Analysis of respiratory-induced tumor motion characteristics in different lung lobes using four-dimensional computed tomography images.

OBJECTIVES

This study aimed to analyze respiratory-induced tumor motion characteristics in different lung lobes based on four-dimensional computed tomography (4DCT) images and explore the relationship between respiratory rates and respiratory-induced tumor motion amplitudes of different lung lobes.

METHODS

The clinical data of 79 patients with 91 lesions who underwent 4DCT scans from 2023 to 2024 at Zhongshan Hospital Fudan University were retrospectively analyzed. Tumors were divided into five groups based on tumor location: left upper lobe group (group A, n = 21), left lower lobe group (group B, n = 23), right upper lobe group (group C, n = 24), right middle lobe group (group D, n = 5), and right lower lobe group (group E, n = 18). Respiratory-induced tumor motion amplitudes were compared among the five groups using one-way analysis of variance. Bivariate linear correlation and receiver operating characteristic curve were used to analyze the relationship between respiratory rates and respiratory-induced tumor motion amplitudes.

RESULTS

The respiratory-induced tumor motion amplitudes of lung tumors in the left-right (LR), superior-inferior (SI), and anterior-posterior (AP) directions were 2.34 ± 1.13 mm, 7.80 ± 7.01 mm, and 3.61 ± 2.10 mm, respectively. In the SI direction, the respiratory-induced tumor motion amplitudes for groups A, B, C, D, and E were 4.33 ± 4.16 mm, 12.39 ± 5.86 mm, 2.75 ± 2.56 mm, 7.20 ± 3.35 mm, and 12.89 ± 8.76 mm, respectively ( P < 0.001). A negative correlation was found between the mean respiratory rate and the respiratory-induced tumor motion amplitude in the LR direction ( r = -0.630, P = 0.005) and SI direction ( r = -0.622, P = 0.006) in group E.

CONCLUSION

The respiratory-induced tumor motion amplitudes of different lung lobes are not the same, with lower lobe tumors having the largest motion amplitude and upper lobe tumors having the smallest motion amplitude. In addition, the respiratory-induced motion amplitude of right lower lobe tumors decreases with the increase of respiratory rate.