Radiation quantity "that expresses the concentration of radiation delivered to a specific area, such as the surface of the human body" The amount of ionizing radiation that may strike an object such as the human body when in the vicinity of a radiation source Amount of radiation in air When a volume of air is irradiated with x-rays or gamma rays, the interaction that occurs between the radiation and neutral atoms in the air causes some electrons to be liberated from those air atoms as they are ionized. Consequently, the ionized air can function as a conductor and carry electricity because of the negatively charged free electrons and positively charged ions that have been created. As the intensity of x-ray exposure of the air volume increases, the number of electron-ion pairs produced also increases. Thus the amount of radiation responsible for the ionization of a well-defined volume of air may be determined by measuring the number of electron-ion pairs or charged particles in that volume of air; radiation ionization in the air A measure of ionization in air and not in other tissue
The breaking down of large molecules into smaller ones through the process of oxidation
What does the OSL dosimeter contain?
A thin layer of aluminum oxide (Al2O3) detector
6 late deterministic somatic effects
Cataract formation Fibrosis Organ atrophy Loss of parenchymal cells Reduced fertility Sterility
3 processes the protoplasm carries on
Complex process of metabolism Reception and processing of food and oxygen Elimination of waste products
1 SI exposure unit equals
C/kg = 1/(2.58 x 10^-4) R
Cells manufacture certain proteins and RNA molecules need to enter and complete the next mitosis When this phase is complete, cells enter the first phase of mitosis (prophase)
G2 (post-DNA synthesis phase)
What is the film badge dosimeter sensitivity?
Most sensitive to photons having an energy level of 50 keV; for values above and below this energy range, dosimetry film sensitivity decreases
What is the equation to determine one gray?
1 Gy = 1 J/kg
Equation of effective dose (EfD)
EfD = absorbed dose (D) x radiation weighting factor (WR) x tissue weighting factor (WT)
3 main parts the cell contains
Cell membrane Cytoplasm Nucleus
The aluminum filter of the OSL dosimeter offers the ______ absorption, whereas the copper filter attenuates the _______
Very small spherical organelles that attach to the ER "Protein factories"; their job is to manufacture (synthesize) the various proteins that cells require by using the blueprints provided by the mRNA
Unit of EfD
Sieverts or millisieverts
Do you want a high or low LET?
Where should the personnel dosimeter be placed during routine radiographic procedures when a protective apron is not being used?
Attached to the clothing on the front of the body at collar level
Biologic effects in humans caused by exposure to ionizing radiation, which appeared within minutes, hours, days, or weeks of the time of radiation exposure
Early deterministic somatic effects
Effect of radiation that is seen in an individual and in subsequent unexposed generations
Sugars that have two units of a simple sugar linked together; ex: lactose, sucrose (cane sugar)
Chemical building material for all living things; living contents of cell
To what exposure range are pocket chambers used in medical imaging sensitive to?
0-5.2 x 10^-5 C/kg (0-200 mR)
6 functions that lipids perform for the body
Acts as a reservoir for the long-term storage of energy Insulate and guard the body against the environment Support and protect organs such as the eyes and kidneys Provide essential substances necessary for growth and development Lubricate the joints Assist in the digestive process
When is exposure monitoring or personnel required?
Whenever radiation workers are likely to risk receiving 10% or more of the annual occupational EfD limit of 50 mSv (5 rem) in any single year as a consequence of their work related activities
8 important electrolytes in the body
Sodium (Na+) Potassium (K+) Calcium (Ca++) Magnesium (Mg++) Chloride (Cl-) Bicarbonate (HCO3-) Phosphate (HPO4-) Sulfate (SO4-2)
The amount of radiation to which the film badge was exposed is determined by locating the exposure value of a control film of similar optical density on this
Provides a common scale whereby varying degrees of biologic damage caused by equal absorbed doses of different types of ionizing radiation can be compared with the degree of biologic damage caused by the same amount of radiation
Chemical secretions manufactured by various endocrine glands and carried by the bloodstream to influence the activities of other parts of the body; regulate body functions such as growth and development Ex: these produced by the thyroid gland located in the neck control metabolism throughout the body
Contains all the miniature cellular components that enable the cell to function in a highly organized manner; little organs of cells Together these structures perform the major functions of the cell in a systemized way DNA determines each function mRNA carries the DNA code from the nucleus into the cytoplasm
Even though SI values and traditional values differ numerically, SI values of dose are all ______ of the older traditional system
Latest type of OSL dosimeter where an unfiltered portion of the aluminum oxide is used to detect dynamic exposures (those received during rapid motion between the source of radiation and the enhanced dosimeter) Examinations of the glow curves from this region demonstrate a shift or spread in their light frequency tat can be correlated with motion
The probability of photoelectric interaction strongly depends on the atomic number of the irradiated material; the _______ the atomic number of material, the greater is the amount of energy absorbed by that material
Where should the personnel dosimeter be placed as a second monitor when a protective apron is worn (during lengthy interventional fluoroscopy procedures [e.g., cardiac catheterization])?
The first/primary dosimeter is to be worn outside the protective apparel at collar level; the second should be worn beneath a wraparound-style lead apron at waist level to monitor the approximate equivalent dose to the lower body trunk
The unprotected head, neck, and lenses of the eye receive how many times more exposure than the protected body trunk?
The chromatids undergo changes in appearance by uncoiling and becoming long, loosely spiraled threads Simultaneously, the nuclear membrane forms anew, and two nuclei (one for each new daughter cell) appear The cytoplasm also divides (cytokinesis) new the equator of the cell to surround the new nucleus After this cell division completes, each daughter cell has a complete cell membrane and contains exactly the same amount of genetic material (46 chromosome) as the parent cell
2 examples of blood disorders
Aplastic anemia (results from blood marrow failure) Leukemia (an abnormal overproduction of white blood cells)
3 disadvantages of the TLD
High cost (twice the cost of a film badge service) Can be read only once/can't be reevaluated; the readout process destroys the stored information The calibrated dosimeters must be prepared and read with each group or batch
Small cavities or sacs containing liquids
Ribosomes are not present on the surface of the ER
Hydrogen-containing compounds that can attack and dissolve metal Ex: HNO3 (nitric acid)
What is an advantage of the ionization chamber survey meter (cutie pie)?
Its ability to measure a wide range of radiation exposures within a few seconds while over a broad expanse of radiation energies
At what degree can the OSL dosimeter provide an accurate reading?
1 mrem (10 uSv) for x-ray photons with energies ranging from 5 keV to greater than 40 MeV
Biologic damage to the body of the exposed individual caused by exposure to ionizing radiation
Approximately what percentage do carbohydrates make up of the cell content?
Simple sugar, ex: glucose
Surface of the patient that is toward the x-ray tube exposed to the unattenuated primary beam of x-rays Where dose to the patient is the highest
Entrance skin surface
What are the metal filters inside the plastic holder of the film badge made of?
Aluminum or copper
3 things the body must do to ensure efficient cell operation
Provide food as a source of raw material for the release of energy Supply oxygen to help break down the food Have enough water to transport inorganic substance into and out of the cell
The protoplasm that exists outside the cell's nucleus Makes up the majority of the cell and contains large amounts of all the cell's molecular components (not DNA) All cellular metabolic functions occur in this
What do the filters of the OSL dosimeter do?
Each filter blocks a portion of the radiation-sensitive aluminum oxide and causes a different degree of attenuation for any radiation striking the dosimeter, depending on its energy When the exposed aluminum oxide layer is read out by a laser, the degree of luminescence detected in the areas from beneath the filters is a measure of radiation dose occurring within different energy ranges
Small, rounded body that manufactures and holds a large amount of RNA and protein inside the ribosomes it contains
3 cell chemical components
Protoplasm Organic compounds Inorganic compounds
4 major classes of organic compounds that compose the cell
Proteins Carbohydrates Lipids Nucleic acids
Which dosimeter can read the lowest dose?
Optically stimulated luminescence (OSL) dosimeter
Traditional nonmetric units gradually becoming obsolete and the SI units presently in use of: 1. Exposure 2. Air kerma 3. Absorbed dose (D) 4. Equivalent dose (EqD) 5. Effective dose (EfD)
1. Roentgen (R) - coulombs per kilogram (C/kg) 2. SI: Gray (Gy) 3. Rad - Gy 4. Rem - Sievert (Sv) 5. Rem - Sv
Radiation exposure received by radiation workers
4 processes the nucleus plays an essential role in by directing protein synthesis
Active transport Metabolism Growth Heredity
How do the filters inside the plastic holder of the film badge allow the measurement of the approximate energy of the radiation reaching the dosimeter ?
Penetrating radiations cast a faint shadow of the filters on the processed dosimetry film, whereas soft radiation cast a more pronounced image of the filters; the density of the image cast by each of the filters permits estimation of the energy of the radiation The direction from which the radiation reached the film (from front to back or from back to front) can be estimated from the appearance of the filter shadows imaged on the processed dosimetry film
5 personnel monitoring devices currently available
Optically stimulated luminescence (OSL) dosimeter Extremity dosimeter (thermoluminescent dosimeter (TLD) ring) Film badge Thermoluminescent dosimeter (TLD) Pocket ionization chamber (pocket dosimeter)
Reddening of the skin caused by radiation
Vast, irregular network of tubules and vesicles spreading and interconnecting in all directions throughout the cytoplasm Enables the cell to communicate with the extracellular environment and transfer food and molecules from one part of the cell to another; functions as the highway system of the cell Ex: mRNA travels from the nucleus to different locations in the cytoplasm; lipids and proteins are routed into and out of the nucleus through the tubular network
Endoplasmic reticulum (ER)
4 advantages of the TLD
The LiF crystals interact with ionizing radiation as human tissue does, hence this monitor determines dose more accurately Exposures as low as 5 mR (1.3 x 10^-6 C/kg) can be measured precisely Humidity, pressure, and normal temperature changes don't affect it After the TLD reading has been obtained, the crystals can be reused, making it somewhat cost effective
Where should the personnel dosimeter be placed as a monitor for the embryo-fetus?
The primary dosimeter is to be worn at collar level; the second is worn at the abdomen
How do you convert from rad to Gy and vice versa?
Gy = rad x 0.01 rad = Gy/0.01
What amount of radiation is considered completely safe?
How do you convert sieverts to millisieverts?
Number of millisieverts (mSv) = number of sieverts (Sv) x 1000
Fertilized ovum (zygote) splits after fertilization and two separate offspring develop
Monozygotic Identical twins
Small, pealike sacs or single-membrane spherical bodies that are great importance for digestion within the cytoplasm Contain a group of different digestive enzymes that target proteins Primary function: the breaking down of unwanted large molecules that either penetrate into the cell through microscopic channels or are drawn in by the cell membrane itself
A protein machine that segregates chromosomes to two daughter cells during the cell division Delicate fibers that are attached to the centrioles and extend from one side of the cell to the other across the equator of the cell
What is the primary inorganic substance contained in the human body?
Water, it is imperative for the correct amount of water in a cell to be maintained
Unit of radiation in air, accepted unit of exposure The photon exposure, that under standard conditions of pressure and temperature, produces a total positive or negative ion charge of 2.58 x 10^-4 C/kg of dry air Used for x-ray calibration because x-ray output intensity is measures directly with an ionization chamber; also used to calibrate radiation survey equipment
Which dosimeter can be worn the longest?
Optically stimulated luminescence (OSL) dosimeter
What dose ranges are film badges sensitive to?
As low as 0.1 mSv (10 mrem) to as high as 5000 mSv (500 rem); doses less than 0.1 mSv (10 mrem) are not usually detected and are reported as minimal (M) on a personnel monitoring report
How many elements form the biomolecules that comprise protoplasm?
3 things the personnel dosimeter does
Provides an indication of the working habits and working conditions of diagnostic imaging personnel Determines occupational exposure by detecting and measuring the quantity of ionizing radiation to which the dosimeter has been exposed over a period of time Does not protect the wearer from exposure because the instrument is just meant to detect and measure the amount of ionizing radiation to which is has been exposed
How many base pairs are in the human genome, how many genes are these base pairs arranged into, and how many proteins are these genes capable of producing?
2.9 billion base pairs 30,000 genes 90,000 proteins
8 early deterministic somatic effects
Nausea Fatigue Diffuse redness of the skin Loss of hair Intestinal disorders Fever Blood disorders Shedding of the outer layer of the skin
Resulting combination of amino acids; peptide bonds generate tandem patterns of various amino acids, forming this
The assembly of larger molecules from smaller ones
2 elements carbon, hydrogen, oxygen and nitrogen combine with to form the essential major organic compounds
What is the most sensitive type of personnel dosimeter
Pocket ionization chamber (pocket dosimeter)
The period of cell growth that occurs before actual mitosis; cells are not yet undergoing division during this phase
An adjustment multiplier that has been used in the calculation of dose equivalence to specify the ability of a dose of any kind of ionizing radiation to cause biologic damage
Quality factor (Q)
1 coulomb equals
The primary personnel dosimeter should be attached to the clothing on the front of the body at the collar level to approximate the location of maximal radiation dose to which 3 body parts?
Thyroid Head Neck
The master chemical in the nucleus Contains all the information the cell needs to function Carries the genetic information necessary for cell replication Controls cell division Determines a persons characteristics by regulating the sequence of amino acids in the person's constituent proteins during synthesis of these proteins
Deoxyribonucleic acid (DNA)
Most elementary building blocks of cells; formed when amino acids combine into long, chainlike molecular complexes
SI unit of electrical current; number of flowing electrons A unit of electric current equal to a flow of one coulomb per second
Located in the center of the cell near the nucleus; the region of the chromosome where the two chromatids join together
Large, double-membranous, oval or bean-shaped structure that functions as the "powerhouse" of the cell because they supply the energy for cells Contain highly organized enzymes in their inner membranes that produce this energy for cellular activity by breaking down nutrients through the process of oxidative metabolism
Minute vesicles that extend from the nucleus to the cell membrane Consist of tubes and a tiny sac located near the nucleus; unites large carbohydrate molecules and the combines them with proteins to form glycoproteins When the cell manufactures enzymes and hormones, this concentrates, packages, and transports them through the cell membrane so that they can exit the cell, enter the bloodstream, and be carried to the areas of the body where they are required
Organic compounds essentially made up of combinations of NH2 ("amine") and COOH (carboxylic acid) molecules Five hundred different ones, natural monomers
What is the constant body core temperature?
98.6 F (37 C)
A pair of small, hollow, cylindrical structures oriented at right angles to each other and embedded in a material mass of more than 100 proteins Organize the spindle fibers during cell division
Made up of molecule of glycerin and three molecules of fatty acid Organic macromolecules Structural paths of cell membranes Present in all body tissues Perform various functions for the body
Provide the body with its shape and form and are a source of heat and energy Ex: those found in muscle
A dose of radiation lower than which an individual has a negligible chance of sustaining specific biologic damage
5 advantages of the film badge
Main: permanent legal record of personnel exposure Economical Used to record exposure to x-radiation, gamma radiation, and all but very low-energy beta radiation in a reliable manner Can discriminate among the types of radiation and the energies of these radiations Mechanical integrity
How is radiation energy discrimination achieved by OSL dosimeters?
A situation in which high-energy radiation strikes the dosimeter would show a similar reading through all filters Conversely, if the dosimeter had been subjected to only very low-energy radiation, then the glow curve would be much more pronounced in the region covered by the aluminum filter than in the other filter-blocked portions Somewhat more energetic radiation would also enhance the glow curve of the region beneath the tin filter
Function as organic catalysts Control the cell's various physiologic activities Cause an increase in cellular activity that in turn causes biochemical reactions to occur more rapidly to meet the needs of the cell; proper cell function depends on this Initiate vital chemical reactions within the cell at the appropriate time
What is the sensitivity of the TLD?
Exposures as low as 5 mR (1.3 x 10^-6 C/kg) can be measured precisely
Unit of LET
2 things protoplasm consists of that are either dissolved or suspended in water
Organic compounds Inorganic compounds
Device that measures the amount of ionizing radiation to which a TLD badge has been exposed by first heating the crystals to free the trapped, highly energized electrons and then recording the amount of light emitted by the crystals (which is proportional to the TLD badge exposure); plotting this light intensity versus the crystal heating temperature generates the glow curve
The sum total of air kerma over the exposed area of the patient's surface; a measure of the amount of radiant energy that has been thrust into a portion of the patient's body surface Modern radiographic and fluoroscopic units have incorporated units have incorporated an ability to determine the entire amount of energy delivered to the patient by the x-ray beam Ability to determine the entire amount of energy delivered to the patient by the x-ray beam Ex: how much radiation goes to the 10 x 12 area you've collimated to
Dose area product (DAP)
By the early 1950s, this replaced the tolerance dose for radiation protection purposes Basically indicated the largest dose of ionizing radiation that an occupationally exposed person was permitted and that was not anticipated to result in major adverse biologic effects as a consequence of radiation exposure Expressed in "radiation equivalent man" (rem)
Maximum permissible dose
When LiF crystals of the TLS are irradiated, the energy emitted is _________ to the difference between the electron-binding energy of the two orbital levels and the intensity of the light is _________ to the amount of radiation that interacted with the crystals
3 things the amount of energy absorbed by a structure depends on
Atomic number (Z) of the tissues comprising the structure The mass density of the tissue (kg/m^3) Energy of the incident photon (low-energy photons are more easily absorbed in a material such as biologic tissue than are high-energy photons)
6 cytoplasmic organelles
Endoplasmic reticulum Golgi apparatus/complex Mitochondria Lysosomes Ribosomes Centrosomes
How many chromosomes do the reproductive/germ cells have?
Reproductive/germ cells exist singly, thus each has only 23 chromosomes, which pair up to form 46 chromosomes when a sperm fertilizes an egg
Unit of ColEfD
Person-sievert previously man-rem
1 rad equals how many cGy?
1 rad = 1 cGy
SI unit for EqD
2 most important inorganic substances
Water Mineral salts
The apparent change in the frequency of a light wave as observer and light source move toward or away from each other
What is the radiation survey instrument of choice when determining exposure rates from patients?
Ionization chamber survey meter (cutie pie)
3 disadvantages of the pocket ionization chamber
Fairly expensive Inaccurate readings No permanent legal record
3 different gas-filled radiation detectors that serve as field instruments
Ionization chamber-type survey instrument ("cutie pie") Proportional counter Gieger-Muller (GM) detector
Frail, semipermeable, flexible structure encasing and surrounding the human cell Allows penetration only by certain types of substances and regulates the speed at which these substances travel within the cell; plays a primary role in the cell's transport system
Much smaller structures that make up nucleic acids; a unit formed from a nitrogen-containing organic base, a five -carbon sugar molecule (deoxyribose), and a phosphate molecule
Sum of the weighted equivalent doses doses for all irradiated tissues or organs A measure of the overall risk arising from the irradiation of biologic tissue and organs that takes into consideration the exposure to the entire body based on the energy deposited in biologic tissue by ionizing radiation Incorporates both the effect of the type of radiation used and the variability in radiosensitivity of the specific organ or body part irradiated through the use of appropriate weighting factors; these factors determine the overall harm to those biologic components and the risk of developing a radiation induced cancer, or, for the reproductive organs, the risk of genetic damage Attempts to take into account the different levels of radiation effects on the parts of the body that are being irradiated to arrive at an index of overall harm to a human by beginning with EqD and then incorporating modifying or weighting factors which correspond to the relative degrees of radiosensitivity of various organs and tissues The quantity that summarizes the potential for biologic damage to a human from exposure to ionizing radiation Accounts for the risk to the entire organism brought on by irradiation of individual tissues and organs
Effective dose (EfD)
The received quantity of radiation that causes diffuse redness over an area of skin after irradiation First unit used to measure radiation exposure
Skin erythema dose
The movement of a substance across a cell membrane is controlled more by the properties and powers of the cell membrane that is is by the relative concentrations of particles in fluid; the cell must expend energy to pump substances into and out of it
What was the first x-ray of?
Roentgen's wife's hand
Weighting factor that takes into account the relative detriment to each specific organ and tissue; a conceptual measure for the relative risk associated with irradiation of different body tissues to account for the carcinogenic sensitivity of each organ Value that denotes the percentage of the summer stochastic (cancer plus genetic) risk stemming from irradiation of tissue (T) to the all-inclusive risk, when the entire body is irradiated in a uniform fashion
Tissue weighting factor (WT)
8 essential functions of water
Acts as the medium in which acids, bases, and salts are dissolved Functions as a solvent by dissolving chemical substances in the cell Functions as a transport vehicle for material the cell uses or eliminates Maintains a constant body core temperature of 98.6 F (37 C) Provides a cushion for vital organs such as the brain and lungs Regulates concentration of dissolved substances Lubricates the digestive system Lubricates skeletal articulation (joints)
What is the effective atomic number of bone and soft tissue?
Bone: 13.8 Soft tissue: 7.4
2 effects of ionizing radiation that appear months or years after exposure
Late deterministic somatic effects Late stochastic effects
What did the Human Genome Project do?
Uncovered the entire sequence of DNA base pairs on all 46 chromosomes
Constituents of salts in the cell, particles carrying a positive or negative electric charge Cause materials to be altered, broken down, and recombined to form new substances via chemical reactions
"Composite"/weighted average of the atomic numbers of the many chemical elements comprising the tissue
Effective atomic number (Zeff)
The multiplication process whereby one cell divides to form two or more cells
What is the traditional and SI unit for SID?
Traditional: R-cm^2 SI: Gy-m^2
8 requirements of radiation survey instruments for area monitoring
Portable Durable enough to withstand normal use Reliable Interact with ionizing radiation similarly to the way human tissue reacts Able to detect all common types of ionizing radiation The energy of the radiation should not significantly affect the response of the detector, and the direction of the incident radiation should not affect the performance of the unit Cost-effective Annually calibrated
A measure of probabilistic health effect on an individual as a result of an intake of radioactive material into the body
1 erg equals
6 things the cytoplasm is composed of
Water (primary) Proteins Carbohydrates Lipids Salts Minerals
3 functions of the cell membrane
Made up of lipids and proteins Barricade to protect cellular contents from the outside environment Controls the passage of water and other materials into and out of the cell
Absorbed doses of ionizing radiation ______ than the established MPD would not result in any appreciable bodily injury to the reproductive cells; however, some small risk of damage could exist with radiation doses at the MPD level
4 things the cytoplasmic organelles consist of
Tiny tubules Vesicles Granules Fibrils
The amount of energy per unit mass absorbed by an irradiated object This absorbed energy is responsible for any biologic damage resulting from exposure of the tissues to radiation; for this reason, this may be used to indicate the amount of ionizing radiation a patient receives during a diagnostic imaging procedure The deposition of energy per unit mass in the patient's body tissue from exposure to ionizing radiation As ionizing radiation passes through an object such as a human body, some of the energy of that radiation is transferred to that biologic material; it is actually absorbed by the body and stays within it Some structures in the body absorb more radiant energy than others
Absorbed dose (D)
Bone absorbs ______ ionizing radiation than dose soft tissue in the diagnostic energy range of 23-150 kilovolts peak (kVp), because the photoelectric process for bone is the dominant mode of energy absorption within this range
What is the weighting factor of x-radiation and alpha particles?
X-ray: 1 Alpha: 20
4 distinct phases of the cellular life cycle that are identifiable
M (mitosis phase) G1 (pre-synthesis phase) S (synthesis phase) G2 (post-DNA synthesis phase)
3 elements carbon combines with to make life possible
Hydrogen Nitrogen Oxygen
The total amount of radiant energy transferred by ionizing radiation to the body during a radiation exposure Determined by the produce of the exposure value (R) and the size of the area (cm^2) that receives the total amount of radiation delivered
Surface integral dose (SID) Historically known as exposure area product
How long can the film badge be worn for personnel monitoring before it is read?
As energy increases, the difference in the amount of absorption between any two tissues of different atomic number ____________
How do you convert grays to milligrays?
Number of grays (Gy) x 1000 = number of milligrays (mGy)
A graphical plot that demonstrates the relationship of light output, or emitted thermoluminescence intensity, to temperature variation; the curve represents a unique signature of the exposure received by the TLD dosimeter Laser readout
Who was the first person to die from x-rays?
Clarence Madsen Dally
Compounds that do not contain carbon, occur in nature independent of living things
3 radiation doses that can be evaluated from a film badge
Deep (penetrating) Eye Shallow (nonpenetrating)
When glucose is broken down in the body during respiration, fats are among the generated intermediate products; when some of these fats combine with an acidic group of atoms, this is formed Constituents of amino acids from which proteins are build Ex: acetic acid - CH3COOH
3 things mineral salts are necessary for
Proper cell performance Creation of energy Conduction of impulses along nerves (wouldn't know if you're touching or moving anything without it)
Foreign objects (ex: bacteria, flu, viruses), molecules that do not belong to the body
2 types of pocket ionization chambers
Self-reading type (contains a built-in electrometer [device that measures an electrical charge]) Non-self-reading type (requires a special accessory electrometer to read the device)
The product of the average absorbed dose in a tissue or organ in the human body and its associated radiation weighting factor (WR) chosen for the type and energy of the radiation in question A radiation quantity used for radiation purposes when a person receives exposure from various types of ionizing radiation; serves as a measure of absorbed energy resulting from ionization Attempts to take into account the potential variation in biologic harm that is produced by different kinds of radiation; both the type and energy of the radiation are considered Takes into account the weighting factor for the radiation you got (ex: x-ray = 1 versus alpha particle = 20)
Equivalent dose (EqD)
An instrument that measures occupational exposure by comparing optical densities of exposed film badge (dosimetry) films
4 things 1 gray equals
1. 1 J/kg 2. 100 rad 3. 100 cGy 4. 1000 mGy
7 advantages of the OSL dosimeter
Lightweight, durable, and easy to carry Contains an integrated, self-contained, preloaded packet Color-coded, contains graphic formats, and body location icons that provide easy identification Not affected by heat, moisture, and pressure Offers complete reanalysis Increased sensitivity, providing accurate readings as low as 10 uSv (1 mrem) for x-ray photons with energies from 5 keV-40 MeV Can be worn for longer periods of time (up to 1 year)
The first phase of cell division The nucleus enlarges, the DNA complex (the chromatid network of threads) coils up more tightly, and the chromatids become more visible Chromosomes enlarge, and the DNA begins to take structural form The nuclear membrane disappears, the centrioles migrate to opposite side of the cell and begin to regulate the formation of the mitotic spindle
Serves as a basis for comparison with remaining dosimeters after they have been returned to the company for processing Supposed to be kept in a radiation-free area within an imaging facility so its optical density reading is zero
Highly coiled strand; one of the two duplicated portions of DNA in a replicated chromosome that appear during cell division
2 functions of water within the cell
The medium in which the chemical reactions that are the bases of metabolic activities occur Acts as a solvent, keeping compounds dissolved so that they can more easily interact and their concentration may be regulated
Agents that affect the rate or speed of chemical reactions without being altered themselves
4 subphases mitosis (M) can be divided into
Prophase Metaphase Anaphase Telophase
Radiation interacting with the film in the film badge causes the film to darken once it is developed; after processing, the density of the image of the filters recorded on the dosimeter film is _______ to the amount of radiation received and the energy of the radiation
2 types of nucleic acids that are contained in cells and important to human metabolism
Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA)
What was Roentgen working with when he discovered x-rays?
A Crookes tube that caused barium plationocyanide to glow
Why do survey instruments respond when in contact with ionizing radiation?
Survey instruments respond because of the charged particles that are produced by the radiation interacting with and subsequently ionizing the gas (usually air) in the detector; these instruments measure either the total quantity of electrical charge resulting from the ionization of the gas or the rate at which the electrical charge is produced
Breaking down organic materials to produce energy
Each pocket ionization chamber must be charged to a predetermined voltage before use so that the quartz fiber indicator shows a zero (0) reading; as the dosimeter is exposed to ionizing radiation, it discharges, and the fiber indicator advances along the scale in a linear fashion, thereby showing the net exposure in milliroentgens
Special charging unit
Enzymes that can mend damages molecules and are therefore capable of helping the cell to recover from a small amount of radiation-induced damage; work effectively in both the diagnostic and therapeutic range If the radiation damage is excessive because of the delivered equivalent dose, the damage will be too severe for these enzymes to have a positive effect; ex: atomic bond
Biologic response whose severity varies with radiation dose; determined by the dose threshold
3 disadvantages of film badges
Temperature and humidity extremes or wetting can cause fogging of the dosimetry film over long periods of time A radiation worker's exposure cannot be determined on the day of occurrence Can be worn for one month before being read
How is one rad expressed mathematically?
1 rad = 100 erg/g 1 rad = 1/100 J/kg = 1/100 Gy
4 major tasks of the cytoplasm
Accepts and builds up unrefined materials and assembles from these materials new substances such as carbohydrates, lipids, and proteins Catabolism Packages substances for distribution to other areas of the cell or to various sites in the body through the circulation Eliminates waste products
The total amount of genetic material (DNA) contained within the chromosomes of a human being
Serves as the primary potable radiation survey instrument for area monitoring in nuclear medicine facilities Sensitive enough to detect particles or photons Audio
Geiger-Muller (GM) detector
What is the most common type of device used for monitoring of occupational exposure in diagnostic imaging?
Optically stimulated luminescence (OSL) dosimeter
The monitoring of radiation exposure to any person occupationally exposed on a regular basis to ionizing radiation
Tiny rod-shaped bodies that under a microscope appear to be long, threadlike structures that become visible only in dividing cells
When the charged electrodes of the pocket ionization chamber are exposed to gamma or x-radiation the air surrounding the central electrode (+) becomes ionized and discharges the mechanism in ________ proportion to the amount of radiation to which is has been exposed
Numerically, the cGy is ________ to the rad; it is replacing the rad for recording of absorbed dose in therapeutic radiology
When the Gy is used to indicate kinetic radiation energy deposited or absorbed in a mass of air, how is it written?
Gya (subscript "a" indicates "air")
How do you find ColEfD?
ColEfD (person-sieverts) = number of people x average effective dose (Sv)
4 types of personnel dosimeters used to measure individual exposure of the body to ionizing radiation
Optically stimulated luminescence (OSL) dosimeter Film badge Thermoluminescent dosimeter (TLD) Pocket ionization chamber (pocket dosimeter)
The work done or energy expended when a force of 1 newton (N) acts on an object along a distance of 1 meter (m)
What is the greatest amount of radiation that can come out of the x-ray tube?
1 mR/hr (10 micrograys per hour)
A molecule consisting of a large number of atoms Large molecules built from smaller chemical structures
Traditionally, this was used as the unit of absorbed dose; unit used to indicate the amount of radiant energy transferred to an irradiated object by any type of ionizing radiation
Radiation absorbed dose (rad)
2 things chromosomes are composed of
2 things 1 coulomb per kilogram of air equals
1. 1 SI unit of exposure 2. 1/(2.58 x 10^-4) R
6 characteristics of personnel dosimeters
Lightweight and easy to carry Made of materials durable enough to tolerate normal daily use Able to detect and record both small and large exposures in a consistent and reliable manner Outside influences should not affect performance of the instrument Should be reasonably inexpensive to purchase and maintain Permit health care facilities to use large numbers of monitors in cost-effective manner
The sharing of one or more pairs of electrons between atoms
Segments of DNA that serve as the basic units of heredity Control the formation of proteins in every cell through the intricate process of genetic coding
2 examples of stochastic effects
Cancer Genetic/hereditary abnormalities
Involves 22 different amino acids The order of arrangement of amino acids determines the precise function of each protein molecule, and the types of protein macromolecules that any given cell contains determine the characteristics of that cell Chromosomes and genes organize the amino acids into different orderings to make the different types of proteins
Proteins constitute approximately what percentage of cell content?
How can the filter images of the film badge be used to determine whether the exposure was the result of excessive amounts of scattered radiation of or a single exposure from a primary beam?
Excessive exposure to scatter, such as that produced by poor working habits (e.g., radiographer standing too close to a patient during an exposure) or poor facility design results in relatively fuzzy images of the filter because the film badge was irradiated from many different angles; a single exposure from a primary beam, such as would result if a radiographer inadvertently left the film badge on a table during an exposure, results in a sharply defined image
How long can the OSL dosimeter be worn, and how long is it commonly worn?
It can be worn for up to 1 year; it is common practice to wear it for a period of 1-3 months
What percentage of the body weight does water comprise?
What is an advantage of the pocket ionization chamber?
Provide immediate exposure readouts
What tissue is most and least radiosensitive?
Most: gonads Least: Bone surface
3 ways in which mineral salts are of vital importance in sustaining cell life
Help produce energy Aid in the conduction of nerve impulses Responsible for the prevention of muscle cramping
Protein molecules produced by B lymphocytes (specialized cells in the bone marrow) Produced when other lymphocytes in the body (T lymphocytes) detect the presence of molecules that do not belong to the body Once the skin has been penetrated, this is the body's primary defense mechanism against infection and disease
Dimensionless factor (multiplier) used for radiation protection purposes to account for differences in biologic impact among various types of ionizing radiation Must be used to determine EqD Places risks associated with biologic effects on a common scale Type of radiation
Radiation weighting factor (WR)
3 materials the 3 different filters incorporated into the detector pack of the OSL dosimeter are made of respectively
Aluminum (Al) Tin Copper (Cu)
How is the OSL dosimeter "read out"?
When laser light at selected frequencies is incident on the sensing material, it becomes luminescent in proportion to the amount of radiation exposure received
Contain several or many molecules of simple sugar; ex: plant starches, animal glycogen
SI exposure unit equal to an electrical charge of 1 C produced in a kilogram of dry air by ionizing radiation Used for x-ray calibration because x-ray output intensity is measures directly with an ionization chamber; also used to calibrate radiation survey equipment
Coulombs per kilogram (C/kg)
4 components of the normal cell
Cell membrane Cytoplasm Cytoplasmic organelles Nucleus
2 most important inorganic compounds
Water Mineral salts/electrolytes
The breaking down of large molecules into smaller ones Enables the cell to perform the vital functions of synthesizing proteins and producing energy
A science that explores living things and life processes
3 different energy ranges of the OSL dosimeter that physically correlate with different penetration depths and therefore different effective radiation energies
"Deep" (most penetrating) "Eye" "Shallow" (skin)
What is the sensing material of the thermoluminescent dosimeter (TLD)?
Crystalline form (powder or, more frequently, small chips) of lithium fluoride (LiF)
The process of locating and identifying the genes in the genome
The sum of effective dose equivalent from external radiation exposure and committed effective dose equivalent (CEDE) from internal radiation exposures Designed to take into account all possible sources of radiation exposure Radiation dosimetry quantity defined to monitor and control human exposure to ionizing radiation
Total effective equivalent dose (TEDE)
Rate meter device (for exposure rate) used for area surveys and an accurate integrating or cumulative exposure instrument; it measures x-radiation and gamma radiation, and, if equipped with a suitable window, it can also record beta radiation
Ionization chamber survey meter (cutie pie)
What dose the outside of the film packet of a film badge form?
A light-free envelope for the dosimetry film
3 things 1 joule equals
1. 10^7 erg 2. 1 newton-meter 3. 6.24 x 10^18 eV
More than two dizygotic twins
Chains of sugar molecules that function as short-term warehouses for the body; primary purpose is to provide fuel for cell metabolism Include starches and various sugars, range from simple to complex Important structural parts of cell walls and intercellular materials
A substance moves through the cell membrane by osmosis; the cell uses no energy to maintain the concentration
2 types of ER the cell has
Rough surfaced (granular) Smooth (agranular)
Committed dose from an internal source is intended to carry the same effective risk as the same amount of equivalent dose applied uniformly to the whole body from an external source of radiation
Committed effective dose equivalent (CEDE)
Approximately what percentage do lipids make up of the cell content?
Absorption _______ as atomic number and mass density increase and also as photon energy decreases
Female germ cell
Molecular units that can chemically combine with other such units in a sequential manner, individual amino acid compound
3 parts the film badge is composed of
Durable, lightweight plastic film holder Assortment of metal filters Film packet
The intensity of light transmitted through a give area of the dosimetry film
2 things ribosomes consist of
Two thirds RNA One third protein
3 disadvantages of the OSL dosimeter
Occupational radiation exposure is recorded only in the body area where the device is worn (not close to reproductive organs) Exposure cannot be determined on the day of occurrence Not an efficient monitoring device if it is not worn
More than one ootid is available for fertilization, and the separate ootids are fertilized by separate spermatozoa
Dizygotic Fraternal twins
The duplicate centromeres migrate in opposite directions along the mitotic spindle and carry the chromatids to opposite sides of the cell; the cell is now ready to begin the last phase of division
SI unit of absorbed dose; an energy absorption of 1 Joule (J) per kilogram (kg) of matter in the irradiated object
2 late stochastic effects
Cancer Genetic (hereditary) effects
A covalent chemical bone formed when the carboxyl group of one amino acid combines with the amine group of another amino acid
Equal absorbed doses of different types of radiation produce ________ amounts of biologic damage
Small insoluble nonmembranous particles found in cytoplasm
Who discovered x-rays and when?
Wilhelm Conrad Roentgen on November 8, 1895
What forms part of the positive electrode of the pocket ionization chamber and what is its function?
A quartz fiber functions as the indicator on the transparent reading scale by casting a shadow onto a scale so that the quantity of charge on the positively charged electrode determines the position of the shadow along the scale and is equivalent to the scale reading at that position
Survey instrument that serves no useful purpose in diagnostic imaging; generally used in a laboratory setting to detect alpha and beta radiation and small amounts of other types of low-level radioactive contamination Can discriminate between alpha and beta particles
4 functions the cells perform for the body
Conduction of nerve impulses Contraction of muscles Support of various organs Transportation of body fluids such as blood
Basic units of all living matter and essential for life; fundamental component of structure, development, growth, and life processes in the human body Human body composed of trillions of these that exist in a multitude of different forms
2 parts of the body carbohydrates are most abundant in
Liver Muscle tissue
Nonthreshold, randomly occurring biologic effects of ionizing radiation Effects can result from relatively low radiation exposure, and can take a long time before they're demonstrated; the probability of occurrence depends on the radiation dose and type and energy of the radiation which means that some radiations are more biologically efficient for causing damage than others for a given dose Probability or frequency of the biologic response to radiation as a function of radiation dose Disease incidence increases proportionally with dose, and there is no dose threshold
What is the metric unit and SI unit of tissue kerma?
Metric: joule per kilogram (J/kg) SI: gray (Gyt)
4 functions of water outside the cell
Functions as a transport vehicle for material the cell uses or eliminates Responsible for maintaining a constant body core temperature of 98.6 F (37 C) Protects organs such as the brain and lungs Regulates concentration of dissolved substances Lubricates the digestive system and skeletal articulations
What is the average annual effective dose and collective effective dose to the whole body of medically exposed personnel?
EfD: 1.5 mSv ColEfD: 416 Person-Sv
The ability to function in a normal manner despite any changes the body may undergo because of outside influences
3 prefixes, subunits, symbols, fractions and factors
Centi-, c, 1/100, 10^-2 Milli-, m, 1/1000, 10^-3 Micro-, u, 1/1,000,000, 10^-6
3 procedures that produce the highest occupational dose for diagnostic imaging personnel
Fluoroscopy Surgery Special radiographic procedures
Because many x-ray examinations require small radiation doses, these may frequently be used to indicate absorbed dose values; only a fraction of a specified unit
Chemical compounds resulting from the action of an acid and a base on each other Chemically they are substances that become ions in solution and acquire the capacity to conduct electricity Present in the human body, and the balance in our bodies is essential for normal function of our cells and organs Keep the correct proportion of water in the cell
The amount of energy transferred on average by incident radiation to an object per unit length of track through the object Helps explain the need for a quality, or modifying, factor per type of energy
Linear energy transfer (LET)
The earliest phase among reproductive events; the gap in the growth of the cell that occurs between mitosis and DNA synthesis A form of RNA is synthesized in the cells that are to reproduce; this RNA is needed before actual DNA synthesis can efficiently begin
G1 (pre-synthesis phase)
Minute fibers or strands that are frequently part of a compound fiber
5 measurements required by state, federal, and health care accreditation organizations that use ionization chambers
X-ray output in mR/mAs Reproducibility and linearity (i.e., proportionality) of output Timer accuracy Half-value layer/beam quality Entrance exposure rates for fluoroscopy
Concept that takes biologic impact into consideration by using a specific modifying, or quality, factor, to adjust the absorbed dose value
Commercially, available lead aprons have a lead equivalent shielding overall of what or, in a less heavy version, a lead equivalent of what in the front and back?
Overall: 0.5 mm lead equivalent Front: 0.35 mm lead equivalent, back: 0.25 mm lead equivalent
Plays an essential part in the translation of genetic information from DNA into protein products by functioning as a messenger between DNA and the ribosomes, where synthesis occurs Carrier of information because DNA is stuck in the nucleus
Ribonucleic acid (RNA)
Male germ cell
How many chromosomes does a normal human being have in each somatic (nonproductive) cell?
46 different chromosomes (23 pairs)
Potassium (K) contributes most of the _______ present in the cell, whereas phosphorus (P) contributes the majority of ________ ions
3 functions proteins are essential for
Growth Construction of new body tissue Repair of injured or debilitated tissue
The amount of photoelectric absorption decreases and the amount of Compton scattering relative to the photoelectric interaction increases as the energy of the x-ray beam __________; the amount of Compton scattering in a material does not depend on the atomic number of the material
Used to describe radiation exposure of a population or group from low doses of different sources of ionizing radiation Determines as the product of the average EfD for an individual belonging to the exposed population or group and the number of persons exposed Used in radiation protection to describe internal and external dose measurements
Collective effective dose (ColEfD)
3 disadvantages of the ionization chamber survey meter (cutie pie)
Delicate detector unit Without adequate warmup time, its meter drifts and produces an inaccurate reading Cannot be used to measure exposures produced by typical diagnostic procedures because the exposure times are too short to permit the meter to respond appropriately
2 types of cell divisions that occur in the body
Those compounds that contain carbon, hydrogen, and oxygen
3 nutrients the mitochondria breaks down
Carbohydrates Fats Proteins
3 intervals of interphase
G1 S G2
Each DNA molecule contained within the chromosome is first copied (replicated) and then is divided into two individual sister chromatids, each containing DNA molecules Each of these identical sister chromatids is now one half of the replicated chromosome The chromatids will join together to form another chromosome by the end of this phase A chromosome consists of two copies of the DNA that is contained in each chromatid Chromosome reproduces itself and splits longitudinally, thus forming two sister chromatids attached to each other at the centromere
S (synthesis phase)
Worn as a second monitor when performing radiographic procedures that require the hands to be near the primary x-ray beam; ring that can be used to monitor the equivalent dose to the hands Badge cover contains information such as the account number, participant's name and number, wear date, indication of hand (right or left), size, and reference number; even though these badges are worn under gloves to avoid contamination, such extremity monitors are laser-etched to ensure the retention of permanent identification The reusable element of the dosimeter is encapsulated with an engraved cover
Extremity dosimeter (thermoluminescent dosimeter [TLD] ring badge)
Basic unit of electrical charge; represents the quantity of electrical charge flowing past a point in a circuit in 1 second when an electrical current of 1 ampere is used
What is the metric unit and SI unit of kerma?
Metric: joule per kilogram (J/kg) SI: gray (Gy)
What is the rule of converting from rads to centigrays (cGy)?
Number of rad/1 = number of cGy
In keeping with ALARA, at what limit do most health care facilities issue dosimetry devices?
When personnel could receive approximately 1% of the annual occupational EfD limit in any month; approximately 0.04 mSv (4 mrem)
Any chemical reaction in which an atom loses electrons
3 inorganic compounds
Acids Bases Salts/electrolytes
2 electrodes of the pocket ionization chamber
One positively charged (central electrode) One negatively charged (outer electrode)
2 effects of ionizing damage to the components of the cells involved in molecular synthesis beyond repair
Behave abnormally Die
Basic constituent of all organic matter
Water normally accounts for what percentage of the protoplasm?
Numerous ribosomes are present on the surface of the ER
Rough surfaced (granular)
Dosimeter that records whole-body radiation exposure accumulated at a low rate over a long period of time
Where should the personnel dosimeter be placed when a protective apron is worn (fluoroscopy, surgery, and special radiographic procedures)?
Outside the apron at collar level on the anterior surface of the body
Equation for EqD
EqD = absorbed dose (D) x radiation weighting factor (WR) sV = Gy x WR
Phase when cells are most radiosensitive At the beginning of this phase, the mitotic spindle forms between the centrioles Each chromosome, which now consists of two chromatids, lines up in the center/equator of the cell attached by its centromere to the mitotic spindle and forms the equatorial plate The centromeres duplicate, and each chromatid attaches itself individually to the spindle At the end, the chromatids are strung out along the mitotic spindle
What is the primary energy source for the cell?
What happens to the LiF crystals of the TLD when irradiated?
Some of the the electrons in the crystalline lattice structure of the LiF molecule absorb energy and are "excited" to higher energy levels or bands The presence of impurities in the crystal causes the electrons to become trapped within these bands When the LiF crystals are passed through a special heating process, however, these trapped electrons enough energy to rise above their present locations into a region called the conduction band From there, the electrons can return to their original/normal state with the emission of energy in the form of visible light
Water tends to move across cell surfaces or membranes into areas of high concentration of ions
4 primary elements that comprise protoplasm
Carbon Hydrogen Oxygen Nitrogen
A parent cell divides to form two daughter cells identical to the parent cell resulting in an approximately equal distribution of all cellular material between the two daughter cells The division and last phase of the cellular life cycle Somatic cells divide Process in which the nucleus first divides, followed by the division of the cytoplasm
What ranges of radiation intensity can the ionization chamber survey meter (cutie pie) measure?
1 mR/hr-several thousand milliroentgens per hour (10-several thousand micrograys per hour)
4 things 1 sievert equals
1. 1 J/kg 2. 100 rem 3. 100 centisievert (cSv) 4. 1000 mSv
2 disadvantages of the GM detector
The meter reading is not independent of the energy of the incident photons meaning that photons of widely different energies cause the instrument to respond quite differently Likely to saturate or jam when placed in very high-intensity radiation area, giving a false reading
3 types of ribonucleic acid (RNA)
Messenger RNA (mRNA) Transfer RNA (tRNA) Ribosomal RNA (rRNA)
3 things genes are responsible for (contain information because of the ordering of its nitrogenous base pairs)
Directing cytoplasmic activities Controlling growth and development of the cell Transmitting hereditary information (e.g., hair color, blood type)
Degree of blackening
7 things cells do
Move Grow React Protect themselves Repair damage Regulate life processes Reproduce
Kinetic energy released in a unit mass (kilogram) of air SI quantity that can be used to express radiation concentration transferred to a point, which may be at the surface of a patient's or radiographer's body X-ray tube output and inputs to image receptors are sometimes described in this Actually denotes a calculation of radiation intensity in air Replacing the traditional quantity, exposure Amount of radiation coming out of the tube
Air kerma "Kinetic energy released in material" "Kinetic energy released in matter" "Kinetic energy released per unit mass"
Kinetic energy released in a unit mass of tissue
What is the purpose of the sheet of lead foil inside the envelope of the film badge?
Backs the film to absorb scatter radiation coming from behind the dosimeter
Special type of cell division that reduces the number of chromosomes in each daughter cell to half the number of chromosomes in the parent cell Genetic/germ cells undergo a process of reduction division of half
A radiation dose to which occupationally exposed persons could be continuously subjected without any apparent harmful acute effects, such as erythema of the skin
Alkali or alkaline earth compounds that can neutralize acids Ex: Mg(OH)2 (milk of magnesia)
2 things EfD takes into account
They type of radiation (e.g., x-radiation, gamma, neutron) The variable sensitivity of the tissues exposed to radiation
Radiation with a high LET transfers a _______ amount of energy into a small area and can therefore do more biologic damage than radiation with a low LET; as a result, a high-LET radiation has a quality factor that is ________ than the quality factor for a low-LET radiation
All cells in the human body except the germ cells
What is the TEDE for occupationally exposed personnel and the general public?
Occupational: 0.05 Sv Public: 0.001 Sv
Of all organic compounds, which contains the most carbon?
What is the most abundant inorganic compound in the body?
Results from personnel monitoring programs must be recorded accurately and maintained for review to meet state and federal regulate These written reports, typically one for each hospital department that is being monitored, list the deep, eye, and shallow occupational exposure of each covered person on a monthly, quarterly, year to date, and lifetime equivalent basis The TEDE for persons of interest can be supplied at year's end
Personnel monitoring reports
Separated from the other parts of the cell by a double-walled membrane, this forms the heart of the living cell Spherical mass of protoplasm (nucleoplasm) that contains the genetic material, DNA, and protein Controls cell division and multiplication and the biochemical reactions that occur within the cell
Very large, complex macromolecules; made up by nucleotides
At all energies, mass density always has an effect on absorption; this effect is linear and ________ proportional