (solar) and beyond the solar system (galactic)
What’s internal radiation definition?
From radioactive atoms, also known as radionuclides, which make up a small percentage of the body’s tissue.
Long lived radioactive elements such as uranium-238, radium-226, and thorium-232 (all emitters of densely ionizing radiations) all present in the earths crust
Terrestrial radiation
2.3 mSv of natural background radiation exposure comes primarily from gaseous radionuclides called
Radon and a much lesser degree of thoron.
Why does Radon behave as a noble gas?
Because it initially does not join or interact with the atoms of other particles.
Noble gas definition?
Behaves as a free agent that floats around in soil.
The average us resident receives approximately how much mSv per year from indoor and outdoor levels of radon?
2.0 mSv
Best time to test for radon in your home?
In colder months when homes and buildings are tightly closed.
What happens if you inhale radon?
Increase risk of lung cancer due to daughter isotopes remaining in epithelial tissue.
Second leading cause of lung cancer?
Radon
The number of radioactive emissions per second that occur on average in 1 liter of air?
Picocuries per liter (pCi/L) of air
Radon should be less than what picocuries (pCi/L)?
Less than 4 pCi/L
Are of extra terrestrial origin and result from nuclear interactions that have taken place in the sun and other stars?
Cosmic radiation
Number of cosmic rays varies with altitude relative to the earths surface because?
Greatest intensity occurs at high altitudes where there’s less attenuation due to low atmospheric density, most moderate intensity occurs at sea-level.
Average US inhabitant receives and EqD of approximately how much mSv per year from extraterrestrial radiation?
0.3 mSv
Cosmic radiation consist of what percentage of high energy photons and have an estimated energy of what?
90% of high energy photons and estimated energy of 300 MeV
Secondary cosmic radiation is a result of interactions with molecules in the earths atmosphere and these protons may be accompanied by??
Alpha particles, atomic nuclei, mesons, gamma rays, high energy electrons.
Ionizing radiation released by radionuclides from various foods or inhaled particles in the air are?
Alpha particles (helium nuclei)
Beta particles (electrons)
Gamma rays (similar to X-rays but
usually of higher energy in range of MeV)
Emissions of X-rays due to some types of radioactive decay affecting the distribution of electrons around atoms.
Examples or radioactive nuclides that exist in small quantities on the human body are:
Potassium-40
Carbon-14
Hydrogen-3
Strontium-90
Average member of the general population received approximately how much mSv per year from combined exposures of radiations from the earths surface (terrestrial) and radiation within the human body?
0.5 mSv.
Ionizing radiation created by humans for various uses is classified as?
Human made or artificial, radiation
Consumer products containing radioactive material, nuclear fuel power plant accidents, nuclear power plant accidents as a consequence of natural disaster, medical radiation are all what type of ionizing radiation
Artificial ionizing radiation
Human made radiation contributes how much mSv to the average annual radiation exposure of the US population?
0.1 mSv
Human made and medical radiation procedures contribute a total of how much mSv?
2.4 mSv
Consumer products and devices that contain radioactive material or producing radiation exposure are:
Airport surveillance scanning systems
Electron microscopes
Ionization type smoke detector alarms
Industrial static eliminators
A flight in a typical commercial airliner results in an EqD rate of?
0.005 to 0.01 mSv per hour
Dose commitment?
A dose that ultimately be delivered from a given intake of radionuclides, may be estimated by using a series of approximations and simplistic models that are subject to considerable speculation.
Three mile island
Mishap on March 27,1979 where overheating of highly radioactive core has a partial meltdown and a significant radiation leak.
Three mile island mSv radiation dose
The average radiation dose to people living within 10 miles of the plant was 0.08 mSv with no more than 1 mSv to any single individual.
Chernobyl
Steam explosion at a nuclear power plant in 1986 where dynamically and got an extended period, radionuclides plumed upward from the reactor into the atmosphere and subsequently contained extensive areas surrounding the plant.
The quantity of radioactive material that was released from Chernobyl ruptured reactor was more than__________ times the amount of radioactive material released at TMI or “30 to 40 times as much radioactivity as Hiroshima and Nagasaki atomic bombs in 1945”.
1 million
200 Chernobyl plant workers received a whole body EqD exceeding ____ Sv.
1 Sv
Types of cancer as a result of the Chernobyl disaster?
Thyroid cancer, leukemia, and breast cancer
Most harmful health effect of the Chernobyl nuclear power plant accident?
Thyroid cancer.
Around_______ cases of thyroid cancer-most of which where treated and cured- was caused by the contamination from Chernobyl.
5000
A large concrete shelter that converted the Chernobyl reactor is known as the
Sarcophagus
Because of sever deficiencies subsequently occurring with the sarcophagus, plans where made to cover the remains of the Chernobyl reactor 4 unit and the concrete sarcophagus that entombs it with a weather proof massive steel vault called what?
The New Confinement Shelter
A 9.0 magnitude earthquake off the north east coast of Japan triggered a tsunami that slammed into the island coast causing 30 ft waves that traveled 6 miles i last d and wrecking everything in its path within minutes including what nuclear plant?
Fukushima Daiichi Nuclear Power Plant
Waves flooded diesel generators powering the pumps enabling the cooling of the nuclear reactor cores of what plant?
Fukushima Daiichi Nuclear power plant
Fuel rods overheated at Fukushima which eventually exploded which three reactors where destroyed and othered where severely damaged allowing what?
Release of considerable amount of radiation into the atmosphere and surrounding areas.
Chernobyl and Fukushima survivors and people living in the surrounding areas have demonstrated an increase in the number of cases of what?
Type 2 diabetes
Clean up of Fukushima is a demanding and difficult task because?
Fuel rods of reactors 1,2, and 3 have to be carefully removed over time.
Removal and storage of contaminated water is an issue because the amount of contaminated water can still increase.
Trace amounts of radioactive tritium and cesium linked to Fukushima reactors have been detected where?
Bering sea and in the waters off the coast of California.
Medical radiation accounts for approximately ____mSv of the average annual individual EfD or ionizing radiation received?
2.3 mSv
Why is the frequency of exposure to human made radiation in medical applications continue to increase rapidly among all age groups in the US?
1) physicians to protect themselves from malpractice lawsuits so they rely on more expensive and sophisticated technology that has more exposure to make a diagnosis than using much less exposure and less radiation options.
2) the use of unnecessary CT scans and repetitive CT scans by many ER departments for convenience.
The amount of radiation received by a patient from a diagnostic X-ray procedure may be indicated in terms such as:
1) entrance skin exposure (ESE) which includes skin and glandular dose.
2) bone marrow dose
3) gonadal dose
Full range of frequencies and wavelengths of electromagnetic waves is known as?
Electromagnetic spectrum
Frequency is measured in?
Hertz
