SU-E-J-189: Determination of Markerless Lung Tumor Position in Real Time: A Feasibility Study Using a Novel Tomo-Cinegraphy Imaging

Journal Article · Mon Jun 15 04:00:00 EDT 2015 · Medical Physics

DOI:https://doi.org/10.1118/1.4924275· OSTI ID:22499294

Yi, B; Hu, E; Yu, C; Lee, M; Lasio, G ^[1]

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1. Univ. of Maryland School Of Medicine, Baltimore, MD (United States)

Purpose: A Tomo-Cinegraphy (TC) is a method to generate a series of temporal tomographic images from projection images of the on-board imager (OBI) while gantry is moving. It is to test if this technique is useful to determine a lung tumor position during treatments. Methods: Tomographic image via background subtraction, TIBS uses a priori anatomical information from a previous CT scan to isolate a SOI from a planar kV image by factoring out the attenuations by tissues outside the SOI (background). This idea was extended to a TC, which enables to generate tomographic images of same geometry from the projection of different gantry angles and different breathing phases. Projection images of a lung patient for CBCT acquisition are used to generate TC images. A region of interest (ROI) is selected around a tumor adding 2cm margins. Center of mass (COM) of the ROI is traced to determine tumor position for every projection images. Results: Tumor is visible in the TC images while the OBI projections are not. The coordinates of the COMs represent the temporal tumor positions. While, it is not possible to trace the tumor motion using the projection images. A source of time delay is the time to acquire projection images, which is always less than a second. Conclusion: TC allows tracking the tumor positions without fiducial markers in real time for some lung patients, if the projection images are acquired during treatments. Partially supported by NIH R01CA133539.

• OSTI ID: 22499294
• Journal Information: Medical Physics, Journal Name: Medical Physics Journal Issue: 6 Vol. 42; ISSN 0094-2405; ISSN MPHYA6
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
ANIMAL TISSUES
ATTENUATION
BIOMEDICAL RADIOGRAPHY
CENTER-OF-MASS SYSTEM
COMPUTERIZED TOMOGRAPHY
FIDUCIAL MARKERS
IMAGE PROCESSING
IMAGES
LUNGS
NEOPLASMS
PATIENTS
RESPIRATION
TIME DELAY