Ch 4-6 Flashcards
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
Exposure (X)
The breaking down of large molecules into smaller ones through the process of oxidation
Oxidative metabolism
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 _______
Least, most
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
Ribosomes
Unit of EfD
Sieverts or millisieverts
Do you want a high or low LET?
Low
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
Genetic/heritable effects
Sugars that have two units of a simple sugar linked together; ex: lactose, sucrose (cane sugar)
Disaccharides
Chemical building material for all living things; living contents of cell
Protoplasm
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
Characteristic curve
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
Sievert (Sv)
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
Hormones
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
Cytoplasmic organelles
Even though SI values and traditional values differ numerically, SI values of dose are all ______ of the older traditional system
1/100
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
“Bare”
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
Higher
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?
10-20
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
Telophase
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
Vesicles
Ribosomes are not present on the surface of the ER
Smooth (agranular)
Hydrogen-containing compounds that can attack and dissolve metal Ex: HNO3 (nitric acid)
Acids
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
Somatic damage
Approximately what percentage do carbohydrates make up of the cell content?
1%
Simple sugar, ex: glucose
Monosaccharide
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
Cytoplasm
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
Nucleolus
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)
- 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
Occupational radiation
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
Radiodermatitis
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?
No amount
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
Lysosomes
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
Mitotic spindle
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
Roentgen (R)
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?
24
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
Polymer
The assembly of larger molecules from smaller ones
Anabolism
2 elements carbon, hydrogen, oxygen and nitrogen combine with to form the essential major organic compounds
Phosphorus Sulfur
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
Interphase (resting)
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
1 ampere-second
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
Proteins
SI unit of electrical current; number of flowing electrons A unit of electric current equal to a flow of one coulomb per second
Ampere (A)
Located in the center of the cell near the nucleus; the region of the chromosome where the two chromatids join together
Centromeres
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
Mitochondria
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
Golgi apparatus/bodies/complex
Organic compounds essentially made up of combinations of NH2 (“amine”) and COOH (carboxylic acid) molecules Five hundred different ones, natural monomers
Amino acids
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
Centrioles
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
Lipids/fats/fatlike substances
Provide the body with its shape and form and are a source of heat and energy Ex: those found in muscle
Structural proteins
A dose of radiation lower than which an individual has a negligible chance of sustaining specific biologic damage
Threshold dose
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
Enzymatic proteins/”enzymes”
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
keV/um
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
TLD analyzer
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
Equal, proportional
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
Sievert (Sv)
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
Doppler shift
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
Cell membrane
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
Nucleotides
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
Active transport
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
Ions