Sci-Sat AM(2): Brachy - 03: Post-Operative CT or Intra-Operative US for Planning Single Fraction Prostate HDR Brachytherapy? The Odette Experience

Abstract

There is a growing body of evidence demonstrating that using HDR brachytherapy as a local boost for patients with intermediate‐risk prostate cancer provides a survival advantage over EBRT alone. In September 2009 we transitioned from using post‐operative CT‐based planning to intraoperative US‐based planning for our single fraction technique. The dosimetric impact of this change is assessed in this retrospective analysis of 23 patients from each of our CT and US cohorts. We also consider the impact of this change on our resource allocations and patient throughput. Generally, US‐based planning can be considered dosimetrically equivalent to CT‐based planning. It was found to produce plans that exceed dosimetric goals less often than CT. US planning offers several other advantages. Importantly, the patient remains in the same position throughout the procedure, thus the needles remain in the intended position. This eliminates uncertainty introduced by motion between planning and delivery and makes needle position QA straightforward. Improved needle positioning also results decreased time required to achieve a clinically acceptable plan. Intraoperative planning has proved to be an efficient mode of delivering HDR brachytherapy. Although each case occupies the brachytherapy suite for up to 2.5hr, elimination of moving the patient to CT, improved contouring tools, and the reduction in both planning and pre‐treatment QA time have made this procedure much quicker for the whole brachytherapy team. Moving to US‐based planning has permitted us to more than double the number of patients we can treat in a year with HDR brachytherapy for prostate.