{
"id": "mammography-image-production",
"modality": "Mammography",
"category": "Image Production",
"title": "Mammography Image Production: Equipment, QC and Image Quality",
"minutes": 9,
"slides": [
{
"id": 1,
"diagram": "title",
"heading": "Image Production",
"bullets": [
"30 of 115 scored questions (26.1%)",
"Beam, geometry, digital detectors and DBT",
"Compression, technique and image quality",
"Technologist QC, physicist tests and MQSA"
],
"narration": "Welcome to Mammography Image Production. This category is 30 of the 115 scored questions on the mammography boards, about 26 percent of your score. We'll start with the equipment: the beam, the geometry, digital detectors and tomosynthesis. Then we'll cover compression, technique factors and what makes a good image. Finally we'll lock down quality control: the technologist tests and how often they're done, what the medical physicist checks, and the M Q S A rules for personnel and records. Let's get started.",
"svg": ""
},
{
"id": 2,
"diagram": "mammo-tube",
"heading": "The mammography beam",
"bullets": [
"Low kVp (about 25-35) maximizes subject contrast",
"Mo, Rh or W targets with Mo, Rh or Ag filters",
"Denser, thicker breast: harder beam (Rh or W)",
"Cathode at chest wall: heel effect aids thick tissue"
],
"narration": "Mammography runs at low k V p, about 25 to 35 for most two-dimensional exams, because low energy maximizes subject contrast between fat, gland and tumor. Target and filter pairs combine molybdenum, rhodium or tungsten targets with molybdenum, rhodium or silver filters. These K-edge filters strip out photons that add dose without helping contrast. A denser or thicker breast needs a harder beam, so the unit moves to a rhodium or tungsten target, and most digital units today use tungsten. Finally, the cathode sits at the chest wall, so the anode heel effect sends more intensity to the thick posterior tissue.",
"svg": ""
},
{
"id": 3,
"diagram": "magnification-geometry",
"heading": "Focal spots, grids, mag",
"bullets": [
"Contact focal spot about 0.3 mm; mag about 0.1 mm",
"Moving grid, low ratio about 4:1 to 5:1",
"Magnification: no grid, air gap removes scatter",
"Mag 1.5-2.0x: more dose, more motion risk"
],
"narration": "Focal spot size controls sharpness. Contact views use about a 0.3 millimeter focal spot, and magnification uses the small 0.1 millimeter spot. On contact views, a moving grid with a low ratio, about 4 to 1 or 5 to 1, cleans up scatter. Here's the classic trap: for magnification, the grid comes out. The breast sits on a magnification stand, and the air gap between breast and detector removes scatter instead. Magnification is usually 1.5 to 2 times. It raises patient dose and lengthens exposure time, so motion blur becomes more likely.",
"svg": ""
},
{
"id": 4,
"diagram": "dbt-arc",
"heading": "Digital detectors and DBT",
"bullets": [
"Direct: amorphous selenium turns x-rays to charge",
"Indirect: cesium iodide + amorphous silicon",
"DBT: low-dose projections over a limited arc",
"Synthesized 2D from DBT data can replace 2D dose"
],
"narration": "Full-field digital mammography uses flat-panel detectors. Direct conversion detectors use amorphous selenium, which turns x-rays straight into electrical charge. Indirect detectors use a cesium iodide scintillator that makes light, read by amorphous silicon photodiodes. Digital breast tomosynthesis, or D B T, takes many low-dose projections as the tube sweeps through a limited arc, then reconstructs thin slices about 1 millimeter thick that cut down tissue overlap. Remember, D B T is not C T: there's no full rotation. And a synthesized two-dimensional image built from the D B T data can replace the separate two-dimensional exposure, lowering dose.",
"svg": ""
},
{
"id": 5,
"diagram": "compression",
"heading": "Compression and technique",
"bullets": [
"Firm compression is the most important factor",
"Thinner: less dose, scatter, motion and overlap",
"Low mAs = too few photons = quantum noise",
"View and laterality marker goes near the axilla"
],
"narration": "Firm compression is the single most important technique factor in mammography. A thinner, evenly spread breast means lower dose, less scatter, less motion blur and less tissue overlap. Next, exposure. k V p controls contrast and penetration, while m A s controls the number of photons. Too few photons from low m A s shows up as quantum noise, or mottle. In digital, a light or dark image alone doesn't prove a technique error, but noise does. Finally, labeling: the view and laterality marker goes near the axilla, along with the patient name, a second identifier, the date, the facility and your technologist I D.",
"svg": ""
},
{
"id": 6,
"diagram": "qc-calendar",
"heading": "Technologist QC schedule",
"bullets": [
"Weekly: ACR DM phantom image quality",
"Monthly: thickness indicator, checklist, monitors",
"Quarterly: facility QC review",
"Semiannual: compression force",
"Annual: medical physicist survey"
],
"narration": "Frequency questions are free points, so learn the schedule from the 2018 American College of Radiology Digital Mammography Q C Manual. Weekly, and after service, you image the A C R digital mammography phantom. Monthly, you check the compression thickness indicator, complete the visual checklist, and run Q C on both the acquisition and radiologist workstation monitors. Quarterly, the facility Q C review brings the Q C technologist, lead interpreting physician and manager together to review records and corrective actions. Semiannually, every six months, you test compression force. And annually, the medical physicist surveys each unit.",
"svg": ""
},
{
"id": 7,
"diagram": "phantom-criteria",
"heading": "QC passing numbers",
"bullets": [
"Phantom: 2 fibers, 3 speck groups, 2 masses",
"Failed phantom: fix before any patient",
"Thickness indicator within 0.5 cm of actual",
"Powered force 25-45 lb (111-200 N)",
"Repeat rate: 2% or less ideal, 5% acceptable"
],
"narration": "Now the passing numbers. The A C R digital phantom passes with at least 2 fibers, 3 speck groups and 2 masses, with no clinically significant artifacts. Don't confuse it with the old film phantom's 4, 3 and 3. A failed phantom must be fixed before you image any patient. The compression thickness indicator must read within plus or minus half a centimeter of the actual thickness. Powered compression force must be 25 to 45 pounds, which is 111 to 200 newtons. And for repeat analysis, 2 percent or less is ideal and 5 percent is acceptable; investigate any change of more than 2 percent.",
"svg": ""
},
{
"id": 8,
"diagram": "dose-physicist",
"heading": "Physicist tests and dose",
"bullets": [
"MEE before a new or majorly repaired unit is used",
"Annual survey, no more than 14 months apart",
"AGD limit: 3.0 mGy for one CC of the ACR phantom",
"kVp accurate within 5%",
"Resolution: 4 lp/mm contact, 6 lp/mm mag"
],
"narration": "The medical physicist performs a Mammography Equipment Evaluation, or M E E, before a new unit, or one with a major repair like a new tube or detector, is used on patients. Then it surveys the unit every year, no more than 14 months apart. The big dose number: average glandular dose for one craniocaudal view of the A C R digital phantom must not exceed 3.0 milligrays, in two-D or D B T. The physicist also confirms k V p is accurate within 5 percent, and that spatial resolution is at least 4 line pairs per millimeter for contact and 6 for magnification.",
"svg": ""
},
{
"id": 9,
"diagram": "mqsa-numbers",
"heading": "MQSA personnel and records",
"bullets": [
"FDA certifies; ACR accredits; 3-year cycle",
"Start: 40 hours, including 25 supervised exams",
"8 hours of training per new modality, like DBT",
"Stay: 15 CEUs/36 months, 200 exams/24 months",
"Records 5 years, 10 if no later mammograms"
],
"narration": "Under M Q S A, the Mammography Quality Standards Act, the F D A or a state certifies the facility, while an accreditation body such as the A C R accredits it, on a three-year cycle. To start, a technologist needs 40 contact hours of mammography training, including 25 exams under direct supervision. Before using a new modality such as D B T, add 8 hours of training. To stay qualified, earn 15 continuing education units every 36 months and perform 200 mammograms every 24 months. Records are kept at least 5 years, or 10 if the patient has no later mammograms there.",
"svg": ""
},
{
"id": 10,
"diagram": "summary",
"heading": "Lock these in",
"bullets": [
"Mag: 0.1 mm focal spot, no grid, air gap",
"Phantom weekly: 2 fibers, 3 specks, 2 masses",
"Compression force every 6 months: 25-45 lb",
"AGD limit 3.0 mGy for one CC of the phantom",
"Tech: 15 CEUs/36 months, 200 exams/24 months"
],
"narration": "Let's lock it in. Magnification uses the 0.1 millimeter focal spot, no grid, and an air gap. The A C R digital phantom is imaged weekly and passes with 2 fibers, 3 speck groups and 2 masses. Compression force is checked every six months and must be 25 to 45 pounds in powered mode. Average glandular dose for one craniocaudal view of the phantom must not exceed 3.0 milligrays. And to stay qualified, technologists need 15 continuing education units every 36 months and 200 exams every 24 months. Nail these five and you're in great shape.",
"svg": ""
}
]
}