Midterm 2 Flashcards
Target filter recommendation
4cm fatty breast
__ target &__ micron __ filter
__-__ kvp
Mo 30 Mo
24-26
Glandular breast 5-7 cm
Mo target & __ micron __ filter
__ kVp
25
27-31
Breast thickess higher 7cm
__ target & __ micron Rh filter
Rh
25
It is used to magnify small
area of the breast for better
visualization
SPOT COMPRESSION
Reduces breast thickness, motion, geometric unsharpness, xray scatter & beam hardening
- lowers radiation dose
-spreads breast tissues apart
-produces a more uniform thickness
- allows use of narrow latitude, high contrast film.
- improve contrast
Breast Compression
Breast biphasic compression Advantages:
1. Provides
2.produces
3. Improves
4. Reduces
Produces radiograph of uniform
density
Improves contrast
Reduces tissue overlap and
improves resolution
Provides immobilization of the part
during exposure
• Flat surface plate used for
uniform compression.
COMPRESSION
DEVICE
Year___who__ uruguanian Radiologists 1st uses breast compression
1949 R.Leborgne
Year__compression devices common on dedicated mammo unjts
1970
2 type of screen film cassette
Conventionql Screen Film
Computed Radiography
must be a moving grid.
•Focused grid, with a
grid ratio 3:1 or 5:1
anti-scatter grids
Chest wall-side
Nipple-side
Cathode
Anode
THE SMALLER THE ANODE ANGLE, THE
___ THE ANODE HEEL EFFECT:
GREATER
One fortunate
consequence of the
line focus principle
• Radiation Intensity
on the cathode side
of the x-ray tube is
higher that the
anode side
ANODE HEEL
EFFECT
__mm for contact mammography (breast compressed against the grid and image receptor
0.3 to 0.4
__ mm for magnification mammography, it
reduces geometric blurring so that
microcalcifications can be resolved.
0.1
source-toimage planedistance (SID)
typical – __ cm
60-65
Mo target with 0.__ mm Mo filter (atomic no. 42)
03
Rh target with __mm Rh filter (atomic no. 45)
0.02
W Target with 0.__mm Rh filter
05
FILTRATION
A. E X IT WINDOW
•Made up of
___
Beryllium
- most common anode target materialused in mammography x-ray tube (soft tissue imaging)
Molybdenum
Dual Targets of Anode
Mo/Rh”
focusing cup to produce 0.__mm
3
0.__mm focal spot size (fss)
1
•The mammography x-ray tube is
configured with dual-filaments in the
focusing cup to produce 0.3mm and
0.1mm focal spot size (fss)
CATHODE
CO MP O NENT S:CCCBMG
▪
C-Arm X-ray Tube Stand
▪ Mammography Tube
▪ Beam Restricting Device
▪ Compression Device
▪ Grid
▪ Cassette Holder
▪ Others
CONVENTIONAL XRAY UNIT
TARGET MATERIAL:
Housing:
Exit window:
Tube target:
Axis of rotation:
Anode Angle:
Filtration:
FSS:
TYPE OF XRAY GENERATOR:
SID:
Tungsten anode
Glass envelope
Pyrex
Tungsten
Horizontal
7-16 degrees
Al
0.1mm
High frequency
Short as possible
Mammography unit
TARGET MATERIAL:
Housing:
Exit window:
Axis of rotation
Tube target:
Anode Angle:
Filtration:
FSS:
TYPE OF XRAY GENERATOR:
SID:
Grounded Mo, Rh anode
Metal tube
Beryllium
Vertical
Mo
0-26 deg.
Mo or Rh filter
0.3-0.4mm
Grids
60-65 cm
• used as it has a low atomic number of
_ and lower absorption of less than _ kVp.
• 1mm of Be is equivalent to __mm
Al material (__
filtration)
4
5
0.1mm
inherent
