TY - JOUR
T1 - Evaluation of lung toxicity risk with computed tomography ventilation image for thoracic cancer patients
AU - Otsuka, Masakazu
AU - Monzen, Hajime
AU - Matsumoto, Kenji
AU - Tamura, Mikoto
AU - Inada, Masahiro
AU - Kadoya, Noriyuki
AU - Nishimura, Yasumasa
N1 - Publisher Copyright:
© 2018 Otsuka et al.
PY - 2018/10
Y1 - 2018/10
N2 - Background Four-dimensional computed tomography (4D-CT) ventilation is an emerging imaging modality. Functional avoidance of regions according to 4D-CT ventilation may reduce lung toxicity after radiation therapy. This study evaluated associations between 4D-CT ventilation-based dosimetric parameters and clinical outcomes. Methods Pre-treatment 4D-CT data were used to retrospectively construct ventilation images for 40 thoracic cancer patients retrospectively. Fifteen patients were treated with conventional radiation therapy, 6 patients with hyperfractionated radiation therapy and 19 patients with stereotactic body radiation therapy (SBRT). Ventilation images were calculated from 4D-CT data using a deformable image registration and Jacobian-based algorithm. Each ventilation map was normalized by converting it to percentile images. Ventilation-based dosimetric parameters (Mean Dose, V5 [percent lung volume receiving ≥5 Gy], and V20 [percent lung volume receiving ≥20 Gy]) were calculated for highly and poorly ventilated regions. To test whether the ventilation-based dosimetric parameters could be used predict radiation pneumonitis of ≥Grade 2, the area under the curve (AUC) was determined from the receiver operating characteristic analysis. Results For Mean Dose, poorly ventilated lung regions in the 0±30% range showed the highest AUC value (0.809; 95% confidence interval [CI], 0.663±0.955). For V20, poorly ventilated lung regions in the 0±20% range had the highest AUC value (0.774; 95% [CI], 0.598±0.915), and for V5, poorly ventilated lung regions in the 0±30% range had the highest AUC value (0.843; 95% [CI], 0.732±0.954). The highest AUC values for Mean Dose, V20, and V5 were obtained in poorly ventilated regions. There were significant differences in all dosimetric parameters between radiation pneumonitis of Grade 1 and Grade ≥2. Conclusions Poorly ventilated lung regions identified on 4D-CT had higher AUC values than highly ventilated regions, suggesting that functional planning based on poorly ventilated regions may reduce the risk of lung toxicity in radiation therapy.
AB - Background Four-dimensional computed tomography (4D-CT) ventilation is an emerging imaging modality. Functional avoidance of regions according to 4D-CT ventilation may reduce lung toxicity after radiation therapy. This study evaluated associations between 4D-CT ventilation-based dosimetric parameters and clinical outcomes. Methods Pre-treatment 4D-CT data were used to retrospectively construct ventilation images for 40 thoracic cancer patients retrospectively. Fifteen patients were treated with conventional radiation therapy, 6 patients with hyperfractionated radiation therapy and 19 patients with stereotactic body radiation therapy (SBRT). Ventilation images were calculated from 4D-CT data using a deformable image registration and Jacobian-based algorithm. Each ventilation map was normalized by converting it to percentile images. Ventilation-based dosimetric parameters (Mean Dose, V5 [percent lung volume receiving ≥5 Gy], and V20 [percent lung volume receiving ≥20 Gy]) were calculated for highly and poorly ventilated regions. To test whether the ventilation-based dosimetric parameters could be used predict radiation pneumonitis of ≥Grade 2, the area under the curve (AUC) was determined from the receiver operating characteristic analysis. Results For Mean Dose, poorly ventilated lung regions in the 0±30% range showed the highest AUC value (0.809; 95% confidence interval [CI], 0.663±0.955). For V20, poorly ventilated lung regions in the 0±20% range had the highest AUC value (0.774; 95% [CI], 0.598±0.915), and for V5, poorly ventilated lung regions in the 0±30% range had the highest AUC value (0.843; 95% [CI], 0.732±0.954). The highest AUC values for Mean Dose, V20, and V5 were obtained in poorly ventilated regions. There were significant differences in all dosimetric parameters between radiation pneumonitis of Grade 1 and Grade ≥2. Conclusions Poorly ventilated lung regions identified on 4D-CT had higher AUC values than highly ventilated regions, suggesting that functional planning based on poorly ventilated regions may reduce the risk of lung toxicity in radiation therapy.
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U2 - 10.1371/journal.pone.0204721
DO - 10.1371/journal.pone.0204721
M3 - Article
C2 - 30281625
AN - SCOPUS:85054455855
VL - 13
JO - PLoS One
JF - PLoS One
SN - 1932-6203
IS - 10
M1 - e0204721
ER -