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Evaluation of the impact of dental artefacts on intensity-modulated radiotherapy planning for the head and neck.
Webster, Gareth J Rowbottom, Carl G Mackay, Ranald I
Webster, Gareth J
Rowbottom, Carl G
Mackay, Ranald I
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Abstract
BACKGROUND AND PURPOSE: High density materials create severe artefacts in the computed tomography (CT) scans used for radiotherapy dose calculations. Increased use of intensity-modulated radiotherapy (IMRT) to treat oropharyngeal cancers raises concerns over the accuracy of the resulting dose calculation. This work quantifies their impact and evaluates a simple corrective technique. MATERIALS AND METHODS: Fifteen oropharyngeal patients with severe artefacts were retrospectively planned with IMRT using two different CT/density look-up tables. Each plan was recalculated using a corrected CT dataset to evaluate the dose distribution delivered to the patient. Plan quality in the absence of dental artefacts was similarly assessed. A range of dosimetric and radiobiological parameters were compared pre- and post-correction. RESULTS: Plans using a standard CT/density look-up table (density 1.8 g/cm(3)) revealed inconsistent inter-patient errors, mostly within clinical acceptance, although potentially significantly reducing target coverage for individual patients. Using an extended CT/density look-up table (density 10.0 g/cm(3)) greatly reduced the errors for 13/15 patients. In 2/15 patients with residual errors the CTV extended into the severely affected region and could be corrected by applying a simple manual correction. CONCLUSIONS: Use of an extended CT/density look-up table together with a simple manual bulk density correction reduces the impact of dental artefacts on head and neck IMRT planning to acceptable levels.
Description
Date
2009-12
Publisher
Collections
Keywords
Radiotherapy
Head and Neck Cancer
Dose Calculation
Head and Neck Cancer
Dose Calculation
Type
Article
Citation
Evaluation of the impact of dental artefacts on intensity-modulated radiotherapy planning for the head and neck. 2009, 93 (3):553-8 Radiother Oncol