Relationship between diseased lung tissues on computed tomography and motion of fiducial marker near lung cancer.
OBJECTIVE
For lung cancer patients with poor pulmonary function because of emphysema or fibrosis, it is important to predict the amplitude of internal tumor motion to minimize the irradiation of the functioning lung tissue before undergoing stereotactic body radiotherapy.


METHODS
Two board-certified diagnostic radiologists independently assessed the degree of pulmonary emphysema and fibrosis on computed tomography scans in 71 patients with peripheral lung tumors before real-time tumor-tracking radiotherapy. The relationships between the computed tomography findings of the lung parenchyma and the motion of the fiducial marker near the lung tumor were investigated. Of the 71 patients, 30 had normal pulmonary function, and 29 had obstructive pulmonary dysfunction (forced expiratory volume in 1 s/forced vital capacity ratio of <70%), 6 patients had constrictive dysfunction (percentage of vital capacity <80%), and 16 had mixed dysfunction.


RESULTS
The upper region was associated with smaller tumor motion, as expected (p = .0004), and the presence of fibrosis (p = .088) and pleural tumor contact (p = .086) were weakly associated with tumor motion. The presence of fibrotic changes in the lung tissue was associated with smaller tumor motion in the upper region (p <.05) but not in the lower region. The findings of emphysema and pulmonary function tests were not associated with tumor motion.


CONCLUSIONS
Tumors in the upper lung region with fibrotic changes have smaller motion than those in the upper region of the lungs without fibrotic changes. The tumor motion in the lower lung region was not significantly different between patients with and without lung fibrosis. Emphysema was not associated with the amplitude of tumor motion.
Onodera
Yuya
Y
Department of Radiology, Hokkaido University Hospital, Sapporo, Japan. yuyaonodera@med.hokudai.ac.jp
Nishioka
Noriko
N
Yasuda
Koichi
K
Fujima
Noriyuki
N
Torres
Mylin
M
Kamishima
Tamotsu
T
Ooyama
Noriko
N
Onimaru
Rikiya
R
Terae
Satoshi
S
Ooizumi
Satoshi
S
Nishimura
Masaharu
M
Shirato
Hiroki
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D005260:Female; D057918:Fiducial Markers; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008168:Lung / Q000528:radiation effects; D008173:Lung Diseases, Obstructive / Q000000981:diagnostic imaging / Q000503:physiopathology; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009068:Movement; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D011658:Pulmonary Fibrosis / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D011832:Radiation Injuries / Q000517:prevention & control; D016634:Radiosurgery / Q000009:adverse effects; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods; D014797:Vital Capacity / Q000502:physiology