Work

Internal Target Volume Estimation for Liver Cancer Radiation Therapy Using an Ultra Quality 4-Dimensional Magnetic Resonance Imaging

Year: 2025

Type: article

Abstract: Purpose Accurate internal target volume (ITV) estimation is essential for effective and safe radiation therapy in liver cancer. This study evaluates the clinical value of an ultraquality 4-dimensional magnetic resonance imaging (UQ 4D-MRI) technique for ITV estimation. Methods and Materials The UQ 4D-MRI technique maps motion information from a low spatial resolution dynamic volumetric MRI onto a high-resolution 3-dimensional MRI used for radiation treatment planning. It was validated using a motion phantom and data from 13 patients with liver cancer. ITV generated from UQ 4D-MRI (ITV 4D ) was compared with those obtained through isotropic expansions (ITV 2 mm and ITV 5 mm ) and those measured using conventional 4D-computed tomography (computed tomography-based ITV, ITV CT ) for each patient. Results Phantom studies showed a displacement measurement difference of <5% between UQ 4D-MRI and single-slice 2-dimensional cine MRI. In patient studies, the maximum superior-inferior displacements of the tumor on UQ 4D-MRI showed no significant difference compared with single-slice 2-dimensional cine imaging ( P = .985). Computed tomography-based ITV showed no significant difference ( P = .72) with ITV 4D , whereas ITV 2 mm and ITV 5 mm significantly overestimated the volume by 29.0% ( P = .002) and 120.7% ( P < .001) compared with ITV 4D , respectively. Conclusions UQ 4D-MRI enables accurate motion assessment for liver tumors, facilitating precise ITV delineation for radiation treatment planning. Despite uncertainties from artificial intelligence-based delineation and variations in patients' respiratory patterns, UQ 4D-MRI excels at capturing tumor motion trajectories, potentially improving treatment planning accuracy and reducing margins in liver cancer radiation therapy.

Source: Advances in Radiation Oncology

DOI: 10.1016/j.adro.2025.101774