Mammography
Introduction
This technique uses a low-energy X-ray beam to maximize differences in soft-tissue density and demonstrates the internal architecture of the breast.
Compression of the breast, a short exposure time and the use of high-quality screen-film equipment improve image quality.
Anatomy
Radiological Anatomy
Common Views
A.
Mediolateral oblique view (MLO)
B.
Craniocaudal view (CC)
1.
Pectoralis muscle
2.
Retroglandular fat
3.
Glandular breast tissue
4.
Nipple
5.
Cooper’s ligaments
Why Compression Is Used
To decrease the thickness of the breast and make it more uniform.
To
bring the breast structures as close to the image receptor (IR) as possible.
To
decrease the dose needed and the amount of scattered radiation.
To
decrease motion and geometric unsharpness.
To
increase contrast by allowing a decrease in exposure factors.
To
separate breast structures that may be superimposed.
Physics
X-ray beams with low penetrating characteristics must be used to produce visible images
Because the normal composition of the breast and the usual signs of cancer are in soft tissue with very little difference or physical contrast.
If very high kVp x-rays are used, very little absorption by tissues and consequently the contrast will be very poor.
Usually 25-30kVp is used.
This results in higher exposure.
The imaging receptors necessary for their visibility require a higher exposure than receptors for other radiographic procedures.
Criteria
Low kVp x-ray beam
Minimum filtration of the beam
Small focal point
Fine grain mammographic films
Breast Types
Fibroglandular Breast (Younger or Pregnancy)
Fibrofatty Breast (30-50 Years)
Fatty Breast
Ultrasound
Why Ultrasound
Safe – No radiation hazard
Can differentiate between solid and cystic lesion
Real time evaluation
Can check the vascularity
Almost exact identification of location