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Ch42 Mammo
| Question | Answer |
|---|---|
| when did mammography first develop | early 1900s |
| when first dedicated mammography machine introduced | 1967, France |
| type of mammography used in US from 1960-1990s | xeromammography |
| first dedicated film screen system | 1972 - DuPont USA |
| designed Min-R screen film & cassette system | 1975 - Kodak USA |
| rare earth phosphor sensitive to what color? | green |
| orthochromatic film is sensitive to what? | blue-green sensitive |
| first reciprocating grid mammography unit | 1978 Phillips Netherland |
| first advanced level exam for mammography for ARRT | 1991 |
| digital mammography introduced | 2006 |
| baseline- never had any symptoms | screening |
| when you have symptoms or have already been diagnosed | diagnostic |
| annual screening is recommended at what age? | 40+ |
| clinical breast exam recommendations | 20-30 every 3 years 40+ annually |
| only modality regulated by FDA | Mammography |
| three types of tissue that make up the breast | fibrous, glandular, adipose (fat) |
| composition of premenopausal breast | primarily have fibrous and glandular |
| composition of postmenopausal breast | primarily have adipose- adipose is tissue is less dense |
| tissue most sensitive to cancer by radiation | glandular |
| first time x-ray machine and personnel were regulated by federal government | Mammography quality standards act of 1999 |
| what kind of subject contrast does breast have? | low subject contrast |
| what technique produces high radiographic contrast in breast images | low kVp |
| disadvantage of low energy x-rays | high absorption contributes to patient dose |
| what kVp is used in mammo? | 22-40kVp usually 25-28kVp |
| what kind of SID is used in mammo? | short SID - 24 to 30" |
| rapid growing very lethal cancer- on outside of breast | inflammatory breast disease |
| average energy preferred in mammo | 17-24keV |
| what happens when x-rays over preferred peak are used | energy overpenetrates, produces scatter and decrease radiographic contrast |
| what sized focal spot used for mammo? | small .1mm / large .3mm |
| material of choice for mammo target & why? | molybdenum. high melting point & conducts heat well. |
| why is tungsten not used in dedicated mammography unit? | too high atomic number, too high energies and degrades image |
| allows vertical central ray to be placed at the chest wall-movement of glass envelope forward | off-center placement |
| filtration used in mammography | beryllium window |
| function of beryllium window | filter, reduce high energy x-ray |
| inherent filtration of beryllium window | .1mm AL equivalent |
| new/additional target material in mammography | rhodium (Z#45) |
| type of target that provides better penetration of larger or very dense breasts & reduces exposure time | rhodium |
| disadvantage of rhodium target | energy level too high to use on small and average sized breast |
| filters beyond the window is what kind of material? | same material as target (molybdenum or rhodium) |
| purpose of filter beyond filtration window | filters out low energy x-rays and higher bremstrahlung x-rays |
| utilization of anode heel effect in mammo? | cathode closest to chest wall, anode end closest to nipple |
| typical grid used in mammo | linear, very low ratio 4:1 or 5:1, moving grid. grid frequency 40 lines/cm |
| Direct Current is fed through an ______, changes power to high-frequency | inverted circuit |
| minimizes OID and improves spatial resolution, positioned after the image receptor. | AEC |
| 2 types of AEC | ionization chambers & solid state diode |
| what is cathode made of? | tungsten |
| how many filaments are in mammo tube? | 1 filament |
| what is the charge of the cathode in the mammo tube? | negative - strong negative charge |
| rotating or stationary anode in mammo? | rotating |
| benefits of magnification | increased resolution, reduction of scatter, improved visibility of detail |
| disadvantage of magnification | exposure to breast is 2-3x higher |
| 4 types of image receptors | direct exposure xeroradiography screen/film digital |
| what are mammo cassettes made out of? | plastic or low-attenuation carbon fiber |
| single or double emulsion film in mammo? | single |
| what is screen mounted on in mammo? | foam pad |
| what are screens made of in mammo? | green emitting gadolinium oxysulfide |
| what is benefit of slow screen speed used in mammo? | reduces noise and increases resolution |
| what is caveat of single emulsion film use in mammo | emulsion side must always be against screen |
| how much is tube tilted in mammo machine? | 6 degrees |
| what is anode degree angle in mammo? | 23 degrees |
| how are images captured in computed radiography for mammo? | photostimulable storage phosphor |
| how are images captured in direct digital radiography | in amorphous selenium |
| how are images captures in indirect conversion system? | flat panel detectors involve the detection of light by a series of smaller photodiodes |
| advantages of digital mammo? | elimination of processor artifacts, contrast enhancement, ability to perform invasive procedures faster, better resolution, reduce time, increased production, images immediately available, ability to digitally magnify |
| 2 reasons we don't want low energy x-rays | increased scatter (image contrast), increased patient dose |
| advantages of compression | red. mag, red. thickness, red. exposure, red. motion unsharpness, improved visualization, more uniform image receptor exposure |
| disadvantages of digital mammo? | cost, integration of equip, comparison of FSM images with digital images, large MB images |
| what does DMT stand for? | digital mammography tomosynthesis |
| what is DMT? | takes 11 different angles and computes into 3D image, uses less compression, 7 second exam |
| principle advantages of digital mammography | capacity to manipulate image contrast & density; capacity to transmit images for consultation; teaching, etc; archiving PACS simplified storage and access |
| types of detectors in digital mammography | phosphor flat panel, phosphor CCD, selenium flat panel, computed radiography |
| 3 categories where digital mammo has shown significant results | under age of 50, of any age with very dense or extremely dense breast tissue, pre- or periomenopausal women with lmp within 12 of last mammo |
| what does MQSA stand for? | Mammography Quality Standards Act |
| when was MQSA enacted by FDA & ACR | 1992 |
| what must be accredited according to MQSA | mammography machine, radiologists, tech, med physicists |
| what must be checked daily according to MQSA? | darkroom cleanliness, processor QC |
| what must be checked weekly according to MQSA? | screen cleanliness, view boxes and viewing conditions |
| what must be checked monthly according to MQSA? | visual checklist |
| what much be checked quarterly according to MQSA? | repeat analysis |
| soft tissue radiography requires special technique because of the low | subject contrast |
| breast tissue tends to be increasingly ___ in older women | fatty |
| dedicated mammo units should have automatic adjustable ___ device | compression |
Created by:
jen.studer
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