The role of hyperpolarized 3-helium MRI in NSCLC

R. H. Ireland, M. McJury, M. Q. Hatton, N. Woodhouse, E. J. van Beek, J. M. Wild Academic Unit of Radiology, University of Sheffield, Sheffield, United Kingdom, Belvoir Park Hospital, Belfast, United Kingdom, Weston Park Hospital, Sheffield, United Kingdom, Carver College of Medicine, University of Iowa, Iowa City, IA, United States Introduction For patients with non-small cell lung cancer (NSCLC), the most common dose limiting complication of radiotherapy is radiation pneumonitis, an interstitial pulmonary inflammation caused by thoracic radiation. The key to lowering the risk of pneumonitis is to reduce the dose to healthy regions of lung while maintaining an adequate dose to the tumor, an approach that requires well ventilated and perfused lung to be identified. The value of incorporating functional information into lung cancer management has been investigated with SPECT [1]. However, hyperpolarized 3Helium (He) MRI has emerged as an alternative lung imaging modality that eliminates the need for radioisotopes and has the potential to provide superior functional information [2]. Although He MRI has been shown to detect radiation induced lung injury in rats [3], no previous work has investigated the potential role of in vivo He MRI for the assessment and radiotherapy treatment planning of lung cancer patients. One role for He MRI could be to enable the calculation of dose-volume histograms that are weighted by functional information, which may be a valuable tool for treatment plan analysis [1]. However, for He MRI to be used in radiotherapy, the images must first be registered with the CT acquired for treatment planning. Therefore, the aim of our work is to investigate the feasibility of in vivo He MR image acquisition and registration to planning CT.