Pilot study comparing patient ese
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Pilot Study Comparing Patient ESE. Manual vs. AEC Technique Factors. Decision Made at Start of QA Program. Test all equipment in manual mode AEC equipment mostly found in hospitals and large radiology suites

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Pilot Study Comparing Patient ESE

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Pilot study comparing patient ese

Pilot StudyComparing Patient ESE

Manual vs. AEC

Technique Factors


Decision made at start of qa program

Decision Made at Start of QA Program

  • Test all equipment in manual mode

    • AEC equipment mostly found in hospitals and large radiology suites

    • Facilities equipped with AEC equipment required to have manual technique charts for times when AEC not functioning

    • NJ test phantom could not be used to simulate patient anatomy in AEC mode

    • Design of Victoreen 4000 meter prevents measuring exposure parameters in AEC mode

Bureau of Radiological Health


Affect on ese numbers

Affect on ESE Numbers?

  • Physicists have raised concerns that our tests do not reflect “reality” at sites using AEC exposures

  • Bureau agreed that the time was right to re-evaluate its testing protocols for AEC radiographic machines and established a pilot study

Bureau of Radiological Health


Goals of study

Goals of Study

  • Measure ESE utilizing both manual and AEC exposure techniques

  • Determine if there is correlation or variance in the measured ESEs

Bureau of Radiological Health


Estimate of aec population

Estimate of AEC Population

Bureau of Radiological Health


Pilot study testing protocol

Pilot Study Testing Protocol

  • Verify that facility has manual technique charts available for AEC units tested

  • Ensure that radiographic machines chosen for study have functioning AEC and are stable by testing kVp, mAs and timer linearity and accuracy

  • Evaluate ESE for AP Lumbosacral Spine exposures at 40” SID

Bureau of Radiological Health


Testing setup

Testing Setup

  • Utilized CDRH NEXT Phantom simulating 21 centimeter patient

  • Utilized a calibrated Radcal MDH 1015-X with 10X5-6 Ion Chamber. Chamber setup 9” above the phantom to eliminate scatter affects

  • Measured mAs, ms, mR and ESE exposures using facility provided manual techniques

Bureau of Radiological Health


Testing setup1

Testing Setup

  • Repeated measurements using AEC technique factors and center sensor

  • Four exposures were taken in each mode and average values were calculated

  • Calculated ESE measurements in both modes and compared differences

Bureau of Radiological Health


Photo of testing setup

Photo of Testing Setup

Bureau of Radiological Health


Sample of machine data collected

Sample of Machine DataCollected


Pilot study comparing patient ese

Bureau of Radiological Health


Pilot study comparing patient ese

Bureau of Radiological Health


Pilot study comparing patient ese

Bureau of Radiological Health


Composition of study

Composition of Study

  • 17 machines tested at four facilities

  • 2 machines discarded from study due to malfunctioning AEC

  • 5 machines used CR image receptors

  • 10 machines used film systems

Bureau of Radiological Health


Raw data

Raw Data

Bureau of Radiological Health


Summary of results

Summary Of Results

Bureau of Radiological Health


Summary data

Summary Data

Bureau of Radiological Health


Summary of results1

Summary Of Results

Bureau of Radiological Health


Pilot study comparing patient ese

Bureau of Radiological Health


Reasons for variance

Reasons for Variance?

  • Manual Technique Charts Not Always Accurate

    • 5 machines not capable of being set at recommended technique factors

    • 3 machines varied by 5 kVp or more between manual and AEC technique settings

  • CDRH phantom not a perfect match for manual technique evaluation

    • 21 cm patient vs. 23-24 cm Techniques

Bureau of Radiological Health


Reasons for variance1

Reasons for Variance?

  • AEC more efficient than manual techniques

    • For Same kVp settings, mAs was 2 to 8 times less than manual counterpart

Bureau of Radiological Health


Where do we go from here

Where Do We Go From Here?

  • Joint BRH/Physicist effort to improve the accuracy of manual technique charts?

  • Joint BRH/Physicist effort to develop an AEC test protocol including valid test phantom(s)?

Bureau of Radiological Health


Brh preliminary tests on alternative phantom materials

BRH Preliminary Tests on Alternative Phantom Materials

  • CDRH Phantom not ideal and not practical

  • Suggestion from physicists and other state programs that copper or aluminum could simulate lumbar spine phantom

  • BRH conducted abbreviated tests using two different thicknesses of copper: 2.4 mm and 2.0 mm

Bureau of Radiological Health


Ese difference lucite vs copper

ESE Difference Lucite vs Copper

Bureau of Radiological Health


Summary of results2

Summary Of Results

Bureau of Radiological Health


Pilot study comparing patient ese

Bureau of Radiological Health


Physicist input

Physicist Input

  • Suggestions?

  • Phantom Materials?

  • Volunteers to Develop AEC Protocol?

Bureau of Radiological Health


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