Speaker
Amina Patel
(U)
Description
Medical imaging is an expanding field tasked with improving diagnostic capabilities. The ProSPECTus project is a Single Photon Emission Computed Tomography (SPECT) system that employs highly segmented semiconductor detectors in Compton camera mode. The ProSPECTus system has been designed to alleviate the limitations present in current SPECT systems.
The basic principle of Compton imaging is that a gamma ray interacts at least once with each detector and deposits its full energy. The energy deposits and position of interaction in each detector is then used via the Compton Scatter formula to locate the position of the incoming radiation.
The ProSPECTus system consists of two highly segmented position and energy sensitive detectors. Both detectors are housed in a single custom-made cryostat. The first detector is made of Lithium drifted Silicon with active area dimension of (64 x64x 9) mm and 256 voxels of size (4 x4 x 9) mm, The second is made of high purity Germanium with active area dimensions (60 x 60 x 20) mm and 141 voxels of size (5 x5 x 20) mm.
A prototype ProSPECTUs system has been set up and optimized to acquire Compton imaging data with point sources and custom made medical phantoms, in order to show and quantify the performance capabilities of ProSPECTus in terms of image resolution and efficiency.
Simulations have been run using GAMOS (Geant-4 based Architecture for Medicine Oriented Simulations) to investigate the influence of position resolution on image quality. It has been found a position resolution of 1mm3 is needed for an optimum image. Pulse shape analysis algorithms and databases are being adapted and developed to improve the position resolution of the ProSPECTus detectors beyond voxel sizes.
Presented will be the basic concepts of Compton imaging, simulation and reconstructed image results of the position resolution investigations carried out, as well as the experimental images acquired with point, extended and phantom sources.
Author
Amina Patel
(U)
