ACR Mammography Protocols

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Resident Physics Series

ACR Mammography
Protocols

Mammography QC Manual


Radiologist


Clinical Image Quality


Radiologic Technologist


Medical Physicist

Revised Edition, 1999

Sections

Quality Assurance (QA)


Every imaging procedure is necessary &
appropriate to clinical problem at hand


images contain information critical to solution
of that problem

QA should ensure

Quality Assurance (QA)


recorded information is


correctly interpreted


made available to patient’s physician in a timely
fashion


consistent with image quality objectives,
examination results in lowest possible


radiation exposure


cost


inconvenience to the patient

Quality Control (QC)


Acceptance Testing


detection of defects in equipment that is newly
installed or has undergone major repair


Baselines


Establishment of baseline equipment
performance


quantitative data when system operating properly

QC is integral part of QA

Quality Control (QC)


Diagnosis


Diagnosis of changes in equipment performance
before they become radiologically apparent


Verification


Verification of correction of causes of
deterioration in equipment performance

Facility Responsibility


Designate
One

Lead Interpreting Physician

Lead Physician’s Responsibilities


Ensure technologists have adequate


orientation


based on procedure manual


training


continuing education


Ensure effective QC program

Radiologist’s Responsibilities


Designate
one

technologist

responsible for
QC


QC tech can delegate responsibilities

Radiologist’s Responsibilities


Ensure availability of appropriate test
equipment






Arrange staffing / scheduling to allow time for
QC

Radiologist’s Responsibilities


provide frequent consistent positive & negative
feedback to technologists about film quality &
QC


Review technologist’s test results


no less than every 3 months


more often if inconsistent

results


Radiologist’s Responsibilities


Select a medical physicist


administers QC program


performs physicist’s tests



Review physicist’s test results

Radiologist’s Responsibilities


Oversee or designate qualified individual to
oversee radiation protection program for


employees


patients


individuals in surrounding area

Radiologist’s Responsibilities


Ensure proper maintenance of records in QC
procedures manual


employee qualifications


mammography technique / procedures


quality control / safety / protection


infection control

Radiologist’s Responsibilities


“The radiologist is ultimately responsible for
the quality of films produced under his or her
direction and bears ultimate responsibility for
both proper QC testing and QA procedures in
mammography.”

The Proliferation of Digital
Mammography


Total mammography units in US (3/1/2012)


12,333


Total digital mammography units (3/1/20112


10,363 (84%)


Total digital mammography units (4/1/2010 or 6
months ago)


9269 (75%)


Increase in digital units


~ 92/month

Number of Accredited FFDM Units

Mar 12

Nov 03

Number of Accredited Units

Mar 12

Nov 03

Physicists & Digital
Mammoraphy


Physicist must insure equipment meets
manufacturer’s specifications


Equipment specs now defined by manufacturer


Specs previously blessed by FDA

Physicist’s Responsibilities


Note: All physicist’s tests are to be done
annually

or after tube replacement or major service

Physicist’s Responsibilities: Mammography Unit
Assembly Evaluation


mechanical stability / identification of
sharp edges


receptor stability


locks / motions / detents


operator shielding


thickness scale accuracy


indicator lights working


technique chart posted

Physicist’s Responsibilities: Mammography Unit
Assembly Evaluation


Override available for auto
-
decompression


display must indicate when auto
-
decompression
turned off


Manual release of compression if power lost

Collimation Assessment


x
-
ray light field alignment


beam does not exceed receptor by >
2% SID


compression paddle / receptor
alignment at chest wall within 1% SID


paddle not visible on image

Physicist’s Responsibilities


Focal Spot Performance


limiting resolution pattern



kVp accuracy / reproducibility



Beam quality (HVL)


minimum &
maximum


minimum: patient dose


maximum: image contrast

Automatic Exposure Control (AEC /
Phototiming)


kVp tracking


Thickness tracking


image mode tracking
(w w/o grid)


automatic mode tracking


unit selects kVp, target, filter


AEC Reproducibility


density control


even steps of ~ 15
-
20%

Density Step Changes
0
2
4
6
8
10
12
14
16
18
-5
-4
-3
-2
-1
0
1
2
3
4
5
Step
% Change
Series1
Physicist’s Responsibilities


Breast Entrance Exposure, Average Glandular Dose,


RMI
-
156 “accreditation” phantom used for entrance
exposure / average glandular dose

Breast Average Glandular Dose
Limits


0.3 rad (300 mrads, 3 mGy) maximum per view for
screen
-
film receptors using a grid


Same for film and digital


0.1 rad (100 mrads, 1 mGy) maximum per view for
non
-
grid

screen
-
film receptors


Radiation output rate > 800 mR/sec

Image Quality Evaluation


use RMI
-
156 “accreditation” phantom


record


fibers


speck groups


masses


optical densities


technique

A Poor Phantom Image


Artifact Identification


Artifact evaluation / description


All target/filter and receptor combinations
checked

Physicist’s Responsibilities


Viewing conditions


ambient light


monitor brightness

Technologist’s Responsibilities

Monthly: Visual Checklist


Weekly


Phantom images


Monthly


visual checklist


SID indicator


angle indicator


locks


field light


smooth motions

Technologist’s Responsibilities

Monthly: Visual Checklist


Compression device & firm
compression


Smooth edges


Holds pressure


hand switch placement


visibility


switches/ lights/ meters


cones/ collimators


Technologist’s Responsibilities

Quarterly


Repeat analysis


breakdown by cause


motion


positioning


technique


static


etc.

Semi
-
Annual Technologist’s Responsibilities

Compression


can use bathroom scale covered with towel


25
-

40 pounds for automatic systems


at least 25 pounds for manual compression

The End

Questions?