Advanced coded-aperture imaging system for nuclear medicine

Abstract

An advanced coded imaging system is described, and some results of phantom experiments are presented. The advanced method uses a pair of coherent codes (+ 1 and -1 codes) and has many advantages compared with conventional ones. One of the greatest advantages is that there are no sidelobes in the focal plane and only a few in other planes. Therefore, when an object can be regarded as two-dimensional, it is perfectly reconstructed with high detecting efficiency, and this is successfully simulated by a thyroid phantom with 99mTc. Moreover, this system has an ability to reconstruct tomograms, which is also shown by using ring phantoms piled on one another with some cold spots in their shells. From these experimental results it may be concluded that the new system is useful for practical applications, for example, to nuclear medicine.

Gamma Radiation Imaging System via Variable and Time-Multiplexed Pinhole Arrays

“…A coded aperture consisting of a number of random pinholes, with an average transmission of 50% was suggested by Dicke for X-ray astronomy [33]. Many other research projects have tried to improve the X-ray and gamma ray imaging systems over the years [34][35][36][37][38][39][40][41][42][43]. The CAI technique has also been adapted by Accorsi to near field geometry of medical imaging [44][45][46].…”

Complementary lattice arrays for coded aperture imaging

“…In coded aperture imaging, a physically realizable coding aperture usually consists of 0/1 binary alphabet (representing closed/open pinholes). If multiple coded images are obtained with different aperture masks and the resulting digital projection images are suitably combined, a complex-valued array C becomes applicable [8], [9]. For example, a {±1} coding aperture could be obtained computationally from two masks with openings at C's 1, −1 locations.…”