Design of rotating collimator for high performances radioisotopic imaging

Abstract

small structures, but its sensitivity is poor. Increased parallel collimator sensitivity is obtained by enlarging hole diameter.spatial resolution leads to artifacts on acquired images.Linear collimator motions can remove these artifacts. However a practical realization of such motions is difficult to perform.Linear collimator motions have previously been proposed 141 for removing artifacts due to the collimator. These motions High resolution radioisotopic detector allows detection of consist in sampling the generic rectangle of the hexagonal collimator structure and as demonstrated by Monte Carlo simulations, lead to images without However, such are therefore very difficult to realize in practice.is studied in this work a hole diameter greater than detector intrinsic motions necessitate acceleration and deceleration phases, and A circular translation motion which minimizes vibrationsTo this end, a circular translation motion is studied in this work. Motion effectiveness was evaluated by an homogeneity index based on hexagon center loci. Several rotation radiuses optimizing this homogeneity were found. Moving collimator transparency was deterministically simulated. The smallest suitable motion radius is 0.32 times the structure diameter, which leads to a very small field of view decrease.A device performing such collimator motions, was realized for a high resolution gamma imaging probe based on a photomultiplier position sensitive tube. The measured spatial impulse response was the same on the whole field of view for a given source to detector distance. Image restoration process allowed to recover spatial resolution.In conclusion, moving a medium sensitivity collimator allows to obtain both good sensitivity and high resolution in radioisotopic imaging.