CT imaging based digitally reconstructed radiographs and their applicationin brachytherapy

The aim of our study was to develop an algorithm to simulate the digitally reconstructed radiograph (DRR) calculation process for different beam quali ties (photon energies) in the range 50 keV to 12 MeV. This was achieved usi ng volumetric anatomical data for the patient obtained from three-dimension al diagnostic CT images. These DRR images can be used in three-dimensional treatment planning for external beam radiotherapy as well as for brachyther apy in the same way as conventional radiographic films. The advantages of u sing such DRRs in modem 30 brachytherapy treatment planning are shown. A nu mber of tools are described, illustrating that the application of DRRs in b rachytherapy is very useful.