Setup error with and without image guidance using two canine intracranial positioning systems for radiation therapy.

Autor: Morimoto CY; Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada., Mayer MN; Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada., Sidhu N; British Columbia Cancer, Prince George, British Columbia, Canada., Bloomfield R; Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada., Waldner CL; Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Jazyk: angličtina
Zdroj: Veterinary and comparative oncology [Vet Comp Oncol] 2020 Dec; Vol. 18 (4), pp. 607-614. Date of Electronic Publication: 2020 Mar 14.
DOI: 10.1111/vco.12584
Abstrakt: Daily image guidance reduces inter-fractional variation in patient position for intracranial radiation therapy. However, the ability to detect and correct positioning errors is limited below a certain level. Because of these limitations, the accuracy achieved with a positioning system prior to image guidance may affect the error remaining after image guidance (the residual setup error). The objective of this study was to compare the setup accuracy achieved before and after megavoltage (MV) and cone-beam computed tomography (CBCT) guidance between two intracranial positioning systems. Equipment included a four degrees-of-freedom couch capable of 1 mm translational moves. Six dog cadavers were positioned 24 times as for clinical treatment in a head re-positioner (HPS), and the coordinates of five fiducial markers were measured before and after image-guided correction. The values obtained for the HPS were compared with those previously reported for the standard positioning system (SPS) used at this facility. The mean three-dimensional distance vector (3DDV) was lower for the HPS than for the SPS when no image guidance was used (P = .019). The mean 3DDV after MV guidance was lower for the HPS than for the SPS (P = .027), but not different after CBCT guidance (P = .231). The 95th percentiles of the 3DDV after MV and CBCT guidance were 2.1 and 2.9 mm, respectively, for the HPS, and 2.8 and 3.6 mm for the SPS. The setup error after MV guidance was lower for the positioning system that achieved a more accurate patient position before image guidance.
(© 2020 John Wiley & Sons Ltd.)
Databáze: MEDLINE
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