TY - JOUR
T1 - Radiation-induced airway changes and downstream ventilation decline in a swine model
AU - Wallat, Eric M.
AU - Wuschner, Antonia E.
AU - Flakus, Mattison J.
AU - Christensen, Gary E.
AU - Reinhardt, Joseph M.
AU - Shanmuganayagam, Dhanansayan
AU - Bayouth, John E.
N1 - Publisher Copyright:
© 2021 IOP Publishing Ltd
PY - 2021/11
Y1 - 2021/11
N2 - Purpose. To investigate indirect radiation-induced changes in airways as precursors to atelectasis post radiation therapy (RT). Methods. Three Wisconsin Miniature Swine (WMSTM) underwent a research course of 60 Gy in 5 fractions delivered to a targeted airway/vessel in the inferior left lung. The right lung received a max point dose <5 Gy. Airway segmentation was performed on the pre- and three months post-RT maximum inhale phase of the four-dimensional (4D) computed tomography (CT) scans. Changes in luminal area (Ai) and square root of wall area (WA) for each airway were investigated. Changes in ventilation were assessed using the Jacobian ratio and were measured in three different regions: the inferior left lung <5 Gy (ILL), the superior left lung <5 Gy (SLL), and the contralateral right lung <5 Gy (RL). Results. Airways (n = 25) in the right lung for all swine showed no significant changes (p = 0.48) in Ai post-RT compared to pre-RT. Airways (n = 28) in the left lung of all swine were found to have a significant decrease (p < 0.001) in Ai post-RT compared to pre-RT, correlated (Pearson R = −0.97) with airway dose. Additionally, WA decreased significantly (p < 0.001) with airway dose. Lastly, the Jacobian ratio of the ILL (0.883) was lower than that of the SLL (0.932) and the RL (0.955). Conclusions. This work shows that for the swine analyzed, there were significant correlations between Ai and WA change with radiation dose. Additionally, there was a decrease in lung function in the regions of the lung supplied by the irradiated airways compared to the regions supplied by unirradiated airways. These results support the hypothesis that airway dose should be considered during treatment planning in order to potentially preserve functional lung and reduce lung toxicities.
AB - Purpose. To investigate indirect radiation-induced changes in airways as precursors to atelectasis post radiation therapy (RT). Methods. Three Wisconsin Miniature Swine (WMSTM) underwent a research course of 60 Gy in 5 fractions delivered to a targeted airway/vessel in the inferior left lung. The right lung received a max point dose <5 Gy. Airway segmentation was performed on the pre- and three months post-RT maximum inhale phase of the four-dimensional (4D) computed tomography (CT) scans. Changes in luminal area (Ai) and square root of wall area (WA) for each airway were investigated. Changes in ventilation were assessed using the Jacobian ratio and were measured in three different regions: the inferior left lung <5 Gy (ILL), the superior left lung <5 Gy (SLL), and the contralateral right lung <5 Gy (RL). Results. Airways (n = 25) in the right lung for all swine showed no significant changes (p = 0.48) in Ai post-RT compared to pre-RT. Airways (n = 28) in the left lung of all swine were found to have a significant decrease (p < 0.001) in Ai post-RT compared to pre-RT, correlated (Pearson R = −0.97) with airway dose. Additionally, WA decreased significantly (p < 0.001) with airway dose. Lastly, the Jacobian ratio of the ILL (0.883) was lower than that of the SLL (0.932) and the RL (0.955). Conclusions. This work shows that for the swine analyzed, there were significant correlations between Ai and WA change with radiation dose. Additionally, there was a decrease in lung function in the regions of the lung supplied by the irradiated airways compared to the regions supplied by unirradiated airways. These results support the hypothesis that airway dose should be considered during treatment planning in order to potentially preserve functional lung and reduce lung toxicities.
KW - 4DCT
KW - Bronchial stenosis
KW - Pulmonary functional imaging
KW - Radiation therapy response
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U2 - 10.1088/2057-1976/ac3197
DO - 10.1088/2057-1976/ac3197
M3 - Article
C2 - 34670195
AN - SCOPUS:85119196799
SN - 2057-1976
VL - 7
JO - Biomedical Physics and Engineering Express
JF - Biomedical Physics and Engineering Express
IS - 6
M1 - 065039
ER -