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Division of Nuclear Medicine SimSET Resources : |
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This library contains angular response functions (ARF) tables (X. Song et al, Physics in Medicine and Biology, 50:8:1791, 2005) created by GATE software (P. Descourt, Physics in Medicine and Biology, 55:9:N253, 2010). ARF tables are a tool for accelerating single photon emission computed tomography (SPECT) simulations. For a given photon energy, an ARF table gives the detection probablity a a function of the photon's incidence angle on the collimator. ARF tables are tomograph-, collimator-, detector-, and energy-window-specific; as the energy window(s) used and the range of photon energies hitting the collimator are isotope-specific, the tables are also isotope-specific.
Our library of ARF tables is thus divided
first by tomograph, then isotope, and then by collimator/detector pair
(as the collimator/detector pair is usually determined by the isotope). ARF tables
for all incident energies and energy windows are in a single compressed file for each
tomograph/isotope/collimator/detector pairing.
While ARF tables can significantly speed SPECT simulation,
computing a set of ARF tables requires considerable compute time. Generally they have
only been used for situations where the same tomograph/collimator/detector/isotope
combination will be simulated repeatedly. However, by creating a library of precomputed
ARF tables, the tables can be profitably used even for single simulations.
The ARF tables themselves are in the format described
in the GATE documentation; we include the parameter files used to generate them as
part of the library.
They can be used directly with GATE or with any other simulation designed to
use ARF tables in this format: a future version of SimSET will include this capability.
Currently the library only includes tables for
123I and 67Ga imaged with the General Electric D670 tomograph. In the long
run we are planning to expand the library to other isotopes and tomographs.
The ARF tables can be downloaded using the following link.
At the top level, the library is divided up by tomograph
type; currently we have only generated ARF tables for one tomograph, the General Electric
Discovery 670 (D670). We have tables for the isotopes 123I and 67Ga.
These are found in the subdirectories named for the isotopes. The
123I ARF tables are generated for the D670's low-energy high-resolution collimator;
the 67Ga ARF tables for the D670's medium-energy general-purpose collimator.
For both isotopes the tables are for a 0.95 cm thick NaI detector.
The isotope directories have tar files
containing the ARF tables and the parameter files used to generate the tables;
for 67Ga there are three tar files for the tables and three tar
files for the parameters, one for each of the three energy windows. The tar files can
be unpacked in Unix or Linux using the 'tar -xvf' command, for instance:
> tar -xvf ARFgenerationParamFiles_I123.tar
The parameter files are based on the original computeARFTables.mac
and generateARFdata.mac in the examples/example_ARF directory of the GATE install package.
Last revised by: Robert Harrison
Revision date: 1 September 2019