Clinical Introduction of Image-guided Radiotherapy and Cone Beam Computed Tomography
Bruno Sorcini PhD Department of Medical Physics, Karolinska University Hospital
Conclusions
The linear accelerator with on-board imager seems to be very useful for the set-up of patients and for verification of the irradiation field just before irradiation. These systems will provide high-quality radiotherapy by delivering higher doses to tumors and fewer doses to normal tissue. The 3-D treatment plan verification using online correction based on soft tissue and target position has been used clinically and adds an approximate additional five minutes to the treatment time slot due to acquisition, reconstruction, and 3-D registration.
The radiographic mode with kV-kV images using the on-board imager systems offers a means for the repositioning of patients. Gold markers implanted into the prostate can be safely used for daily organ tracking using online set-up verification by OBI. The patient position is corrected according to the position of the markers detected in the localization images, acquired prior to set-up, and also changes in work flow and responsibilities for the therapist. The workloads generated by set-up correction in relation to their benefits have to be considered.The initial experience of CBCT is very encouraging with the image quality adequate for internal soft target localization.
