Proton Pencil Beam Scanning Plan utilizing apertures/multi leaf collimators

General
1

Hi,

I’m new to openTPS and am currently looking into the generation and optimization of proton pencil beam scanning plans that incorporate apertures or multileaf collimators. I’m wondering if anyone has conducted similar research or has successfully implemented this approach in openTPS.

Thank you!

2

Dear Jljw,

I unfortunately do not know of anyone who has conducted similar research with OpenTPS. However, there are some features that might help you:

  1. MCsquare (the PBS dose engine of OpenTPS) has a material conversion table that could let you model an MLC in a fixed position. A module that might give you inspiration is the flash module, where a hedgehog filter has been modeled in the CT.
  2. The optimization is modular, so you could input a cost function based on MLC position, although you would have to code it.

I hope this helps you somehow. Do not hesitate to reach us if you have more questions.

Regards,
Eliot

3

Dear Eliot,

Thank you for your previous reply. You mentioned the flash module in OpenTPS, as well as the modeling of a hedgehog filter within the CT geometry. I am currently working on proton FLASH radiotherapy dosimetry research, so I am very interested in these FLASH-related capabilities and would like to apply them to my work.

Specifically, I encountered some compatibility issues while trying to install and configure the opentps_flash extension with OpenTPS 3.0+ (e.g., ModuleNotFoundError due to module path mismatches following recent core refactoring), and I noticed that the current README may not fully reflect the latest release. Therefore, the following materials would be immensely helpful:

  1. Documentation or tutorials for the flash module: Is there any guidance on how to invoke and configure the FLASH module in OpenTPS? For example, how can one define a hedgehog filter or similar FLASH-specific modulator within the CT geometry?
  2. Sample code or configuration files: You noted that the hedgehog filter has been modeled in the CT. If possible, would you be able to share any code snippets, parameter files, or a minimal working example?
  3. Workflow for FLASH dose calculation: Is there a complete workflow guide for FLASH scenarios, covering CT import, material assignment, beam setup, and final dose calculation? In particular, are there any additional settings to be aware of when using MCsquare for FLASH, compared to conventional PBS calculations?
  4. Integration guidance for the opentps_flash extension: Do you have any installation or configuration recommendations for the latest OpenTPS (3.0+), such as how to properly set PYTHONPATH to resolve module dependencies after the core refactoring?

If some of these materials are not yet publicly available, any informal pointers, GitHub repository links, or relevant references would be greatly appreciated.

I look forward to your reply. Thank you very much for your time and assistance.

Best regards,
xdwang

4

Dear ddxxwang,

As previously mentioned by my colleague Romain Schyns the repository of the OpenTPS FLASH plug-in is unfortunately no longer maintained and provided as is.

However I must add to his answer that, based on the commits to this repository, I see that it has been updated for OpenTPS 3.0.
Regarding the installation, you should follow the guidelines provided in the repository and try to add it to your PYTONPATH (as pip install will not work with this plug-in).

Examples can be found in this repository. In addition there are two master’s theses on the subject that might help you:

They should be available in open-access;, however the access is provided by the UCLouvain university and therefore not handled by us.

I hopes this somewhat complete the answer of my colleague.

Regards,

Eliot

5

Dear Eliot,

Thank you very much for your detailed supplementary reply. I really appreciate your help.

Best regards,

ddxxwang