Measuring Radiotherapy Setup Errors in IMRT Treated Head and Neck Cancer Patients Requiring Bilateral Neck Irradiation, NCI-Egypt Experience
- 1 Radiation Oncology Department, National Cancer Institute, Cairo University, Cairo, Egypt
- 2 Radiation Oncology Department, National Cancer Institute, Cairo University, Cairo, Egypt
- 3 Radiation Oncology Department, National Cancer Institute, Cairo University, Cairo, Egypt
- 4 Radiation Oncology Department, National Cancer Institute, Cairo University, Cairo, Egypt
- 5 Physics Unit, Radiation Oncology Department, National Cancer Institute, Cairo University, Cairo, Egypt
- 6 Physics Unit, Radiation Oncology Department, National Cancer Institute, Cairo University, Cairo, Egypt
Abstract
Objective: We aim to quantify the magnitude of setup errors in intensity-modulated radiotherapy (IMRT) treated Head and Neck cancer patients and recommend appropriate PTV margin. Methods: 60 patients with head and neck cancer required bilateral neck irradiation were planned and treated by simultaneous integrated boost IMRT technique either treated radically or postoperative. Patients undergoing image-guided radiotherapy (IGRT) each with once weekly scheduled cone beam computed tomography (CBCT). The 3D displacements, systematic and random errors were calculated. The appropriate PTV expansion was determined using Van Herk’s formula. Results: Mean 3D displacement was 0.16 cm in the vertical direction, 0.14 cm in the horizontal direction and 0.16 cm in the longitudinal direction. Conclusion: Use of weekly CBCT allows the planning target volume (PTV) expansion to be reduced according to our setup. The appropriate clinical target volume (CTV) - PTV margin for our institute is 0.30 cm, 0.38 cm, and 0.33 cm in the horizontal, vertical, and longitudinal directions, respectively.
- De Ruyck, K., Duprez, F., Werbrouck, J. and Young, W. (2013) A Predictive Model for Dysphagia Following IMRT for Head and Neck Cancer: Introduction of the EMLasso Technique. Radiotherapy Oncology, 107, 295-299. https://doi.org/10.1016/j.radonc.2013.03.021
- Murphy, B. (2009) Late Treatment Effects: Reframing the Questions. Lancet Oncology, 10, 530-531. https://doi.org/10.1016/S1470-2045(09)70118-4
- Van Der Laan, H., Christianen, M., Bijl, H., Shilstra, C. and Langendijk, J.A. (2012) The Potential Benefit of Swallowing Sparing Intensity-Modulated Radiotherapy to Reduce Swallowing Dysfunction: An in Silico Planning Comparative Study. Radiotherapy Oncology, 103, 76-81. https://doi.org/10.1016/j.radonc.2011.11.001
- Werbrouck, J., De Ruyck, K., Duprez, F., Veldeman, L., Claes, K., et al. (2009) Acute Normal Tissue Reactions in Head and Neck Cancer Patients Treated with IMRT: Influence of Dose and Association with Genetic Polymorphisms in DNA DSB Repair Genes. International Journal of Radiation Oncology Biology Physics, 73, 1187-1195. https://doi.org/10.1016/j.ijrobp.2008.08.073
- Van Herk, M. (2004) Errors and Margins in Radiotherapy. Seminar Radiation Oncology, 14, 52-64. https://doi.org/10.1053/j.semradonc.2003.10.003
- ICRU (1993) Prescribing, Recording and Reporting Photon Beam Therapy ICRU Report No 50. ICRU, Bethesda, MD.
- Cacicedo, J., Perez, J., Ortiz de Zarate, R., Del Hoyo, O., Casquero, F., et al. (2015) A Prospective Analysis of Inter- and Intrafractional Errors to Calculate CTV to PTV Margins in Head and Neck Patients. Clinical and Translational Oncology, 17, 113-120. https://doi.org/10.1007/s12094-014-1200-z
- Li, H., Zhu, X.R., Zhang, L., Dong, L., Tung, S., et al. (2008) Comparison of 2D Radiographic Images and 3D Cone Beam Computed Tomography for Positioning Head-and-Neck Radiotherapy Patients. International Journal of Radiation Oncology Biology Physics, 71, 916-925. https://doi.org/10.1016/j.ijrobp.2008.01.008
- Hamlet, S., Ezzel, G. and Aref, A. (1994) Larynx Motion Associated with Swallowing during Radiation Therapy. International Journal of Radiation Oncology Biology Physics, 28, 467-470. https://doi.org/10.1016/0360-3016(94)90073-6
- Van Asselen, B., Raaijmakers, C.P., Lagendijk, J.J. and Terhaard, C.H. (2003) Intrafraction Motions of the Larynx during Radiation Therapy. International Journal of Radiation Oncology Biology Physics, 56, 384-390. https://doi.org/10.1016/S0360-3016(02)04572-8