The Impact of Pre-Treatment Image Guidance on Tumor and Normal Tissue Dosimetry During VMAT for Cervical Cancer

The significance of accurate beam delivery has been examined both in theory and in practice, considering the movements of the organs and interfractional targets during the treatment process. The shifts from the plans simulated for each image were collected and averaged separately for each axis. The tumor coverage was most affected by the shifts, resulting in an underdosage for the EPID group. Significant differences were observed in the CBCT group for the rectum and femoral heads. Pre-treatment patient setup and organ movement during radiotherapy are key issues for an accurate treatment delivery, affecting tumor coverage and protection of OARs alike.