Medical Physicist Test Flashcards
Mammography equipment evaluation (MEE)
-Purpose: ensure equipment meets section 900.12 (b) of FDAs final rule for mammo
-Frequency: part of MEE of new units, after service, and after component replacement
Collimation assessment
-purpose: 1) xray field aligns with light field 2) chest wall edge of compression paddle aligns with chest wall edge of IR
-frequency: 1) for 2D units; as part of MEE of new units, after relevant service, after component replacement 2) for DBT units; part of MEE of new units, annually, after relevant service
System resolution test
spatial resolution (line pair)
-purpose: to measure the limiting spatial resolution as an indicator of detector performance
-frequency: part of MEE of new units, annually, and after relevant service
Modulation transfer function (MTF)
-purpose: 1) more detailed eval to monitor contrast delivered by detector 2) contrast at low frequencies 1-2 lp/mm aid in detecting masses and fibers 3) contrast at high freq. 4-5 lp/mm aid in detecting micro calcifications
-frequency: part of MEE of new unit, annually, and after relevant service
Low contrast performance tests
Signal to noise ratio (SNR)
-purpose: 1) measurement that shows how much signal is used by the detector and how much noise is present 2) higher SNR provides better image
-frequency: part of MEE of new unit, annually, and after relevant service
Low contrast performance tests
Contrast to noise ratio (CNR)
-purpose: ability to see objects (of a given size) at low contrast to their surroundings is limited by the noise (mottle) in the image. both high and low contrast needed
-frequency: part of MEE of new unit, annually, and after relevant service
AEC system performance
-purpose: to assess performance of AEC function and verify consistency in detector signal to noise level
-frequency: part of MEE of new unit, annually, and after relevant service
artifact evaluation
-purpose: ensure image acquisition chain is consistently producing adequate image quality, artifacts are not clinically significant, and SNR and CNR are adequate
-frequency: part of MEE of new unit, annually, and after relevant service
kVp accuracy and reproducibility
-purpose: ensure that kVp is accurate (within +/-5% of indicated kVp) and that kVp is reproducible, having coefficient of variation equal to or less than 0.02
-frequency: part of MEE of new units, after relevant service, and after component replacement
beam quality assessment
half-value layer (HVL)
-purpose: ensure that HVL of xray beam is adequate to minimize pt dose, but not so excessive that contrast is lost in image
-frequency: part of MEE of new units, after relevant service. Or if technique factors impacting beam quality changed
average glandular dose
-purpose: measure entrance exposure for average pt (4.2 cm thick compressed breast w/ 50% glandular 50% adipose tissue), calculate associated average glandular dose, and ensure unit indicated average glandular dose is accurate
-frequency: part of MEE of new unit, annually, and after relevant service
room illuminance (ambient light)
-purpose: evaluate reading room environment where RW resided for appropriate ambient light levels for mammography interpretation
-frequency: part of MEE of new unit, annually, and after relevant service
evaluation of technologist QC program
-purpose: ensure tech QC is performed correctly, compare tech QC’s to medical physicist’s score, identify where it can improve
-frequency: annually
application of compression
-purpose: ensure mammo equip. meets MEE required tests
-frequency: part of MEE of new unit, annually, and after relevant service
compression paddle deflection
-purpose: ensures adequate compression is applied uniformly over breast for paddles that are designed to be flat and parallel to the breast support (dont use curved paddle for this test)
-frequency: part of MEE of new unit, annually, and after relevant service, after component replacement
