# partial volume pet reconstruction

**URL:** <https://castor-project.discourse.group/t/partial-volume-pet-reconstruction/237>\
**Category:** General Discussions\
**Created:** [November 15, 2021, 2:52pm UTC](https://castor-project.discourse.group/t/partial-volume-pet-reconstruction/237 "2021-11-15T14:52:51Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Hamid\_Nezampour](https://avatars.discourse-cdn.com/v4/letter/h/bb73d2/32.png) [@Hamid\_Nezampour](https://castor-project.discourse.group/u/Hamid_Nezampour)\
**Post date:** [November 15, 2021, 2:52pm UTC](https://castor-project.discourse.group/t/partial-volume-pet-reconstruction/237/1 "2021-11-15T14:52:51Z")

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Dear CASToR users and developers:

We designed a partial PET scanner but we could not reconstruct the exact image. Is there a limit to the Castor application that cannot reconstruct a partial PET scanner?

Is there any way to reconstruct the partial volume in aCastor ?

Have you heard anything about" look up tables"?

Thank you for your help.

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**Author:** ![sstute](https://avatars.discourse-cdn.com/v4/letter/s/8c91f0/32.png) [@sstute](https://castor-project.discourse.group/u/sstute)\
**Post date:** [November 15, 2021, 3:01pm UTC](https://castor-project.discourse.group/t/partial-volume-pet-reconstruction/237/2 "2021-11-15T15:01:48Z")

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Hi,

In terms of reconstructing images from tomographic data, CASToR can do whatever you tell it to do.

There is not limit, you can even design a “two crystals” PET scanner.

The use of look-up-tables is detailed in the documentation.

The limit for partial PET scanners is physical and not methodological.

Simon

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**Author:** ![sstute](https://avatars.discourse-cdn.com/v4/letter/s/8c91f0/32.png) [@sstute](https://castor-project.discourse.group/u/sstute)\
**Post date:** [November 15, 2021, 3:23pm UTC](https://castor-project.discourse.group/t/partial-volume-pet-reconstruction/237/3 "2021-11-15T15:23:07Z")

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Please always reply to the mailing list as any info could be useful for others.

What method are you talking about, the normalization, the optimization algorithm, or other ?

Yes it can as soon as you have at least 180 degrees of data, otherwise you will need to include prior knowledge into the reconstruction.

Simon

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**Author:** ![sstute](https://avatars.discourse-cdn.com/v4/letter/s/8c91f0/32.png) [@sstute](https://castor-project.discourse.group/u/sstute)\
**Post date:** [November 15, 2021, 3:27pm UTC](https://castor-project.discourse.group/t/partial-volume-pet-reconstruction/237/4 "2021-11-15T15:27:16Z")

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The TOF information also decreases the need for full ring tomographic data.

Simon