Spatial Comparison of CT-Based Surrogates of Lung Ventilation With Hyperpolarized Helium-3 and Xenon-129 Gas MRI in Patients Undergoing Radiation Therapy.

Purpose: To develop and apply an image acquisition and analysis strategy for spatial comparison of computed tomography (CT)-ventilation images with hyperpolarized gas magnetic resonance imaging (MRI).

Methods And Materials: Eleven lung cancer patients underwent xenon-129 (Xe) and helium-3 (He) ventilation MRI and coregistered proton (H) anatomic MRI. Expiratory and inspiratory breath-hold CTs were used for deformable image registration and calculation of 3 CT-ventilation metrics: Hounsfield unit (CT), Jacobian (CT), and specific gas volume change (CT).

Impact of field number and beam angle on functional image-guided lung cancer radiotherapy planning.

To investigate the effect of beam angles and field number on functionally-guided intensity modulated radiotherapy (IMRT) normal lung avoidance treatment plans that incorporate hyperpolarised helium-3 magnetic resonance imaging (He MRI) ventilation data. Eight non-small cell lung cancer patients had pre-treatment He MRI that was registered to inspiration breath-hold radiotherapy planning computed tomography. IMRT plans that minimised the volume of total lung receiving  ⩾20 Gy (V) were compared with plans that minimised He MRI defined functional lung receiving  ⩾20 Gy (fV).