Sensitivity and resolution study of a small-field γ-Camera system on a tomographic level

Abstract

The sensitivity and the spatial resolution of a small field y-Camera system based on a Position Sensitive PhotoMultiplier Tube (PSPMT) on a tomographic level are examined in this study. A cylindrical Gel-Phantom (d=40 mm, h=50mm) with cylindro-conoidal tubes and capillaries (from 64 to 640 mm3) containing water solution of 99mTc is used as a test phantom in the present work. A total of 24 projections covering the full angle region (0°_360°) are obtained with the y-Camera system under examination. The planar information is further analyzed to reconstruct the tomographic images taking into account all off-line corrections needed to remove barreloid deformations appearing at the edges of the field-of-view. The reconstruction procedure is performed with iterative algorithms and for comparison reasons two different techniques (MLEM and accelerated ART) are used. The variety of the 99mTc_volu mes in the phantom with the given specific radioactivity and the phantom axial asymmetry, due to the different radial distances of the tubes in the gel environment, allow a realistic characterization of the system's performance on a tomographic level. Obtained experimental results for the system sensitivity and spatial resolution are presented and discussed in this work;they are also directly compared with ideal tomographic results acquired from the fully simulated y-Camera system through GATE.

Simulating a Time-Resolved Optical Tomographic Modality

“…The extra load of ionizing radiation (CT), the high cost (MRI) and also the mobility of such devises make those methods aggravating. A small-field γ-Camera system based on Position Sensitive Photomultipliers (PSPMT) has been already developed in our laboratory and also evaluated on a tomographic level [1]. Therefore, in order to gain the necessary anatomic information, a non invasive, non-ionizing, low cost and portable modality is proposed.…”

Συνεισφορά της οπτικής τoμογραφίας OCT (optical computed tomography) στην μονοφωτονική τομοσπινθηρογραφία

“…Parallel to the previous described experimental study, the γ-Camera system together with the test phantom (including the glass container) was fully described in terms of the simulation package GEANT4/GATE (Fig. 2.12) [MIK12]. This Monte Carlo simulator is a very useful tool created by CERN for studying the interaction of the electromagnetic radiation with matter and is especially dedicated to medical applications.…”