# How to apply 'time resolution (200 ps)' and 'random&scatter correction' to the offset detector

**URL:** <https://castor-project.discourse.group/t/how-to-apply-time-resolution-200-ps-and-random-scatter-correction-to-the-offset-detector/253>\
**Category:** General Discussions\
**Created:** [March 7, 2022, 11:13am UTC](https://castor-project.discourse.group/t/how-to-apply-time-resolution-200-ps-and-random-scatter-correction-to-the-offset-detector/253 "2022-03-07T11:13:06Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Shwan\_K](https://avatars.discourse-cdn.com/v4/letter/s/5f9b8f/32.png) [@Shwan\_K](https://castor-project.discourse.group/u/Shwan_K)\
**Post date:** [March 7, 2022, 11:13am UTC](https://castor-project.discourse.group/t/how-to-apply-time-resolution-200-ps-and-random-scatter-correction-to-the-offset-detector/253/1 "2022-03-07T11:13:06Z")

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Dear CASToR Users and Developers,

Hi I am Suhwan Kim

I designed the offset detector of ‘PETscanner’ using the GATE tool.

I want to apply ‘time resolution (200 ps)’ and ‘random&scatter correction’ when performing image reconstruction.

I don’t know how to proceed.

can you help me??

Thanks

Suhwan Kim

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**Author:** ![Xin\_Zhao](https://avatars.discourse-cdn.com/v4/letter/x/f05b48/32.png) [@Xin\_Zhao](https://castor-project.discourse.group/u/Xin_Zhao)\
**Post date:** [July 29, 2022, 9:14am UTC](https://castor-project.discourse.group/t/how-to-apply-time-resolution-200-ps-and-random-scatter-correction-to-the-offset-detector/253/2 "2022-07-29T09:14:53Z")

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Hellow, about TOF, you can extract time information of coincidences by calculating Δt of two singles. Then you can write the Cdf file with delta time as what has been shown in CASToR Official Guide.

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**Author:** ![tmerlin](https://yyz2.discourse-cdn.com/free1/user_avatar/castor-project.discourse.group/tmerlin/32/216_2.png) [@tmerlin](https://castor-project.discourse.group/u/tmerlin)\
**Post date:** [July 29, 2022, 5:02pm UTC](https://castor-project.discourse.group/t/how-to-apply-time-resolution-200-ps-and-random-scatter-correction-to-the-offset-detector/253/3 "2022-07-29T17:02:23Z")

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Hi,  
Using castor-GATERootToCastor, you can convert TOF data using the _-TOF\_reso_ option along with a value corresponding to the CRT.  
The tool does not perform scatter/random correction though and you would have to generate the datafile yourself (or modify castor-GATERootToCastor.cc to do so) .  
Regarding scatter correction with TOF, have a look at this previous thread which discusses the matter:

> [@Question on ToF scatter estimation](https://castor-project.discourse.group/t/question-on-tof-scatter-estimation/127):
>
> Dear Marina, dear other CASToR developers, I am struggling with the scatter correction in CASToR due to ToF and it would be greatly appreciated if you could help me out. First, let me introduce my setup: My list-mode dataset is simulated using GATE and I specify the scanner’s time resolution in the GATE file (e.g. 320ps). When creating a CASToR data-file, I want to include corrections for scatter (and randoms, eventually). The implemented scatter correction rate calculated by CASToR using the…

Hope this helps,  
Thibaut