Scatter estimation using 2 energy windows

Usage Questions
1

Hello,

I want to reconstruct files using Tc99m from a GE850 SPECT/CT with 2 energy windows:
emission 126 - 155Kev
scatter 114 - 126 Kev
If I run the following line will the scatter tensor be correct?

scatter = dicom.get_scatter_from_TEW(file_NM, index_peak=0, index_lower=1, index_upper=1)

Mark

2

Hello,
I am not 100% sure, but you won’t get the correct result. I would suggest creating a new file_NM in which you stack an array filled with zeros (so you would get 3 different arrays) to feed the get_scatter_from_TEWmethod.
Best regards
Ludovic

3

I also stumbled into this issue when I wanted to try and reconstruct a phantom with Tc99m.

Is this pseudo code something that can be used?

import pydicom

ds = pydicom.dcmread(‘SPECT projection we want to reconstruct’)

new_upper_scatter_energy=0
new_lower_scatter_energy=0

ds.EnergyWindowInformationSequence[2].EnergyWindowUpperLimit = new_upper_scatter_energy

ds.EnergyWindowInformationSequence[2].EnergyWindowUpperLimit = new_lower_scatter_energy

I do get error message that “list index is out of range” . Any ideas on how to improve the code so that it’s possible to create a new energy window?
Should I aim to use a DICOM tag in terms of numbers instead? For example 0054,0015.

Comments,ideas or suggestions are all welcomed.