Dataset Information
Cone beam computed tomography-based monitoring and management of target and organ motion during external beam radiotherapy in cervical cancer.
Ontology highlight
ABSTRACT: Background and purpose
Organ motion is a challenge during high-precision external beam radiotherapy in cervical cancer, and improved strategies for treatment adaptation and monitoring of target dose coverage are needed. This study evaluates a cone beam computed tomography (CBCT)-based approach.Materials and methods
In twenty-three patients, individualized internal target volumes (ITVs) were generated from pre-treatment MRI and CT scans with full and empty bladders. The target volumes encompassed high-risk clinical target volume (CTV-T HR) (gross tumor volume?+?remaining cervix) and low risk (LR) CTV-T (CTV-T HR?+?uterus?+?parametriae?+?upper vagina). Volumetric Modulated Arc Therapy (VMAT) was used to deliver a dose of 45?Gy in 25 fractions. CBCTs were used for setup and for radiation therapists (RTTs) to evaluate the target coverage (inside/outside the planning target volume). CBCTs were reviewed offline. Estimates of the dose delivered with minimum (point) doses across all fractions to CTV-T HR (aim 42.75?Gy) and CTV-T LR (aim 40?Gy) were assessed. In patients with insufficient dose coverage, re-plans were generated based on previous imaging.Results
Median (range) of the ITV-margins (mean of anterior-posterior margins) related to uterus and cervix was 1.2 (0.5-2.2 and 1.0-2.1) cm. RTTs were able to assess the target coverage in 90% of all CBCTs (505/563). With re-planning, one patient had considerable benefit (12.7?Gy increase of minimum dose) to CTV-T LR_vagina, four patients had improved dose to the CTV-T LR_uterus (1.2-1.8?Gy), and 3 patients did not benefit from re-planning.Conclusions
Daily CBCT-based monitoring of target coverage by the RTTs has proven safe with limited workload. It allows for reduction in the treated volumes without compromising the target dose coverage.
SUBMITTER: Jensen NBK
PROVIDER: S-EPMC7807672 | biostudies-literature | 2019 Jan
REPOSITORIES: biostudies-literature
Publications
Cone beam computed tomography-based monitoring and management of target and organ motion during external beam radiotherapy in cervical cancer.
Physics and imaging in radiation oncology 20181220
<h4>Background and purpose</h4>Organ motion is a challenge during high-precision external beam radiotherapy in cervical cancer, and improved strategies for treatment adaptation and monitoring of target dose coverage are needed. This study evaluates a cone beam computed tomography (CBCT)-based approach.<h4>Materials and methods</h4>In twenty-three patients, individualized internal target volumes (ITVs) were generated from pre-treatment MRI and CT scans with full and empty bladders. The target vol ...[more]