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Hi all,</div>
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I hope you are all having a relaxing weekend.<br>
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Does anyone have any experience with multi-isotope SPECT acquisitions with GATE? I seem to be having difficulties configuring the energy resolution properly in the digitizer. I have specified the energy resolution according to the inverse square law using the
commands:</div>
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/gate/digitizer/Singles/insert blurring</div>
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/gate/digitizer/Singles/blurring/setLaw inverseSquare</div>
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/gate/digitizer/Singles/blurring/inverseSquare/setResolution 0.15</div>
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/gate/digitizer/Singles/blurring/inverseSquare/setEnergyOfReference 140.5 keV</div>
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In a simple test using two capillary tubes of Tc-99m/I-123, I would expect the energy resolution for I-123 to be around 14.1% centered at 159 keV according to the inverse square law. However, when I separate the multi-isotope data according to their respective
sources, I am finding that the energy resolution for I-123 is much larger than the expected 14.1% and the peak appears to be pushed towards 140 keV which causes excessive counts to be excluded from the energy window (see attached energy spectra). I can confirm
that the counts are still associated with I-123 since reconstruction of the primary window counts reveals only one line source in the dataset.<br>
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I have also tried specifying independent resolutions for each energy of reference, but this causes the photopeaks to become blurred multiple times. My next attempt would be replacing the inverse square law with the linear law but I am not convinced that this
will introduce the expected functionality. <br>
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How can I specify the energy resolution so that blurring is automatically and correctly applied to each photopeak in the acquisition? Is this an issue with GATE due to undefined functionality for multiple photopeaks?</div>
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Regards,<br>
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<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-family:Calibri,Helvetica,sans-serif">Matthew</span></p>
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<p class="x_MsoNormal" style="margin-top: 0px; margin-bottom: 0px;"><span style="font-size:10.5pt; color:black; font-family:Calibri,Helvetica,sans-serif">Matthew Strugari</span><span style="font-size:10.5pt; color:black"></span></p>
<span style="font-family:Calibri,Helvetica,sans-serif"></span><span style="font-size:10.5pt; color:black" lang="EN-US"><span style="font-family:Calibri,Helvetica,sans-serif">Biomedical Translational Imaging Centre -
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