(Tuesday, 7/16/2019) 10:30 AM - 11:00 AM
Room: Exhibit Hall | Forum 4
Purpose: To introduce a method of adaptive high dose-rate (HDR) brachytherapy (ABT) for CT/MR quidded gynecological patients’ treatments. To outline a novel treatment workflow, technical innovations, and clinical results.
Methods: Pre-treatment 3D imaging is not yet a standard quality assurance (QA) step in treatments of gynecological cancer. Upon implementation of the process, displacements and deviations of needle/applicator positions were noticed. We developed an ABT method as a response to such scenarios. The ABT includes two principal phases: a) quick quantitative dose assessment(QDD) and b) rapid re-planning(RRP). The QDD consists of: image registration, evaluation and adjustment of the contours, automatic re-positioning of the applicators/needles (to match the clinical scenario), and EQD2 dose recalculation. The PRP consists of: activation (deactivation) of the dwell positions that are inside (outside) high-risk-CTV (HR-CTV), and rapid dose optimization. The PRP is performed only when the EQD2 dose to the HR-CTV or organ-at-risk (OAR) was inadequate.
Results: We investigated 128 gynecological patients treated with interstitial(49), intracavitary(56) or combined(23) HDR brachytherapy during 2017 and 2018. The patients included in this study received external beam radiation therapy followed by twice-daily treatment for a total of 591 HDR brachytherapy fractions. Prior to delivery of each fraction, a CT scan was taken and registered to the CT/MR images used for treatment planning. For twenty-seven fractions (4.6%), the QDD was required due to significant discrepancies in the needle/applicator position (up to 21.1mm). Eleven patients (8.6%) required PRP due to suboptimal dose to the HR-CTV or potential overdose of the OARs. On average, the QDD was performed within 5 minutes, and the PRP within 10-15 minutes while the total ABT process was shorter than 20 minutes.
Conclusion: ABT is a novel approach for treatments of gynecological cancer. The method is fast, robust and has a potential to notably improve quality of such treatments.
Keywords
Not Applicable / None Entered.
Taxonomy
Not Applicable / None Entered.
Contact Email
