BACKGROUND: The objective of this study was to explore the 10-year plus outcomes of Intensity Modulated Radiotherapy with concomitant chemotherapy (CRT) combined with preventive swallowing rehabilitation (CRT+) for head and neck cancer (HNC).METHODS: Subjective and objective swallowing, trismus, and speech related outcomes were assessed at 10-year plus after CRT+. Outcomes were compared to previously published 6-year results of the same cohort.RESULTS: Fourteen of the 22 patients at 6-year follow-up were evaluable. Although objective swallowing-related outcomes showed no deterioration (eg, no feeding tube dependency and no pneumonia), swallowing-related quality of life slightly deteriorated over time. No patients had or perceived trismus. Voice and speech questionnaires showed little problems in daily life. Overall quality of life (QOL) was good.CONCLUSIONS: After CRT with preventive rehabilitation exercises for advanced HNC, swallowing, trismus, and speech related outcomes moderately deteriorated from 6 to 10 years, with an on average good overall QOL after.
Background and purpose: Treatment plan verification of intensity modulated radiotherapy (IMRT) is generally performed with the gamma index (GI) evaluation method, which is difficult to extrapolate to clinical implications. Incorporating Dose Volume Histogram (DVH) information can compensate for this. The aim of this study was to evaluate DVH-based treatment plan verification in addition to the GI evaluation method for head and neck IMRT.Materials and methods: Dose verifications of 700 subsequent head and neck cancer IMRT treatment plans were categorised according to gamma and DVH-based action levels. Fractionation dependent absolute dose limits were chosen. The results of the gamma- and DVH-based evaluations were compared to the decision of the medical physicist and/or radiation oncologist for plan acceptance.Results: Nearly all treatment plans (99.7%) were accepted for treatment according to the GI evaluation combined with DVH-based verification. Two treatment plans were re-planned according to DVH-based verification, which would have been accepted using the evaluation alone. DVH-based verification increased insight into dose delivery to patient specific structures increasing confidence that the treatment plans were clinically acceptable. Moreover, DVH-based action levels clearly distinguished the role of the medical physicist and radiation oncologist within the Quality Assurance (QA) procedure.Conclusions: DVH-based treatment plan verification complements the GI evaluation method improving head and neck IMRT-QA.
The COMPASS system (IBADosimetry) is a quality assurance (QA) tool whichreconstructs 3D doses inside a phantom or a patient CT. The dose is predictedaccording to the RT plan with a correction derived from 2D measurementsof a matrix detector. This correction method is necessary since a directreconstruction of the fluence with a high resolution is not possible becauseof the limited resolution of the matrix used, but it comes with a blurring of thedosewhich creates inaccuracies in the dose reconstruction. This paper describesthe method and verifies its capability to detect errors in the positioning of aMLC with 10 mm leaf width in a phantom geometry. Dose reconstruction wasperformed forMLC position errors of various sizes at various locations for bothrectangular and intensity-modulated radiotherapy (IMRT) fields and comparedto a reference dose. It was found that the accuracy with which an error inMLCposition is detected depends on the location of the error relative to the detectorsin the matrix. The reconstructed dose in an individual rectangular field for leafpositioning errors up to 5 mm was correct within 5% in 50% of the locations.At the remaining locations, the reconstruction of leaf position errors larger than3 mm can show inaccuracies, even though these errors were detectable in thedose reconstruction. Errors larger than 9 mm created inaccuracies up to 17% ina small area close to the penumbra. The QA capability of the system was testedthrough gamma evaluation. Our results indicate that themean gamma providedby the system is slightly increased and that the number of points above gamma 1ensures error detection for QA purposes. Overall, the correction kernel methodused by the COMPASS system is adequate to perform QA of IMRT treatmentplans with a regular MLC, despite local inaccuracies in the dose reconstruction.
