Mammography Study Guide

Mammography Finals

Mammography

• A diagnostic imaging study using ionizing energy to determine normal and abnormal breast structures.
• X-ray imaging method for early breast cancer detection (before palpable).
• X-ray Production: Uses characteristic x-rays.
• Low kVp is used to:
  • Minimize Compton scattering.
  • Maximize the photoelectric effect.
  • Enhance differential absorption by breast tissues.
  • Reduce radiation dose to the radiosensitive glandular tissue.

Risk of Mammogram

• Mean Glandular Dose (MGD): Best indicator of radiation risk.
• Average MGD: $320 \text{ mrad}$

History of Mammography

• 1898 - William Halstead: Introduced Radical Mastectomy.
  • Halstead Radical Mastectomy: Removal of the whole breast, underarm lymph nodes, and chest wall muscles.
• 1913 - Albert Soloman: Performed the first mammogram on an excised breast and axilla using a standard x-ray machine.
  • Compared tissue with X-ray images to identify diseased tissue spread and differentiate it from healthy tissue.
• 1927 - Otto Kleinschimdt: Published the first known image of living patient's breast tissue.
• 1930 - Stafford Warren MD: Authored the first article in mammography, "A Roentgenologic Study of the Breast."
• 1957: The first systematic study of breast radiography was performed at the University of Heidelberg, Germany, using Siemens TRIDOROS 4 equipped with mammocones.
• 1930 - LeBorgne, Gershon-Cohen, Gros: Made excellent comparisons of mammographic and pathologic anatomy and developed clinical techniques.
• 1960s - Robert Egan: Known as the “Father of Mammography,” he published work on diagnostic x-rays in breast disease management.
• 1960s - John Wolfe and Francis Ruzicka: Introduced Breast Xerography (Xeromammography).
• 1967 - CGR (France): Developed the first dedicated mammography unit.
• 1975 - Kodak & Dupont: Introduced Screen-Film combination.
• 1992: Mammography Quality Standard Act (MQSA) was implemented.
• 2000 - General Electric: Introduced full-field digital mammography.

Breast Cancer Screening

• Women over 50 should undergo annual mammography.
• Women between 40-49 should have a mammogram every year or every other year.

Screening Mammography

• Applied to asymptomatic patients without known breast problems.

Diagnostic Mammography

• A problem-solving examination to rule out cancer or demonstrate a suspicious area seen on screening.

Diagnostic Mammography: Clinical Findings

• Refer to physical examination results and any other symptoms or signs observed or reported during clinical examination.

Diagnostic Mammography: Clinical Breast Examination (CBE)

• Physical examination of the breasts for abnormalities or changes.
• Look for signs like breast lumps, skin changes, or abnormal nipple discharge.
• Steps of a Clinical Examination:
  1. Visual Inspection: Observe for changes in size, shape, or symmetry, skin changes (redness, dimpling, puckering), and nipple changes (inversion, discharge).
  2. Palpation (Physical Exam): Feel breasts and underarms (axilla) for lumps, thickening, or unusual tissue changes. Done in different positions (arms at sides, raised, or hands on hips).

Recall from Screening

• Patient returns for additional tests after a routine screening mammogram.
• Doesn't necessarily mean cancer is suspected.
• Reasons for recall:
  • Suspicious finding or abnormality.
  • Dense breast tissue.
  • Technical problems with images.
• Next steps:
  • Additional imaging (diagnostic mammogram, ultrasound, MRI).
  • Biopsy.
• Recall does not mean a diagnosis of cancer; further investigation is needed.

Breast Self-Examination (BSE)

• Technique to check your own breasts for abnormalities.
• Important to become familiar with the normal look and feel of your breasts.
• Steps:
  1. Visual Check (In Front of a Mirror): Look for changes in shape, size, or skin of breasts.
     • Arms at sides, raised arms, hands on hips.
  2. Feel Your Breasts: Use pads of fingers in small, circular motions to feel breasts while lying down with a pillow under your shoulder.
     • Check from collarbone to abdomen and sternum to armpit.
  3. Check Your Armpits: Raise one arm and use the opposite hand to feel for lumps.
  4. Nipple Check: Gently squeeze each nipple to check for discharge.

Patient Communication and Preparation

• Ensures patient comfort, knowledge, and readiness for the procedure.
• Before the Mammogram:
  • Explain the Procedure: Mammogram is an X-ray of your breast to look for signs of breast cancer or other changes in the breast tissue. It usually takes 15-30 minutes.
  • Address Concerns and Answer Questions: Some patients may be nervous or unsure. Answer any questions they might have.
  • Clarify the Purpose: Early detection of breast cancer, even without symptoms; diagnostic mammogram if a lump is felt.
• During the Mammogram:
  • Provide Reassurance: Keep the patient informed about the steps.
  • Encourage Communication: Let them know they can speak up if they feel discomfort or have questions during the procedure .
• After the Mammogram:
  • Discuss Next Steps: Radiologist review; results in a few days; contact for further investigation if needed.

Infection Control

• Maintaining proper hygiene reduces the risk of contamination or transmission of infections.
  1. Hand Hygiene: Wash hands or use hand sanitizer before and after patient interaction. Remind patients to do the same.
  2. Cleaning and Disinfecting Equipment:
     • Clean and disinfect the mammography machine surfaces between each patient.
     • Use hospital-grade disinfectants on compression plates, control buttons, etc.
     • Use disposable covers on parts in direct contact with the patient and change after each use.
  3. Personal Protective Equipment (PPE):
     • Wear gloves when handling equipment or touching potentially contaminated surfaces.
     • Use a mask and eye protection when potential for contamination.
  4. Cleanliness of the Exam Room: Regular disinfection of surfaces such as exam table, chairs, door handles, etc.
  5. Patient Hygiene:
     • Encourage patients to clean their breasts before the exam if needed.
     • No deodorants, lotions, or powders on breasts or underarms.
     • Wear a two-piece outfit.

Terms

• Anode: Positively charged side of an x-ray tube containing the target.
• Atomic Number (Z): Number of protons in the nucleus.
• Automatic Exposure Control (AEC): Determines radiation exposure during radiography.
• Baseline Mammography: A woman’s first radiographic examination of her breasts, used for comparison.
• Bremsstrahlung X-ray: X-ray resulting from interaction of projectile electron with a target nucleus; braking radiation.
• Cathode: Negative side of the x-ray tube; contains the filament and focusing cup.
• Central Ray: Center of the x-ray beam that interacts with the image receptor.
• Characteristic X-ray: X-ray released from the photoelectric effect; energies determined by electron binding energy.
• Classical Scattering: Scattering of x-rays with no loss of energy; also called Coherent, Rayleigh, or Thompson scattering.
• Collimator: Device used to restrict x-ray beam size and shape.
• Collimation: Restriction of the useful x-ray beam to reduce patient dose and improve image contrast.
• Compression Device: Maintains close screen-film contact when the cassette is closed and latched.
• Compression: Act of flattening soft tissue to improve optical density.
• Compton Scattering: Interaction between an x-ray and loosely bound outer-shell electron, resulting in ionization and x-ray scattering.
• Diagnostic Mammography: Examination performed on patients with symptoms or elevated risk factors for breast cancer.
• Differential Absorption: Different degrees of absorption in different tissues that result in image contrast and formation of the x-ray image.
• Exposure: Measure of the ionization produced in air by x-rays or gamma rays. Quantity of radiation intensity expressed in roentgen ($R$), Coulombs per kilogram ($C/kg$), or air kerma ($Gy$).
• Filtration: Removal of low-energy x-rays from the useful beam to increase beam quality and reduce patient dose.
• Focal Spot: Region of the anode target in which electrons interact to produce x-rays.
• Grid: Device used to reduce the intensity of scatter radiation in the remnant x-ray beam.
• Heel Effect: Absorption of x-rays in the heel of the target, resulting in reduced x-ray intensity to the anode side of the central axis.
• High Voltage Generator: Principal part of x-ray tube; always close to the x-ray tube.
• Ionizing Radiation: Radiation capable of ionization.
• Inherent Filtration: Filtration of useful x-ray beams provided by permanently installed components.
• Kilovolt Peak (kVp): Measure of maximum electrical potential across an x-ray tube; expressed in kilovolts.
• Mammographer: A radiologic technologist who specializes in breast x-ray studies.
• Mammography: Radiographic examination of the breast using low kilo voltage.
• Microcalcifications: Calcific deposits that appear as small grains of varying sizes in the x-ray film.
• Molybdenum: Target material for x-ray tubes used in mammography.
• Object to Image Receptor Distance (OID): Distance from the image receptor to the object that is to be imaged.
• Operating Console: Console that allows the rad tech to control x-ray tube current and voltage.
• Optical Density: Degree of blackening of a radiograph.
• Photoelectric Effect: Absorption of an x-ray by ionization.
• Radiation: Energy emitted and transferred through matter.
• Scatter Radiation: X-rays scattered back in the direction of the incident x-ray beam.
• Screening Mammography: Imaging examination performed on the breasts of asymptomatic women with a two-view protocol to detect unsuspected cancer.
• Source to Image Receptor Distance (SID): Distance from the x-ray tube to the image receptor.

Dedicated Mammography

• Specialized imaging using low-dose X-rays specifically for examining breast tissue

C-arm X-ray Tube Stand

• Used for real-time, fluoroscopic imaging in operating rooms and interventional procedures.
• C-shaped arm connects the X-ray source (tube) and the image detector.

Breast Anatomy

• Young breasts are dense and harder to image due to glandular tissue.
• Older breasts are more fatty and easier to image.
• Normal breasts consist of fibrous, glandular, and adipose (fat) tissues.
• Premenopausal: Fibrous and glandular tissues are structured into ducts, glands, and connective tissues surrounded by fat.
• Postmenopausal: Degeneration of fibroglandular tissue and an increase in adipose tissue.
• Glandular and connective tissue: High optical density (OD).
• Adipose tissue: Appears dark on film with higher OD and requires less radiation exposure.
• Malignancy: Appears as a distortion of normal ductal and connective tissue patterns.
• Approximately 80% of breast cancer is ductal and may have microcalcifications.
• Microcalcifications smaller than $500 \mu m$ are of interest.
• Incidence of breast cancer is highest in the upper lateral quadrant.
• Conventional radiographic technique is useless due to similar mass density and atomic number of the soft tissue components of the breast.
• Low kVp must be used to maximize the photoelectric effect and thereby enhance differential absorption and improve contrast resolution.
• X-ray absorption in tissue occurs principally by photoelectric effect and Compton scattering.
• Absorption caused by differences in mass density is proportional to the mass density for both photoelectric effect and Compton scattering.
• Absorption caused by differences in atomic number is directly proportional for Compton scattering and proportional to the cube of the atomic number for photoelectric effect.
• Technique factors of approximately 23 to 28 kVp are used.

The Mammographic Imaging System

• X-ray mammography became clinically acceptable with Molybdenum and dedicated single-emulsion screen-film image receptor.
• Dedicated mammographic imaging systems are designed for flexibility in patient positioning and have an integral compression device, a low ratio grid, AEC, and a microfocus x-ray tube.
• High-Voltage Generation: All mammography imaging systems incorporate high frequency generators.
• The resulting voltage ripple in the x-ray tube is approximately 1%.
• A maximum limit of 600 mAs is standard for preventing excessive patient radiation dose.

Target Composition

• Mammographic x-ray tubes are manufactured with a tungsten ($W$), molybdenum ($Mo$), or rhodium ($Rh$) target.
• Useful x-rays for enhancing differential absorption in breast tissue: 17 to 24 keV.
• Molybdenum's atomic number is 42 compared with 74 for tungsten.
• Rhodium has a slightly higher atomic number ($Z = 45$).

Comparison of Target Materials

Focal-Spot Size

• Important due to higher demands for spatial resolution in mammography.
• Smaller focal spots are better for imaging microcalcifications.
• Manufacturers shape the focal spot through cathode design and focusing cup voltage bias.
• Medical physics acceptance testing is essential.
• Line-focus principle and tilt of the x-ray tube are used to obtain small focal-spot size and adequate x-ray intensity.
• Effective focal spots—0.3/0.1 mm—are obtained with an approximate 23-degree anode angle and a 6-degree x-ray tube tilt.
• Normally, the cathode is positioned to the chest wall for easier patient positioning and application of the anode heel effect.
• Tilting the x-ray tube ensures imaging of the tissue next to the chest wall.

Filtration

• Dedicated mammography x-ray tubes have either a beryllium ($Z=4$) window or a very thin borosilicate glass window.
• Most mammography x-ray tubes have inherent filtration in the window of approximately 0.1 mm Al equivalent.
• Tungsten target x-ray tube should have a molybdenum or rhodium filter.
• 50 µm rhodium ($Z=45$) is a better filter for imaging thicker and denser breasts when the x-ray tube target is tungsten.

Heel Effect

• Important to mammography because the conic shape of the breast requires higher radiation intensity near the chest wall.
• Positioning the cathode to the chest wall ensures near-uniform exposure of the image receptor.
• Spatial resolution of tissue near the chest wall is reduced because of the increased focal spot blur.
• Dedicated mammography imaging systems use a source-to-image receptor distance (SID) of 60 to 80 cm, with the cathode to the chest wall and the x-ray tube tilted.

Compression

• Particularly important in mammography.
• Advantages:
  • More uniform thickness.
  • Reduces underexposure/overexposure.
  • Reduces focal-spot blur, absorption blur, and scatter radiation.
  • Immobilizes the breast to reduce motion blur.
  • Spreads out the tissue.
  • Improves contrast resolution.
  • Lowers patient radiation dose.
• Built-in stiff compression device.

Grids

• Used routinely in mammography.
• Moving grid with a ratio of 4:1 to 5:1 focused to the SID to increase image contrast.
• Grid frequencies of 40 lines/cm for the moving grid are typical.
• Increases patient dose.
• Use of a 4:1 ratio grid approximately doubles the patient dose compared with nongrid mammography.

Automatic Exposure Control

• Designed to measure x-ray intensity and quality.
• AEC devices are positioned after the image receptor.
• Two types: Ionization chamber and solid-state diode.
• Compensated AEC (CAEC): AEC can estimate the beam quality after passing through the breast.
• Thick, dense breasts are imaged better with Rh–Rh; thin, fatty breasts are imaged better with Mo–Mo.
• CAEC should be accurate to ensure reproducible images at low patient radiation dose.
• For screen-film mammography, the CAEC should be able to hold OD within 0.1 OD as voltage is varied from 23 to 32 kVp and for breast thickness of 2 to 8 cm.

Magnification Mammography

• Magnification techniques are used frequently in mammography, producing images up to twice the normal size.
• Requires special equipment such as microfocus x-ray tubes, adequate compression, and patient positioning devices.
• Effective focal-spot size should not exceed 0.1 mm.

Digital Mammography

• The same mammographic imaging system can be used for screen-film and digital mammography.
• Digital mammography was equal to screen-film mammography for mature, fatty breasts, but it was superior when imaging younger, denser breasts.

Screen-Film Mammography

• Radiographic intensifying screens and films have been designed specially for x-ray mammography.
• The films are single-emulsion and are matched with a single back screen.
• Special emulsions coupled with rare earth screen material are available.
• The screen-film combination is placed in a specially designed cassette.
• The use of the radiographic intensifying screen significantly increases the speed of the imaging system, resulting in a low patient radiation dose.

Comparison of General X-Ray Tube and Mammography Tube

Mammography Quality Control

• Part of an overall analysis and includes performance monitoring, record keeping, and evaluation of results.
  1. The radiologist, who has specific duties of administration and tracking diagnostic results;
  2. The medical physicist, who examines and monitors the performance of imaging systems
  3. The QC mammographer, who performs many tests and evaluations involving imaging systems, film processing, and viewing mammographic images.
• Daily routines include maintaining darkroom cleanliness and performing processor QC.
• Weekly routines include cleaning intensifying screens and viewbox illuminators, producing phantom images, and performing equipment checks.
• Repeat analysis, based on at least 250 mammographic examinations, should occur four times a year. A repeat rate of less than 2% is required.
• Semiannually, the darkroom fog check is conducted and screen-film contact tests are performed.
• Finally, the compression test is done with the use of a bathroom scale under the compression paddle. Compression should never exceed 40 pounds of pressure.
• Digital mammography QC routines are also time scheduled, and some such as repeat analysis and compression checks are similar to screen-film QC.
• Digital display devices require daily QC evaluation.
• To get a quality mammogram, the facility should have the following:
  • FDA certification
  • Mammogram machine that’s calibrated annually
  • Registered Radiologic Technologist

Radiographic Positioning

• Patient Preparation:
  • Patient puts on a gown designed for mammography.
  • Removes jewelry, talcum powder, antiperspirant, or lotions, which may cause artifacts.
  • Technologist explains the procedure and documents any relevant patient history.
• Patient history should include:
  • Number of pregnancies
  • Family history of cancer
  • Medications
  • Previous breast surgery
  • Previous mammograms
  • Reason for current visit
• Breast Positioning:
  • Base of breast: Portion near the chest wall.
  • Apex: Area near the nipple.
  • Use compression device in combination with a specially designed tube.
• Indications:
  • pain/tenderness
  • swelling
  • nipple discharge (mild)
  • calcifications
  • benign and malignant tumor
  • lymph node enlargement
• Contraindications:
  • breast implant
  • sever nipple discharge
  • large palpable mass
  • inflammation
  • women with reproductive age (15-40 benefit over risk)

Alternative Modalities and Procedures

• Sonography (Ultrasound):
  • Distinguish between a cyst and a solid lesion.
  • Reveal fluid, abscess, hematoma, and silicone gel.
  • Ability to find cancers in women with dense breasts.
  • Image quality depends heavily on sonographer expertise.
• MRI:
  • Effective for certain special applications- Palpable masses not seen with mammography or ultrasound
  • Possible screening of a young woman at very high risk for breast cancer because of familial history or women who carry the BRCA1 and BRCA2 genes
  • Staging breast cancer or assessment of leakage from silicone breast implants
• Digital Breast Tomosynthesis:
  • Eliminates detection challenges associated with overlapping structures in the breast
  • Offers other potential benefits, including increased lesion and margin visibility, help in localizing structures in the breast, a reduction in recall rates, and increased cancer detection

Mammography Terminology

Mediolateral Oblique (MLO) Projection: Mammography

• Clinical Indications:
  • Detection or evaluation of calcifications, cysts, carcinomas, and other abnor.
• Technical Factors
  • SID-fixed, varies with manufacturer, about 60 cm (24 inches)
  • IR size 18 x 24 cm, or 24 x 30 cm, crosswise
  • Grid or not
  • Analog and digital systems-to 28 kv

Craniocaudal (CC) Projection: Mammography

• Clinical Indications:
  • Detection or evaluation of calcifications, cysts, carcinomas, or other abnormalities or changes in the breast tissue indicating a possible pathology
  • Two breasts are imaged separately for comparison
• Technical Factors
  • SID-fixed, varies with manufacturer, about 60 cm (24 inches)
  • IR size-18 x 24 cm, or 24 x 30 cm, crosswise
  • Analog and digital systems-23 to 28 kV

Mediolateral (ML) Projection: True Lateral Breast Position

• Clinical Indications:
  • Breast pathology, especially inflammation or other pathology in the lateral aspect of the breast
  • May be requested by the radiologist as an optional projection to confirm an abnormality seen only on MLO
• Technical Factors
  • fixed, varies with manufacturer, about 60 cm (24 inches)
  • IR size-18 x 24 cm, or 24 x 30 cm, crosswise
  • Grid
  • Analog and digital systems-23 to 28 kV

Exaggerated Craniocaudal (Laterally) (XCCL) Projection

• Clinical Indications:
  • Potential breast pathology or change in breast tissue; also emphasizes axillary tissue
• Technical Factors
  • SID-fixed, varies with manufacturer, about 60 cm (24 inches)
  • IR size-18 x 24 cm, or 24 x 30 cm, crosswise
  • Grid
  • Analog and digital systems-23 to 28 kV

Implant Displaced (ID) (Eklund Method)

• Clinical Indications:
  • Detection and evaluation of breast pathology underlying the implant
  • Take note:
    • For projections done with the implant in place, only manual exposure techniques should be set on the generator because the implant prevents the x-rays from reaching the AEC detector. This causes overexposure of the breast, and the AEC system possibly may go to maximum backup exposure time.

Gynecomastia/ Prominent Male Breast

• Gynecomastia: Benign glandular enlargement of the male breast.
• Common causes:
  • Puberty
  • Estrogen/androgen exposure
  • Marijuana use
  • Medication side effects
  • Klinefelter’s syndrome
• Breast cancer accounts less for less than 1% in men - Most common symptoms is nipple ulceration
• Most common type of cancer in the male is Infiltrating ductal carcinoma (IDC)/ or Invasive Ductal Carcinoma
• About 80% of male breast cancer patients are treated by mastectomy. The most important factor influencing prognosis in male breast cancer is the size of the tumor.