week ten

breast screening

a cancer detection program set in place to allow early detection of breast tumours

screening mammography

offered to asymptomatic, average risk women biennialy

ages 40-74

available every 2 years for patients over the age of 40

screening program contraindications

• patient is pregnant

• patient is lactating (wait 3 months after breastfeeding)

• have had breast cancer
  (may need a diagnostic mammo or breast ultrasound of if symptomatic patient is below 40)

• patient has breast implants

• patient has a new lump on the breast

high risk of breast cancer

• breast cancer gene (BRCA1 or BRCA2)

• parent, sibling or child has had breast cancer or carries the gene

• 2 or more relatives on same side of family has had breast cancer before the age of 50

• 3+ relatives on same side of family had breast cancer at at least one was under the age of 50

• they have had radiation to the chest

Mammos are recommended every year for people in this categories

breast location

attach anteriorly at ribs 2-7

extend from the lateral margin of the sternum to the axillary plane and form a tear drop shape

the axillary tail- extends from the upper lateral aspect of the breast to the armpit region

(composed of various structures that all them to change in shape and composition as the body changes)

lobes

each breast contains 15-20 of these

contain milk secreting components (lobyles) controlled by hormones

composed of glandular tissue

become very dense during pregnancy or hormonal therapy

adipose tissue

fat tissue that fills spaces betwene lobes

gives shape to breasts

replace glandular tissue as the aging process progresses and contribues to a homogenous appearance in later life

pectoralis major muscle

triangular in shape and originates from the clavicle, sternum and ribs

inserts into the lateral border of the bicipital groove of the humerus and lies between the breast tissue and ribs

shows as white trainagular densitis

lactiferous ducts

transport milk from the lobes / lobules to the nipples

these are a common site of cancer

retro-mammary space

composed of fibrous connective tissue and is located between the posterior breast fat and the pectroalis muscle

lymph nodes

there are 12-30 of these located in each axillary space

drain intercellular fluid from the chest and arms

these are biopsied for positive malignant breast cells and for sentiel node assessment

we include the axilla and pectroalis to include this region and rule out any potential patholoyg present

compression

a technique used for all mammograms that creates a uniform thickness of the breast tissue

if the overall thickness is reduced, there is a decrease in radiation dose to patient

decreases motion and distortion

spreads out SI structures into a single layer

should be able to see the pectoralis muscle and the nipple directed forward in profile

BI-RADS A

fatty breast consists of mainly adipose tissue with minimal glandular tissue

(remember density can only be determined on a mammogram as the look and feel of a breast does not indicate the ratio of fatty to fibroglandular tissue

BI-RADS B

these breasts have a small amount of glandular tissue and extensive adipose tissue

BI-RADS C

mixed density breasts are composed of glandular tissue infiltrated with adipose tissue

BI-RADS D

the dense breast consists of primarily connective tissue with very little adipose tissue

minimal tissue differentiation between the two types of tissue

lactating breast

this breasts consists of extensive glandular tissue with minimal adipose tissue since the glands are actively producing milk

the breast is extrenely dense and radioopaque

25-32

the kVp used for mammo:

(AEC is typically used for mAs selection)

a lower one of kVp permits high contrast imaging - will result in a higher absorbed radiation dose than conventional radiogrpahy- byt the rad must be able to visualize the contrast of the breast

50-80

what is the SID used

(this number is needed as the kVp is low)

might affect image sharpness and distortion, a small focal spot and compressed (decreased OID) will aidn in this

Molybdenum

the most common alloy used for the anode | has a low atomic number and therefore lower energy photons are produce

(may also be Rhodium and Tungsetn is a better fit to penetrate thick and extremely dense breast)

anode rotates and is anhled +10 degrees to -9

cathode is nearest to the chest wall for anode heel effect

filtration

typically constructued of beryllium (Be)
the units must be kept low

units are often equipped with added __ made of Mo or Rh

different ones are used for different anode targets

(also the focal spot size are 0.3-0.4 for screening and 0.1 to 0.15mm for diagnostic)
a small focal spot will compensate when magnification is needed as mag will reduce the resolution

patient prep

• no deodorant or powder (mimic micro-calcification)

• reduce or refrain from caffeine intake (causes th ebody to retain fluid and the breats tissue is a common place for accmulation)

• avoid any artifacts (includding clipping hair back)

• gown that opens from the front

• complete history questionnaire is filled out

• try to relax (when patient is tense, compression is difficult)

posterior nipple line

an imaginary line drawn from the nipple to the edge of the image, chest wall or pectoralis muscle (whichever comes first)

used to measure the depth of the breast in both CC and MLO images

determines whether sufficient breast tissue was imagied

(compared between both CC and ML images and should be within 1cm of each projection

should demonstrate the inferior aspect of the pectoralis muscle extending to or below the line for the MLO

images will inclyde the pectroalis muscle 30% of the time for CC

digital breast tomosynthesis

a 3D imaging technology being used by several sites

machine acquires images of the breasts at multiple angles instead of 90-degrees

tube moves in an arc, taking a series of low dose images to allow view of breast tissue slices in as thin as 1mm

allows for better visualization of breast abnormalities, as it separates breast tissue with each slide