Elekta Reconstruction¶

Elekta provides easy access to raw data. The data and projection images are stored in a single directory which is user-configurable. The default location is D:\db. In this folder, there is a database in DBase format. Each table is contained in a .DBF file. RTK needs the IMAGE.DBF and FRAME.DBF tables.

Patient data are stored in individual folders. By default, the name of each patient folder is patient_ID where ID is the patient ID. In these folders, one can access the planning CT in the CT_SET subfolder and the cone-beam projections in IMAGES/img_DICOM_UID subfolders, where DICOM_UID is the DICOM UID of the acquisition. The projection images are .his files. The reconstructed images are the IMAGES/img_DICOM_UID/Reconstruction/*SCAN files.

Reconstruction Steps¶

The first step before proceeding with the reconstruction is to convert Elekta’s database information into an RTK geometry file using a command-line tool. Follow these steps:

1. Download Elekta Dataset¶

Download the dataset from Elekta-data.

2. Convert Geometry¶

Run the application to convert Elekta’s geometry into RTK’s format (DICOM_UID is contained in the subfolder name of the .his files):

rtkelektasynergygeometry \
  --image_db IMAGE.DBF \
  --frame_db FRAME.DBF \
  --dicom_uid 1.3.46.423632.135428.1351013645.166 \
  -o elektaGeometry

Since XVI v5, the geometry is contained in a separate _Frames.xml file, which can be used as follows:

rtkelektasynergygeometry \
  --xml _Frames.xml \
  -o elektaGeometry

An example of such a file is available in the test data here.

3. Reconstruct Using RTK Applications¶

Use the rtkfdk algorithm to reconstruct a single axial slice (e.g., slice 29.5) of the volume:

rtkfdk \
  --lowmem \
  --geometry elektaGeometry \
  --path img_1.3.46.423632.135428.1351013645.166/ \
  --regexp '.*.his' \
  --output slice29.5.mha \
  --verbose \
  --spacing 0.25,0.25,0.25 \
  --dimension 1024,1,1024 \
  --origin -127.875,29.5,-127.875

4. Apply the FOV Filter¶

Apply the field-of-view (FOV) filter to mask out everything outside the FOV:

rtkfieldofview \
  --geometry elektaGeometry \
  --path img_1.3.46.423632.135428.1351013645.166/ \
  --regexp '.*.his' \
  --reconstruction slice29.5.mha \
  --output slice29.5.mha \
  --verbose

5. Visualize the Result¶

You can visualize the result using a viewer (e.g., VV). The resulting image should look like the following:

Elekta.jpg