Abstract
WE-AB-202-03: Quantifying Ventilation Change Due to Radiation Therapy Using 4DCT Jacobian Calculations
Medical physics (Lancaster), Vol.43(6), pp.3794-3795
06/2016
DOI: 10.1118/1.4957744
Abstract
Purpose:
Four-dimensional computed tomography (4DCT) and image registration can be used to determine regional lung ventilation changes after radiation therapy (RT). This study aimed to determine if lung ventilation change following radiation therapy was affected by the pre-RT ventilation of the lung.
Methods:
13 subjects had three 4DCT scans: two repeat scans acquired before RT and one three months after RT. Regional ventilation was computed using Jacobian determinant calculations on the registered 4DCT images. The post-RT ventilation map was divided by the pre-RT ventilation map to get a voxel-by-voxel Jacobian ratio map depicting ventilation change over the course of RT. Jacobian ratio change was compared over the range of delivered doses. The first pre-RT ventilation image was divided by the second to establish a control for Jacobian ratio change without radiation delivered. The functional change between scans was assessed using histograms of the Jacobian ratios.
Results:
There were significantly (p < 0.05) more voxels that had a large decrease in Jacobian ratio in the post-RT divided by pre-RT map (15.6%) than the control (13.2%). There were also significantly (p < .01) more voxels that had a large increase in Jacobian ratio (16.2%) when compared to control (13.3%). Lung regions with low function (<10% expansion by Jacobian) showed a slight linear reduction in expansion (0.2%/10 Gy delivered), while high function regions (>10% expansion) showed a greater response (1.2% reduction/10 Gy). Contiguous high function regions > 1 liter occurred in 11 of 13 subjects.
Conclusion:
There is a significant change in regional ventilation following a course of radiation therapy. The change in Jacobian following RT is dependent both on the delivered dose and the initial ventilation of the lung tissue: high functioning lung has greater ventilation loss for equivalent radiation doses. Substantial regions of high function lung tissue are prevalent.
Research support from NIH grants CA166119 and CA166703, a gift from Roger Koch, and a Pilot Grant from University of Iowa Carver College of Medicine
Details
- Title: Subtitle
- WE-AB-202-03: Quantifying Ventilation Change Due to Radiation Therapy Using 4DCT Jacobian Calculations
- Creators
- T Patton - University of Wisconsin–MadisonK Du - University of Wisconsin–MadisonG Christensen - University of IowaJ Reinhardt - University of IowaJ Bayouth - University of Wisconsin–Madison
- Resource Type
- Abstract
- Publication Details
- Medical physics (Lancaster), Vol.43(6), pp.3794-3795
- DOI
- 10.1118/1.4957744
- ISSN
- 0094-2405
- eISSN
- 2473-4209
- Number of pages
- 2
- Language
- English
- Date published
- 06/2016
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Radiology; Electrical and Computer Engineering; Iowa Technology Institute; Radiation Oncology; Radiation Research Laboratory; The Iowa Institute for Biomedical Imaging; Advanced Pulmonary Physiomic Imaging Laboratory; Holden Comprehensive Cancer Center
- Record Identifier
- 9984198008702771
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