Clinical assessment and characterization of a dual tube kilovoltage X-ray localization system in the radiotherapy treatment room.

Autor: Lee SW; Radiation Oncology, St. Anne's Hospital, Fall River, Massachusetts., Jin JY; Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan., Guan H; Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan., Martin F; Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan., Kim JH; Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan., Yin FF; Department of Radiation Oncology, Duke University Medical Center, North Carolina, U.S.A.
Jazyk: angličtina
Zdroj: Journal of applied clinical medical physics [J Appl Clin Med Phys] 2008 Jan 13; Vol. 9 (1), pp. 1-15. Date of Electronic Publication: 2008 Jan 13.
DOI: 10.1120/jacmp.v9i1.2318
Abstrakt: Introduction: Although flat-panel based X-ray imaging has been well tested in diagnostic radiology, its use as an image-guided-radiotherapy (IGRT) system in a treatment room is new and requires systematic assessment.
Materials and Methods: BrainLab Novalis IGRT system was used for this study. It consists of two floor mounted kV X-ray tubes projecting obliquely into two flat-panel detectors mounted on the ceiling. The system automatically fuses the 2D localization images with 3D simulation CT image to provide positioning guidance. The following characteristics of the system were studied: (1) Coincidence of the isocenters between the IGRT and Linac; (2) Image quality; (3) Exposure; (4) Linearity, uniformity and repeatability.
Results: (1) Localization accuracy and coincidence of the isocenters between the IGRT and Linac was better than 1-mm. (2) The spatial resolution was quantified using the relative modulation-transfer-function with f50=0.7-0.9 lp/mm. The variation of contrast-noise-ratio with technical settings was measured. (3) The maximal exposure of an image was less than 95 mR. An empirical relation between the exposure and the X-ray technical setting was derived. (4) The linearity, uniformity and repeatability of the system generally meet the requirements.
Conclusion: The system can be safely and reliably used as a target localization device.
Databáze: MEDLINE
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