HELICAL TOMOTHERAPY SETUP VARIATIONS IN CANINE NASAL TUMOR PATIENTS IMMOBILIZED WITH A BITE BLOCK

• Published in: Veterinary radiology & ultrasound Vol. 53; no. 4; pp. 474 - 481
• Main Authors: Kubicek, Lyndsay N., Seo, Songwon, Chappell, Richard J., Jeraj, Robert, Forrest, Lisa J.
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.07.2012
• Subjects: Animals; canine nasal tumor; Dog Diseases - radiotherapy; Dogs; helical tomotherapy; Immobilization - veterinary; Nose Neoplasms - radiotherapy; Nose Neoplasms - veterinary; radiation therapy; Radiotherapy, Image-Guided - instrumentation; Radiotherapy, Image-Guided - methods; Radiotherapy, Image-Guided - veterinary; setup variations
• ISSN: 1058-8183; 1740-8261
• DOI: 10.1111/j.1740-8261.2012.01947.x

The purpose of our study was to compare setup variation in four degrees of freedom (vertical, longitudinal, lateral, and roll) between canine nasal tumor patients immobilized with a mattress and bite block, versus a mattress alone. Our secondary aim was to define a clinical target volume (CTV) to planning target volume (PTV) expansion margin based on our mean systematic error values associated with nasal tumor patients immobilized by a mattress and bite block. We evaluated six parameters for setup corrections: systematic error, random error, patient–patient variation in systematic errors, the magnitude of patient‐specific random errors (root mean square [RMS]), distance error, and the variation of setup corrections from zero shift. The variations in all parameters were statistically smaller in the group immobilized by a mattress and bite block. The mean setup corrections in the mattress and bite block group ranged from 0.91 mm to 1.59 mm for the translational errors and 0.5°. Although most veterinary radiation facilities do not have access to Image‐guided radiotherapy (IGRT), we identified a need for more rigid fixation, established the value of adding IGRT to veterinary radiation therapy, and define the CTV–PTV setup error margin for canine nasal tumor patients immobilized in a mattress and bite block. © 2012 Veterinary Radiology & Ultrasound.