SlicerOpenDose3d

A Slicer3D extension module performing full 3D dosimetry for molecular radiotherapy procedures using multiple time point 3D datasets, either SPECT/CT or PET/CT.

SlicerOpenDose3D is an OpenDose software project implementing a Slicer3D extension module aiming for molecular radiotherapy dosimetry.

Workflows

The SlicerOpenDose3D module implements two workflows, one for activity integration and another for absorbed dose rate integration. The general schema consist on:

Standardise the dicom importation: extracting relevant data and properly renaming and locating all files. One folder per time point is created.
Resample CT: If one CT per time point is provided then it is rescaled to the SPECT/PET resolution to avoid resolution artifacts in absorbed dose calculations. If only one CT is provided, it is used (copied) for all time points. Currently, at least one CT is needed. Further developments will allow for no CT workflows.
Rescale data: In this step the CT volumes are converted to density maps using CT calibration data (by default Schneider2000 curve), and the SPECT/PET volumes are converted into activity maps using camera factor. The camera factor can be calculated in the module Calibration if you provide a sensitivity tank acquisition.
Registration: the module provides automatic CT-CT registration using SlicerElastix module if it is installed and if one CT per time point is provided. In the case of only one CT is provided, it is the user who must guarantee the registration of all data by the using of the General Ragistration (BRAINS) module.
Segmentation: Slicer contains a lot of segmentation tools, it is recommended to install the ExtraSegmentationEffects and the TotalSegmentator modules that provides extra functionality like masking volumes and auto-segmentation. The TotalSegmentator module has an extra requirement to work, in its main interface it allows to install everything it needs. One segmentation must be done in the reference time point and then propagated using the given functionality.

After this point, each workflow differs:

For activity integration workflow:

Extraction of activity per segment per time point: A table is created with the relevant information of activity, volume and mass per segment per time point. it is a completely automatic process
Integration of activity in time: the module provides PK integration in time functionality. A table with the integrated activity, the absorbed dose by local energy deposited (LED) in organ and the calculation uncertainty is reported.

For absorbed dose rate integration workflow:

Calculation of absorbed dose rate maps: currently 3 method are available (LED in voxel, homogeneous FFT convolution, and Monte Carlo).
In the case of Monte Carlo, a set of Gate macros are produced. The user is expected to run in a dedicated gate workstation or through docker command as:

docker run -ti --rm -v $PWD:/APP opengatecollaboration/gate:9.3-docker mac/executor.mac in linux/Mac
docker run -ti --rm -v $curr_path\:/APP opengatecollaboration/gate:9.3-docker mac/executor.mac in Windows powershell (You must have WSL2 activated).

Finally, the Gate outputs can be reimported to Slicer easily using a dedicated button.
Extraction of absorbed dose per segment per time point: this method allows to consider organ mass/shape/volume variation in time.
Integration of absorbed dose rate in time: as described before, the module implements a PK integration in time functionality. A table with the absorbed dose per segment and the calculation uncertainty is reported

OpenDose3D is created and maintained by the OpenDose collaboration, which brings together the open-source resources and expertise of research teams involved in nuclear medicine dosimetry. The OpenDose collaboration aims to facilitate the practice of dosimetry in Nuclear Medicine by providing: