Optimization of calculation times in CIVA CT: Import of Monte-Carlo calculation results with a variable step

A functionality has been developed in CIVA CT to reduce the computation time of tomographic configurations including Monte-Carlo calculations (allowing to take into account scattered radiation).

This option allows to import Monte-Carlo calculation results with a variable positioning step.

It is thus possible to refine the calculation of the scattered radiation on irregular regions or strong variations in thickness and, conversely, to widen the step on flat or quasi-planar areas where the thickness is constant (see image below).

 

 

Two import modes are proposed via a drop-down menu:

• File in CSV format: the description of the imports to be carried out is made in a CSV file,
• Manual: the description of the imports to be made is done directly in the CIVA interface.

 

Import CSV file

N.B.: The CSV file and the CIVA configurations containing the scattered results (Monte-Carlo calculations) to be imported must be in the same folder.

The CSV file must contain three columns separated by semicolons, and as many lines as there are positions.

The content of each line is as follows:

• First column: index (tomographic position). The initial value is 1.
• Second column: CIVA tomographic or radiographic configuration to be considered (*.civa). Only the name of the configuration is to be specified (since all the configurations are in the same directory as the CSV file).
• Third column: position to be considered for the reloading of the scattered radiation calculation. If the loaded configuration is a radiographic configuration (1 position), do not put anything. If the loaded configuration is a tomographic configuration (several positions), fill in the position to be loaded.

An example of a *.csv file is shown below:

 

 

Lines 1 and 2: The configuration “Config_pos_0.civa” is a radiographic configuration, so there is no need to enter the position to be loaded in column 3.

Lines 3 and 4: The configuration “Config_pos_22-5_to_42-5.civa” is a tomographic configuration. In that case, it is the first position of the configuration “Config_pos_22-5_to_42-5.civa” that has to be loaded.

For lines 5 and 6, it is the second position of the same CIVA file that must be reloaded.

 

“Manual” import

The description of the imports is made in the CIVA interface through a table with the following fields:

• Index: number of the import. The increment is done automatically when a new line is added by the user (using the + symbol).
• Nb of positions: number of successive tomographic positions for which the imported diffusion will be used.
• File name: CIVA configuration in which the previously calculated diffusion will be imported. The window allowing for the selection of the configuration is accessible by clicking in the box. It is not necessary for all configurations to be in the same folder (absolute paths are specified).
• Position number in scatter file: position to be considered for the scatter in the CIVA configuration specified in the previous column (if tomographic configuration).