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Author Langerak, Thomas ♦ Mens, Jan Willem ♦ Quint, Sandra ♦ Bondar, Luiza ♦ Heijkoop, Sabrina ♦ Heijmen, Ben ♦ Hoogeman, Mischa
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword RADIOLOGY AND NUCLEAR MEDICINE ♦ BEAMS ♦ BIOMEDICAL RADIOGRAPHY ♦ COMPUTERIZED TOMOGRAPHY ♦ FIDUCIAL MARKERS ♦ GOLD ♦ NEOPLASMS ♦ PATIENTS
Abstract Purpose: To evaluate a new type of marker and a new method of marker implantation and to assess interfraction cervix motion for a large population of patients with locally advanced cervical cancer by daily cone beam computed tomographic (CBCT) imaging. Methods and Materials: We investigated the position of markers in 50 patients treated in prone position during at least 23 fractions. To reduce streaking artifacts in the planning CT scan, a new type of polymeric marker was used and compared with conventional gold markers. In addition, a new method of implantation was used in an attempt to reduce marker loss. In each fraction, a CT scan was acquired before dose delivery and aligned to the bony anatomy of the planning CT scan, simulating the clinical setup protocol. First, sufficient visibility of the markers was verified. Then, systematic and random displacement of the marker centroids was recorded and analyzed in 3 directions with regard to the planning CT and the first CBCT (to evaluate the presence of a vaginal catheter in the planning CT). Streaking artifacts were quantified with the standard deviation of the mean squared intensity difference in a radius around the marker. Results: Marker loss was minimal during treatment: in only 3 of the 50 patients 1 marker was lost. Streaking artifacts for the new markers were reduced compared with conventional gold markers. For the planning CT, M/Σ/σ were 0.4/3.4/2.2 mm, 1.0/5.5/4.5 mm, and −3.9/5.1/3.6 mm for the left-right, anterior-posterior, and cranial-caudal directions, respectively. With regard to the first CBCT scan, M/Σ/σ were 0.8/2.8/2.1, 0.6/4.4/4.4, and −1.3/4.5/3.6 mm. Conclusions: A new type of marker and implantation method was shown to have significantly reduced marker loss and streaking artifacts compared with gold fiducial markers. The recorded marker displacement confirms results reported in the existing literature but for a larger dataset.
ISSN 03603016
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-11-01
Publisher Place United States
Journal International Journal of Radiation Oncology, Biology and Physics
Volume Number 93
Issue Number 3


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