Correction of transmission contamination in ⁶⁷Ga

SPECT (single photon emission computed tomography) is a tomographic technique used for measurement of radiotracer concentration in vivo. The effect of attenuation and Compton scatter severely impacts the quantitative accuracy of SPECT images. Direct measurement using a transmission technique is the most accurate way of compensating for attenuation. This thesis cover SPECT study using ^^Ga, but has relevance to other radionuclides with multiple energies. Since post-injection transmission is required, the transmission and emission data are acquired simultaneously using ^^^Gd and ^^Ga respectively. The disadvantage of simultaneous acquisition is the contamination of transmission data by the spillover from the 93.5 keV photopeak and downscatter from the higher energy photopeaks (184 keV and 300 keV) of ^^Ga. The aim of this thesis is to develop a correction method to produce a corrected attenuation map that can be used for attenuation correction in the emission reconstruction.