Safety
which of the following contributes most to the patient dose 1. photoelectric effect 2. compton scatter 3. classic scatter 4. thompson scatter
1. photoelectric effect
how many electrons may occupy the M-shell of an atom
18 formula equals 2n^2 (KLMNOP) 2(m=3)^2 = 18 electrons
which of the following is the speed of x-rays?
186,000 miles/second or 3x10^8 meters/second
a .5mm lead gonadal shield will reduce female gonadal exposure by approx. what percentage? 1. 25% 2. 50% 3. 75% 4. 99%
3. 75%
which of the following occurs when radiation transfers its energy to DNA? 1. Indirect effect 2. Target theory 3. Direct effect 4. mutations
3. Direct effect
which of the following is used to illustrate the relationship between exposure to ionizing radiation and possible resultant biologic responses? 1. ionization chamber 2. thermoluminescent dosimeter 3. Dose-response curve 4. electromagnetic spectrum
3. Dose-response curve
In radiation protection, the product of absorbed dose, tissue weighting factor, and radiation weighting factor is used to determine 1. C/kg 2. mR 3. Efd 4. Qf
3. Efd effective dose
all of the following have an effect on patient dose, EXCEPT 1. kvp 2. ma 3. focal spot size 4. inherent filtration
3. Focal spot size
which of the following will NOT have an effect on patient dose? 1. Filtration 2. SID 3. Focal spot size 4. kVp
3. Focal spot size Focal spot size controls recored detail on a radiogragh, but no effect on the quantity of xrays reaching patient
the quality of an x-ray beam can be measured by which of the following methods? 1. Rate meter 2. sensitometry 3. Half Value Layer (HVL) 4.Spinning top
3. Half Value Layer (HVL)
the Wr used in calculating sievert takes into account which of the following? 1. meiosis 2.age 3. LET 4. prenancy
3. LET
Classify the following tissues in order of increasing radiosensitivity 1. Liver cells 2. Intestinal crypt cells 3. Muscle cells A. 1, 3, 2 B. 2, 3, 1 C. 2, 1, 3 D. 3, 1, 2
3. Muscle cells 1. Liver cells 2. Intestinal crypt cells 3,1,2
the single most important scattering object in both radiography and fluroscopy is the 1. x-ray table 2. x-ray tube 3. patient 4. IR
3. PATIENT
which of the following is the unit for biological dose? 1.Sv 2. Gy 3. RBE 4. C/kg
3. RBE
the least radiosensitive stage of human cell mitosis is 1. M 2. G1 3. S 4. G2
3. S - synthesis MOST radiosensitve is M - mitosis
what unit of measure is used to express ionizing radiation dose to biologic material? 1. air kerma (gya) 2. gyt 3. Sv 4. RBE
3. Sv also used to express occupation and effective dose
fluorscopy: exposure factors
high kVp (100 kVp or more) allows mA to be between 1 and 5 mA MOST fluoro equipments is calibrated to emit (21mGy/minute/mA) NOT to exceed (100mGy/minute) at maximum output; with an optional high level control fluoro device the limit is (200mGy/minute) Limit the number of spot films, magnification features, tight collimation
Epithelial Tissue
highly radiosensitive, divides rapidly, lines body tissue
what term best describes the approximate skin dose where the x-ray beam is entering the patient?
Air kerma - depositing energy specific at a point
a controlled area is defined as one 1. that is occupied by people trained in radiation safety. 2. that is occupied by people who wear radiation monitors. 3. whose occupancy factor is 1.
All are CORRECT 1. that is occupied by people trained in radiation safety. 2. that is occupied by people who wear radiation monitors. 3. whose occupancy factor is 1. meaning the area is always occupied and requires max shielding controlled: 100mR/week uncontrolled: 10 mR/week - general public
How do fractionation and protraction affect radiation dose-effects? 1. they reduce the effect of radiation exposure 2. they permit cellular repair 3. they allow tissue recovery
All are CORRECT 1. they reduce the effect of radiation exposure 2. they permit cellular repair 3. they allow tissue recovery fractionation: radiation delivering in portions protraction: over a length of time
Fluoroscopy: DOSE OR TIME DOCUMENTATION
All fluoro machines should have the ability to track and display patient dose in real time and cumulatively If not... Minimize beam on time, vary site of entrance port as possible, optimally collimate, use less magnification
fluroscopic procedure performed on a pregnant female could result in which of the following? 1.still birth 2.miscarriage 3.congential abnormalties
All three 1.still birth 2.miscarriage 3.congential abnormalities
which of the following is the unit of absorbed radiation dose
Gray
Units of Radiation Measurement
Gray - absorbed dose Gray (Gya) - air kerma Gray (Gyt) - absorbed dose in tissue Sievert (Sv) - unit of effective and equivalent dose Becquerel (Bq) - unit of radioactivity
frequency and wavelength are directly or inversley related?
Inversley proportional, the higher the frequency the shorter the wavelength
which of the following is used to represent the mean marrow dose?
MMD
how often should personnel radiation monitoring devices be changed?
MONTHLY
Frequency
frequency of an xray is the number of times per second the electric and magnetic fields regenerate themselves; the higher the energy of the xray, the higher the frequency; the unit is Hertz(Hz) or cycles per second
Adult Nerve tissue
Requires very high doses (beyond medical levels to cause damage, is very specialized has no cell division, is relatively insensitive to radiation
which of the following is correct concerning a neutral atom
SAME number of protons as electrons
a recommendation that is necessary to meet the accepted standards is indicated by the use of which term
SHALL
which of the following may be used 3 months at a time 1. TLD 2. Film badge 3. pocket ionization chamber 4. handheld ionization chamber
TLD
Genetically Significant Dose (GSD)
average annual gonadal dose of radiation to individuals of childbearing age; addresses the relationship of gonadal doses to individuals versus an entire population and the overall effects
mean marrow dose
average dose of radiation to the bone marrow
which of the following is sensitive to extremes in an environment? 1. TLD 2. Film badge 3. pocket ionization chamber 4. handheld ionization chamber
film badge
Central Nervous System (CNS)
for the CNS to be affects there would have to be a large radiation exposure; since nervous cells are seldom divide, they are considered radiosensitive
What is a push or pull on an object?
force
What must be applied in order to set a resting body in motion? 1. potential energy 2.force 3.work
force only
electromagentic spectrum from highest energy to lowest energy
gamma rays - shortest wavelength x-rays ultraviolet radiation visible light infrared radiation radio waves
dose-response curve
graphs that illustrate the relationship between radiation dose and the response of the organism to exposure; may be linear or nonlinear, threshold or nontreshold
Hemopoietic
includes bone marrow, circulating blood, lymph nodes, spleen, and thymus lymphocytes (and spematogonia) are the most radiosensitive cells in the body flat boes contain most bone marrow (pelvis,sacrum, T&L vertebrae, ribs, and skull) principle response of this system is a decreasse in the number of types of blood ccells in the circulation
In the production of Bremsstrahlung radiation, the incident electron:
is deflected, with resulting energy loss
Half Value Layer (HVL)
the amount of filtration that reduces the intensity of the x-ray beam to one-half its original value. measured at least ANNUALLY by a qualified radiation physicist
the primary function of filtration is to reduce 1. patient skin dose 2. operator dose 3. image noise 4. scattered radiation
patient skin dose
Fluoroscopy: POSITIONING
patient the position with fluoro off (avoid breasts, eyes, and gonads) and limiting the size of the field are important
which of the following is responsible for creating contrast on an image
photoelectric interaction
Charged Coupled Device (CCD): Image Receptor
photograph the image that is emitted from an intensifying screen; they would be considered a 400 speed class
which of the following personnel monitoring devices is capable of providing an immediate reading?
pocket dosimeter
POCKET DOSIMETER
pocket ionization chamber an mR reading is immediately available after exposure by looking into the dosimeter
the "direct Hit" theory of cell irradiation can be described by which of the following?
the DNA molecule is struck whereas an "indirect hit" means the radition struck a water molecule which released a free radical that struck the DNA Most common
kinetic energy
the ability of a moving object to work motion
what is the definition of energy
the ability to do work
linear
when the radiation dose is doubled, the the response to radiation is likewise doubled (directly proportional)
the effects of radiation on biologic material depend on several factors. if a large quantity of radiation is delivered to a body over a short period of time, the effect
will be greater than if it were delivered in increments
Fluoroscopy: MAGNIFICATION MODE
with conventional, multi-field image intensifiers a magnified image is less distorted and makes small details easier to see, but if comes at cost of more radiation to the patient digital, flat-panel detectors allow the operator to zoom without an increase in exposure
Intensity refers to
with depend on the distance from the x-ray tubes focal spot; it refers to the number of x-rays within an arean of the x-ray beam; the further from the tube the lower the intensity caluclated by inverse square law
Conversion for fahrenheit and Celsius
F = (9/5 * C) = 32 C= 5/9 (F-32)
isotopes are atoms that have the same 1.
atomic number and different mass number
positive beam limitation is also known as
automatic collimation
probabilistic (stochastic) effects
" all or nothing " effects Late effect happens years later NO TRESHOLD randomly occurring effects of radiation; the probability of such effects is proportional to the dose (increased dose equals increased probability, not severity, of effects) occurs in months or years later, with no treashold dose
a recommendation that is applied when pratical is indicated by the use of which of these terms?
"should" good practice
embryonic fetal risk
(2-8) weeks first trimester prenatal death neonatal death congenital abnormalities malignancy induction general impairment of growth genetic effects and mental retardation are all possible biological effects of radiation during pregnancy
Fluoroscopy: RECEPTOR POSITIONING
)21 CFR states that source-to-skin distance cannot be less than 38 cm on stationary fluoroscopes or less than 30 cm on mobile fluoro Mobile Fluoro: C-ARM should be positioned so the x-ray tube is under the patient and the image intensifier is close to the patient as possible (the top piece) the scatter is towards the tube and forward to the image intensfier so keeping the tube under the patient the scatter goes towards the floor mobile fluoro shall provide intensified imaging (The image intensifier is an electronic vacuum tube that converts the remnant beam to light, then to electrons, then back to light, increasing the light intensity in the process. It consists of five basic parts: the input phosphor, photocathode, electrostatic focusing lenses, accelerating anode, and output phosphor.)
Late somatic effects of radiation
- carcinogenesis; (formation of cancer) - cataractogenesis; (opacity of the crystalline lens, is the leading cause of avoidable blindness worldwide) non-linear, threshold dose response curve - embryologic effects; (Embryology is the branch of biology that studies the prenatal development of gametes, fertilization, and development of embryos and fetuses. Additionally, embryology encompasses the study of congenital disorders that occur before birth, known as teratology.) MOST SENSITIVE during the first trimester of gestation - thyroid dysfunction; (Thyroid disease is a medical condition that affects the function of the thyroid gland. The thyroid gland is located at the front of the neck and produces thyroid hormones that travel through the blood to help regulate many other organs, meaning that it is an endocrine organ) VERY RADIOSENSITIVE organ - life span shortening: does not occur in modern radiation workers
Gonadal Shields
- gonadal shielding may reduce female gonad dose by 50% (75%) -gonadal shielding may reduce male gonad dose by 95% (90%) -Most common Shields are 1.Flat Contact Shield: flat piece of lead or a lead apron placed over the gonads, can be a piece of vinyl lead 2.Shadow Shield: suspended from the x-ray tube housing and placed in the x-ray beam light field; requires no contact with the patient; especially useful during procedures requiring sterile technique, 3. shaped contact: molded to fit the males gonads 4.protective lenses: glasses Gonads, breasts, and bone marrow be shielded!!
Early somatic effects of radiation
- hematopoietic syndrome; decreases total number of all blood cells, can result in death - gastrointestinal (GI) syndrome; causes total disruption of GI tract structure and function and can result in death - central nervous system syndrome; causes complete failure of nervous system and results in death
linear, threshold
- indicates that at lower doses of radiation exposure (to the left of the line intersecting the x-axis), no response is expected -when the threshold dose is exceeded, the response is directly proportional to the dose received EXAMPLE - cataractogenesis doesnt occur at low levels of radiation exposure; there is a threshold dose below which cataractogenesis does not occur
linear, nonthreshold
- indicates that no level of radiation can be considered completely safe - a response occurs at every dose -the degree of response to exposure is directly proportional to the amount of radiation received
International Commission on Radiological Protection (ICRP)
-Conducts research and provides recommendations on radiation protection to the worldwide community based on fundamental scientific principles -has no legal power -most countries base radiation protection legislation on ICRP recommendations
Effective Dose **Sievert
-Estimates the risk present when various tissues are irradiated -Uses a tissue weighting factor (Wt); takes into account the relative radiosensitivity of the irradiated organ or body part -Effective dose is the product of absorbed dose times the radiation weighting factor times the tissue weighting factor (Wt) - Sv = (Gy) x (Wr) x (Wt) tissue weighting factors include gonads(.08) , breast (.12), red bone marrow (.12), lung (.12), thyroid (.04), bone surface (.01), and the remaining organs (.12)
Nonlinear, Threshold
-Indicates that a lower doses of radiation exposure (to the left of the line intersecting the x-axis), no response is expected -when the threshold dose is exceeded, the response is directly proportional to the dose received and is increasingly effective per unit dose
Nonlinear, nonthreshold
-Indicates that no level of radiation can be considered completely safe -a response occurs at every dose -the degree of the response is not directly proportional to the dose recieved -the effect is large even with a small increase in dose
National Council on Radiation Protection and Measurements (NCRP)
-formulates and publishes scientifically researched recommendations on radiation protection and measurements in the United States
photoelectric effect
-absorption of x-ray photons in the atoms of the body -photon absorption interaction -Incoming x-ray photon strikes K-shell electron -Energy of x-ray photon is transferred to electron -That energy pushed out the electron and is now ejected from the K-shell and is now called a PHOTOELECTRON -X-ray photon deposited all of its energy into that electron and now doesnt exist, it has been completely absorbed -The photoelectron may ionize or excite other atoms until it has deposited all of its energy -The Hole in K-shell is replaced by electrons from outer shells, releasing energy that creates LOW energy characteristics photons that are locally absorbed -Photoelectric interaction results in INCREASED dose to the patient Photoelectric produces CONTRAST in the radiograph because of the differential absorption of the incoming x-rays photons in the tissues -The ejected electron (photonelectron) imparts the atom with an energy EQUALS to the excess imparted by the photon
repeat exposures
-always result in an increase in radiation dose to the patient -must be kept to a minimum -should be tract by department -reasons of repeat should be documented -education in repeats should be conducted by radiologists and radiographers
Pair Production
-doesn't occur in radiography. -produced at photon energies greater than 1.02 million electron volts. -Involves an interaction between the incoming photon and the atomic nucleus.
Somatic effects
-effects of radiation on the body being irradiated -damage to the exposed individual - somatic effects are evident in the organism being exposed doses causing these effects are much higher than the levels of radiation used in diagnostic radiation caused by when a large dose of radiation is received by large area of the body (can also be caused by local areas of the body receiving high doses of radiation during radiation therapy)
Genetic effects
-effects of radiation on the genetic code of a cell; affects the next generation (DNA) -may be passed to the next generation -linear, nonthreshold, no such thing as safe gonadal dose; any exposure can represent a genetic threat -DOUBLING DOSE: amount of radiation that causes the number of mutations in a population to double is (approx. 1.56 Sv for humans -Genetic mutations dont cause defects that are not already present in humans from other causes; that is, no defects are unique to radiation
mutation
-erroneous (incorrect) information passed to subsequent generation via cell division -the changing of the structure of a gene, resulting in a variant form that may be transmitted to subsequent generations, caused by the alteration of single base units in DNA, or the deletion, insertion, or rearrangement of larger sections of genes or chromosomes.
aperture diaphragm
-flat piece of lead with a circle or square opening in the middle -placed as close to the x-ray tube window as possible -has no moving parts
Ionizing Radiation
-radiations that possesses the ability to remove electrons from atoms by a process called ionization -Ionization may cause unstable atoms, free electrons, or formation of new molecules harmful to the cell -Natural background radiation is present in the environment -Greatest natural background exposure to humans is RADON -Human produced radiation is created by human activities (ex-medical imaging) or inventions -CT accounts for the largest increase in total dose and medical dose to the population -Total radiation dose to the US population has doubled since 1980s
Basic Principles of Radiation Protection
-responsible for protecting the patient from unnecessary exposure -smallest amount of radiation that produces an image -Radiographer/Radiologist shared responsibility for radiation of the patient *best accomplished by consultation *should not order unnecessary exams -safe use of radiation in diagnostic imaging to determine the extent of disease or injury should outweigh the risk involved from the exposure
Equivalent dose (dose equivalant) **SIEVERT (Sv)
-unit of effective dose and also unit of equivalent dose -the product of absorbed dose (Gy) times the radiation weighting factor (Wr) v - Sv = (Gy) x (Wr) Wr = takes into the account the biological impact of the type and energy of the radiation being used Wr = takes into account Linear Energy Transfer (LET), which is the amount of energy transferred by ionizing radiation per unit length of tissue traveled ionizing radiation (is radiation with enough energy so that during an interaction with an atom, it can remove tightly bound electrons from the orbit) High-ionization radiations such as alpha particles and neurons have high LET (cause more biological damage) Lower ionization radiations such as x-rays and gamma rays have lower LET (cause less biological damage) Unit of measurement tissue is sievert (Sv) Since the Wr for x-rays and gamma rays is 1** 1Sv = 1 Gy when using those two forms of radiation
Unit of radioactivity
-used to measure the quantity of radioactive material (is not used to measure the radiation emitted but rather the number of atoms decaying per second ) -SI unit = Becquerel (Bq) -used primarily in Nuclear Medicine
which of the following describes the fluoroscopic system designed to maintain a constant image brightness? 1. automatic exposure rate control (AERC) 2.automatic exposure control (AEC) 3.automatic collimation 4. anatomically programmed radiography
. automatic exposure rate control (AERC) NOT AEC that controls KVp like for a chest exam
1 millimeter equals
.001 meters
In the normal diagnostic range, what is the wavelength range of the x rays?
.1 to .5 angstroms 25 keV will produce xrays with wavelengths of .5 angstroms and 125 kEv will produce wavelengthd of .1 angstroms
what is the effective dose limit to the fetus of a pregnant radiologic technologist?
.5 mSv/month or 5 mSv/year
lead apron lead equivalency
.50 mm Pb
Level of negligible risk is
0.01 mSv
what percentage of the primary exposure to the patient will reach a radiographer standing 1 meter away? 1. .1 % 2. .5% 3. 2.5% 4. 5.0%
0.1% one thousandth of its original value
Blood count can be depressed with a whole-body dose of 1. 0.25 Sv 2. 25 Sv 3. 1 Sv 4. 10 Sv
0.25 Sv
according to NRCP, the pregnant radiographers gestational dose-equivalent limit for 1 month period is
0.5 mSv
minimum requirement for lead aprons
0.5 mm pb equivalent
Embryo fetus - equivalent dose limit per month is
0.5mSv
which of the following results from restriction of the x-ray beam 1. less scattered radiation production 2. less patient hazard 3. less radiographic contrast
1 and 2 only 1. less scattered radiation production 2. less patient hazard it would improve contrast
Immature cells are referred to as 1 undifferentiated cells 2 stem cells 3 genetic cells
1 and 2 only 1 undifferentiated cells 2 stem cells
which of the following factors will affect BOTH quantity and quality of the primary beam 1. HVL 2.KVP 3.mA
1 and 2 only 1. HVL 2.KVP
the operation of personal radiation monitoring can be based on stimulated luminescence. which of the following personal radiation monitors functions in that matter? 1. OSL dosimeter 2. TLD 3. Pocket dosimeter
1 and 2 only 1. OSL dosimeter 2. TLD
LET is best defined as 1 a method of expressing radiation quality 2 a measure of the rate at which radiation energy is transferred to soft tissue 3 absorption of polyenergetic radiation
1 and 2 only 1. a method of expressing radiation quality 2. a measure of the rate at which radiation energy is transferred to soft tissue
which of the following body parts is/are included in whole body dose? 1. gonads 2. blood-forming organs 3. extremeties
1 and 2 only 1. gonads 2. blood forming organs
guidelines for the use of protective shielding state that gonadal shielding should not be used 1. if the patient has reasonable reproductive potential 2. when the gonads are within 5 cm of the collimated field 3.when tight collimation is NOT possible
1 and 2 only 1. if the patient has reasonable reproductive potential 2. when the gonads are within 5 cm of the collimated field
which of the following has/have been identified a sources of radon exposure 1. indoors, in houses 2. smoking cigarettes 3. radiology departments
1 and 2 only 1. indoors, in houses 2. smoking cigarettes
the advantages of beam restriction include which of the following? 1. less scattered radiation is produced 2. less biological material is irradiated 3. less total filtration will be necessary
1 and 2 only 1. less scattered radiation is produced 2. less biological material is irradiated
early symptoms of acute radiation syndrome include 1. leukopenia 2. nausea and vomiting 3. cataracts
1 and 2 only 1. leukopenia 2. nausea and vomiting
factors that contribute to the amount of scattered radiation produced include 1. radiation quality 2. field size 3. grid ratio
1 and 2 only 1. radiation quality 2. field size not grid ratio because that absorbs scatter
which of the following statements regarding the human gonadal cells is/are true? 1. the female oogonia reproduce only during fetal life 2. the male spermatogonia reproduce continuously 3. both male and female stem cells reproduce only during fetal life
1 and 2 only 1. the female oogonia reproduce only during fetal life 2. the male spermatogonia reproduce continuously
which of the following is.are acceptable ways to monitor the radiation exposure of those who are occupationally employed? 1. TLD 2. OSL dosimeter 3. quarterly blood cell count
1 and 2 only 1. TLD 2. OSL dosimeter
which of the following types of radiation is/are considered electromagnetic? 1. x-ray 2. gamma 3. beta
1 and 2 only 1. x-ray 2. gamma
the photoelectric effect is more likely to occur with 1. absorbers with having a high Z number 2. high-energy incident photons 3.positive contrast media
1 and 3 only 1. absorbers with having a high Z number 3.positive contrast media
somatic effects from radiation exposure can 1. have possible consequences on the exposed individual 2. have possible consequences on future generations 3. cause temporary infertility
1 and 3 only 1. have possible consequences on the exposed individual 3. cause temporary infertility
Law of Bergonie and Tribondeau states that cells are more radiosensitive if they are 1. highly proliferated (multiply) 2. highly differentiated 3. immature
1 and 3 only highly proliferated immature
leakage radiation from x-ray tube cannot exceed which of the following distance of one meter?
1 mGy/hr/meter
radiography student may recieve on one year if he is under 18?
1 mSv
common conversions
1 meter = 100 centimeter = 39.37 inches 2.54 centimeters = 1 inch 1 kilogram (kg) = 2.2 pounds (lb)
Measurement
1 meter = 100 centimeters 1 centimeter = .01 meters 1 inch = 2.54 centimeters 1 meter = 39.37 inches 1 inch = 0.0254 meters
An increase of 1.0 mm added aluminum filtration of the x-ray beam would have which of the following effects? 1. Increase in average energy of the beam 2. Increase in patient skin dose 3. Increase in milliroentgen output A. 1 only B. 1 and 2 only C. 2 and 3 only D. 1, 2, 3
1 only 1. Increase in average energy of the beam
which of the following tissues is/are considered to be particularly radiosensitive 1. intestinal mucous membrane 2. epidermis of extremities 3. optic nerves
1 only 1. intestinal mucous membrane
which of the following is/are likely to improve image quality and decrease patient dose? 1. beam restriction 2. low kvp, high mA 3. grids
1 only beam restriction
The correct way to check for cracks in lead aprons 1.to fluoroscope them once a year. to radiograph them at low kvp twice a year 3. by visual inspection
1 only to fluoroscope them once a year.
each of the following is/are used to account for the differences in tissue characteristics when determining effective dose to biologic material? 1. tissue weighting factor (Wt) 2. Radiation weighting factor (wr) 3. absorbed dose
1 only 1. tissue weighting factor (Wt) Not Wr = takes into account Linear Energy Transfer (LET), which is the amount of energy transferred by ionizing radiation per unit length of tissue traveled
The annual dose limit for medical imaging personnel includes radiation from 1. occupational exposure 2. background radiation 3. medical x-rays A. 1 only B. 1 and 2 only C. 2 and 3 only D. 1, 2, 3
1 only occupational exposure
Protective devices such as lead aprons function to protect the user from 1. scattered radiation 2. the primary beam 3. remnant radiation
1 only scatter radiation
If the image intensifier is moved farther from the patient 1. SID increases 2. patient dose decreases 3. image quality improves
1 only SID increases
which of the following relates to the equivalent dose limits for a non-radiation worker? 1. 1/10 that of radiation worker 2. 1/2 that of radiation worker 3. the same as a radiation worker 4. twice that of radiation worker
1. 1/10 that of radiation worker this would equal 5.0 mSv (.5 rem)
standards state that the expoosure in air from fluoroscopic equipment shall not exceed this output per mA 1. 21mGy/minute 2. 21 mGy/hour 3. 100 mGy/minute 4. 100mGy/hour
1. 21mGy/minute/mA
high risk exams for females
1. BE 9.03 2.L-spine 7.21 3.IVU 5.88 4.abdomen 2.21 5.pelvis 2.10 6.hip 1.24 7. HSG 8.cystourethrogram
The cell contains three main parts
1. Cell membrane 2.cytoplasm 3.Nucleus
Pediatrics
1. Children need to be carefully protected from unnecessary exposure; high speed image receptors should be used along with adequate immobilization
beam limitation
1. Collimator 2. Cylinder Cones 3. Aperture Diaphragm
Monitoring Personnel Exposure FILM BADGES
1. Consider of plastic case, film, and filters 2. Plastic case holds film and filters and provides clip for attaching to clothing 3. film used is similar to dental x-ray film 4. Measure doses as low as 100 uGya u 5. Doses below 100 uGya u are reported as minimal 6. Film is sensitive to extremes in temperature and humidity 7. Filters is made of aluminum and copper measure intensity and type of radiation striking the film 8. Film badges are usually changed MONTHLY inexpensive heat can cause fogging .1 mSv are reported as minimum (M) the density on the exposed and processed film is proportional to the exposure received by the film badge
Primary Protective Barriers
1. Consist of 1/16 inch lead equivalent 2. located wherever the useful beam may strike the wall or the floor. 3. If in the wall, extend from the floor to a height of 7 feet
Portable Radiographic Equipment and Procedure
1. Exposure switch must be on a cord at least 6 feet long 2. Lead aprons must be worn if mobile barriers are unavailable 3. Least scatter is 90 degrees angle from patient 4. Apply the inverse square law to reduce dose by using exposure cord at full length 5. radiographer should never hold the IR in place for portable exam because of possible exposure to the primary beam 6. Commercial image receptor holders, pillows, and sponges should be used to hold IR in place
Mitosis - Somatic Cells
1. INTERPHASE -cell growth before mitosis -consists of three phases G1, S, G2 -G1: pre DNA synthesis -S: DNA synthesis -G2: post - DNA synthesis, prep for mitosis 2. FOUR SUBPHASES a) Prophase: nucleus enlarges b) Metaphase: Nucleus elongates c) Anaphase: two complete sets of chromosomes d) Telophase: seperates the two sets of genetic material; division complete; 46 chromosomes in each new somatic cell
what occurs when radiation transfers its energy to the cellular cytoplasm? 1. Indirect effect 2. Target theory 3. Direct effect 4. mutations
1. Indirect effect
Cylinder Cones
1. Metal cylinders that attach to the bottom of the collimator 2.used to strict the beam in a tight circle 3.diameter of the far end of the cone determines field size 4.Cones may be extended a additional 10 to 12 inches by a telescoping action for even tighter restriction of the beam 5.cones may be used in exams like os calcis (calcaneus), skull projections, and cone down vies of the vertebral bodies 6.when cones are used mAs should always be increrased to make up for the rays attenuated by the cone 7.cylinder cones do not work by focusing the x-ray beam down the cone; xrays cannot be focused
which of the following means there is no safe level of radiation and the response to the radiation is not directly proportional to the dose received 1. Nonlinear, non-threshold effect 2. Linear, non-threshold effect 3. Linear, threshold 4. Nonlinear, threshold effect
1. Nonlinear, non-threshold effect
Meiosis: Cell division of sperm or ovum (germ cells) that halves the number of chromosomes in each cell
1. Replication division -G1 -S -G2 -M 2.Reduction of division -G1 -No S Phase -G2 -M 3. Note: Sperm and ovum unite to return the number of chromosomes in each cell of the new individual to 46
General types of radiation damage
1. Somatic effects 2.Genetic
which of the following i accurate as low as 50 uGya 1. TLD 2. Film badge 3. handheld ionization chamber 4. geiger-mueller detector
1. TLD
results of ionization in human cells
1. Unstable atoms 2. Free electrons 3.Production of low energy x-rays 4.formation of new molecules harmful to the cell 5.Cell damage may be exhibited as abnormal function or loss of function
Monitoring Personnel Exposure OPTICALLY STIMULATED LUMINESCENCE (OSL) DOSIMETERS
1. Used aluminum oxide to record dose powdered 2. radiation absorbed causes electrons to be trapped 3. Aluminum oxide layer is stimulated by a laser beam after wear period 4. Electrons release energy as visible light 5. Light is in direct proportion to the amount of radiation received 6. Measures exposures as low as 10 uGya = .01 mSv 7. Relatively unaffected by temp. and humidity 8. Can be worn 3 MONTHS at a time 9. can be reanalyzed multiple times, if necessary 10. Exposures below 10 uGya are reported as minimal POSITIVES: 1.not affected by heat 2.doesnt need chemical developent 3. no limit to dose exposure range
Monitoring Area Exposure GEIGER-MUELLER DETECTOR
1. Used to detect radioactive particles in nuclear medicine facilities 2. Sounds audible alarm when struck by radiation, with sound increasing as readiation becomes more intense 3. meter reads in counts per minute
Monitoring Area Exposure HANDHELD IONIZATION CHAMBER
1. Used to measure radiation in an area (fluoro room), storage areas for radioisotopes, doses traveling through barriers, and patients who have radioactive sources within them 2. not used to monitor short exposure times 3. measures exposure rates as low as 10 uGya per hour 4. Operates similar to pocket ionization chamber, with internal as being ionized when struck by radiation
which of the following is/are composed of non-dividing, differentiated cells? 1. neurons and neuroglia 2. epithelial tissue 3.lymphocytes
1. neurons and neuroglia radioresistant
the interaction between x-ray photons and tissue that is responsible for radiographic contrast but also contributes significantly to patient dose
1. photoelectric effect
Monitoring Personnel Exposure THERMOLUMINESCENT DOSIMETERS (TLDS)
1. Uses lithium fluoride crystals instead of film to record dose 2. Electrons of crystals are excited by radiation exposure and release this energy on heating (excited electrons in the crystalline lattice) 3. Energy released is visible light, which is measured by a photo-multiplier tube 4. Light is in direct proportion to the amount of radiation received 5. TLDs are used mainly in ring badges worn by NUCLEAR MEDICINE technologists 6. Measure exposures as low as 50 uGya = .05 mSv 7. Relatively unaffected by temperature and humidity 8. Can be worn for longer periods than film badges 9. TLDS and equipment used to read them is expensive 10. Exposures below 50 uGya are reported minimal
X-Ray Tube Housing
1. X-rays may leak through the housing tube during exposure 2.Everyone must be protected from leakage radiation 3.Leakage radiation may not exceed 1 mGya per hour at a distance of 1 meter from the housing
Patient considerations: POSITIONING
1. avoid breasts, eyes, gonads, and thyroids 2.PA skull/FB to reduce exposure to the lends 3.PA C-spine to reduuce exposure to the thyroid 4.PA t-spine to for scoliosis to reduce exposure to the breasts USE immobilization devices to prevent patient motion
Target interactions:x-rays are produced by one of these two methods when electrons interact with the anode (target)
1. bremsstrahlung (braking): happens when an accelerating electron is slowed down or stopped by the tungsten atom, as an electron decelerates, its lost energy is converted to either heat energy or x-ray energy; the energy of the x-ray will be equal to the energy lost by the electron; the maximum energy equal to the peak kVp applied during the exposure 2. Characteristic- go to flashcard ; must be over 70keV worth of energy the electron knocks out a K-shell electron in the tungsten atom, If the L-shell electron drops down to the fill the hole by the K shell electron a 57.4 keV x-ray will be produced and if M shell electron drops down to fill the hole left by k-shell electron a 66.7 keV x-ray will be produced
Secondary Protective Barriers
1. consist of 1/32 inch lead equivalent 2. Extend from where primary protective barrier ends to the ceiling, with 1/2 inch overlap 3.Located where scatter or leakage may strike 4. x-ray control booth is secondary barrier -Exposure switch must have a cord short enough that the radiographer has to be behind the secondary protective barrier to operate switch -Lead window by control booth is 1.5mm lead equivalent
In the production of characteristic radiation at the tungsten target, the incident electron 1. ejects an inner-shell tungsten electron 2. ejects an outer-shell tungsten electron 3. is deflected, with resulting energy loss 4. is deflected, with resulting energy pain
1. ejects an inner-shell tungsten electron
what are two general types of radiation detection devices? 1. field survey and personnel monitoring 2. survey meters and badges 3. pocket and portable dosimeters 4. particle and ray detectors
1. field survey and personnel monitoring field survey units (ionization chambers and GM counters) are used to determine exposure rates and detection of radiation. and personnel monitoring (film badges and TLDS) measure dose (dosimetry
Inherent Filtration
1. glass envelope in xray tube 2.insulating oil around the tube 3.diagonal mirror used for positioning light
which of the following characteristics makes lead such an excellent protective barrier
1. high density 2. high atomic number 3. high absorption coefficient
high risk exams for Males
1. hip/pelvis 6.00 2.l-spine 2.18 3.IVU 2.07 4.BE 1.75 5.abdomen .97 6. voiding cystourethrogram
which of the following is responsible for producing free radicals? 1. Indirect effect 2. Target theory 3. Direct effect 4. mutations
1. indirect effect
the automatic exposure device that is located immediately under the x-ray table is 1. ionization chamber 2. scintillation camera 3. photomultiplier 4. photocathode
1. ionization chamber
does filtration affect the primary beam? 1. it increases the average energy of the primary beam 2. it decreases the average energy of the primary beam 3. it makes the primary beam more penetrating 4. it increases the intensity of the primary beam
1. it increases the average energy of the primary beam filtration filters out the low energy x-rays that would potentially stay inside the body rather than exit
Pregnant patients
1. it responsible for the referring physician to determine whether a diagnostic exam involving x-rays is necessary; benefit should outweigh the risk; if abdomen/pelvis is involved, the radiologist should communicate the risk of the exam to the doctor and patient 2.most diagnostic x-ray exams have equivalent dose of less then 0.01 mSv 3. radiation doses of less than 0.01 mSv to the embryo or fetus are considered lower risk
Automatic Brightness Control (ABC) or Automatic Exposure Rate Control (AERC) in FLuoroscopy
1. kVp and mA are automatically adjusted during fluoro, which keeps image brightness level 2. The ABC or AERC delivers to the image receptor only the exposure that is required to maintain the necessary image quality adjusts to part thickness its efficient reducing time and patient exposure AERC: is defined to keep the SIGNAL TO NOISE (SNR) constant by adjusting the exposure factors automatically when the generator responds by increasing the kVp, the subject contrast decrease, but the dose to the patient is kept low, because more x-rays penetrate the patient at higher kVp
types of protection NRCP #102
1. lead aprons: .5mm Pb 2. lead gloves: .25mm Pb 3. thyroid shields: 4. protective eyewear 5. fixed or mobile 6. lead barriers ***Primary barrier: 7 feet high, 1/16 in. thick protects against primary radiation (useful) radiation ***secondary barrier: protects against scatter and leakage radiation ex) control booth Pb 1/32 in. thick extended to ceiling , lead apron, wall
which of the following radiation induced- conditions is most likely to have the longest latent period? 1. leukemia 2. temporary infertility 3. erythema 4. acute radiation lethality
1. leukemia : late effect (stochastic) the rest are deterministic effects that happen onset
Dose Area Product (DAP) in Fluoroscopy
1. may be read on a DAP meter on the fluoro monitor 2.expressed as mGy-cm^2 measures the radiation dose to air, times the area of the x-ray field
what would be the probable result of any major radiation exposure during the first few days of pregnancy? prenatal death postnatal death 3.a child with genetic deficiencies 4.a normal birth and infant
1. prenatal death major exposure would probably cause a spontaneous abortion
Fluoroscopy: AIR KERMA and Cumulative air kerma
1. provides an approximate skin dose where the x-ray beam is entering the patient 2.is displayed during fluoro procedure 3. Monitoring air kerma is a way to keep dose to the patient lower, especially during long procedures 4. Expressed as Gya (a = deposited in a mass of air) Gya/minute shall be continuously displayed the cumulative air kerma in units of mGy shall be displayed either within 5 seconds of termination of an exposure or displayed continuously and updated at least once every 5 seconds
last image hold (LIH) in Fluoroscopy
1. provides for keeping the most recently aquired fluoro image displayed on the monitor without continued radiation exposure to the patient 2. using last image hold reduces patient exposure by allowing the fluoroscopist to evaluate an image without continuing to expose the patient
Measuring patient dose you need
1. skin entrance dose 2. Mean Marrow Dose (MMD): average dose to active bone marrow
all of the following radiation - exposure responses exhibit a nonlinear, threshold dose response relationship
1. skin erythema 2. hematologic depression 3. radiation lethality (death/harm) Leukemia is (linear, nontreshold)
Source of Radiation Exposure to Radiographer
1. source of radiation exposure to the radiographer is Scatter Radiation from Compton interactions in the patient 2. greatest exposure to the radiographer is Fluoro, portable radiography, and surgical radiography 3. lead should be worn 4. photons lose energy after scattering 5. scatter beam intensity is about 1/1000 the intensity of the primary beam at a 90 degree angle at a distance of 1 meter from the patient 6. beam collimation reduces the incident of Compton interactions, resulting in reduced scatter 7. The use of high-speed image receptors may further reduce the scatter produced because of decreased quantity of radiation needed for exposure
effects of radiation where the probability of occurence, not severity of occurence, is proportional to the dose are called? 1. stochastic effects 2. genetic effects 3. deterministic effects 4. somatic effects
1. stochastic effect
somatic effects manifest in 1. the person who is being irradiated 2. the next generation 3. newborns 4. imaging technologist
1. the person who is being irradiated
Attenuation
1. thickness of the body part- body part may be the same like chest and abdomen but the abdomen will attenuate (absorb) more x-rays because its more dense 2. Type of tissue (atomic number) - the higher the atomic number of body part, the greater the attenuation of the x-ray beam and the greater the biological effect
Fundamental properties of x-rays
1. travels in a straight line 2.highly penetrating, invisible rays 3.electrically neutral 4.wide range of wavelengths (heterogenerous) 5.travels at the speed of light 6.capable of ionizing matter 7.cannot be focused by lens 8.effects digital images 9.causes certain crystals to fluorence 10.produces secondary and scatter radiation
Exposure Factors (EF)
1. use optimal/highest kVp with digital imaging (CR and DR) higher kvp techniques should be used to compensate for the slower disital systems the contrast of the image is controlled by the LOOK -UP-Table 2.lowest possible mAs to reduce the amount of radiation striking the patient 3.use calipers 4.reliable technique chart 5.use of automatic exposure control (AEC) reduces the number of repeat exposures
Collimator
1. variable aperture device 2.contains 2 sets of lead shutters pthe trat right angles to eachother 3.higher set of lead shutters is placed near the x-ray tube window to absorb off-stem (off focus radiation) 4.Lower set of lead shutters is placed near the bottom of the collimator box to restrict the beam further as it exits 5.accuracy of the collimator is subject to strict quality control standards 6.collimators should be no larger than the size of the IR being used 7.Collimators that automatically restrict the beam to the size of the IR have a feature called: POSITIVE BEAM LIMITATION, also called AUTOMATIC COLLIMATION 8.PBL responds when an IR is placed in the tray containing sensors that measure its size
According to NRCP Report No. 116, what is the annual effective dose limit for the general public, assuming frequent exposure?
1.0 mSv
To prevent leakage radiation from exposing the patient, an x-ray tube must have how much protective lead? 1. 1.5 mm 2. 2.5mm 3. 3.5mm 4. 4.5mm
1.5 mm
fluoroscopy
1.Use intermittent fluoroscopy not constant beam on condition 2.tight collimation 3.high kyp 4.source-to-tabletop for fixed fluoro not less than 15in 5.source-to-tabletop distance for portable fluoro not less than 12 in 6.proper filtration 7.fluoro timer that sounds alarm for 5 mins (300 sec) of beam on time 8.fluoro timer should not be reset before alarm goes off; 9.exposure switch must be dead-man type 10.limit dose at tabletop to no more than 100 mGya per minute 11.Limit the use of High-Level-Control Fluoro (used to reduce quantum mottle in angiography) during interventional procedures to no more than 200mGya per minute 12. Long exposure times greater than 30 minutes can lead to skin effects, (erythema, epilation) 13. Fluoro times should be recorded 14.pulsed fluoro or low dose modes should be used when possible to achieve ALARA 15. personnel should be standing on the image intensifier side of the C-arm during lateral/oblique projections 16.when possible use the C-arm with the xray tube below the patient for anterposterior and posterioanterior projections 17.radiaition dosimeter should be worn outside of lead at collar level 18.avoid using electronic magnification because it increase dose for patient and everyone in room
added filtration
1.aluminum sheets placed in the path of the beam near x-ray tube window 2.mirror placed in collimator head
stochastic effects of radiation can be defined by which of the following? 1.cells that survive an initial irradiation but produce late effects 2.cells that require a threshold dose before an effect will occur 3. the greater the dose, the greater the biological effect 4.the risk of malignancy is negligible
1.cells that survive an initial irradiation but produce late effects examples are cancer and genetic defects
Cytoplasm
1.composed primarily of water 2.conducts all cellular metabolism 3.contains organelles *Centrosomes: participate in cell division. *Ribosomes: synthesize protein *lysosomes: Contain enzymes for intracellular digestive processes * Mitochondria: produce energy *Golgi Apparatus: combines proteins with carbohydrates *Endoplasmic Reticulum: acts as a transportation system to move food and molecules within the cell
Cardinal principles of radiation protection
1.distance, 2.time, 3.shielding
which of the following measurements is equal to 1 joule per kilogram 1.gray 2.sievert 3.RBE 4.C/kg
1.gray
Cell Membrane
1.protects the cell 2.holds in water and nucleus 3.allows water, nutrients, and waste products to pass into and out of the cell (it is semipermeable)
Grids
1.result in an increase in patient dose because increased mAs is required 2.Use of appropriate type and ratio of grid for part being imaged and exam being performed Grids should not be used for small children. a 12:1 rato grid will increase exposure 5 times New DR systems use a 15:1 ratio grids, requiring 6 times more radiation than non grid
personnel monitoring is required when there is a likelihood that an individual will receive more than what percentage of the effective dose limit?
1/10
primary radiation barriers usually require which thickness of shielding?
1/16 inch > 1.6 mm
if a neutral atom has an atomic number of 10, then how many electrons will it have?
10 for an atom to be neutal, it has has to have the same number of positive charges (protons = atomic number) as negative charges = electrons)
How many angstroms are in a meter?
10,000,000,000 1 angstrom = 1x10^(-10) meters
how many centimeters are in a meter
100
the dose rate at the table top during fluoroscopy cannot exceed how many milliGray per minute. 1. 50 2. 100 3. 200 4. 250
100 mGy/min most calibrated to produce 21 mGy/mA/min. for the avg patient, 1-3 mA is required to produce an adequate image. the average patient recieves 20 - 60 mGy/min with no high level control then the radiation exposure shall be less than 100 mGy/min
minimum source-to-skin distance for mobile radiography is
12 inches
General Public - annual effective dose limit for frequent exposure is
1mSv
What quantity of radiation exposure to the reproductive organs is required to cause temporary infertility? 1. 1 Gy 2. 2 Gy 3. 3 Gy 4. 4Gy
2 Gy
which of the following is/are possible long-term somatic effect of radiation exposure? 1. blood changes 2. cataractogenesis 3. embryologic effects
2 and 3 only 2. cataractogenesis 3. embryologic effects
Stochastic effects of radiation are those that 1 have a threshold 2 may be described as "all-or-nothing" effects 3 are late effects
2 and 3 only 2. may be described as "all-or-nothing" effects 3. are late effects
the bucky slot cover is in place to protect the 1. patient 2. radiologist 3. technologist
2 and 3 only 2. radiologist 3. technologist NRCP 102 0.25 mm Pb
Patient dose during fluoroscopy can be minimized by which of the following? 1. Decrease tube to tower distance 2. Restrict beam size 3. Increase fluoroscopic milliamperage A. 1 only B. 2 only C. 3 only D. 1 & 3 only
2 only Restrict beam size
radiation monitoring instruments depend on which of the following? 1. space charge 2. ionization 3. electrification
2 only IONIZATION
which of the following will reduce exposure to the patient as well as improve image contrast? 1. Increase grid ratio 2. beam restriction 3. increase kVp 4. All the above
2 only beam restriction will produce less scatter
what percentage of the SID must the collimator light and actual irradiated area be accurate
2%
What is the intensity of scattered radiation perpendicular to and 1 m from a patient compared with the useful beam at the patients surface? 1. 0.01 % 2. 0.1 % 3. 1.0% 4. 10.0%
2. 0.1 %
According to NRCP regulations, leakage radiation from the x-ray tube must not exceed 1. 0.1 mGya/h (10 mR/h) 2. 1.0 mGya/h (100 mR/h) 3. 0.1 mGya/min (10 mR/min) 4. 1.0 mGya/min (100 mR/min)
2. 1.0 mGya/h (100 mR/h) HOUR
a 400 speed class requires how much less radiation than a 200 speed class? 1. 25% LESS 2. 50% LESS 3. 100% LESS 4. 200% LESS
2. 50% LESS to achieve the same brightness
which of the following is a radiation survey instrument? 1.OSLD 2.cutie pie 3.pocket dosimeter 4.TLD
2. CUTIE PIE radiation survey instruments are designed to detect x, gamma and beta radiation. A cutie pie looks like a space gun and is commonly found in nuclear medicine department
which of the following refers to the amount of ionizing radiation energy transferred by any type of radiation to and target material? 1.C/kg 2.gray 3.sieverts 4.kerma
2. Gray
which of the following may be used to express exposure in air? 1. air kerma 2. Gy 3. Sv 4. RBE
2. Gy - air kerma - radiation exposure (roentgen), quantity of ionizations in air Sv - biological material to express occupational and effective dose RBE - biological tissue Gyt
which of the following terms is correctly used to describe x-ray beam quality? 1. mA 2. HVL 3. Intensity 4. Dose rate
2. HVL and kVp
the interaction between ionizing radiation and the target molecule that is most likely to occur is? 1. direct effect 2. indirect effect 3. target effect 4. random effect
2. INDIRECT EFFECT
which of the following describes a primary protective barrier? 1. a lead apron 2. a barrier to absorb primary radiation 3. a barrier to absorb secondary radiation 4. a barrier to absorb leakage radiation
2. a barrier to absorb primary radiation
which of the following primarily involves loosely bound outer-shell electrons? 1. photoelectric interaction 2. compton interaction 3. coherent scatter 4.pair production
2. compton interaction
which of the following contributes most to occupational exposure exposure? 1. the phtoelectric effect 2. compton scatter 3. classic scatter 4. thompson scatter
2. compton scatter
which of the following photon-tissue interactions necessitates the use of a grid? 1. photoelectric interaction 2. compton interaction 3. coherent scatter 4.pair production
2. compton scatter
which of the following terms refers to the period between conception and birth? 1. gestation 2. congenital 3. neonatal 4. in vitro
2. congential
somatic effects of radiation refer to effects that are manifested 1. in the descendants of the exposed individual 2. during the life of the exposed individual 3. in the exposed individual and his or her descendants 4. in the reproductive cells of the exposed individual
2. during the life of the exposed individual examples are erythema, epilation, cataracts
which of the following cells are most radiosensitive? 1. myelocytes 2. erythrocytes 3. megakaryocytes 4. myocytes
2. erythrocytes myelocytes- WBCs erythrocytes- RBCs megakaryocytes- platelets myocytes - mature muscle cells
which of the following includes filters for measurement of radiation energy? 1. TLD 2. Film badge 3. handheld ionization chamber 4. geiger-mueller detector
2. film badge
which of the following is accurate as low as 100 uGya? 1. TLD 2. Film badge 3. handheld ionization chamber 4. geiger-mueller detector
2. film badge
which of the following government agencies is responsible for governing the use of radiation? 1. health, education, and welfare 2. food and drug administration 3. nuclear regulatory commission 4. environmental protection agency
2. food and drug administration
which of the following anomalies is/are possible if an exposure dose of 400 mGy (40 rad) were delivered to a pregnant uterus in the 3rd week of prenancy? 1. skeletal anomaly 2. organ anomaly 3. neurologic anomaly
2. organ anomaly
Some patients, such as infants and children, are unable to maintain the necessary radiographic position without assistance. If mechanical restraining devices cannot be used, which of the following should be requested or permitted to hold this patient? 1. transporter 2. patients father 3. patients mother 4. student radiographer
2. patients father
what is the term used to describe x-ray photon interaction with matter and the transference of part of the photons energy to matter? 1. absorption 2. scattering 3. attentuation 4. divergence
2. scattering
the most effective type of shield for anterior and lateral male gonadal protecting during fluoroscopy is? 1. flat contact 2. shaped contact 3. shadow 3. cylindrical
2. shaped contact
Late effects of radiation, whose incidence is dose related and for which there is no threshold dose, are referred to as 1. nonstochastic/deterministic 2. stochastic/probablistic 3. chromosomal abberration 4. hematologic depression
2. stochastic/probablistic
which of the following states that each cell has a master molecule thats directs all cellular activities and that, in inactivated, results in cellular death 1. Indirect effect 2. Target theory 3. Direct effect 4. mutations
2. target theory
the fact that some material can store energy, then emit light when heated, is the principle that is used for which of these? 1.Ion detector 2. thermolumescent dosimeter 3. rate meter 4. proportional spectometer
2. thermoluminescent dosimeter they are crystals that emit light when heated after being exposed to radiation
what should be the radiographers main objective regarding personal radiation safety? 1. not to exceed his or her dose limit 2. to keep personal exposure as far below the dose limit as possible 3. to avoid whole-body exposure 4. to wear protective apparel when "holding" patients for exposure
2. to keep personal exposure as far below the dose limit as possible
How many pounds are in a kilogram?
2.2 pounds the maximum amount of iodinated contrast media that can be given to a patient is 2 ccs per kilogram.
How many cm in an inch?
2.54 cm = 1 inch
which type of tissue will absorb the most radiation 1.air sacs 2.bone 3.muscle 4.soft tissue
2.BONE
which of the following definitions describes dose equivalent limits? 1. the maximum dose a body can tolerate 2.a dose that ensurers radiographers have the same risk as those in safe industries 3. the dose a worker will recieve/year 4. the maximum dose a radiation monitor records
2.a dose that ensurers radiographers have the same risk as those in safe industries limits are set to assure radiation workers are practicing in a safe environment
why is radiation exposure to the gonads such a critical concern? 1.the person may become sterile 2.mutations in offspring may result 3.gonadal cancer may develop
2.mutations in offspring may result radiation exposure to the gonads may alter the genetic code in the DNA molecule and cause mutation in future generations
The tabletop exposure rate during fluoroscopy shall not exceed
21 mGya/min/ma @ 80kvp
The electron limit per shell can be calculated from the expression _________
2n2
the annual dose limit for occupationally exposed individuals is valid for 1. alpha, beta, and x-radiation 2. x- and gamma radiations only 3. beta, x-, and gamma radiations 4. all ionizing radiation
3. beta, x-, and gamma radiations not alpha because it rapidly is ionizing
which of the following is the only photon-tissue interaction that does not result in ionization? 1. photoelectric interaction 2. compton interaction 3. coherent scatter 4.pair production
3. coherent scatter
which of the following produces scatter as a result of vibration of orbital electrons? 1. photoelectric interaction 2. compton interaction 3. coherent scatter 4.pair production
3. coherent scatter classical scatter
where do metabolic functions of a cell take place? 1. nucleus 2.chromosomes 3.cytoplasm 4.DNA molecule
3. cytoplasm
which of the following ionizing radiations is described as having an RBE of 1.0? 1. 10 meV protons 2. 5 MeV alpha particles 3. diganostic x-rays 4. fast neutrons
3. diganostic x-rays
what occurs when the master molecule is struck by radiation? 1. Indirect effect 2. Target theory 3. Direct effect 4. mutations
3. direct effect
which of the following is used to survey an area for radiation detection and measurement? 1. TLD 2. Film badge 3. handheld ionization chamber 4. geiger-mueller detector
3. handheld ionization chamber
how is coulomb per kilogram (C/kg) unit determined? 1.absorbed dose 2.ionization in air 3.half-value layer 3.compared with rem
3. ionization in air
a thermoluminescent dosimetry system would use which of the following crystals? 1.silver halide 2.sodium thiosulfate 3.lithium fluoride 4.aluminum oxide (OSL) most accurate
3. lithium fluoride
automatic exposure rate control (AERC) is designed to compensate for changes in which of the following?: 1.examination time 2. technique selection 3. patient positioning 4. patient dose
3. patient positioning as the patient is moved and repositioned, the anatomical areas allow more or less x-rays through. this changes the brightness of the fluoro image. The AERC automatically changes the mA or kVp settings to adjust for these changes in brightness so the image is always easy to view
which of the following refers to a regular program of evaluation that ensures the proper functioning of x-ray equipment, thereby protecting both radiation workers and patients? 1. sensitometry 2. quality assurance 3. quality control 4. Modulation transfer function
3. quality control
A time of 1.5 minutes is required for a particular fluoroscopic examination, whose exposure rate is 150 mGya/h. what is the approximate radiation exposure for the radiologic staff present in the fluoroscopy room during the examination? A. 100 mGya B. 40 mGya C. 5.62 mGya D. 3.75 mGya
3.75 mGya (150/60(min)) = (x mGya)/1.5 min) (150 * 1.5) / 60 = 3.75 mGya
which of the following types of equipment has a great effect on reducing population exposure? 1. fluoroscopic devices 2.tomographic machines 3.automatic exposure controls (AEC) 4.Computerized tomography equipment
3.automatic exposure controls (AEC) AEC automatically adjusts mAs for patient size and pathology, eliminating the guess work, and reducing the national repeat rate
the exposure of a radiation monitoring device is compared to which of these to determine the occupational exposure to the worker? 1. regional standard 2.national standard 3.control radiation monitoring device 4.fellow technologists monitoring device
3.control radiation monitoring device the exposure of the control radiation monitoring device is subtracted from the exposure of the workers radiation monitoring device to account for background radiation from transportation, handling, and storage
when radiation exposure causes hematopoietic death, what is the main reason why the person died? 1. hemorrhage 2.respiratory distress 3.immune system is destroyed 4.heart failure
3.immune system is destroyed since lymphocytes are the cells that are easiest to destroy, the person will die from infection
the exposure rate to a body 1.2m from a source of radiation is 53mGya/h. which of the following distances would best decrease the exposure to 6mGya/hr ? 1. 43m 2. 11m 3. 4m 4. 2m
4 m INVERSE SQUARE LAW 53 * (1.2)^2 = 76.32 / 6 = 12.72 square root = 3.56 m
how much radiation exposure reduced if the distance between the patient and technologist is doubled? 1. 2 times less 2. 4 times less 3. 6 times less 4. 8 times less
4 times less
the ESE for a particular exposure is 1.1 mGy what will be the intensity of the scattered beam perpendicular to and 1 m from the patient? 1) 1.0 mGy 2) 0.1 mGy 3) 0.01 mGy 4) 0.001 mGy
4) 0.001 mGy 1/1000 intensity = 0.1% of 1.1 = 0.001
the average annual patient dose from medical imaging procedures in 1990 was 0.6 mSv. in 2017 the average annual patient dose is? 1. 0.6 mSv 2. 1.2 mSv 3. 2.2 mSv 4. 3.2 mSv
4. 3.2 mSv they have tripled their dose since then
the information that cells require for metabolism is coded in which of the following? 1.cytoplasm 2.spindle fibers 3.RNA molecule 4.DNA molecule
4. DNA molecule
which of the following refers to the measuring the quantity of an x-ray beam? 1.quality control 2.quantity control 3.beam assurance 4.dosimetry
4. Dosimetry
which of the following methods is used to determine if an x-ray tube has adequate filtration? 1.read tube specifications 2. physical examination of tube 3. visual inspection of tube 4. Half-value layer (HVL) measurement
4. Half-value layer (HVL) measurement determines beam filtration. Title 21 coded of federal regulationss list minimum HVLs for various tube potentials
what term best describes the approximate skin dose where the x-ray beam is entering the patient 1. effective dose 2. nonoccupational dose 3. in-air exposure 4. air kerma
4. air kerma depositing energy at a certain point
which of the following is the unit of exposure dose of gamma or x-rays? 1. gray 2. joule 3. sievert 4. coulomb per kilogram
4. coulomb per kilogram
what detection device sounds an alarm to indicate the presence of radioactivity? 1. TLD 2. Film badge 3. handheld ionization chamber 4. geiger-mueller detector
4. geiger-mueller detector
which of the following cell types has the greatest radiosensitivity in the adult human? 1. nerve cells 2. muscle cells 3. spermatids 4. lymphocytes
4. lymphocytes
what is the minimum level of radiation exposure below which no genetic or somatic damage occurs? 1. 5 R 2. 10 R 3. 15 R 4. no minimum level is known
4. no minimum level is known there is no treshold dose, even the smallest amount of radiation has potential harmful effects
which of the following involves interaction between an incident photon and an atomic nucleus 1. photoelectric interaction 2. compton interaction 3. coherent scatter 4.pair production
4. pair production
which of the following personnel radiation monitors will provide an immediate reading? 1. TLD 2. Film Badge 3. Lithium Fluoride chips 4. pocket dosimeter
4. pocket dosimeter
During a radiographic examination, which of the following would produce the greatest skin dose? 1.high KVp technique 2. low mA technique 3.Long SID 4.Short SID
4.Short SID a short SID allows low energy x-rays to reach patient skin. SID can be no less than 12" in Radiographic exams
what does genetically significant dose mean? 1.dose that will cause damage 2.dose that will cause genetic damage 3.dose that will cause a mutation 4.estimated dose received by the population
4.estimated dose received by the population
which of the following filters would produce an x-ray beam with the highest average photon energy? 1. 1 mm Al 2. 2mm Al 3. 3mm Al 4. 4mm Al
4mm Al the thicker 4mm Al filter would filter out more energy x-rays, leaving a beam with only high energy photons
According to NRCP Report No. 116, the annual effective dose limit for for the general public assuming infrequent exposure
5 mSv
According to NRCP Report No. 116, what is the embryo or fetus equivalent dose limit for gestation
5 mSv
Occupational radiation monitoring is required when it is likely that an individual might receive more than? 1. .05 mSv 2. 0.1 mSv 3. 5 mSv 4. 50 mSv
5 mSv which is 1/10 of 50 mSv
personnel monitoring shall be performed if there is a possibility of exceeding how many millisievert per year?
5.0 mSv
what is the effective dose limit for a non radiation worker?
5.0 mSv/year
which of the following will produce the least ALARA to the patient
50 mAs, 60 kVp 25 mAs, 70 kVp Techcniques will produce equal amount of exposure due to 15% rule to the image recpetor, but the lower mAs and higher kVp will produce least exposure to the patient
natural background radiation represents what percentage of humans radiation exposure?
50%
what percentage of public exposure to ionizing radiation is from medical sources? 5% 10% 25% 50%
50%
Gonadal shields may reduce exposure to female gonads by up to: a. 50% b. 95% c. 10% d. 75%
50% 95% for males
what is the equivalent dose limits for the hands of a technologist a. 50 mSv/year b. 250 mSv/year c. 500 mSv/year d. 750 mSv/year
500 mSv NRCP #116
what is the equivalent dose limits for the hands and feet of a technologist?
500 mSv/year
Occupational exposure-annual effective dose is
50mSv
Students (older than age 18) annual effective dose limit is
50mSv
which of the following radiographic techniques will provide the least amount of exposure to the patient? 400 mas, 60kvp 200 mas, 70kvp 100mas, 80kvp 50mas, 92kvp
50mas, 92kvp lowest mAs, highest kVp
Embryo fetus - total equivalent dose for gestation is
5mSv
General Public - annual effective dose limit for infrequent exposure is
5mSv
Total annual background radiation dose
6.25 mSv annually (double compared to 1980s) 1980s = (3.125mSv)
primary radiation barriers must be at least how high?
7 feet (2.1 m)
primary radiation barriers in walls must be how high?
7 feet high
scatter radiation
A form of secondary radiation that occurs when an x-ray beam has been deflected from its path by interaction with matter major source of technologist exposure proper collimation stand 90 degrees to the x-ray beam because most scatter bounces back backscatter from other sources include walls, floor, x-ray table scatter from patients produce the most scatter
which of the following represents a form of stored or potential energy?
A rubber band
A student radiographer who is under 18 years of age must not receive an annual occupational dose of greater than A. 0.1 rem (1 mSv) B. 0.5 rem (5 mSv) C. 5 rem (50 mSv) D. 10 rem (100 mSv)
A. 0.1 rem (1 mSv)
What minimum total amount of filtration (inherent plus added) is required in x-ray equipment operated above 70 kVp A. 2.5 mm Al equivalent B. 3.5 mm Al equivalent C. 2.5 mm Cu equivalent D. 3.5 mm Cu equivalent
A. 2.5 mm Al equivalent
The symbols 130-56Ba and 138-56 Ba are examples of which of the following? A. Isotopes B. Isobars C. Isotones D. Isomers
A. Isotopes because they have the same atomic number but different mass numbers ISOBARS: same mass number different atomic number ISOTONES: same number of neutrons but diff. atomic #s ISOMERS: same atomic number and same mass numer
Filters used in radiographic x-ray tubes generally are composed of A. aluminum B. copper C. tin D. lead
A. aluminum
Diagnostic x-radiation may be correctly described as A. low energy, low LET B. low energy, high LET C. high energy, low LET D. high energy, high LET
A. low energy, low LET
Aluminum filtration has its greatest effect on A. low-energy x-ray photons B. high-energy x-ray photons C. low-energy scattered photons D. high-energy scattered photons
A. low-energy x-ray photons
The term effective dose refers to A. whole-body dose B. localized organ dose C. genetic effects D. somatic and genetic effects
A. whole-body dose
Advantages of anatomic compression during imaging include 1. decreased patient dose 2. improved image contrast 3. improved spatial resolution
ALL THREE 1. decreased patient dose 2. improved image contrast 3. improved spatial resolution MRI? compressed to specific anatomy that they want on image
which of the following are by-products of photoelectric absorption? 1.photoelectron 2.characteristic radiation 3.ionized atom
ALL THREE photoelectric absorption results when a primary photon is absorbed by and ejects an electron (photoelectron). this produces a positive ion an characteristic radiation because the absent electron
types of secondary radiation barriers include - the control booth, - lead aprons, - the x-ray tube housing
ALL THREE - the control booth, - lead aprons, - the x-ray tube housing it includes scatter and leakage leakage radiation less than 1 mGya/h at a distance of 1m
Patient dose during fluoroscopy is affected by 1. distance between the patient and the input phosphor 2. amount of magnification 3. tissue density
ALL THREE -distance between the patient and the input phosphor -amount of magnification -tissue density
Moving the image intensifier closer to the pt during fluoroscopy: 1. decreases the SID 2. decreases the pt dose 3. improves the image quality
ALL THREE 1. decreases the SID 2. decreases the pt dose 3. improves the image quality
types of structural damage to DNA molecule by ionizing radiation include which of the following? 1. single side scission 2. double side rail scission 3. cross-linking
ALL THREE 1. single side scission 2. double side rail scission 3. cross-linking
which of the following accounts for an x-ray beams heterogeneity 1. incident electrons interacting with several layers of tungsten target atoms 2. energy differences among incident electrons 3. electrons moving to fill different shell vacancies
ALL are CORRECT 1. incident electrons interacting with several layers of tungsten target atoms 2. energy differences among incident electrons 3. electrons moving to fill different shell vacancies
the operation of personnel radiation monitoring devices can depend on which of the following? 1. ionization 2. luminensence 3. thermoluminescence
ALL are CORRECT 1. ionization 2. luminensence 3. thermoluminescence
which of the following statements is/are true with respect to radiation safety in fluoroscopy? 1. tabeltop radiation intensity must not exceed 21 mGya/min/mA 2. tabletop radiation intensity must not exceed 100 mGya/min 3. in high level fluoroscopy, tabletop intensity should be up to 200 mGya/min
ALL are CORRECT 1. tabeltop radiation intensity must not exceed 21 mGya/min/mA 2. tabletop radiation intensity must not exceed 100 mGya/min 3. in high level fluoroscopy, tabletop intensity should be up to 200 mGya/min
According to 21 CFR, which of the following is/are true concerning fluoroscopic equipment manufactured after June 10, 2006? A. Air kerma rate (AKR) must be updated every 1 second B. Cumulative air kerma must be updated every 5 seconds C. Irradiation time must be updated every 6 seconds D. All of the above
ALL the Above A. Air kerma rate (AKR) must be updated every 1 second B. Cumulative air kerma must be updated every 5 seconds C. Irradiation time must be updated every 6 seconds D. All of the above
which of the following are possible long-term somatic effects of ionizing radiation 1.life-span shortening 2.malignant neoplasm 3.blood deficiences
ALL three 1.life-span shortening 2.malignant neoplasm 3.blood deficiences
a person exhibiting radiation sickness would have which of the following symptoms? 1.nausea 2.diarrhea 3.loss of appetite
ALL three 1.nausea 2.diarrhea 3.loss of appetite
which of the following determines what the final effect from radiation will be? 1.type of radiation 2.type of tissue 3.energy of radiation
ALL three 1.type of radiation 2.type of tissue 3.energy of radiation
of the following types of radiation, which one is considered the most ionizing? alpha beta x-ray gamma
ALPHA gamma and xray are least ionizing
what is the device called that allows current to flow in only one direction? 1. Insulator 2. Conductor 3. Semiconductor 4. Capacitor
Answer is SEMICONDUCTOR 1. Insulator: A material or an object that does not easily allow heat, electricity, light, or sound to pass through it. like glass think for a house 2. Conductor:a conductor is an object or type of material that allows the flow of charge in one or more directions. Materials made of metal are common electrical conductors 4. Capacitor: (originally known as a condenser) is a passive two-terminal electrical component used to store energy electrostatically in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors (plates) separated by a dielectric (i.e., insulator).
what is meant by ionizing radiation
Any radiation capable of removing an orbital electron ionizing radiation is potentially harmful
How many half-value layers are required to reduce a 100 C/kg/minute exposure rate to 25 C/kg/minute? A. 1 B. 2 C. 4 D. 8
B. 2 one HVL will reduce the 100 C/kg/minute to 50 C/kg/minute, a second HVL will reduce 50C/kg/minute to 25 C/kg/minute
Standards state that the exposure in air from fluoroscopic equipment shall not exceed how many Coulomb/kg/minute? A. 1.29 x 10-3 Coulomb/kg (5 R) B. 2.58 x 10-3 Coulomb/kg (10 R) C. 3.87 x 10-3 Coulomb/kg (15 R) D. 5.16 x 10-3 Coulomb/kg (20 R)
B. 2.58 x 10-3 Coulomb/kg (10 R) most fluorscopic equipment is calibrate to emit R/minute/mA. since fluoroscopic mA usually between 3-5 mA, if calibrated properly it could not exceed 10 R/minute even at maximum output
How many HVLs are required to reduce the intensity of a beam of monoenergetic photons to less than 15% of its original value? A. 2 B. 3 C. 4 D. 5
B. 3
An optically stimulated luminescence dosimeter contains which of the following detectors? A. Gadolinium B. Aluminum oxide C. Lithium fluoride D. Photographic film
B. Aluminum oxide
Patient dose increases as fluoroscopic A. FOV increases B. FOV decreases C. FSS increases D. FSS decreases
B. FOV decreases as the diameter decreases the magnification will increase which in return increases contrast and resolution
Mobile fluoroscopic equipment must have which of the following? A. VCR capabilities B. Image intensification C. T.V. monitoring D. Solid state circuitry
B. Image intensification brightens the image about 4000 times which allow less radiation to the patient
With milliamperes (mA) increased to maintain output intensity, how is the ESE affected as the source-to-skin distance (SSD) is increased? A. The ESE increases. B. The ESE decreases. C. The ESE remains unchanged. D. ESE is unrelated to SSD.
B. The ESE decreases.
The purpose of filters in a film badge is A. to eliminate harmful rays B. to measure radiation quality C. to prevent exposure by alpha particles D. as a support for the film contained within
B. to measure radiation quality
The amount of time that x-rays are being produced and directed toward a particular wall is referred to as the A. workload B. use factor C. occupancy factor D. controlling factor
B. use factor workload: # of x-rays per week occupancy factor: jobs
the largest amount of diagnostic x-ray absorption is most likely to occur in which of the following? 1. lung 2. adipose 3. muscle 4. bone
BONE
Converting Fahrenheit to Celsius
C = 5/9 (F-32)
For exposure to 1 rad (10 mGy) of each of the following ionizing radiations, which would result in the greatest dose to the individual? A. External source of 1-MeV x-rays B. External source of diagnostic x-rays C. Internal source of alpha particles D. External source of beta particles
C. Internal source of alpha particles
A dose of 250 mGy (25 rad) to the fetus during the seventh or eighth week of pregnancy is likely to cause which of the following? A. Spontaneous abortion B. Skeletal anomalies C. Neurologic anomalies D. Organogenesis
C. Neurologic anomalies
The dose of radiation that will cause a noticeable skin reaction is referred to as the A. LET B. SSD C. SED D. SID
C. SED A sedimentation rate, or "sed rate", is a blood test that detects and is used to monitor inflammation activity. ... It increases (the RBCs sediment faster) with more inflammation.
Which type of dose-response relationship represents radiation-induced leukemia and genetic effects? A. Linear, threshold B. Nonlinear, threshold C. Linear, nonthreshold D. Nonlinear, nonthreshold
C. linear, nontreshold
In which type of monitoring device do photons release electrons by their interaction with air? A. Film badge B. TLD C. Pocket dosimeter D. OSL dosimeter
C. pocket dosimeter
If a human is exposed to radiation levels in the 100 to 200 R range, which of the following is expected? 1 to 2 Gy range A. No clinical effects B. Slight reduction in lymphocytes C. Complete recovery in 90 days D. Death within 30 days
Complete recovery within 90 days they would experience nausea, vomiting, diarrhea, and decreasing blood counts but completely recover
the x-ray interaction with matter that is responsible for the majority of scattered radiation reaching the image receptor is? 1.the photoelectric effect 2. compton scatter 3. classical scatter 4. thompson scatter
Compton scatter
Examples of late effects of ionizing radiation on humans include 1. leukemia 2. local tissue damage 3. malignant disease A. 1 only B. 1 and 2 only C. 1 and 3 only D. 1, 2, 3
D. 1, 2, 3 1. leukemia 2. local tissue damage 3. malignant disease
The target theory applies to A. spermatagonia B. oocytes C. lymphocytes D. DNA molecules
D. DNA molecules
Which type of personnel radiation monitor can provide an immediate reading? A. Thermoluminescent dosimeter (TLD) B. Optically stimulated luminescence (OSL) C. Film badge D. Ionization chamber
D. Ionization chamber located under the x-ray table
How will x-ray photon intensity be affected if the source-to-image distance (SID) is doubled? A. Its intensity increases two times. B. Its intensity increases four times. C. Its intensity decreases two times. D. Its intensity decreases four times.
D. Its intensity decreases four time
A readout on the fluoroscopic monitor that indicates air kerma striking the surface of the patient is ___________.
DAP meter
Automatic Exposure Control (AEC)
Device that terminates the exposure when a specific quantity of radiation has reached the image receptor (IR). AEC controls the exposure time and the total mAs used for the exposure has to have an audible sound and visible detector
Determinants of Barrier Thickness: Distance
Distance: between the source of radiation and the barrier
Photodisintegration
Does not occur in diagnostic radiography
Fluoroscopic Equipment
Exposure Switch: must be dead-man type Protective Curtain: Minimum of 0.25mm lead equivalent Bucky Slot Shield: Minimum of 0.25mm lead equivalent 5 minute timer with audible alarm
which of the following is least expensive type of radiation monitoring device? 1. thermoluminescent dosimeter (TLD) 2.Optically stimulated luminescent dosimeter (OSL) 3.film badge 4.pocket dosimeter
FILM BADGE
what is the molecule called that has one or more unpaired electrons and is unusually chemically reactive? 1. ion 2.mutation 3.free radical 4.excited molecule
Free radical they are highly energized and travel at high speeds causing more damage than the radiation
Frequency and wavelength
Frequency: number of oscillations per second (Hz) Wavelength: distance from one peak to the next successive peak in a ray. --Frequency and wavelength are inversely proportional
which of the following units would be used to describe the radiation present in the fluoroscopic room? 1. Bq 2. Sv 3. Gya 4. Gyt
Gya
Alpha, beta, neutrons are considered
High LET radiations
which describes a beta particle
High speed electron
The fact that distance is the best protection against radiation is proven by which of these laws? A. Ohm's law B. Inverse square law C. Coulomb's law D. Law of conservation of energy
INVERSE SQUARE LAW when distance increases radiation intensity decreases
which describes an atom that has lost one or more of its electrons
ION
Oxygen Enhancement Ratio (OER)
If cells are more oxygenated, they are more susceptible to radiation damage oxygen creates additional free radicals which increases the damage to the cell OER is 3 for low LET radiation (xrays, gamma ) 1.5 for fast neutrons 1 for high LET radiation (alpha)
Reproductive cells
Immature sperm cells: Very radiosensitive, divide rapidly, unspecialized, require 10 rads or more (which is beyond most commonly used diagnostic levels) to increase chances of mutations Ova in female fetus and child are very radiosensitive Ovarian radiosensitivity decreases until near middle age, then increases again
what is the most radiosensitve area of the eye
LENS cataracts could develop but would need high C/kg exposure
RBE (relative biological effectiveness) biological damage produced by radiation increases as
LET of radiation increases RBE s affected by type of radiation, dose rate, and tissue type
Cardinal principles of radiation protection - SHIELDING
Lead equivalent shielding absorbs most of the energy of the scatter radiation 1. a lead apron of at least 0.25 mm lead equivalent MUST be worn (0.5mm lead equivalent should be worn) during exposure to scatter radiation; thyroid shield of at least 0.5 mm lead equivalent should be worn for fluoroscopy 2. Radiographer should never be exposed to the primary beam 3. If exposure to the primary beam i unavoidable then the exam should not be performed 4. family members, nonradiology employees, or radiology personnel not routinely exposed should e first to assist with immobilization of the patient 5. radiographer and student radiographer should be the last one chosen to assist in with immobilization during an exposure 6. Thickness recommendations for lead devices have determined by NCRP Report #102
X-rays and Gamma rays are considered?
Low LET The more energy that is transferred, the more ionizations occurs which more biological damage occurs
"Added tube filtration should be adjusted by the radiographer: a. To "harden" the x-ray beam b. To remove the soft rays from the x-ray beam c. To exercise radiation protection d. Never"
NEVER
all of the following statements regarding TLDs are true except 1. TLDs are reusable 2. a TLD is a personal radiation monitor 3. TLDs use a lithium fluoride phosphor 4. after x-ray exposure, TLDs emit heat in response to stimulation by light
NOT TRUE 4. after x-ray exposure, TLDs emit heat in response to stimulation by light they dont emit heat they emit light
which of the following is not a function of a DNA molecule 1.it carries the genetic code 2. it duplicates exact copies of itself 3.it synthesizes proteins 4. it divides during mitosis
NOT TRUE: synthesizes proteins because thats RNAs job
annual dose is published by the
NRCP
which of the following is NOT a property of x-rays?
Negatively charged because they dont have a charge nor a mass
Unit of force
Newton
Indirect effect results
No effect - Most common formation of free radicals formation of H2O2 (hydrogen peroxide) **Most damage to the body occurs as a result of indirect effect because most of the body is water, and free radicals are readily mobile in water
Results of Direct effect
No effect is MOST COMMON -Disruption of chemical bonds, causing alteration of cell structure and function -Cell Death -Cell line death -Faulty info. passed on in the next cell division; results could be mutations, cancer, and abnormal information
When were x-rays discovered?
November 8, 1895 by Wilhelm Roentgen
where would the RNA molecules be found in a human cell, other than the cytoplasm?
Nucleus transfers RNA from nucleus to cytoplasm
which of the following is the most sensitive personnel monitoring device? 1. TLD 2.Film badge 3. OSL dosimeter 4. geiger-mueller detector
OSL dosimeter
Determinants of Barrier Thickness: Occupancy CONTROLLED AREA
Occupancy : Who occupies a given area Controlled Area: occupied by persons trained in radiation safety and wearing personnel monitoring devices; shielded to keep exposure under 1 mSv per week
Determinants of Barrier Thickness: Occupancy UNCONTROLLED AREA
Occupancy : Who occupies a given area Uncontrolled Area: areas where personnel are not provided radiation exposure monitors (dosimeters) or radiation safety training should be shielded to ensure an effective dose limit to the general public of 20 uSv per week
what is the primary purpose of beam filtration
Protect patient from low energy x rays
Other cell components
Proteins - 15% of cell Carbohydrates - 1% of cell Lipids - 2% of cell Nucleic Acids - 1% of cell Water - 80% of cell Acids, Bases, Salts (electrolytes) - 1%
the ability of different types of radiation to produce the same biological response in an organism is called: 1. LET 2. Wr 3. RBE 4. doubling dose
RBE
Genetically Significant Dose (GSD)
Radiation dose that, if received by the entire population, would cause the same geterm-136netic injury as the total of doses received by the persons actually being exposed; the average gonadal dose to the childbearing-age population
A controlled area is one occupied primarily by:
Radiology personnel Patients
Muscle Tissue
Relatively insensitive because of high specialization and lack of cell division
Other human man-made background radiation (artificially produced radiation)
Remaining 2% of effective dose (.05 mSv) Sources - 1. Occupational exposure 2.Various consumer products 3.and other sources
the unit of measurement used to express occupational exposure is 1. Gya 2. Gy 3. Sv 4. RBE
Sv
Convert 68 degrees Fahrenheit to degrees Celsius.
T(°C) = (68°F - 32) × 5/9 = 20 °C
which of the following would never be considered as a primary barrier in normal diagnostic radiograpghy? 1.a wall 2. the floor 3. the ceiling 4. a mobile shield
THE CEILING tube never pointed at the ceiling when doing exams
Sievert is calculated by multiplying gray by 1, Wr 2. Wt 3.Wa 4. mAs
WR radiation weighting facor
Sievert is calculated by multiplying gray by
WR radiation weighting factor
Exposures made at 100 mA, 200 mA, and 300 mA produced mR reasing of 40 mR, 76 mR, and 126 mR respectively, does this pass the mA linearty test?
YES 40mR/100 mA = .4mR/Mas 76mR/200mA = .38 mR/mAs 126mR/ 300 mA = .42 mAs they are all within (+/-) 10% of each other
Blood Cells
Whole body dose of 25 rads depresses blood count - caused by irradiation of bone marrow -lymphocytes are the most radiosensitive blood cells in the body -stem cells in bone marrow are especially radiosensitive
which of the following are disadvantages of using a flat piece of lead for gonadal shielding? 1. cannot be used for erect views 2.difficult to keep in place 3.is not very useful for fluoroscopy
all THREE 1. cannot be used for erect views 2.difficult to keep in place 3.is not very useful for fluoroscopy MOST OFTEN USED
minimal (M) readings on dosimeter reports mean:
a dose below the sensitivity of the dosimeter has been recieved
Filtration
a filter is placed in the x-ray beam to remove long-wavelength (low energy) x-rays. which increases patient dose through the photoelectric effect Two types of filtration INHERENT and ADDED
The presence of ionizing radiation may be detected in which of the following ways? 1 Ionizing effect on air 2 Photographic effect on film emulsion 3 Fluorescent effect on certain crystals
all are CORRECT 1 Ionizing effect on air 2 Photographic effect on film emulsion 3 Fluorescent effect on certain crystals
Effects of deoxyribonucleic acid (DNA) irradiation include 1. mitotic delay 2.reproductive death 3. chromosome breakage
all are CORRECT 1. mitotic delay 2.reproductive death 3. chromosome breakage
the reduction of intensity of radiation as it passes through a material is known as
attenutation
which of the following radiation situations is potentially the most harmful?
a large dose to the whole body all at one time
Biologic material is least sensitive to irradiation under which of the following conditions? A. Anoxic B. Hypoxic C. Oxygenated D. Deoxygenated
a. anoxic (without oxygen)
1. x-ray production - the following four conditions are necessary to produce x-rays
a. source of free electrons (thermionic emission) - electrons are released from the surface of one of the two filament wires by a process called thermionic emission while current passed through the filament wire heat (therm) causes the separation of electrons (ionic) which will be released from the wire (emission) b. acceleration of electrons - the free electrons must be accelerated across the x-ray tube from cathode to anode kilovoltage (kVp) forces the electrons across the tube giving them kinetic energy; the higher the kVp the more energy the accelerating electrons will have c. focusing of electrons - a focusing cup houses the filament wires, the focusing cup holds the released electrons around the filament wires in a tiny cloud called a spcae charge until the exposure switch is engaged; when the kilovoltage is applied, during the exposure, the electrons are focused into a narrow beam that is directed toward the anode d. deceleration of electrons - to convert kinetic energy into x-ray energy the accelerating electrons must be slowed down or stopped (deceleration), the electrons decelerate when they strike the anode, a tungsten disk which has a high atomic number and high melting point
Occupational exposure - annual equivalent dose limits for deterministic effects a. lens of the eye - b. localized areas of skin, hands, feet -
a.150mSv b.500mSv
Relative Biological Effectiveness (RBE)
ability to produce biological damage; varies with the LET So as LET increases so does RBE the Wr used to calculate sievert is a measure of the RBE of the radiation being used Ionizing radiation may change the molecular structure of a cell, affecting its ability to function properly Somatic cell exposure may result in a disruption in the ability of the organism to function Reproductive (germ cell) exposure may result in changes, called mutation: being passed to the next generation Basically, radiation striking a cell deposits energy in either DNA (direct effect) or water in the cytoplasm (an indirect effect) if an interaction occurs Most radiation passes through the body without interacting because atoms are composed mainly of empty space
attenuation
absorption and scatter (loss of intensity) of the x-ray beam as it passes through the patient describes changes in the intensity of the x-ray beam as it traverses the patient leads high atomic number assures that most scatter x-rays will be absorbed
High-level, whole body radiation exposure, delivered in a period of seconds to minutes, produces a clinical pattern known as what? A. Mortality irradiation B. Cumulative exposure C. Whole body dose D. Acute radiation syndrome
acute radiation syndrom acute(sudden onset) syndrome(set of symptoms)
cumulative effective dose limit is
age (in years) x 10mSv
which of the following has (have) an effect on the amount and type of radiation induced tissue damage 1. quality of radiation 2. type of tissue being irradiated 3. fractionation
all are CORRECT 1. quality of radiation 2. type of tissue being irradiated 3. fractionation
Which of the following factors can affect the amount or the nature of radiation damage to biologic tissue? 1. radiation quality 2. absorbed dose 3. size of irradiated area
all are CORRECT 1. radiation quality 2. absorbed dose 3. size of irradiated area
which of the following statements regarding the pregnant radiographer is/are true? 1. she should declare her pregnancy to her supervisor 2. she should be assigned a second personnel monitor 3. her radiation history should be reviewed
all are CORRECT 1. she should declare her pregnancy to her supervisor 2. she should be assigned a second personnel monitor 3. her radiation history should be reviewed
which of the following radiation protection concepts/measures apply to mobile radiography 1. the radiographer should be at least 6 feet from the patient and the x-ray tube during the exposure 2. the least amount of scattered radiation is perpendicular to the scattering object 3. at least one lead apron should be assigned to each mobile unit
all are CORRECT 1. the radiographer should be at least 6 feet from the patient and the x-ray tube during the exposure 2. the least amount of scattered radiation is perpendicular to the scattering object 3. at least one lead apron should be assigned to each mobile unit
which of the following safeguards is/are taken to prevent inadvertent irradiation in early pregnancy? 1. patient postings 2. patient questionnaire 3. elective booking
all are Correct 1. patient postings 2. patient questionnaire 3. elective booking
which of the following is/are considered especially radiosensitive tissues? 1. bone marrow 2. intestinal crypt cells 3. erythroblasts
all are correct 1. bone marrow 2. intestinal crypt cells 3. erythrocytes
which of the following is/are features of the fluoro equipment designed especially to eliminate unnecessary radiation to a patient and/or personnell? 1. protective curtain 2. filtration 3. collimation
all are correct 1. protective curtain 2. filtration 3. collimation
examples of stochastic effects of radiation exposure include 1. radiation-induced malignancy 2. genetic effects 3. leukemia
all are correct 1. radiation-induced malignancy 2. genetic effects 3. leukemia
possible response to irradiation in utero include 1. spontaneous abortion 2. congential anomalies 3. childhood malignancies
all are correct 1. spontaneous abortion 2. congential anomalies 3. childhood malignancies
the biologic effect on an individual depends on which of the following? 1. type of tissue interactions 2. amount of interactions 3. biologic differences
all are correct 1. type of tissue interactions 2. amount of interactions 3. biologic differences
which of the following are reasons for using beam restricting devices? 1.reduce scatter radiation 2.reduce patient exposure 3.Improve image contrast
all are excellent reasons to collimate 1.reduce scatter radiation 2.reduce patient exposure 3.Improve image contrast
which of the following could result from excessive radiation exposure to the fetus during the first trimester? 1. prenatal death 2. neonatal death 3. congenital abnormalities
all three 1. prenatal death: at 10 rem the first two weeks 2. neonatal death: would need a large dose during 2-8 weeks 3. congenital abnormalities: 10rem during 2-8 weeks
Gross structural changes that arise when radiation breaks a chromosome may be referred to as what? 1. Aberrations 2. Anomalies 3. Lesions A. 1 & 2 only B. 1 & 3 only C. 2 & 3 only D. 1, 2 & 3
all three 1. Aberrations 2. Anomalies 3. Lesions
which of the following can be an effective means of reducing radiation exposure? 1. barriers 2. local tissue damage 3. malignant disease
all three are correct 1. barriers 2. local tissue damage 3. malignant disease
artificially produced radiation
also called man-made radiation (ex: medical x-rays) gamma rays
optically stimulated luminescence (OSL) uses which of the following to detect radiation
aluminum oxide
Linear Energy Transfer (LET)
amount of energy deposited by radiation per unit length of tissue
Cardinal principles of radiation protection - TIME
amount of exposure is directly proportional to duration of exposure
Minimum source-to-skin distance for portable radiography
at least 12 inches
Determinants of Barrier Thickness: Use Factor
amount of time the beam is on and directed at a particular barrier
air gap technique
an alternative to using a grid. Primary applications in magnification radiography and, to a lesser extent, in chest radiography. The technique involves placing the pt at a greater OID, creating an air gap b/w the pt and the IR. The amt of scatter reaching the IR will be reduced. This can reduce the exposure as much as 5 times
non-treshold
any dose has the potential to cause a response (x-axis)
most common photon-tissue interactions in diagnostic radiography
are Photoelectric and Compton interactions
An increase in total filtration of the x-ray beam will increase A. patient skin dose B. beam HVL C. image contrast D. milliroentgen (mR) output
b. beam HVL
Most somatic effects occur: a. At doses delivered during diagnostic radiography b. At doses beyond doses used during diagnostic radiography c. In middle age d. In old age because of an increase in medical care
b. At doses beyond doses used during diagnostic radiography
Cell radiosensitivity is described by the: a. Inverse square law b. Law of Bergonie and Tribondeau c. Reciprocity law d. Ohm's law
b. Law of Bergonie and Tribondeau
the law that states that cells are most sensitive to radiation when they are nonspecialized and rapidly dividing is the a. Inverse square law b. Law of Bergonie and Tribondeau c. Reciprocity law d. Ohm's law
b. Law of Bergonie and Tribondeau
Lead aprons are worn during fluoroscopy to protect the radiographer from exposure to radiation from A. the photoelectric effect B. compton scatter C. classic scatter D. pair production
b. compton scatter
distance
best protection against radiation exposure if the distance is doubled, the exposure is reduced 4 times at 1 meter from the patient, at a roght angle to the beam, the scatter intensity is .1% of the primary beam incident on the patient 2 meters is desirable to stand back
which of the following is also known as coherent scattering
classical scatter
Fluoroscopy: TIME
cumulative timer: 5 minutes alarm intermittent fluoro, where the rad periodically activates the x-ray beam instead of a continuous beam and Last image Hold to reduce time
The most radiosensitive portion of the GI tract is the A. upper esophagus B. stomach C. small bowel D. cecum and ascending colon
c. SMALL BOWEL * crypt cells of lieberkuhn cells are constantly be replaced highly mitotic and undifferentiated
Radiation output from a diagnostic x-ray tube is measured in which of the following units of measurement? A. sievert B. gray C. air kerma D. becquerel
c. air kerma
Ionization can result from which of the following interactions of radiation with tissue? A. Characteristic B. Bremsstrahlung C. Photoelectric absorption D. Coherent (classical) scatter
c. photoelectric absorption Cant be classical scatter because it doesnt remove an electron just vibrates
Law of Bergonie and Tribondeau
cells are most sensitive to radiation when they are immature, undifferentiateterm-102d, and rapidly dividing
As Low As Resonably Achievable (ALARA)
concept of radiologic practice that encourages radiation users to adopt measures that keep the dose to the patient and themselves at minimal levels
Nucleus
contains deoxyribonucleic acid (DNA- the master molecule) and the nucleolus (with ribonucleic acid (RNA)) DNA controls cell division DNA controls all cellular functions
what is the unit for radiation exposure in air
coulomb/kg Kerma is the preferred term
exposure
coulomb/kg is a direct measurement of the electrical charge generated by the ionization of air molecules coulomb/kg is measured with an ion chamber coulomb/kg is also the unit of joules, actually deposited in a unit of mass (kg) of air coulomb/kg is not used instead of the unit roentgen for the term exposure
effects of radiation that become more severe as dose increases are called: 1.dose-response curve 2. deterministic effects 3. genetic effects 4. somatic effects
deterministic effects
Each time an x-ray beam scatters, its intensity at 1 m from the scattering object is what fraction of its original intensity? A. 1/10 B. 1/100 C. 1/500 D. 1/1,000
d. 1/1000
During Compton effect, as the energy increases and the mass density of the absorber..
decreases the xray more likely to be scattered than absorbed
During Photoelectric absorption, the probability that an x-ray will be absorbed increase when the energy
decreases, the atomic number of absorber increases or the mass density of the absorber increases
NRCP report #116
defines annual exposure limits; makes recommendations pertaining to risk-benefit analysis of radiation exposure; states that somatic and genetic effects should be kept to a minimum when radiation is used for diagnostic imaging
Direct Flat Panel Detectors : Image Receptor
directly capture the x-ray image so it requires more radiation to produce an acceptable image; they would be considered a 200 speed class; to compensate for this HIGHER kVp can be the mAs ALARA
Fluoroscopy: Pulsed
doesnt need a continuous x-ray beam to produce 30 frames per second, therefore the pulse the xray beam, reducing patient exposure
the frequency of radiation-induced mutations is directly proportional to`
dose the effect is dependant on the rate at which the radiation is delivered (protraction) and on the time between exposures (fractionantion) Females are less sensitive to the genetic effects than males most radiation induced mutation is recessive and the frequency is low the effects are extremely low in diagnostic medicine
The total of air kerma over the exposed area of the patient is called
dose area product
Target Theory
each molecule has a master molecule (DNA) that direct cells activities if the DNA is the target of radiation damage and is inactivated, then the cell dies DNA may be inactivated by either direct or indirect effects All photons-cell interactions occur by chance whether a given cell death was a result of direct or indirect effects cannot be determined
Radiolysis of water
effect that occurs as radiation energy is deposited in the water of the cell; the result of radiolysis is an ion pair in the cell: a positively charged water molecule (HOH+) and a free electron
Direct effect
effect that occurs when radiation directly strikes DNA in the cellular nucleus or RNA As the macromolecules are ionizez, cell processes may be disrupted, some of the damage can be repaired IF DNA has sufficient damage, specifically to nitrogenous base - MUTATION can occur
Indirect effect
effect that occurs when radiation strikes the water molecules in the cytoplasm of the cell Since water makes up most of the cell, the probability of that it will be struck by radiation is greater The result of radiolysis is an ion pair in a cell: a positively charged water molecule (HOH+) and a free electron If the two ions recombine no damage occurs positive and negative water molecules may be formed and then break into smaller molecules such a free radicals free radicals may cause biological damage by transferring their excess energy to surrounding molecules or disrupting chemical reactions Some free radicals may combine to form hydrogen peroxide (H2O2) which can cause further damage to the cell Indirect effect results from ionization or excitation of water molecules
deterministic effects
effects of radiation that become more severe at high levels of radiation exposure and do not occur below a certain threshold dose when radiation increases its severity with an increase in radiation dose, occurs within days and typically has a TRESHOLD
equivalent dose
equal to the effective dose multiplied by the radiation weighting factor
leakage
escapes from the x-ray tube from places other than the window leakage cant exceed 1 mGy/hr/meter mobile radiography the tech should stand away from tube as far as possible
which of the following is a digital monitor that may be used to measure dose in area? 1. TLD 2. Film badge 3. pocket ionization chamber 4. handheld ionization chamber
handheld ionization chamber
which of the following may be used to measure in-air exposures in a fluoroscopic room 1. TLD 2. Film badge 3. handheld ionization chamber 4. geiger-mueller detector
handheld ionization chamber
when referring to a whole body dose, which of the following is NOT included? 1. eyes and neck 2. hands and feet 3. reproductive organs 4. blood forming organs
hands and feet whole body dose refers to thyroid, bone marrow, breasts, lungs
increasing field size, while leaving technical factors unchanged, will? 1. decrease the DAP 2. decrease SR production 3. Increase the DAP 4. Increase the EFS size
increase the DAP field size and DAP are proportional
MOST cell damage from ionizing radiation occurs when x-rays interact with: 1. direct effect 2. mutations 3. law of bergonie and tribondeau 4. indirect effect
indirect effect
Which interaction between ionizing radiation and the target molecule involves formation of a free radical? A. Direct effect B. Indirect effect C. Target effect D. Random effect
indirect effect
Occupational exposure
individuals exceeding 10% of the occupational dose limit of 50 mSv/year must wear radiation monitor NEW facilities should be designed to limit annual occupational exposures to a fraction of the 10mSv per year allowed by the cumulative dose
the photoelectric effect is an interaction between an x-ray photon and?
inner shell electron
DR's indirect flat panel detector : Image Receptor
intensifying phosphors are used for indirect flat panel detectors to reduce the amount of radiation to the patient; they would be considered 400 speed class
what is the name of the stage of cell division that is commonly referred to as the resting stage?
interphase
the phases of cellular life in order
interphase (G1, S, G2), prophase, metaphase, anaphase, telephase
if an exposure of 16mR is recorded at 1 meter, what would the exposure rate be at 4 meters?
inverse square law 1 mR
wavelength
is the distnce the x-ray travels during one regeneration of electric and magnetic fields, the unit is Angstrom (10 billionth of a meter)
LD 50
is the dose of whole body radiation that will kill 50% of the exposed individual; LD 50/60 means that 50% of the exposed individuals will die within 60 days; a whole body dose of 3.5 mSv would e necessary to kill 50% of the exposed inidviduals within 60 days
linear, nontreshold
is when its at 0,0 the straight line means its linear (effect increases as dose increases) and since its starts at zero there is no treshold (no amount of radiation would be considered safe)
treshold
it will take a certain dose before a response will manifest (ex-acute radiation syndrome) whole body dose must be 1 sievert (stays on Y-axis)
the difference between gamma and x-rays are
its origin
the term used to express kinetic energy released in matter is
kerma
what determines the wavelength of an x-ray
kilovoltage
the amount of energy deposited by radiation per unit length of tissue being traversed is
lET, which determines the use of a Wr when the equivalent dose is being calculated
which of the following materials is the most effective as a protective barrier?
lead
Protective drapes
lead screen drapes and table side shields "shall" be provided to minimize over-table scatter radiation from reaching operator .25mm Pb
radiation that leaves the tube housing by any means other than through the window is called what? 1. primary 2. scatter 3. leakage 4. remnant (exit)
leakage
compared with ova in younger and older women, ova in women of reproductive age are: 1. more radiosensitive 2. less radiosensitive 3. about the same
less radiosensitive
Biologic material irradiated under hypoxic conditions is
less sensitive than when under oxygenated conditions
cumulative effective dose
lifetime occupational exposure must not exceed the radiographers age multiplied by 10 mSv
all X-rays travel at the speed of...
light
the dose-response curve that appears to be for genetic and somatic effects is the
linear nontreshold
which of the following is a measure of the rate of energy loss along the track of ionizing particle through tisue
linear energy transfer
which of the following is the basis for all radiation protection standards? 1. Nonlinear, non-threshold effect 2. Linear, non-threshold effect 3. Linear, threshold 4. Nonlinear, threshold effect
linear, nonthreshold
which of the following means there is no safe level of radiation and the response to the radiation is directly proportional to the dose received 1. Nonlinear, non-threshold effect 2. Linear, non-threshold effect 3. Linear, threshold 4. Nonlinear, threshold effect
linear, nonthreshold
which of the following means there is a safe level of radiation for certain effects and those effects are directly proportional to the dose received when the safe level is exceeded? 1. Nonlinear, non-threshold effect 2. Linear, non-threshold effect 3. Linear, threshold 4. Nonlinear, threshold effect
linear, threshold effect
Coherent Scatter (Classical Scatter) or Thompsons scattering or Unmodified scatter
lowx energy xray at 10kev interacts with an electron it raises the electron to a higher energy state and cant brake the nucleus so it returns to normal state giving off the energy as a scatter photon, since the electron is not removed there is nobiological effect -Produced by low energy x-ray photons term-159 -Atomic electrons are not removed but vibrate because of the deposition of energy from the photon -as the electrons vibrate, they emit energy equal to that of the original photon -this energy travels in a path slightly different than the path of the original photon -ionization has not occurred, although the photon has scattered -doesnt effect the image less than 70kvp May have negligible effect on FOG greater than 70kVp
radiosensitivity of tissues and organs from Most sensitive to LEAST sensitive
lymphoid tissue bone marrow gonads epithelial tissue growing bone kidney liver thyroid muscle tissue nervous tissue
NRCP Report #102
makes recommendations on equipment design and protection regarding lead shielding and fluoroscopic and mobile exposure rates
medical background radiation (artificially produced radiation)
makes up 3.2 mSv of the annual dose (50% of total radiation dose) Increased exposure is usually because of CT CT accounts for 24% of total radiation exposure
Natural background radiation
makes up 3mSv of the annual dose (48% of total radiation dose) largest source is Radon other sources are 1.Space (cosmic) 2.Internal 3.Terrestrial
Determinants of Barrier Thickness: Workload
measured in mA minutes per week (mAxmin/wk); takes into account the volume and types of exams performed in the room
what is the prefix for one million
mega linear accelerators can produce xray with 20 megavolts or 20,000,000 volts
the process of cell division for germ cells is called
meiosis
which stage of cell division is most radiosensitive
metaphase
fundamental metric units of physics - MKS system
meters, kilograms, and seconds
one thousandth of an ampere would be referred to as what
milliampere milli stands for 1 thousandth (1/1000). radiographers refer it to (mA)
the SSD in mobile fluoro is
minimum of 30 cm
Cardinal principles of radiation protection - DISTANCE
most effective protections from ionizing radiation 1. dose is governed by the INVERSE SQUARE LAW 2.the greater the distance from the radiation, the lower dose 3.dose varies inversely according to the square of the distance; Example: if the exposure is 5 mGya at a distance of 3 feet, stepping back to a distance of 6 feet causes the exposure to decrease to 1.25 mGya 5mgya= (6ft^2)/(3ft^2) = 1.25 mGya ****** 4. the INVERSE SQUARE LAW should always be used in during Fluoro in which close contact with the patient is not required and during mobile radiography
what is the name for changes in genetic code passed on to the next generation? 1. Indirect effect 2. Target theory 3. Direct effect 4. mutations
mutations
What agency publishes radiation protection standards based on scientific research?
national council on radiation protection and measurements (NRCP)
which of the following means there is a safe level of radiation for certain effects and those effects are not directly proportional to the dose received when the safe level is exceeded? 1. Nonlinear, non-threshold effect 2. Linear, non-threshold effect 3. Linear, threshold 4. Nonlinear, threshold effect
nonlinear, threshold effect
Agency that enforces radiation protection standards relating to radioactive material at federal level
nuclear regulatory commission (NRC)
the probablity of photoelectric absorption occuring increases with an increase in which of the following 1.kvp 2.atomic number of material 3.distance from material
number 2 ONLY: atomic number of material and it would be a decrease in KVP not increase
the atomic number of an atom is equal to which of the following?
number of protons
which of the following radiation monitoring devices is considered to be the most accurate?
optically stimulated luminescence dosimeter are accurate to 10 mSv TLD is only accurate to 50 mSv film badge is 100 mSv
Nuclear Regulatory Commission (NRC)
organization that enforces radiation protection standards at the federal level related to use of radioactive material
National Academy of Sciences/National Research Council Committee on the Biological Effects of Ionizing Radiation (NAS/NRC-BEIR)
organization that publishes radiation protection guidelines
which of the following photon tissue interactions does not occur in diagnostic imaging
pair production megavolts 1.02 million electron volts
which of the following refers to the x-ray beam after it has passed through the beam restricting device?
primary
mass number (atomic mass) of an atom is equal to
protons + neutrons
natural background radiation
radiation contained in the unpolluted environment -Greatest natural background exposure to humans is RADON cosmic rays - radiation that reaches the Earth from space. Terrestrial radiation (rocks and soil - some rocks are radioactive and give off radioactive radon gas.) Internal radiation (living things - plants absorb radioactive materials from the soil and these pass up the food chain.) Inhaled/ingested
primary radiation
radiation exiting the x-ray tube exposure to primary radiation will most likely happen during fluoro and holding patients
the person responsible for ascertaining that all radiation guidelines are adhered to and that personnel understand and use radiation safety measures is the
radiation safety officer
shielding
radiation-absorbing material that is used to decrease exposure to radiation, especially gamma rays, from nuclear reactors lead aprons are good for protecting you from scatter in x-ray but not for the primary beam of x-rays , high energy gamma, or linear accelerator x-rays stand in control booth when possible
Fluoroscopy
radiographic procedure that uses a fluorescent screen instead of a photographic plate to produce a visual image from x-rays that pass through the patient, resulting in continuous imaging of the motion of internal structures and immediate serial images
Irradiation of water molecules within the body and their resulting breakdown is termed
radiolysis
NCRP Report #116
recommends balance between the risk and benefit of using radiation for diagnostic imaging recommends that somatic and genetic effects be kept to a minimum when using radiation for diagnostic imaging takes into account that all human organs that may be vulnerable to radiation damage
Changing alternating current to direct current is called:
rectification
which of the following is the major function of the process of meiosis
reduce number of chromosomes by half
Remote Control Fluoroscopy
remote control devices that let you work away from the table-top are increasing
non- linear
response will increase rapidly, or taper off as dose increase
a radiographer will receive most of his occupational exposure from which of these types of radiation?
scatter
radiation that changes direction as it passes through a material is called what?
scatter once "changes direction" after passing through then its scatter
compton interaction Also called: Compton Scattering or Modified Scattering
scatter of x-ray photons from the atoms of the body -incoming x-ray photon strikes a loosely bound, outer-shell electron -photon transfer part of its energy to the electron -electron is removed from its orbit as a scattered electron (RECOIL ELECTRON) -ejected electrons may ionize other atoms or recombine with an ion needing an electron -the photon scatters in another direction with LESS energy than before because of its encounter with the electron -the scattered photon may interact with other electrons; causing more ionization, additional scattering events, or photoelectric absorption, or it may exit the patient -scattered photons emerging from the patient travel in divergent paths in random directions -scattered photons may also be present in the room and expose the radiographer or radiologist -The ejected electron (Compton Electron) leaves the atom with an energy equal to the excess imparted by the photon -The photon continues on a altered path, scattered with LESS energy and a LONGER wavelength before the collision
which of the following would most likely result in the greatest skin dose? 1. short SID 2. high kVp 3. Increased filtration 4. Increased mA
short SID
mobile units
should wear lead aprons right angles to patient max source to skin distance to the patient cannot be less than 12" should be 15"
what unit of measurement is used for effective dose limits>
sieverts
Fluoroscopy: MINIMUM SOURCE - TO - SKIN DISTANCE
stationary: 38cm mobile: 30cm
potential energy
stored energy
Gastrointestinal (GI)
the lining of the GI tract divides rapidly and is considered radiosensitive; a large exposure could result in nausea, vomiting, and diarrhea
quantity refers to
the number of the x-ray photons, mAs determines the quantity (number) of x-ray phtons in the x-ray beam; the higher the mAs the higher the quantity
during fluoroscopy, which of the following will produce the greatest amount of scatter radiation
the patient
quality of the beam refers to
the penetration of the beam, kVp determines the quality of the (energy) of the x-ray beam, the higher the kVp the higher the quality
what is the definition of power?
the rate at which work is done power = work/time
total filtration
the sum of inherent and added filtration -must equal at least 2.5 mm aluminum equivalent for x-ray tubes operating at greater than 70kVp
Fluoroscopic: GRIDS
the use of grids will increase patient exposure 5 times; high kVp fluoro will produce scatter radiation which will degrade the image without a grid; the radiologist decides with fluoro procedures could be done without a grid
CR's Photostimulable Phosphor Plate : Image Receptor
they are directly exposed to x-rays (no intensifying screens), therefore they would be equal to a 200 speed class; to compensate for this HIGHER kVp can be used to keep the mAs ALARA
As cells mature and become specialized
they are less sensitive to radiation
cells that have been damaged by a sublethal dose of radiation survive or die
they can survive due to to a repair enzyme inherent in the biochemistry of the cell
late induced somatic effects
thyroid cancer cataractogensis genetic mutation
Protective Bucky slot cover
to attenuate all scatter or leakage radiation originating under the table minimum .25 mm Pb
what is the purpose of fluorscopy?
to view dynamic anatomy
Non- linear, threshold
treshold means no effects will be observed at doses below that level so it will MOVE to the right on the (y-axis) and not move up
Air Kerma (Gya) KERMA (Kinetic Energy Released in Matter, Kinetic Energy Released in Material, Kinetic Energy Released per unit Mass
unit of exposure used to define radiation exposure or radiation delivered to a specific point unit of measurement is gray (Gy) usually expressed as Gya (A indicates air) 1 Gy = 1 joule/kilogram (J/kg) - described as energy absorption per kilogram of tissue irradiated (object exposed to radiation) COULUMBS / KILOGRAM = SOMETIMES used to measure exposure but air kerma is preferred unit
gray
unit of radiation absorption, measured in joules per kilogram (J/kg); 1 Gy = 1 J/kg amount of energy absorbed per unit mass of tissue -absorbed dose IN tissue unit of measurement of tissue is is (Gy) ; normally expressed as (Gy t) (T indicates tissue)
effective dose limit
upper boundary dose that can be absorbed, either in a single exposure or annually, with a negligible risk of somatic or genetic damage to the individual; effective dose implies whole-body radiation exposure
the factors that must be considered in the design of structural shielding for a radiology room or department include
use, occupancy, workload
what refers to the number of electrons in the outer shell of an electron
valence number
The likelihood of adverse radiation effects to any radiographer whose dose is kept below the recommended guideline is A. very probable B. possible C. very remote D. zero
very remote
heterogenous beam
x-ray beam that contains photons of many different energies
Exit radiation (remnant radiation; image-producing radiation)
x-rays that emerge from the patient and strike the image receptor composed of PRIMARY and SCATTERED RADIATION