Development of a biological at-risk volume using apparent diffusion coefficient for parotid-sparing radiation therapy planning

Katelyn Cahill; Catriona Hargrave; Patrick O’Connor; Mark Denham; Nathan Hearn; Dinesh Vignarajah; Zack Y Shan; Myo Min

doi:10.1093/bjro/tzaf020

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Development of a biological at-risk volume using apparent diffusion coefficient for parotid-sparing radiation therapy planning

Journal article

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Development of a biological at-risk volume using apparent diffusion coefficient for parotid-sparing radiation therapy planning

Katelyn Cahill, Catriona Hargrave, Patrick O’Connor, Mark Denham, Nathan Hearn, Dinesh Vignarajah, Zack Y Shan and Myo Min

BJR Open, Vol.7(1), pp.1-8

2025

DOI: https://doi.org/10.1093/bjro/tzaf020

PMCID: PMC12401576

PMID: 40901382

Appears in Thompson Institute Research Collection

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Abstract

apparent diffusion coefficient

diffusion-weighted MRI

biological at-risk volume

head and neck cancer

parotid gland

radiotherapy

Thompson Institute Special Collection

Other Collaborations

Objectives Xerostomia toxicity continues to contribute towards a decrease in quality of life in head and neck cancer patients. Diffusion weighted MRI and the associated apparent diffusion coefficient (ADC) may identify the radiosensitive region within the parotid gland (PG). This study retrospectively assesses the feasibility of using percentile threshold values from the ADC map to generate a biological at-risk volume (BRV). The location and distribution of BRV are evaluated across the PG. Methods Image registration between the planning CT and MRI-simulation images was performed and reviewed to ensure accurate translation of ADC data when contouring the PG. Histogram analysis was undertaken using the 20th, 30th, and 50th percentile ADC values of each contoured PG to form the BRV. The whole PG was split into 8 anatomical sectors at a common intersection point to evaluate the distribution of BRV throughout. Results The BRV distribution for each percentile was mapped across the whole contoured PG and each anatomical sector contour. The largest distribution was predominantly found in the superolateral sectors. Conclusions The 20th and 30th percentile ADC values can be used to form a BRV of the PG. The location of the BRV distribution indicates a potential relationship between ADC thresholds and the functional region of the PG. Advances in knowledge The BRV is located in a favourable position within the PG and could be used to further spare this salivary gland during dose optimization. The feasibility of this approach will be explored in a future retrospective dosimetry study.

Details

Title: Development of a biological at-risk volume using apparent diffusion coefficient for parotid-sparing radiation therapy planning
Authors: Katelyn Cahill (Corresponding Author) - University of the Sunshine Coast, Queensland, Thompson Institute
Catriona Hargrave - Queensland University of Technology
Patrick O’Connor - Sunshine Coast University Hospital
Mark Denham - Sunshine Coast University Hospital
Nathan Hearn - University of the Sunshine Coast, Queensland, Thompson Institute
Dinesh Vignarajah - Sunshine Coast University Hospital (Australia)
Zack Y Shan - University of the Sunshine Coast, Queensland, Thompson Institute
Myo Min - University of the Sunshine Coast, Queensland, Thompson Institute
Publication details: BJR Open, Vol.7(1), pp.1-8
Publisher: Oxford University Press
Date published: 2025
DOI: 10.1093/bjro/tzaf020
ISSN: 2513-9878
PMID: 40901382; PMC12401576
Copyright note: © The Author(s) 2025. Published by Oxford University Press on behalf of the British Institute of Radiology. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
Grant note: This research was undertaken using funding from a Wishlist-SERTF Collaborative Research grant (202105CRG) at the Sunshine Coast University Hospital, Birtinya, QLD, Australia.
Organisation Unit: Thompson Institute
Language: English
Record Identifier: 991156740002621
Output Type: Journal article

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