In low volume clinics what can used fixer be collected in?
it can be collected in storage drums and sold to a refiner
What is the chemical precipitiation method?
-involves mixing sodium sulfite or zinc chloride with used fixer, causing a chemical reaction to take place in which silver precipitates or shrinks to the bottom.
-takes a lot of space
-produces toxic fumes
What are used to remove silver from the wash water?
ion exchange or resin systems
The longer the dwell time the ? the efficiency.
The more agitiation, the ? the efficiency.
As surface area of the recovery defice increases, efficiency?
What must the fixer pH be kept at for efficiency of silver recovery?
What is film that has not been processed and out of all film types contains the most silver(100%)?
What is film that has been exposed and processed but is rejected?
What is film that has been exposed and processed, was part of the patient's file, but not old enough to discard?
T/F Green film should be sold separately form the other discarded film and at a higher price.
How is silver recovered from films?
a refiner reclaims the silver from films by incineration or chemical treatment.
What are the three components of QC for radiographic units?
How often should lead aprons and gloves be checked for cracks?
should be viewed on acceptance and then every 6 months
When evaluating high tension cables, if the outside is dicolored what does this mean?
indicate internal heat and a potention short circuit.
What is the least sensitive chambers or radition measurement but is useful in the performance testing of diagnostic radiographic equipment?
ion chamber, (can be pocket dosimeter or analog/digital dosimeter)
Wht is used in stationary laboratory counters to measure small quantities of radioactive material?
What counter is the most sensitive and is used for contamination control in nuclear medicine?
What is the most common type of detector in performance testing and ionizes gas?
gas filled chamber
T/F proportional counter is more sensitive than an ion chamber.
What are we testing for when testing reproducibility of exposure?
th ability of an x-ray generator to produce the same radiation intensity when the exact same technical factors are used
What are the acceptance limits for reproducibility?
the max. variability us +- 5%
What equipment do we use for reproducibility?
a dosimeter, lead apron, radiographic table
What happens when we are outside the limits for reproducibility?
could cause inconsistent exposure to films, resulting in repeats
What are we testing for in radiation output?
x-ray generators emitting a specific amount of radiation per unit of mAs
What are the acceptances limits for radiation output?
the percent of deviation between readings should be with in +- 10%
radiation output from different rooms with same generator type should be within 10%
What happens when radiation output is outside of limits/what does it mean for the tech?
separate technique charts must be used for each room
What are we testing for when doing a filtration test?
we are measuring the HVL to make sure the low energy xray photons are being removed, but image quality is not being compromised
Describe the process of a filtration check.
measure HVL with a dosimeter, repeating a process 6-8 times, its plotted and then the HVL is determined by locating the point on the y-axis that represents one half of max. radiation and then drawing a line form this point to the curve and then reading the x coordinate.
What are the acceptance limits for filtration check?
HVL should be greater than or equal to 2.3 mm Al.
What happpens if a filtration check is outside of limits?
patient skin dose can be increased significantly
T/F Filtration can be measured directly.
F, its measured indirectly from HVL
What is the amount of filtration that reduces the exposure to one half of its original value?
Half value layer HVL
What happens when HVL is too low? too high?
What are we testing for in kVp accuracy?
the kVp that is set on the control panel being consistent with the kVp that is actually produced.
What are the acceptance limits in kVp accuracy?
Variatons between stated kVp and actual kVp should be within +- 5%.
What tools are used in kVp accuracy?
digital kVp meter
What happens if kVp accuracy is outside limits?
image contrast, optical density and patient dose would be significantly affected.
What are the acceptance limits for timer accuracy?
variability for timer accuracy is 5% for exposures greater than 10ms and 20% for exposures less than 10ms.
What test looks at the quantity of xray photons emitted?
In timer accuracy what does a digital timer measure?
the total time of xray production and then displays the value in LED readout
What equipment is used for timer accuracy?
spinning top or digital xray timer
When testing a single phase what equipment is used in timer accuracy? three phase?
manual spinning top (single)
synchronous spinning top (three phase)
What happens if timer accuracy is outside acceptance limits?
patient dose and radiographic quality?
In which of the spinning tops does a solid line appear instead of a series of dots?
synchronous, (manual=series of dots)
T/F when a timer less than 1 sec. is chosen, an arc will appear that is some fraction of 360 degrees
What are we testing for in a reciprocity test?
the same mAs value selected using different combinations of mA and time, producing the same radiation output
Know difference in reciprocity, reproducibility, and linearity!!!!:)
What equipment is used in reciprocity?
dosimeter placed on tabletop, lead apron, three to five exposures read by dosimeter, reciprocity variance is calculated
WHat are the acceptance limits for reciprocity?
reciprocity variance should be within 10%
What happens if reciprocity is outside acceptance limits?
xray tube filament temperature could get too high/be affected?
What are we testing for in linearity?
sequential increases in mAs should produce the same sequential increase in exposure
What are the acceptance limits for linearity?
linearity variance should be within 10%
What equipment is used for linearity?
dosimeter placed tabletop on lead apron, 4 exposures made, dosimeter readings taken and divided by the mAs, variance in linearity is calculated
What happens when linearity is outside the acceptance limits?
patient exposure and radiographic quality will be comprimised?
Why do we test focal spot size?
to see if its getting larger because it blooms with age/or with increase in mA
What is the equipment used in FSS testing?
directly=pinhole camera where measuring directly
indirectly=test pattern/star test pattern
What are the acceptance limits for focal spot size testing?
-fss less than .8mm the blooming variation allowed is 50%
-fss .8-1.5mm is 40%
-fss greater than 1.6 is 30%
What happens when Fss is outside acceptance limits?
overradiation can occur or anatomy cutoff/repeats
What are we testing for with light field radiation field congruence?
light field should be a true representation of the xray field
What tools are used for light field-radiation field congruence?
collimator test too or nine penny test
What is the acceptance limits for light field-radiation field congruence?
should be ccongruent to within 2% of the SID
What happens if light field- radiation field congruence is outside acceptance limits?
inconsistencies caused by collimator shutter malfunctions or mirror shift.
What are we testing for in image receptor-radiation field alignment?
malfunctions in the sensors detecting the size of the image receptor and colimation automatically adjusting to match it.
What are the acceptance limits for image receptor-radiation field alignment?
-automatic collimation variance should be within 3% of SID
-Manual collimation should be within 2% of SID
What tools are used with image receptor-radiation field alignment?
collimator test tool and film in Bucky
What happens when image receptor- radiation field alignment is outside acceptance limits?
cutoff of anatomy, increase patient dose
What are we testing for with perpendicularity?
xray tube must be mounted in teh housing properly for CR to be perpendicular otherwise distortion may occur. CR should be perpendicular
What equipment do we use for perpendicularity?
beam alignment tool placed in center of collimator test tool., image receptor,
What are the acceptance limits for perpendicularity?
CR should be within 1% of perpendicular
In a perpendicularity test what does it mean when the steel balls of the alignment tool are superimposed? when they are a distance from eachother?
superimposed=CR is completely perpendicular
not superimposed=CR is not completely perp.
What happens if perpendicularity is outside acceptance limits?
xray tube is shifted and distortion will occur
What are we testing for with x-ray beam-bucky tray alignment?
center of the bucky tay and the center of the xray beam must be aligned.
What equipment is used for xray beam bucky tray alignment?
bucky, beam alignment test tool tabletop,cross hairs of positioning light center to cassette
What are the acceptance limits for xray beam-bucky tray alignment?
should be within 1% of SID
What happens if xray beam-bucky tray alignment is outside acceptance limits?
clipping of anatomy
If SID indicator is not accurate what adverse effects can come into play?
density, patient dose, and detail will all be affected
How do we test SID indicator?
tape measure compare the SID indicator readout to actual distance. or image object and used object size, image size, and OID to calculate actual SID
What are the acceptance limits for SID indicator?
2% of the SID
What are we testing for with tube angualation indicator?
improper tube angulation
What tools do we used with tube angulation indicator?
protractor to compare angulation indicator to the actual tube angles
What are the acceptance limits for tube angulation indicator?
angualtion indicator must be accurate to within 5 degrees.
What happends if tube angualtion indicator is outside acceptance limits?
T/F AEC controls exposure time.
What is the built in backup time for any unit that uses AEC?
600mAs or 6 s, which ever comes first
T/F If set my density at normal in AEC it should be able to adjust to different mA, different kVp, different part thicknesses, and different field size.
T/F if collimation of anatomy out of our area, it wont effect AEC and AEC will perform optimally.
F, AEC will not work right
What % of change in density should there be between density control settings?
What are we testing for in Reciprocity law failure?
no matter what combination of mA and time is used, if mAs is the same, radiation output should be the same and the optical density of the resulting imaging should be the same.
How is reciprocity law failure tested?
a homogeneous phantom is imaged at 10 kvp, 40in.SID, bucky normal density and at both the largest and smallest MA stations available.
When is there reciprocity law failure?
when resulting OD will vary by more than .2.
What does the fulcrum level determine? slice thickness?
-determines the level of the objective plane
-its determined by the tomographic angle, the greater the angle, the thinner the slice.
T/F The mAs for tomography is less than the mAs for conventional radiography of the same view.
F, its greater
What are the two types of test we do for grids?
grid uniformity and grid alignment
Why do we test our grids?
for uniformity, because overtime the get a lot of wear and tear
With grid alignment what are we testing for?
the centering of the tube to the center of the greid and maintiang the proper distance within the focal range of the focused grid.
T/F Portables do not have to undergo the same QC testing as stationary equipment.
F, it does
T/F Fluoro xray tubes have to have a higher heat compacity than conventional xray tubes.
In fluoro what amplifies the brightness of the image?
What is the purpose of the input screen?
absorbs xray photons and emit light
What is the purpose of the photocathode?
absorb light and emit electrons through photoemission
What is in direct contact with the input screen and absorbs the light emitted by the input screen and emits light?
What are negatively charged electrodes inside the galss envelope of the tube? and what are the purpose of them
purpose is to accelerate and focuse the electrons of the beam
T/F Patient dose increases when we use magnification.
What is positively charged and attracts the electron from the photocathode?
What is the purpose of the anode?
has a hole that permits the electrons to pass through to the output screen.
What contains silver activiated zinc-cadmium sulfide phosphors that absorbe the electrons and emit light photons?
T/F the diameter of teh output screen is much smaller than the diameter of the input screen.
What are the components of total brightness gain?
Minification gain and flux gain
What is an increase in the brightness or intensity of the image and is achieved by compressing the image?
What is the increase in light photons due to the conversion efficiency of the output screen?
What does the brightness control system do?
automaticaly maintain image density and contrast.
What are the image intensifier artifacts?
veiling glare, pincushion distortion, barrel distortion, vignetting, and S distortion
What is when moving from one portion of the patients anatomy to another and is seen as a sudden increase in brightness and is caused by reflected lgith from the output screen?
What is caused by projecting an image from a curved surface to a flat surface (input screen to output screen) which caused image t be magnified on lateral edges?
What has the same cause as pincushhion distortion, but the magnification is more pronounced in the center of the image?
What is a decrease in image brightness on the lateral edges?
What is caused by the presence of a magnetic field near the image intensifier and appears as a warping of the image in a S shape?
T/F Closed circuit televion monitoring is the most common method of viewing the fluoroscopic image.
What are the different types of photoconductive tubes used?
-Vidicon:antimony trisulfide target material
-Plumbicon:faster, used lead oxide
-CCD: contains an array of photodiodes that absorb light and release electrons, generating a signal based on the intensity of light recieved.
T/F Because Fluoro increases dose in testing, this does not mean we have to increase QC testing.
F, we increase it to every 6 months
What do we test for when testing for reproducibility of exposure in Fluro?
use homogenous phantom on the fluoro tabletop and use dosimeter between phantom and image, select kVp and mA and depress exposure button for 10 sec. and record. Repeat two times.
-variance must be less than 5 %
How do we evaluate focal spot size for Fluoro?
place test tool on top of homogenous phantom on tabletop. set mA and kVp to most commonly used setting. tape nonscreen film to bottom of image intensifier and exposed. image should then be printed on film with laser printer.
How do we evaluate filtration check for fluoro?
use aluminum plates and a dosimeter to measure HVL dosimeter should be placed on a stand halfway between the tabletop and image intensifier. the HVL should be determined using most common kVp.
Describe how we evaluate kVp accuracy for fluoro?
digital kVp meter should be used, make sure the meter faces the tube. The kVp variance should be greater than or equal to 5%
Describe how we test for mA linearity in fluoro?
place dosimeter between the phantom and image intensifier. Make 10 sec. exposure at .5mA and record reading. Repeat using other mA stations. Determine the mR/mAs value, and lineartiy variance shoul be within 10%.
What is the difference between automatic brightness stabilization and automatic gain control in terms of function?
-ABS shoul automatically adjust technical factors to accommodate changes in part thickness
-AGC maintain brightness by varying the gain of the video system
What is the difference in the testing of automatic brightness stabilization and automatic gain control?
dosimeter should be placed between a 7.5 phantom and x-ray source and exposed 10 sec for both. repeat exposures by using a 15cm phantom.
-For ABS readings should double
-for AGC readings should be the same
What is the difference in maximum exposure rate and standard exposure rate?
-max: is the highest possible exposure rate that the fluoro unit can deliver to a patient
-standard:represent typical usage
What tools are used for standard exposure rate?
dosimeter, CDRH fluroscopic phantom is used. Exposure should be mult. by two to obtain R/min.
What is the exposure range for standard exposure rate?
What is the minimum Source to skin distance for the FDA for stationary? mobile?
stationary: 38cm (15in)
mobile: 30cm (12in)
How would we perform a distortion test/what equipment would you use?
wire mesh pattern taped to bottom of the image intensifier and a homogenous phantom is placed on the x-ray table. The image of the wire mesh is observed under fluoro
What are the two sources noise can come from in Fluoro?
quantum mottle or electronic noise,
-to determine which one observe monitor with no fluoro image, if no noise present, it is electronic noise.
What is a measure of the amount of light produced by the output phosphor per unit of radiation incident on the input phosphor of the image intensifier?
relative conversion factor
T/F image intensifiers can deteriorate at a rate of 10% per year.
When should you call a service engineer for an image intensifiers?
when it has deteriorated by more than 50%.
In quality control of digital radiographic equipment who does routine checkups?
What involves radiation measurements and noninvasive adjustments?
Who performs full inspection?
What involves hardware and software maintenance?
Who does system adjustments?
vendor service personnel
What are the weakest link in the digital imaging chain?
What are acceptances tests and who are they performed by?
Erasure thoroughness and phantom image test to evaluate specific system parameters
- done by medical physicist
What are daily tests in digital and who performs them?
General inspection, laser printer functioning, erasure of IP, network works properly, processor should be checked with densitometer.
-performed by technologist.
What are the weekly tests for digital and who performs them?
Monitor calibration, phantom image testing, and system cleanlliness.
-performed by technologist
What are monthly tests in digital and who performs them?
Processor maintenance, image receptors inspected and cleaned, and repeat analysis
-performed by the technologist
What are Semiannual/Annual tests for digital and who performs them?
Image quality (viewing both actual patient images and phantom images, repeat acceptance test, Reviw exposure trends/repeat analysis data/QC records/service history, and Determine the necessity for system adjustment
-performed by medical physicist.
What are the physics and instramentation of Digital fluorscopy with image intensifiers?
Adding an analog to digital convertor (ADC) and a computer.
-the ADC is placed after CCD camera, digitizes the output video signal. The digital signal is then sent to a computer for processing and then to monitor for display.
T/F High frequency generator is used for digital fluoroscopy.
Describe digital fluoro with Flat panel detectors.
it includes the xray tube and generator, grid, flat panel detector, computer, and monitor.
-it overcomes some issues with image intensifier such as image lag, vignetting, s distortion, increased dose with magnification
What is the advantage of flat panel detectors over image intensifiers?
overcomes vignetting, image lag, distortion, and increased dose with magnification
What is a flat panel detector used in fluoro produce dynamic images?
What is the difference between dynamic FPD and static FPD?
pixel size is larger for dynamic, dynamic offer a zoom mode which enables the examination of smaller structures, readout for dynamic provides high frame rate and fast data transfer rate
What is the difference between primary display devices and secondary display devices?
-primary-those that will be used for interpretation of diagnostic images by the radiologist or other physician
-secondary-are those used for viewing images for purposes other than interpretation.
Which matrix size is bigger primary or secondary?
When talking about QC for electronic display, describe luminence testing?
measured with a photmeter by taking readings at the center of the display over the high contrast resolution patch, as well as four corners.
What should luminence readings for Electronic display be?
should be within 20% of each other
How would we evaluate spatial distortion for electronic display?
evaluated by viewing the squares throughout the image. they should appear as perfect squares. ruler measures height and width.
What is acceptable in spatial distortion of electronic display?
the difference between teh expected and measured lengths within the pattern should not exceed 2% for primary displays and 5% for secondary.
How would we evaluate spatial resolution in electronic display?
assesed by viewing high contrast line pairs.
When evaluating contrast what is the 100% squares? 0% squares? contrast patches?
What are some equipment used in checkin our electronic display device?
SMPTE test pattern is evaluated, photometer, contrast line pairs
What are the two components we are testing when testing a pressure injector?
injected volume and injected time
What should be done for QC of Bone Densitometry?
use of a phantom and should be done every day before patient exams are done.
STUDY TOO: What am i testing? how is it done? what are my acceptance limits? what happens if outside limits?
-For every single QC test
5= reproducibility- kvp accuracy
10= radiation output - reciprocity- linearity
5 degree= angulation
5% greater 10 ms 20% less that 10 ms
2 manual radiaiton field 3 auto
control settings 25 to 30
.8 or less 50% .8-1.5 40% 1.6 or greater 30%
reciprocity law failure .2 %
exposure rate for standard- 1-3 R/min
20% luminence for electronic reading
2% primary 5% secondary spatial distortion