Physics - Mamms Flashcards
What is the focal spot size for general xray?
0.6 and 1.2 mm
What is PPV 2?
of actual caners found in a year / Total BR 4,5 (Recommend biopsy)
How many mamms months must you have to graduate residency?
3
What is the spatial resolution (lp/mm) of CT
0.7
What does the RSNA say for lp/mm in the left-right direction?
11
What radiation effect dominates at lower energies?
Photoelectric
How many documented hours of mamms education do you have to have?
60
What is used to reduce scatter in mag views?
Air gap
Cancers/1000 screened
3-8
What grid ratio is used in general rad?
6-16
What is the effective anode angle?
Anode angle + tube angle
What is the max dose to the breast phantom with a grid?
3 mGy (300 milirads)
What happens to the dose with a grid?
Increased
What is the max dose to the breast phantom without a grid?
1 mGy
What target/filter is used for denser breast tissue?
RH/RH
What can you do to Mo anode to make the beam harder for denser tissue?
Add aluminum filter
What target/filters will some digital systems use?
Tungsten/Rho Tungsten/Silver (Higher energy)
How often must you do: Viewbox conditions? (Mammo)
Weekly
What is the flat field test? What is it done for?
Imaging with a large piece of acrylic. Done to improve image quality and calibrate digital detectors
What is PPV 3?
of actual cancers found in a year / Total BR 4,5 with biopsy
What is the binding energy of Moly?
18 keV
What is the focal spot size for mammo?
0.1 and 0.3 mm
What is the bucky factor general xray?
5
How do you increase the spatial resolution in the mag view? What other variables change as a result?
Smaller focal spot. mA drops (~25) and exposure time increases
What is the probibility of a photoelectric effect occuring?
1 / z3 (cubed) (z = energy)
How is the ma affected by decreasing the focal spot size?
it is lowered
How often must you do: Repeat analysis (Mammo)
Quaterly
What is the spatial resolution (lp/mm) of screen film mammo?
15
What is the ideal energy for diagnostic Mammography
16-23 kEv
How many mamms must you have read under direct supervision during the last 2 years of training?
240
What is MQSA required lp/mm for screen film?
12
What grid ratio is used in mammo?
4-5
How often must mammo centers be acreditied?
3 years
What is grid ratio?
H/W, H = height, W= width between grids
What is PPV 1?
of actual cancers found in a year / Total BR 0,4,5
What are the target annodes for Diagnostic Mammo?
Moly and Rhodium
What is the spatial resolution (lp/mm) of Digital radiograph
3
How is the exposure time effected in mammo for the smaller focal spot?
increased, but usually less than 2 seconds.
What is the MQSA phantom consist of?
50% fat 50% glandular tissue
What is the spatial resolution (lp/mm) of MR
0.3
How often must you do: Phantom Evaluation (Mammo)
Weekly
Who oversees the MQSA?
FDA
What is the bucky factor for mammo
2
How often must you do: Darkroom Fog? (Mammo)
Semi-Annually
How often must you do: Screen-Film Contrast (Mammo)
Semi-Annually
What window is used in regular diagnostic imaging?
Pyrex
What is ghosting?
Residual image from prior exposures. Why no lead in flat panel digital systems
What is the mA limts for 0.1 mm focal spot?
50
What is dark noise? What is it related to?
electronic fluctuations within the detector element. Proportional to the temperature to the detector.
How often must you do: Compression Test?
Semi Annually
What is the spatial resolution (lp/mm) of digital mammo
7
What is the voltage needed to get diagnostic Mammo energies?
25-30 kVp
What is the binding energy of tungston?
69.5 kev
What target/filter is used for intermediate tissue?
mo/rh
How often must you do: Processor QC? (Mammo)
Daily
What has a higher spatial resolution digital or analog?
Digital 5-11 lp/mm. analog 11 - 13 lp/mm (winner)
What is the target recall rate for mammo?
5-7%
What is the mA limits for a 0.3 mm focal spot?
100
What is the primary factor affecting the total noise in an image?
Number of photons interacting with the detector. This is fixed after the exposure.
What target/filter is used for less dense breast tissue?
MO/MO
What is MQSA standard for Lp/mm for digital systems?
There isn’t one ( manufacture specs ~7)
What is the max dose to a patient’s breast in mammo?
There isn’t one
What does the RSNA say for LP/MM in the anode-cathode directioN?
13
What is the dose of Digital compared to analog?
1.8 mGy for Analog, 1.6 for digital
What happens to total dose with mag views? Why?
Increases. Breast tissue is moved closer to the source.
What window is used in mammo? Why?
Beryllium. Pyrex causes excessive attenuation of the energies needed in mammo
What is the general target annode for regular diagnostic imaging?
Tungston
How often must you do: Darkroom Cleanliness? (Mammo)
Daily
