difference in energy between primary and scattered radiation

scatter has less energy and is not as easy to control

Name the mobile device under the xray table that contains a grid and holds the IR?

Bucy (*grid absorbs most scatter radiation from pt*)

formula for determining new mAs to compensate for change in SID?

mAs1 (SID1)^2 ---- = -------- mAs2 (SID2)^2

Fundamental particles that compose atoms are?

neutrons, protons, and electrons

U.S. and Canda deliver electrical current at what frequency?

60 cycles or 60 hertz per second

2 types of xray transformers that can raise or lower voltage?

step up or step down transformers

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Basic Xray Tech Cert

Basic Xray Chap 1-6

Question	Answer
Where and who were xrays discovered by?	Germany, 1895, Roentgen
Xrays exit the tube port thru an opening called?	The tube port
Xray tube is surrounded by a lead lined device called?	Tube Housing
Center of the xray beam line used for centering is called?	Central Ray
Square lighted area on pt and table where xray strikes is called?	Radiation Field
Name the radiation that exits the pt?	Remnant Radiation
Unseen image contained within the plate phosphor is called?	Latent Image
Xray beam that leaves the tube is called?	primary beam
absorption of the xrays by a human is called?	Attenuation
Primary source of scatter radiation is the?	Patient
Primary beam xrays that leave the body in all directions are called?	scatter radiation
difference in energy between primary and scattered radiation	scatter has less energy and is not as easy to control
unwanted radiation exposure on the xray image caused by scatter radiation is called?	scatter radiation fog
satter radiation exits the pt in which direction?	all
radiology dept IR consists of two components	cassettes and plates
which digital imaging system do most places use today?	CR (computed radiography)
name of device that accepts CR plate and scans it?	CR Reader
Most frequent adverse incident that happens in radiology dept?	Pt falling
Name the mobile device under the xray table that contains a grid and holds the IR?	Bucy (grid absorbs most scatter radiation from pt)
Device that allows xrays to be taken in upright position is called?	upright Bucky
Lowering the head on the xray table at least 15 degrees is called?	Trendelenburg position
The answer to a division problem is called?	Quotient
If mAs are increased from 20 to 30, what % increase is that?	50%
exposure at 10mAs and 90kvp, what new technique will provide more contrast?	mAs reduced by half
formula for determining new mAs to compensate for change in SID?	mAs1 (SID1)^2 ---- = -------- mAs2 (SID2)^2
3 basic forms of matter are?	gases, solids, and liquids
Fundamental particles that compose atoms are?	neutrons, protons, and electrons
Atomic name of the particles that circle the nucleus of the atom?	Electrons
Name the innermost shell of an atom that is important to radiology?	K-Shell
Electrons are held in place in their shell by a?	Binding energy
Important element used in production of xray?	Tungsten
When an electron is removed from an atom in the human body, it's called?	ionization
the official name of the type of xrays energy that occurs in high frequency sine wave?	electromagnetic
in a sine wave, name of distance from one crest of a wave to another?	wave length
unit of electromagnetic frequency?	Hertz
U.S. and Canda deliver electrical current at what frequency?	60 cycles or 60 hertz per second
type of wave lengths xrays have?	short
xrays consist of what type of radiation on the electromagnetic spectrum?	Ionizing
type of frequency xrays have?	very high
current is the quantity of electrons flowing in electrical circuit, what's it measured in?	Ams or milliamps
potential difference is the force behind the current in an electrial current. What's it measured in?	Volts or kilovolts
typical xray tube operates in what KILOVOLT range?	50-125kv
typical xray tube operates in what MILLIAMPERAGE range?	50-500ma
type of current delivered to homes in US and Canada?	Alternating
the process of changing AC to DC is called?	Rectification
High frequency xray generators can change hertz to as high as?	5,000 hz
electrical current uses its magnetic field to create a secondary current called?	electromagnetic induction
the device that produces high voltage needed for xray production?	transformer
2 types of xray transformers that can raise or lower voltage?	step up or step down transformers
typical step up transformer has what ratio between primary and secondary side?	500:1
Roentgen discovered xrays while working with what type of tube?	crookes
what material is the filament and target/anode made of?	tungsten
what is added to the port to remove the long wave length radiation?	Aluminum
heating of an element to a hot temp and the expanding of it's electrons is called?	Thermionic emission
is the cathode side of the xray tube positive or negative?	negative (bad to fill a cath)
is the anode side of the xray tube positive or negative?	positive (a nod is positive)
what is the purpose of having a "high speed" anode?	heat is distributed
what are the two rotation speeds for the anode?	3,600 and 10,000 rpm during exposure
what type of radiation production makes up the greatest portion of the xray beam?	bremsstrahlung
Characterisitic radiation is not produced below what kVp level?	70 kvp
the majority of the energy in the xray tube is converted to?	heat
what is the name of the radiation produced when an incoming electron into the anode is suddenly braked and deviated?	bremsstrahlung (have to slow down to say it)
the degree of angulation of the xray tube target (anode) will determine the?	Effective focal spot
how is the volume or intensity of xrays effected by the heel effect?	greater intensity on cathode side, intensity increases from anode to cathode (A-C is stronger)
to take advantage of the heel effect on a body part that has both thick and thin areas, where should the cathode be placed?	cathode side should have thicker part
the power and speed of the electrons inside the xray tube and engergy of the xrays that emerge are controlled by the?	kVp (p=penetrating power)
Current or volume of xray production is measured in units of?	mA (amount)
the mA or mAs used for an exposure determines the?	rate of exposure
the penetrating power of the xray beam is controlled by the?	kVp
name two characteristics of tungsten?	heat tolerent, efficent and conducting heat away from anode
how much aluminum filtration must be in the xray tube to meet govt standards?	TOTAL of 2.5 Al
what is the advantage of using aluminum filtration in the port of the xray tube?	absorbs low energy and allows the higher energy to pass
3 components that make up the inherent filtration?	oil, glass, mirror
amount of detail or resolution see on the radiographic image is referred to as?	spatial resolution
what type of motor us used to turn the anode inside the xray tube?	induction motor
when is the large focal spot used?	larger pts, thick body parts
the anode heel effect is most pronounced when using what size of IR?	large IR (14''x17'')
what are the names of the 3 xray circuits?	low voltage, high voltage, filament
whats the purpose of the autotransformer?	vary the voltage on primary side of transformer
whats the purpose of the filament circuit?	heat the filament
what is the purpose of the high voltage circuit?	supply xray tube with enough voltage to create xrays
name the 3 transformers?	auto, step up, step down
which circuit has the step down transformer?	filament
which circuit has the step up transformer?	high voltage
the process of changing AC to DC is ?	rectification
how many pulses of radiation occur in a full wave rectified xray machine?	120 a second
what type of rectification is used in most modern xray generators?	full wave
3 types of xray generators?	single, three phase, high frequency
which xray generator has the lowest power?	single
how much more xray output is achieved by using a three phase xray generator?	40%
the most common xray generator and the most efficient?	high frequency
standard 60 Hz frequency of the electric current is brought up to what level with a high frequency generator?	6,000 hz
4 advantages of using high frequency generators?	1. efficient xray production 2. less exposure for pt 3. single source of AC current power 4. same exposure technique for great amount of xrays
most common type of xray exposure timer is?	electronic timmers
which exposure control system request the kVp, mA and exposure time to be selected?	manual
with AEC (automatic exposure control), what factor is auto selected?	exposure time
when using AEC for exposure, what must be accurate?	POSITIONING
if overcollimation occurs when using AEC, the resultant image will be?	too light or under exposed
if the AEC system fails for any reason, what system will terminate the exposure?	back up timer
according to Public Law 90-602, xray generators must terminate the exposure at what mAs?	600 mAs
when using anatomically programmed radiography for the exposure techinque, what factors are auto set?	kvp, ma, time, aec detectors, body habitus, bucky, and SID
the max xray tube capacity for a single xray exposure can be determined by the?	tube rating chart
whats the formula for determining a heat unit(HU)?	kvp x ma x time
xray tubes last longer if they are operated at what capacity or less?	80%
what can happen to an xray tube of not warmed properly?	ball bearings burn out, anode cracking, filament breaking
how to properly warm up a tube?	3 low technique exposures should be made 30 seconds apart
"prime" factors of radiography exposure?	mA, exposure time, kVp, SID
factors that affect xray QUANTITY?	mA, exposure time, mAs, kVp, SID, filtration
factors affect xray QUALITY?	kVp, Filtration
mA affects the?	quantity of xrays
if the mA, exposure time, or mAs double, the number of photons will?	double
the the mA, exposure time, or mAs double, the patient exposure will?	double
the unit used to indicate the total quantity of xrays in an exposure is?	mAs
how is the energy of the xray beam affected when the kVp is adjusted?	if energy is decreased, kVp is decreased and vice versa
which technique factors, if adjusted upward, will increase density?	mA, mAs, exposure time, kVp
primary controller of radiographic denisty?	mAs
double kvp will result in how many more photons?	4 TIMES
whats factor is the primary controller of penetration and radiographic contrast?	kVp
what is the distance between the tube target and the IR called?	SID
the inverse suare law tells us the relationship between what two factors?	SID and intensity
if the SID is doubled, what will happen to intensity or quantity?	v 1/4
if the SID is reduced by 50%, what happens to the intesity or quantity?	^ 4 times
whats the typical SID used in rad depts?	40 inches
density?	black or darkness if radiographic image
contrast?	difference in density between adjancent portions of the image
Distortion?	differences between subject and radiographic image
recorded detail?	sharpness in image
Term used to describe a dark image is (too much denisty)?	over exposed
an image that is too light is (not enough density)?	under exposed
tissue denisty refers to	mass density or atomic # of a body part
term used to describe density in digital enviroment?	darkness/brightness
how does a decrease and increase in kvp affect contrast?	decrease = low contrast (long scale) increase = HIgh contrast (short scale)
what is a penetrometer?	step up scale that shows grays/densities in bodies
describe short scale and long scale contrast	high contrast is short, long contrast is low (long is low)
Densities of the tissues within the pt are referred to as?	subject contrast
contrast is influenced by?	fog
fog?	unwanted exposure
how does collimation affect fog?	if collimator is too open, more scatter radiation reaches the IR
term to describe contrast in digital enviroment?	Blackness
low kvp produes an image with ______ contrast?	high
high kvp produces an image with ______ contrast?	Low
another name for size distortion is?	magnification
the distance between the object or part and the ir is called?	OID
define elongation	image appears longer than it really is
define foreshortening	image appears shorter than it really is
4 factors that effect spatial resultion?	oid, sid, pt motion, focal spot
having unsharp or fuzzy edges of structures in an image is called?	penumbra
changing from the small to the large focal spot will result in	less recorded detail
an increase in the oid will result in	less recorded detail
motion of the pt, tube, or IR during the exposure results in	motion blurr
if an xray image is blurred or has motion, which exposure factor is used to correct this?	shorter exposure
patient motion can be categorized in what two ways?	involuntary and voluntary
the first step in avoiding motion is to use?	pt communication and understanding
the principal method of reducing involuntrary motion is to?	reduce exposure time
the technical term for a grain or spotty image is?	quantum mottle
what causes an image to have a grainy appearance?	not enough photons, not enough kvp
what are two ways to minimize shape distortion?	ensure part is parallel to ir and the cr is perpendicular
what will increase spatial resolution	reduce motion, use max allowed sid, shortest oid, use small focal spot
what is the name of the cassette based digital imaging system?	computed radiography
the psp in the cr imaging plate is made of?	barium fluorhalide with europim
imaging plates from digital cr are processed in a	cr reader
how many times can a cr imaging plate be used?	10,000
how does scatter radiation affect the cr imaging plate?	it's more sensitive to it and can cause fog
what type of light source is used in the CR reader unit to release the stored xray energy?	laser light
what type of light source is used to erase the stored image in a CR imaging plate?	intense white light
the cassette-less digital imaging system is called?	digital radiography
flat panel detector is used in which digital imaging system?	digital radiography
what material is used as the conductor in a flat panel detector system?	amorphous selenium
what is the size of the flat panel detector in the table of a dr imaging system?	17'' x 17''
what are two categories of DR imaging systems?	indirect conversion and direct conversion
how long does it take to process a cr or dr image?	3-5 seconds
one of the major advantages of digital imaging systems is the ability to?	see images fast
2 steps in processing an indirect conversion DR image	light and electric signal
with direct conversion DR systems,the engery is converted directly to?	an electrical signal
on a digital viewing monitor, the active area of the monitor is called the?	matrix
on a digital viewing monitor, each individual picture element square is called the?	pixel
the amount of detail or sharpness in a digital image is termed?	spatial resolution
how many pixels are there in a 1200 x 1200 matrix viewing monitor?	1,440,000 (multiply the two together)
how do smaller pixels affect spatial resolution?	more pixels means more spatial resolution
how will larger matrix affect the pixels?	larger matrix means more pixels means more spatial resolution
the ability of a digital systm is to distinguish anatomic structures that have similar subject contrast is termed?	contrast resolution
the number of gray shades that an imaging system can produce is termed?	dynamic range
"noise" in the digital image is referred to as?	quantum mottle
the ability of a digital system to convert the xray input electral signal into a useful image is termed?	signal to noise ration (SNR)
how does a greater electrical signal in a digital imaging system affect noise and image quality?	lowers noise
what adjustment controls the denisty or brightness of the digital image on the viewing monitor and printed image?	window level
what adjustment controls the contrast of the digital image on the viewing monitor and printed image?	window width
what 2 entities require that exposure technique charts be placed in every radiography room?	state laws and JC
the acronym for maintaing optimal image quality and low radiation exposure to the pt is	ALARA
one of the most important aspects of setting the exposure technique in digital imaging systems is to ensure that which factor is set correctly?	kVp
the numeric representation of the amount of exposure in the imaging plate is termed the	exposure indicator number
in digital imaging, sensitivity numbers, exposure indicators numbers, and logarithm of median numbers are collectively known as?	exposure indicator number
the further adjustment of a digital image after it is processed is termed?	post processing
the universally accepted standard for exchanging medical images and viewing images from different manufacturers is termed?	DICOM
the method of calibrating a digital display system so that all images are presented cosistently is termed?	DICOM gray scale function
two common postprocessing techniques are?	subtracting and contrast enhancing
what causes the quantum mottle artifact in the digital image?	low kvp or mas
what causes the moire pattern artifact in the digital image?	grid lines aren't align with the laser
what causes the phantom or ghost image artifact in the ditigal image?	incomplete IP erasure
what causes the fogged image artifact in the digital image?	CR plates being much more sensitive
What causes the extraneous line pattern artifacts in the digital image?	noise on image reader
the management system used in digital imaging to store and view images is termed	PACS
what types of pt info must be included on every digital image?	pt id, dob, dos, xray facility info
what technical exposure adjustment can be made to reduce radiation exposure to patient?	increase kVp
what device should be used when imaging body parts that have widely different thickness of structures?	compensating filter
what types of images from a radiology dept are stored in a PACS system?	ALL types (xrays, u/s, mri, ct, nuc...)
where should the body part be ideally placed on a CR plate?	center
what device should be available if one CR plate is divided in half for two images?	lead shield
if a digital image appears on the viewing monitor is overexposed or underexposed, what should be checked?	the exposure indicator number
how many margins of the collimator should idealy be seen on a digital image?	4 but minimum of 2
with CR imaging plates, how much of the engergy of the xray image in the phosphor is lost in 8 hours?	25%
two main types of interactions that occur when radiation is absorbed by matter are?	compton and photoelectric effect
compton scatter leaves the body in what directions?	ALL
scatter radiation that is directed back to the xray tube is termed?	back scatter
most of the photons that scatter will scatter in which specific direction?	scatters outside the body
what happens to the xray photon during the compton effect?	scatters outside the body
what happens to the xray photon during the photoelectric effect?	totally absorbed in the body
what happens to the engergy of the photon when it is scattered?	decreases in speed
when the kVp is increased, the compton scatter is?	increased
when the kvp is increased, the photoelectric effect is	decreased
the production of scatter radiation during an exposure results in what on the xray image?	fog
name the 4 primary factors that directly affect the quantity of scatter radiation fog?	volume of tissue, kvp, density of matter, field size
the primary consideration that affects the volume of scatter radiation is the	volume of the tissue
how is scatter affected when the body part is thicker or larger?	increased
fog on the radiograph becomes objectionable when the body part size is larger than?	10cm or greater
what is the effect of increased kvp on scatter radiation fog	increased fog
how is scatter affected when the body part is very dense or has a high atomic number?	less scatter
on of the most important things a BXMO can do to control scatter radation is	select the right field size
the principal method of reducing scatter radiation fog is to use which device?	grid
name 3 strategies that can be used to reduce scatter fog?	grid for body parts larger than 10 cm, reduce kvp, reduce field size and collimation to only the body part
a grid is typically used when the body part size and kvp reach	10 cm or greater and kvp is over 60
decreasing collimation does what to the contrast in the image	increases contrast
when fog prevents specific details from being seen in the image, what type of image may be requested?	coned down image
name the two quality control test that are done regularly to check the collimators light field size and the central ray alignment?	collimator template and beam alignment cylinder
the control limit for the collimators light field and the actual radation field must be within	above or below 2% of SID
the control limit for the xrays tubes beam alignment is that the beam must be within	0.8 inches of radation field and 1 degree prependicular
a listing of the examinations and the exposure factors used for those examinations that must be placed in every room is called?	exposure technique chart
what is the name of the organization that provides accrediation for hospitals and clinics	Joint Comission
name several technical factors that must be included on an exposure technique chart	exposure time, kvp, mas, sid
a technique chart that requires every factor to be set individually is called	manual technique chart
an exposure technique chart may not need to be posted for the ------ type of exposure control system	APR
what is the name of the device or tool that is used to measure pt part size?	calliper
the kvp can be determined for a technique chart using what two types of kvp settings?	variable kvp and fixed kvp
what does optimal kvp mean	highest kvp setting
what does the 15% rule mean	15% change in kvp will produce same change in denisty as doubling or halving mas.
the small focal spot can only be used at which ma setting	200 ma or less
when there is a likelihood of motion in a radiography, how should the ma and exposure time be set?	higher ma with short exposure time
2 ways that an exposure technique chart can fail	BXMO makes mistakes, generator out of calibration
speciality exposure techinques charts must be provided for which two diverse groups of pts	pediatrics and obese
major limitation in imaging obese pts is	inadequate penetration of the body part
most important technical factor adjustment that should be made when imaging obese pts?	increase kvp
what is the minimum change in the mAs that will promopt a visible change in image density?	30%
when a radiograph needs to be repeated because the orginal image was too dark or light, what is the min change in mAs that should be made in each case?	100% if image is too light, 50% if imgae is too dark
what type of body part will requre a compensating filter?	varied tissue density (ap t spine, al hip, ap shoulder, ap foot)
where are compensating filters placed?	btwn tube and ir
unit of radiation EXPOSURE is?	Gray
the amount of xrays ABSORBED by irradiated tissue, or the pt, is called?	asorbed dose
the absorbed dose in the body based on type of energy of matter is called?	equivalent dose
xray photons have a radiation weighting factor of?	1
measurement of units of exposure	Roentgen (R)(Gy-a)
measurement of units of absorbed dose	Rad (rad) (Gy-t)
measurement of units of equivalent dose	Rem (rem) Sievert (Sv)
in our everyday work the equivalent dose is used for?	radiation protection purposes
ESE?	Entrance Skin Exposure
Law of Bergonie-Tribondeau tells us what about radiation exposure?	Cell sensitivity to radiation
4 characteristics of the Law of B-T?	Age (young more sensitive vs old) Differentiation (simple more sensitive than complex) Metabolic Rate (cells that use more energy are more sensitive than slower cells) Mitotic Rate (cells that divide and muliply faster are more sensitive)
Cells in the body that are sensitive to radiation?	blood, glandular, fetuses, thyroid
Not as sensitive cells to radiation are?	nerve, muscular, cortical bone
Radiation effects are classified in what 4 ways?	short term, long term, somatic (effect body tissue), genetic
radiation effects in 3 months would be considered?	short term effects
long term effects from radiation exposure are often?	unpredictable
when radiation damages affects the reproductive cells its called?	genetic effects
Lethal dose (LD) 50/30 is what?	3,000-4,000 mGy-t (Rad)50% of population would die in 30 days
how much radiation does the skin have to receive for erythema to develop?	2000 mSv (Sievert)
what body part should be protected with a lead shield to prevent mutation?	gonads
mutations caused by radiation exposure may be seen in a baby are?	cleft plates, spina bifida, polydactyly
how much radiation is the average person living in the US exposed to?	6.3 mSv (sievert) per year
4 ways to protect from unnecessary radiation?	use smallest radiation field, highest kVp, reduce repeats, never use less than 40 in SID
2 categories of gonad sheilds are	contact shields (touch pt) shadow shields (are on collimator)
dose to gonads will be reduced if shield is used when primary beam is within ___ cm of gonads	5 cm
2 fields of occupational exposure is highest?	fluroscopy and mobile xrays
3 principals to protect BXMO from unnecessary radiation?	time, distance, shielding
lead aprongs and gloves must have a quality control check every	6 months
lead equivalency of aprons and gloves must be	aprons 0.5 mm gloves 0.25 mm
OSL (optically stimulated luminescense) personal dosimeters have what advantages?	measures small doses accurately, acurate over wide range of exposures, long term stability
purpose of control badge that comes with depts personal dismeters?	monitors batch in transit
Where do you were a personal dosimeter?	collars
according to the NCRP, the upper limit of occupational exposure is called?	Effective dose
lifetime risk of occupational exposure is refered to as the?	cummulative effective dose
max effective dose an occupational worker can receive in 1 year is?	50 mSv or 5 rem
formula for determining the cumulative effective dose?	10 mSv x age
NCRP studies confirm that women exposed to radiation in excess of _____ to the uterus is caused for conern to fetus?	150 Gy-t (rad)
greatest risk for fetus exists during which portion of pregnancy?	0-3 months
NCRP recommended monthly equivalent dose limit to the embryo or fetus for a pregnant worker of?	0.5 mSv or 0.05 rem
9 month equivalent dose limit to the embryo or fetus for a pregnat worker is?	5 mSv or 0.5 rem
pregnant workers wear a second OSL where?	waist level under apron

Created by: lkfreeze8611

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