Background and purpose: Creating an individualized tissue equivalent material build-up (i.e. bolus) for electron beam radiation therapy is complex and highly labour-intensive. We implemented a new... Show moreBackground and purpose: Creating an individualized tissue equivalent material build-up (i.e. bolus) for electron beam radiation therapy is complex and highly labour-intensive. We implemented a new clinical workflow in which 3D printing technology is used to create the bolus.Material and methods: A patient-specific bolus is designed in the treatment planning system (TPS) and a shell around it is created in the TPS. The shell is printed and subsequently filled with silicone rubber to make the bolus. Before clinical implementation we performed a planning study with 11 patients to evaluate the difference in tumour coverage between the designed 3D-print bolus and the clinically delivered plan with manually created bolus. For the first 15 clinical patients a second CT scan with the 3D-print bolus was performed to verify the geometrical accuracy.Results: The planning study showed that the V85% of the CTV was on average 97% (3D-print) vs 88% (conventional). Geometric comparison of the 3D-print bolus to the originally contoured bolus showed a high similarity (DSC = 0.89). The dose distributions on the second CT scan with the 3D print bolus in position showed only small differences in comparison to the original planning CT scan.Conclusions: The implemented workflow is feasible, patient friendly, safe, and results in high quality dose distributions. This new technique increases time efficiency. (C) 2016 Elsevier Ireland Ltd. All rights reserved. Show less
Knegjens, J.L.; Hauptmann, M.; Pameijer, F.A.; Balm, A.J.; Hoebers, F.J.; Bois, J.A. de; ... ; Rasch, C.R. 2011
Background. Tumor volume is an important predictor of outcome in radiotherapy alone. Its significance in concomitant chemoradiation (CCRT) is much less clear. We analyzed the prognostic value of... Show moreBackground. Tumor volume is an important predictor of outcome in radiotherapy alone. Its significance in concomitant chemoradiation (CCRT) is much less clear. We analyzed the prognostic value of primary tumor volume for advanced head and neck squamous cell carcinoma (HNSCC) treated with CCRT.Methods. Three hundred sixty patients treated with definitive CCRT for advanced HNSCC were selected. The pretreatment MRI or CT scan was used to calculate the primary tumor volume. Median follow-up was 19.8 months.Results. The average primary tumor volume was 37.0 cm(3) (range, 2.1-182.7 cm(3); median, 28.7 cm(3)). Multivariate analysis showed a significant effect of tumor volume on local control. The hazard ratio for a local recurrence increased by 14% per 10 cm(3) volume increase (95% CI, 8% to 21%). There was no significant independent effect of T and N status on local control.Conclusion. For advanced HNSCC, tumor volume is more powerful for predicting outcome after CCRT than TNM status. (C) 2010 Wiley Periodicals, Inc. Head Neck 33: 375-382, 2011 Show less
