3D dosimetric validation of ultrasound-guided radiotherapy with a dynamically deformable abdominal phantom

Charles K Matrosic; Wesley Culberson; Andrew Shepard; Sydney Jupitz; Bryan Bednarz

doi:10.1016/j.ejmp.2021.04.007

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3D dosimetric validation of ultrasound-guided radiotherapy with a dynamically deformable abdominal phantom

Journal article

Open access

Peer reviewed

3D dosimetric validation of ultrasound-guided radiotherapy with a dynamically deformable abdominal phantom

Charles K Matrosic, Wesley Culberson, Andrew Shepard, Sydney Jupitz and Bryan Bednarz

Physica medica, Vol.84, pp.159-167

04/2021

DOI: 10.1016/j.ejmp.2021.04.007

PMCID: PMC8216233

PMID: 33901860

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https://doi.org/10.1016/j.ejmp.2021.04.007View

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Abstract

The purpose of this study was to dosimetrically benchmark gel dosimetry measurements in a dynamically deformable abdominal phantom for intrafraction image guidance through a multi-dosimeter comparison. Once benchmarked, the study aimed to perform a proof-of-principle study for validation measurements of an ultrasound image-guided radiotherapy delivery system. The phantom was dosimetrically benchmarked by delivering a liver VMAT plan and measuring the 3D dose distribution with DEFGEL dosimeters. Measured doses were compared to the treatment planning system and measurements acquired with radiochromic film and an ion chamber. The ultrasound image guidance validation was performed for a hands-free ultrasound transducer for the tracking of liver motion during treatment. Gel dosimeters were compared to the TPS and film measurements, showing good qualitative dose distribution matches, low γ values through most of the high dose region, and average 3%/5 mm γ-analysis pass rates of 99.2%(0.8%) and 90.1%(0.8%), respectively. Gel dosimeter measurements matched ion chamber measurements within 3%. The image guidance validation study showed the measurement of the treatment delivery improvements due to the inclusion of the ultrasound image guidance system. Good qualitative matching of dose distributions and improvements of the γ-analysis results were observed for the ultrasound-gated dosimeter compared to the ungated dosimeter. DEFGEL dosimeters in phantom showed good agreement with the planned dose and other dosimeters for dosimetric benchmarking. Ultrasound image guidance validation measurements showed good proof-of-principle of the utility of the phantom system as a method of validating ultrasound-based image guidance systems and potentially other image guidance methods.

Radiometry

Phantoms, Imaging

Radiotherapy Dosage

Radiotherapy Planning, Computer-Assisted

Ultrasonography, Interventional

Details

Title: Subtitle: 3D dosimetric validation of ultrasound-guided radiotherapy with a dynamically deformable abdominal phantom
Creators: Charles K Matrosic - University of Wisconsin–Madison
Wesley Culberson - University of Wisconsin–Madison
Andrew Shepard - University of Wisconsin–Madison
Sydney Jupitz - University of Wisconsin–Madison
Bryan Bednarz - University of Wisconsin–Madison
Resource Type: Journal article
Publication Details: Physica medica, Vol.84, pp.159-167
DOI: 10.1016/j.ejmp.2021.04.007
PMID: 33901860
PMCID: PMC8216233
NLM abbreviation: Phys Med
ISSN: 1120-1797
eISSN: 1724-191X
Grant note: R01 CA190298 / NCI NIH HHS
Language: English
Date published: 04/2021
Academic Unit: Radiation Oncology
Record Identifier: 9984313071202771

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