%0 Journal Article
%T How to determine margins for planning target volume (PTV): from 2D to 3D planning in radiotherapy for head and neck cancer? Portal imaging assessment for set-up errors
%A Evrim BAYMAN
%A £¿zlem Uruk ATAMAN
%A M¨¹nir KINAY
%A Fadime AKMAN
%J Turkish Journal of Oncology
%D 2010
%I KARE Publishing
%X OBJECTIVES: To evaluate set-up errors using Electronic Portal Imaging (EPI) for Three Dimensional Conformal Radiotherapy (3D CRT) protocol for head and neck carcinoma in Dokuz Eyl¨¹l University Department of Radiation Oncology (DEUDRO). METHODS: Ten patients between July 2004 - September 2005 were included. Seven EPIs/5 weeks per patient were planned to evaluate by two independent observers. Differences between Digitally Reconstructed Radiography (DRR) images and EPIs measured in cranio-caudal (CC), anterior-posterior (AP) and medio-lateral (ML) directions. Random (¦Ò) and the systematic (¡Æ) errors were calculated and used in van Herk margin formula (2.5 x ¦² + 0.7 x ¦Ò) for PTV margin. RESULTS: Ninety three EPIs with 186 [93 (50%) CC, 78 (42%) AP and 15 (8%) ML] measurements were evaluated. The ¦Ò were AP: 2.6 mm, CC: 2.9 mm, ML: 1 mm. The ¡Æ AP: 3.9 mm, CC: 1.8 mm, ML: 1.9 mm. PTV margins calculated were AP: 11.7 mm, CC: 6.6 mm, ML: 5.8 mm. CONCLUSION: 3DCRT protocol for head and neck cancer was amended using these PTV margins. These maybe wide especially for IMRT, and can reduce with better immobilization systems.
%K Portal imaging for head and neck radiotherapy
%K set-up errors.
%U http://onkder.org/pdf.php3?id=755