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UCL / PETPVC

Partial Volume Correction in PET
Apache License 2.0
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Change number of iteration of RL with petpvc #60

Closed ubersexualShupeng closed 4 years ago

ubersexualShupeng commented 4 years ago

Hi,

Nice implementation of PVC tool. It is an essential tool for quantitative PET imaging in clinical applications.

We doing some experiments using the Richardson-Lucy algorithm in PETPVC. Could you let us know how to change the number of iterations? Currently, we only use the default setting with iteration always = 10. Thanks.

SChen

KrisThielemans commented 4 years ago

This is a bug in petpvc unfortunately. However, as a work-around you can do it via the dedicated executable:

petvc_rl -x 6 -y 6 -z 9 -i 5 blur.nii.gz RL5.nii.gz

will run for 5 iterations

bathomas commented 4 years ago

Does the -k switch not work when running petpvc?

KrisThielemans commented 4 years ago

aha, yes, it does. The -i switch doesn't. This then seems to just be a confusion between the 2 options. Where is number of iterations used. Iterative Yang? Why have 2 different options?

bathomas commented 4 years ago

I debated this for a while. I use -i for iterations of iterative Yang, but -k for number of iterations during a deconvolution i.e. Richardson-Lucy or van-Cittert. This enables the combination of techniques, such as iterative Yang followed by RL. This is confusing and the confusion it introduces is possibly not worth the flexibility.

KrisThielemans commented 4 years ago

ok. I think we should address this by just improving the documentation then (e.g. usage message)