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Star Shot

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Mushfiq Rahman edited this page Nov 13, 2017 · 2 revisions

QALMA star shot module comes with both automatic and manual mode. Star shot images are assumed to have a lower intensity branches than the background. In case, the branches have a higher intensity than the background, the image is needed to be inverted (section 2.3).

Fig 3: QALMA star shot window

2.1 Automatic Mode

QALMA Star Shot module be opened from the main window or simply type ‘star_shot’ in the MATLAB command window. Next, the user can follow the procedure below:

  1. Click the “Browse Image” and load ‘img_star_shot.tif’ from the ‘samples’ folder provided with the package.
  2. Select whether the image belongs to either Gantry, Couch or Collimator.
  3. Add a comment if you have any.
  4. Check Configuration. Check your film manufacturer manual to find the resolution. To get the result in pixel, simply input ‘1’ for the ‘Resolution’.
  5. Click ‘Analyze’.
  6. Select the row and click ‘Delete’ if you want to remove a trial.
  7. Click ‘Report’ to generate a pdf report in the current working directory. To save file in another directory or in a different format, please select ‘File’ from menu and click ‘save as’. Current working directory can be found by typing ‘pwd’ in the command line.
  8. Click ‘image’ if you want to analyze another image.
  9. Go to QALMA main window by clicking ‘Home’.

2.2 Manual Mode:

QALMA can be used in automatic mode most of the time. In case, the software cannot detect even number of legs it will pop a massage to the user to choose an initial point. To activate the manual mode, the user must check the checkboxes ‘Activated’ and ‘Choose Center’. Then click somewhere in the image, preferably around the center. Rest of the procedure is same as the automatic mode.

Fig 4: QALMA Star Shot Analysis

2.3 Inverting Images:

Image provided with the QALMA package has branches with lower intensity. If you have an image with higher intensity branches than the background check the boxes for ‘Activated’ and ‘Invert’. Before processing the image QALMA will invert the image automatically.

2.4 Miscellaneous:

In case, the software is not detecting the branches as shown in the result (fig. 4) and the radius of the circle is not as expected, the user must try changing the parameters of ‘winer2’ and ‘moving average’ filers.

Auto crop is on by default. Uncheck ‘Auto crop’ if you don’t want to trim the edges of the image.

Disclaimer: QALMA was developed for research purpose. We are not responsible for clinical application.

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