Lung Cancer

PV QA 4 - Poster Viewing Q&A 4

TU_34_3658 - 4D CT Ventilation Predicts for Changes in Pulmonary Perfusion After Radiation Treatment for Lung Cancer.

Tuesday, October 23
2:45 PM - 4:15 PM
Location: Innovation Hub, Exhibit Hall 3

4D CT Ventilation Predicts for Changes in Pulmonary Perfusion After Radiation Treatment for Lung Cancer.
A. Thompson1, N. K. Myziuk2, E. Castillo2, I. S. Grills1, and T. M. Guerrero2; 1Dept. of Radiation Oncology, Beaumont Health, Royal Oak, MI, 2Beaumont Health (Department of Radiation Oncology), Royal Oak, MI

Purpose/Objective(s): The current gold standard for measuring ventilation and perfusion of the lungs is with nuclear imaging using V/Q scans or SPECT. An ongoing prospective trial is investigating if the 4DCT imaging routinely captured during simulation for lung cancer radiotherapy (RT) can provide a ventilation assessment for functional lung avoidance RT and reduce pulmonary toxicity. In this study, we investigate if changes in perfusion measured on SPECT imaging before and after treatment correspond with changes measured by 4DCT ventilation imaging.

Materials/Methods: Data was acquired from 8 patients enrolled on a functional lung imaging trial. All patients underwent pre and post treatment 4D CT scans, as well as pre and post treatment 99mTc-MAA SPECT/CT scans. Custom designed in-house software was used to measure ventilation and perfusion in the lungs. The lungs were evaluated as whole lungs, and broken up into segments representing 1/3 of each lung. Ventilation and perfusion were calculated as a percent of total ventilation or perfusion respectively (right lung + left lung = 100%). Changes in ventilation by lung segment were measured before and after treatment and compared to segmentally correlated changes in perfusion as measured by SPECT imaging before and after treatment. Three groups of lung segments were evaluated: segments which showed ≥ 3%, ≥ 5%, or ≥ 7% change in ventilation after treatment (positive or negative). These segments were then analyzed for corresponding changes in segmental perfusion.

Results: 6 patients had a complete set of analyzable scans. No segment showed a change in ventilation ≥ 10%. When a lung segment experienced a ≥ 7% change in ventilation, the associated segmental change in perfusion showed a correlational R2 = 0.810. For a ≥ 5% change in ventilation, the associated segmental change in perfusion showed a correlational R2 = 0.697. When a lung segment experienced a ≥ 3% change in ventilation, the associated segmental change in perfusion showed a correlational R2 = 0.232. Of 6 evaluable lung segments where ventilation changed by ≥ 7%, 2 segments experienced a corresponding change in perfusion in the opposite direction. In the ≥ 5% group, 3 of 8 segments experienced a corresponding change in perfusion in the opposite direction. And for the ≥ 3% group, 8 of 18 segments experienced a corresponding change in perfusion in the opposite direction.

Conclusion: Quantitative measurement of lung segment ventilation changes by 4DCT were correlated with anatomically associated changes in lung segment perfusion as measured by SPECT when the ventilation change in a segment is ≥ 7% or ≥ 5%. This correlation was strongest in lung segments with a ≥ 7% change in ventilation.

Author Disclosure: A. Thompson: None. I.S. Grills: Board of Directors; Greater Michigan Gamma Knife. T.M. Guerrero: None.

Send Email for Andrew Thompson


Assets

TU_34_3658 - 4D CT Ventilation Predicts for Changes in Pulmonary Perfusion After Radiation Treatment for Lung Cancer.



Attendees who have favorited this

Please enter your access key

The asset you are trying to access is locked. Please enter your access key to unlock.

Send Email for 4D CT Ventilation Predicts for Changes in Pulmonary Perfusion After Radiation Treatment for Lung Cancer.