Quality Management Flashcards
(36 cards)
Measure of the sensitivity and accuracy by which the image receptor converts the incoming data to the output viewing device.
Detective Quantum Efficiency
The measurement of the quantity and quality of the external radiation beam.
external beam evaluation
All activities that provide adequate confidence that a radiology service will render consistently high-quality images and services.
Quality Assurance
The aspect of quality assurance that monitors technical equipment to maintain superior standards.
Quality Control
Focal Spot Estimation
Radiographic Systems
Ensures proper spatial resolution
Line pair tool
Star test pattern
Pinhole camera
Slit camera
Half Value Layer
Radiographic Systems
2.5 mm Al for 70 kV beam
Collimator
Central Ray
Bucky Tray Accuracy
(Radiographic Systems)
2% SID error is allowed between the primary beam & light field size
Distance indicators
centering indicators
(Radiographic Systems)
Distance indicators +/- 10%
Centering indicators +/- 2%
Angulator or protractor accuracy
Radiographic Systems
Angle +/- 1%
kV Accuracy
Radiographic Systems
+/- 5 of control panel setting
Timer Accuracy
Radiographic Systems
+/- 5%
time setting
mA/mAs linearity
Radiographic Systems
+/- 10% of each mA station
i.e. 50, 100, 200, 300, 400
Exposure Reproducibility
Fluoroscopy
+/- 5% mAs/mR of several different exposures of the same exposure factors
Exposure Rate
Fluoroscopy
must not exceed 10 mR/min for equipment with ABS (0.1 /min
- ABS may need calibration
Field Size Accuracy & Beam Alignment
Fluoroscopy
Should display everything within 1cm of the edge of Image Intensifier
Source-to-skin distance limits
Fluoroscopy
Tube target should NOT be closer than 38 cm (15”) stationary
30cm (12”) for mobile
Viewing System Resolution
Fluoroscopy
Fluoroscopy mesh tool
Viewing System Contrast
Fluoroscopy
Test tool - two plates of aluminum with 1-7 mm holes drilled into one plate
Plates are put together and viewed with fluoroscope - low contrast based on being able to see the smallest visible hole
Image Display System
Fluoroscopy
Fluoroscopic mesh test tool or resolution test tool
Automatic Brightness Control
Computerized Dosimeter is used to measure exposure after the beam passes through a phantom
- Phantom thickness reduced to 1/2 and exposed again
Ion Chamber Sensitivity
AEC
produce an image of ion chamber using low kV
- use lead to block all but one chamber (test each)
All - chambers should respond to +/- 10% of each otherif not, recalibration of generator AEC circuitry
IR exposure variation control accuracy
AEC
Measures density differences
computerized dosimeter measures the mR/mAs to verify the intensity differences of each control
(-3 -2 -1 0 +1 +2 +3)
Back-up timer verification
AEC
- Lead plate over AEC chamber & make exposure
- back-up timer should terminate the exposure with an audible & visual warning
- 6 seconds or 600 mAs
LUMINANCE
The intensity of light emitted from a surface in any given direction
higher maximum luminance is preferred for medical images (300 - 600 cd/m2)
