Purpose: The purpose of this study was to develop a method for dose distribution visualization in the case of Electron Beam Intraoperative Radiotherapy based on the images obtained in the operating room. This cannot be relied on CT images obtained before surgery due to significant tissue deformation.
Methods: The ultrasound scanning is the only method to obtain 3-dimensional (3D) reconstruction of a patient's tissue under operating room conditions. We decided to apply this modality as a background to visualize 3D dose distribution in terms of intraoperative radiotherapy (IORT). Dose distribution was obtained on the basis of dosimetric measurements carried out in the water phantom (PDD curves, transversal profiles).
Results: The method which has been developed in our department helps optimize the treatment. The amount of information depends strongly on the quality of the ultrasound image. We have verified the method (spatial correctness of dose painting) using commercially available phantom typically used for performance and quality assurance in ultrasound imaging (CIRS) and we noticed good correlation between 3D dose distribution and ultrasound image.
Conclusions: Using up-to-date ultrasound tissue images allows better treatment optimization compared to the previous method that uses pre-surgery scans (CT or MRI). It helps optimize the angle of the beam axis and choose the beam with adequate range (energy) and avoid the risk of inaccurate irradiation of the area of interest.