ABSTRACT
Objective To measure and evaluate slice sensitivity profile(SSP)and the full width at half-maximum(FWHM)for a 64-slice spiral CT system.Methods Using the same CT technique and body mode as those used for clinical CT,delta phantom was scanned with Somatom Sensation 64-slice spiral CT.SSPs and FWHM were measured both with reconstruction slice width of 0.6 mm at pitch = 0.50,0.75,1.00,1.25,1.50 and with reconstruction slice width of 0.6,1.0,1.5 mm at pitch = 1 respectively.Results For normal slice width of 0.6 mm,the measured FWHM,i.e.effective slice width,is 0.67,0.67,0.66,0.69,0.69 mm at different pitch.All the measured FWHM deviate less than 0.1mm from the nominal slice width.The measured SSPs are symmetrical,bell-shaped curves without far-reaching tails,and show only slight variations as a function of the spiral pitch.When reconstruction slice width increase,relative SSP become wider.Conclusions The variation of pitch hardly has effect all on SSP,effective slice width,and z-direction spatial resolution for Sensation 64-slice spiral CT system,which is helpful to optimize CT scanning protocol.