Role of the software in brachytherapy



In brachytherapic clinical practice the software is used to define the treatment planning in terms of:
  • source exposition time and position determination in order to obtain the scope of the treatment in the case of endocavitary and superficial brachytherapy.
  • Number of sources and position of each source in the tissue in the case of interstitial brachytherapy in order to deliver the therapeutic dose uniformely to the target. 

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    In interstitial brachytherapy the software is also used to check the realised treatment planning on the patient: the software calculates the dose delivered to the patient, thanks to the spatial localisation of the sources in the treatment target (obtained with Computerised Tomography Interface).
     

    What kind of software is available in hospitals in the present


    Commercial softwares
    The features of commercial softwares available, used commonly in the clinical practice, are the following:

  • the softwares are based on analytical calculation methods,
  • all the tissues are approximated to water.
  • the sorce is approximated to a point (the real source dimensions are not considered).


  • Advantage of commercial softwares: these softwares are very fast by a computational point of view.
    Disadvantage:these softwares are chacterised by
  • rough approximate dose calculation;
  • density insensitivity.
  • Besides 
  • it's not available a dose calculation commercial software for superficial brachytherapy
  • a general brachytherapy dose calculation software is not available: a specific software is provided for each specific brachytherapic technique.

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    MonteCarlo simulations
    A MonteCarlo simulation calculates the dose distribution in an accurate way, without geometry or physics approximations, but it's characterised by slow computational time.
    In the present MonteCarlo simulations are not used in the clinical practice for this cause: in brachytherapy  the time factor is very important; medical physicist often must decide in real time the treatment .

    A solution to this problem is given by tha MC simulation parallelisation and the access to distribuited computering resources.