# Bone Thickness Mapping use with skull CT images
**URL:** https://discourse.slicer.org/t/bone-thickness-mapping-use-with-skull-ct-images/32463
**Category:** Support
**Created:** [October 29, 2023, 11:25pm UTC](https://discourse.slicer.org/t/bone-thickness-mapping-use-with-skull-ct-images/32463 "2023-10-29T23:25:05Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@Gonzalo\_Rojas\_Costa](https://discourse.slicer.org/u/Gonzalo_Rojas_Costa)
#### Post date: [October 29, 2023, 11:25pm UTC](https://discourse.slicer.org/t/bone-thickness-mapping-use-with-skull-ct-images/32463/1 "2023-10-29T23:25:05Z")
Hi:
I want to obtain the bone thickness using skull CT images. Do skull CT images need to have any specific characteristics in order to use the BoneThicknessMapping extension?
Sincerely
Gonzalo Rojas Costa
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### Author:  [@zarcow](https://discourse.slicer.org/u/zarcow)
#### Post date: [November 30, 2023, 4:42am UTC](https://discourse.slicer.org/t/bone-thickness-mapping-use-with-skull-ct-images/32463/2 "2023-11-30T04:42:35Z")
Gonzalo, there is a workaround to make that module to run:
- download Slicer-4.11.20200930-linux-amd64 (or any OS -mac, win, linux-)
[SPKC](https://slicer-packages.kitware.com/#collection/5f4474d0e1d8c75dfc70547e/folder/60add36dae4540bf6a89be6c)
- download and install the “BoneThicknessMapping” module
[@KitwareMedical/slicer-extensions-webapp](https://extensions.slicer.org/catalog/All/30822/linux) (or any OS -mac, win, linux-)
- Open ‘/home/.config/NA-MIC/Extensions-29402/BoneThicknessMapping/lib/Slicer-4.11/qt-scripted-modules/BoneThicknessMapping.py’
and Change ‘airCellTable’ to ‘airCellTableNode’in line 931, save and restart slicer.
That should do
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### Author:  [@Gonzalo\_Rojas\_Costa](https://discourse.slicer.org/u/Gonzalo_Rojas_Costa)
#### Post date: [December 23, 2023, 2:31pm UTC](https://discourse.slicer.org/t/bone-thickness-mapping-use-with-skull-ct-images/32463/3 "2023-12-23T14:31:20Z")
Hi:
I followed the instructions that you sent me. I tested the module using brain CT included in the 3D Slicer examples. But I got the thickness of only one skull hemisphere… Why ?
Sincerely,
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### Author:  [@zarcow](https://discourse.slicer.org/u/zarcow)
#### Post date: [December 29, 2023, 2:28am UTC](https://discourse.slicer.org/t/bone-thickness-mapping-use-with-skull-ct-images/32463/4 "2023-12-29T02:28:36Z")
Hi Gonzalo,
The ‘bone thickness mapping’ module uses the ray-casting technique to estimate the bone “depth”, hence it only computes the depth where the prescribed rays cast. Once you load the module, there is a section in which you can specify the ray casting direction (RAS & LPI). Just run the module for each view of your interest, and you will cover the whole skull.
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### Author:  [@Gonzalo\_Rojas\_Costa](https://discourse.slicer.org/u/Gonzalo_Rojas_Costa)
#### Post date: [January 1, 2024, 12:55am UTC](https://discourse.slicer.org/t/bone-thickness-mapping-use-with-skull-ct-images/32463/5 "2024-01-01T00:55:05Z")
Hi:
Ok. Thank you very much for your answer.
I have skull CT of two different populations. How can I do the comparison of both skull thicknesses?
Sincerely,
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### Author:  [@Gonzalo\_Rojas\_Costa](https://discourse.slicer.org/u/Gonzalo_Rojas_Costa)
#### Post date: [January 2, 2024, 12:15am UTC](https://discourse.slicer.org/t/bone-thickness-mapping-use-with-skull-ct-images/32463/6 "2024-01-02T00:15:33Z")
Hi:
Another question. How can I get the values of bone thickness from the model generated by "BoneThicknessMapping” module ?.. the complete head skull?.. some areas or lobules?
Sincerely,
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### Author:  [@zarcow](https://discourse.slicer.org/u/zarcow)
#### Post date: [January 19, 2024, 10:37pm UTC](https://discourse.slicer.org/t/bone-thickness-mapping-use-with-skull-ct-images/32463/7 "2024-01-19T22:37:53Z")
I would explore the source code (I am not a developer of the module) and look where the array of values is manipulated to save it for further processing