IMAGE QUALITY

SPATIAL RESOLUTION CONTRAST RESOLUTION RADIATION DOSE NOISE IMAGE ARTIFACTS

Resolution in CT Spatial Resolution Contrast Resolution

SPATIAL RESOLUTION DEGREE OF BLURRING IN THE IMAGE MEASURE OF THE ABILITY TO DISCRIMINATE OBJECTS OF VARYING DENSITY A SMALL DISTANCE APART AGAINST A UNIFORM BACKGROUND

MTF MODULATION TRANSFER FUNCTION MOST COMMONLY USED TO DESCRIBE SPATIAL RESOLUTION IN CT

MTF MTF OF 1 – 100% TRANSFER OF OBJECT TO IMAGE

HIGH CONTRAST PHANTOM

FACTORS AFFECTING SPATIAL RESOLUTION SLICE THICKNESS FOCAL SPOT SIZE DETECTOR WIDTH TYPE OF CONVOLUTION FILTER (KERNEL) MATRIX SIZE FOV

SLICE THICKNESS S. RESOLUTION 5 MM 1 MM

FOCAL SPOT SIZE FOCAL SPOT SIZE S. RESOLUTION LARGE FOCAL SPOT = LARGE PENUMBRA (BLURR)

DETECTOR WIDTH S. RESOLUTION

TYPE OF CONVOLUTION FILTER SHARP KERNEL S. RESOLUTION SMOOTH SHARP

MATRIX SIZE S. RESOLUTION

DFOV SIZE DFOV S. RESOLUTION 20CM 10CM

CONTRAST RESOLUTION SENSITIVITY OF THE SYSTEM LOW CONTRAST RESOLUTION LOW CONTRAST DETECTIBILITY

LOW CONTRAST RESOLUTION ( TISSUE RESOLUTION) THE ABILITY OF AN IMAGING SYSTEM TO DEMONSTRATE SMALL CHANGES IN TISSUE CONTRAST

CONTRAST RESOLUTION SENSITIVITY OF THE SYSTEM LOW CONTRAST RESOLUTION LOW CONTRAST DETECTIBILITY

CONTRAST RESOLUTION PHANTOM

FACTORS AFFECTING LOW CONTRAST RESOLUTION PHOTON FLUX SLICE THICKNESS PATIENT SIZE DETECTOR SENSITIVITY RECONSTRUCTION ALGORITHM IMAGE DISPLAY QUANTUM NOISE

PHOTON FLUX (INTENSITY) PHOTON FLUX C. RESOLUTION mAs P. FLUX kVp P. FLUX

LOW TECHNIQUE ADEQUATE TECHNIQUE

SLICE THICKNESS C. RESOLUTION 8 mm 5 mm

10 mm – 100 PHOTONS 5 mm – 50 PHOTONS

PATIENT SIZE C. RESOLUTION NORMAL LARGE

DETECTOR SENSITIVITY C. RESOLUTION

TYPE OF CONVOLUTION FILTER SMOOTH KERNEL C. RESOLUTION SMOOTH SHARP

MONITOR RESOLUTION C. RESOLUTION IMAGE DISPLAY MONITOR RESOLUTION C. RESOLUTION

QUANTUM NOISE C. RESOLUTION HIGH NOISE LOW NOISE

NOISE IN CT FLUCTUATION OF CT# BETWEEN POINTS IN THE IMAGE FOR A SCAN OF UNIFORM MATERIAL SUCH WATER.

NOISE SOURCES IN CT QUANTUM NOISE – X-RAY INTENSITY AT THE DETECTORS MATRIX SIZE DFOV SLICE THICKNESS CONVOLUTION FILTER TYPE PITCH

QUANTUM NOISE – CONTROLLED BY THE TECHNOLOGIST mA Time kVp NOISE

NOISE QUANTUM (STATISTICAL) –CONTROLLED BY THE TECHNOLOGIST ELECTRONIC – INHERENT IN THE EQUIPMENT

QUANTUM NOISE – CONTROLLED BY THE TECHNOLOGIST DFOV MATRIX COLLIMATION FILTER SPATIAL FREQUENCY PITCH NOISE

DOSE vs IMAGE QUALITY RADIATION DOSE IMAGE QUALITY