Richard Benson

Anatomical change during radiotherapy for head and neck cancer, and its effect on delivered dose to the spinal cord

Highlights • A cohort of 133 head & neck cancer patients treated with TomoTherapy was examined.• Differences between planned and delivered maximum spinal cord dose were small.• Substantial weight loss and anatomical change during treatment was observed.• No link between weight loss or anatomical change, and dose differences was seen.

Automatic contour propagation using deformable image registration to determine delivered dose to spinal cord in head-and-neck cancer radiotherapy

Abstract To determine delivered dose to the spinal cord, a technique has been developed to propagate manual contours from kilovoltage computed-tomography (kVCT) scans for treatment planning to megavoltage computed-tomography (MVCT) guidance scans. The technique uses the Elastix software to perform intensity-based deformable image registration of each kVCT scan to the associated MVCT scans. The registration transform is then applied to contours of the spinal cord drawn manually on the kVCT scan, to obtain contour positions on the MVCT scans. Different registration strategies have been investigated, with performance evaluated by comparing the resulting auto-contours with manual contours, drawn by oncologists. The comparison metrics include the conformity index (CI), and the distance between centres (DBC). With optimised registration, auto-contours generally agree well with manual contours. Considering all 30 MVCT scans for each of three patients, the median CI is \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}

De-escalation treatment protocols for human papillomavirus-associated oropharyngeal squamous cell carcinoma

0.759 \pm 0.003

Minimally invasive surgery versus radiotherapy/chemoradiotherapy for small-volume primary oropharyngeal carcinoma

\end{document}0.759±0.003, and the median DBC is (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}

Minimally invasive surgery versus radiotherapy/chemoradiotherapy for early-stage oropharyngeal carcinoma

0.87 \pm 0.01

Non-surgical interventions for human papilloma virus-positive local advanced oropharyngeal squamous cell cancer

\end{document}0.87±0.01) mm. An intra-observer comparison for the same scans gives a median CI of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}

Identifying risk factors for L’Hermitte’s sign after IMRT for head and neck cancer

0.820 \pm 0.002

The efficacy of adjuvant radioactive iodine therapy for patients with recurrent differentiated thyroid carcinoma

\end{document}0.820±0.002 and a DBC of (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}

OC-0543: Acute toxicity with helical IGIMRT for head and neck cancer: Unilateral vs bilateral nodal irradiation

0.64 \pm 0.01

Dose density of weekly cisplatin delivered concurrent with radiotherapy in head and neck cancer patients

\end{document}0.64±0.01) mm. Good levels of conformity are also obtained when auto-contours are compared with manual contours from one observer for a single MVCT scan for each of 30 patients, and when they are compared with manual contours from six observers for two MVCT scans for each of three patients. Using the auto-contours to estimate organ position at treatment time, a preliminary study of 33 patients who underwent radiotherapy for head-and-neck cancers indicates good agreement between planned and delivered dose to the spinal cord.