Dose variations in tumor volumes and organs at risk during IMRT for head-and-neck cancer
Beltran, Mercè (Hospital Universitari Vall d'Hebron)
Ramos, Mónica (Hospital Universitari Vall d'Hebron)
Rovira, Juan José (Hospital Universitari Vall d'Hebron)
Perez-Hoyos, Santiago (Hospital Universitari Vall d'Hebron. Institut de Recerca)
Sancho, Marc (Hospital Universitari Vall d'Hebron)
Puertas, Enrique (Hospital Universitari Vall d'Hebron)
Benavente, Sergi (Hospital Universitari Vall d'Hebron)
Ginjaume, Mercè (Universitat Politècnica de Catalunya. Institut de Tècniques Energètiques)
Giralt López de Sagredo, Jordi (Hospital Universitari Vall d'Hebron)
Universitat Autònoma de Barcelona

Fecha:	2012
Resumen:	Many head-and-neck cancer (HNC) patients treated with radiotherapy suffer significant anatomical changes due to tumor shrinkage or weight loss. The purpose of this study was to assess dose changes over target volumes and organs at risk during intensity-modulated radiotherapy for HNC patients. Sixteen HNC IMRT patients, all requiring bilateral neck irradiation, were enrolled in the study. A was performed and the initial dose distribution was calculated. During the treatment, two subsequent CTs at the 15th and 25th fractions were acquired. The initial plan was calculated on the and , and dose-volume differences related to the were assessed. For target volumes, mean values of nearmaximun absorbed dose () increased at the 25th fraction, and doses covering 95% and 98% of volume decreased significantly at the 15th fraction. Contralateral and ipsilateral parotid gland mean doses increased by 6. 1% (range: -5. 4, 23. 5%) and 4. 7% (range: -9. 1, 22. 3%), respectively, at . The in the spinal cord increased by 1. 8 Gy at . Mean absorbed dose increases at and were observed in: the lips, 3. 8% and 5. 3%; the oral cavity, 3. 5% and 2. 5%; and lower middle neck structure, 1. 9% and 1. 6%. Anatomical changes during treatment of HNC patients affect dose distribution and induce a loss of dose coverage to target volumes and an overdosage to critical structures. Appropriate organs at risk have to be contoured and monitored in order to know if the initial plan remains suitable during the course of the treatment. Reported dosimetric data can help to identify patients who could benefit from adaptive radiotherapy. PACS numbers: 87. 53. Kn, 87. 55. Dk.
Derechos:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió publicada
Materia:	Head-and-neck cancer ; IMRT ; Dose-volume changes ; Organs at risk
Publicado en:	Journal of Applied Clinical Medical Physics, Vol. 13 (november 2012) , p. 101-111, ISSN 1526-9914

DOI: 10.1120/jacmp.v13i6.3723
PMID: 23149770

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