# Comprehensive analysis and mitigation of the clinical effects of delineation and geometric uncertainties in conformal radiation therapy

> **NIH NIH R01** · UNIVERSITY OF VIRGINIA · 2020 · $369,431

## Abstract

Project Summary / Abstract
Advances in radiotherapy (RT) delivery seek to improve dose conformity to increase the therapeutic ratio. A
key step in this process is the delineation of treatment targets and normal tissue avoidance regions. As
treatment margins around delineated volumes shrink, if delineation variability is not accounted for, disparate
volumes identified by different delineators, different imaging modalities, and different structure mapping
algorithms may dominate the efficacy of both an individual patients' treatment and the collective results of
clinical trials. While efficacy should be enhanced with improved delineation consistency, improved baseline
imaging (including functional imaging) to more clearly see the tissues, and improved deformable registration
algorithms to better align delineations from different images, benefits from such improvements will be
jeopardized until methods to quantify and communicate the clinical effects of the patient-specific residual
uncertainties in these processes exist. Uncertainty quantification enables mitigation as well as determination
of when further uncertainty reductions provide no benefit. This project aims to (1) identify clinical situations in
which delineation variability negatively impacts treatment efficacy in light of other inherent treatment
uncertainties, (2) model delineation variability so that it may be estimated on a per-patient basis and
communicated to the treatment team, and (3) develop treatment planning and delivery methods that mitigate
the joint effect of delineation and other uncertainties in radiation therapy, thereby creating efficacious radiation
therapy treatment plans.

## Key facts

- **NIH application ID:** 9987571
- **Project number:** 5R01CA222216-03
- **Recipient organization:** UNIVERSITY OF VIRGINIA
- **Principal Investigator:** JEFFREY Vincent SIEBERS
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $369,431
- **Award type:** 5
- **Project period:** 2018-08-01 → 2023-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9987571

## Citation

> US National Institutes of Health, RePORTER application 9987571, Comprehensive analysis and mitigation of the clinical effects of delineation and geometric uncertainties in conformal radiation therapy (5R01CA222216-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9987571. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*