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HELICAL TOMOTHERAPY SETUP VARIATIONS IN CANINE NASAL TUMOR PATIENTS IMMOBILIZED WITH A BITE BLOCK
Author(s) -
Kubicek Lyndsay N.,
Seo Songwon,
Chappell Richard J.,
Jeraj Robert,
Forrest Lisa J.
Publication year - 2012
Publication title -
veterinary radiology and ultrasound
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.541
H-Index - 60
eISSN - 1740-8261
pISSN - 1058-8183
DOI - 10.1111/j.1740-8261.2012.01947.x
Subject(s) - medicine , image guided radiation therapy , nuclear medicine , radiation therapy , block (permutation group theory) , random error , surgery , mathematics , statistics , geometry
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.