Exploratory models comparing ethiodized oil-glue and gold fiducials for bladder radiotherapy image-guidance. (January 2021)

• Record Type: Journal Article
• Authors: Lim Joon, Daryl; Berlangieri, Alexandra; Harris, Benjamin; Tacey, Mark; O'Meara, Rachel; Pitt, Brent; Viotto, Angela; Brown, Kerryn; Schneider, Michal; Lawrentschuk, Nathan; Sengupta, Shomik; Berry, Colleen; Jenkins, Trish; Chao, Michael; Wada, Morikatsu; Foroudi, Farshad; Khoo, Vincent
• Is Part Of: Physics and imaging in radiation oncology. Volume 17(2021)
• Page Start: 77
• Page End: 83
• Publication Date: 2021-01
• Subjects: Bladder cancer -- Prostate cancer -- Radiotherapy -- Glue fiducials -- Liquid fiducials -- Image-guided radiotherapy; Radiotherapy -- Periodicals; Radiation dosimetry -- Periodicals; Cancer -- Imaging -- Periodicals; Oncology -- Periodicals; 615.842
• DOI: 10.1016/j.phro.2021.01.008
• Languages: English
• ISSNs: 2405-6316

Abstract

Highlights: Novel liquid glue fiducials consisting of a radiographic contrast agent and tissue glue. The first demonstration of visible liquid ethiodized oil tissue glue fiducials being delivered into a fluid-filled bladder. Ex vivo Pigs bladder and Pig pelvis to demonstrate the deliverability of visible discrete fiducials into a fluid-filled bladder. Utilization of clinical tools to analyze CT number voxel histograms to characterize the glue fiducials and artifact and compare them to gold fiducial markers in a 3-dimensional manner. Ethiodized oil glue fiducials have online visualization qualities comparable to gold fiducials without the associated metal related artifact. Abstract: Background and purpose: Image-guidance with fiducials has been shown to improve pelvic radiotherapy outcome. However, bladder fiducials using ethiodized oil (EO) alone can disperse widely, and gold causes Computed Tomography scan (CT) metal artifacts. The study's purpose was to investigate the ability to deliver EO-tissue glue fiducials and compare them to gold for bladder radiotherapy image guidance. Materials and methods: A fluid-filled porcine bladder model was used to assess the ability to cystoscopically inject visible EO glue fiducials into the submucosa. We then transferred the bladders into a porcine pelvis for imaging and compared them to gold fiducials using CT, Cone Beam CT (CBCT), and kilovoltage (KV) planar views. A tissue-equivalent phantom was utilized to analyze the CT number Hounsfield Unit (HU) characteristics and artifacts of the glue and gold fiducials. Percentile ranges and normal tissue voxel percentages of the subsequent CT number voxel histogram from a 2 cm sphere surrounding the fiducial was used to characterize the artifact . Results: We successfully delivered all EO glue fiducials into the porcine bladders as discrete fiducials. They were well seen on CT, CBCT, and KV imaging. The glue fiducials had lower CT number values, but less CT number spread of the voxel percentile ranges consistent with the diminished contrast and less artifact than gold. The glue fiducial types had similar CT number characteristics. Conclusion: This study has shown that EO glue fiducials can be delivered with online visualization qualities comparable to gold fiducials without metal-related artifacts.