SU‐E‐J‐86: Lobar Lung Function Quantification by PET Galligas and CT Ventilation Imaging in Lung Cancer Patients

Abstract

Purpose:The purpose of this study was to quantify the lobar lung function using the novel PET Galligas ([68Ga]‐carbon nanoparticle) ventilation imaging and the investigational CT ventilation imaging in lung cancer patients pre‐treatment.Methods:We present results on our first three lung cancer patients (2 male, mean age 78 years) as part of an ongoing ethics approved study. For each patient a PET Galligas ventilation (PET‐V) image and a pair of breath hold CT images (end‐exhale and end‐inhale tidal volumes) were acquired using a Siemens Biograph PET CT. CT‐ventilation (CT‐V) images were created from the pair of CT images using deformable image registration (DIR) algorithms and the Hounsfield Unit (HU) ventilation metric. A comparison of ventilation quantification from each modality was done on the lobar level and the voxel level. A Bland‐Altman plot was used to assess the difference in mean percentage contribution of each lobe to the total lung function between the two modalities. For each patient, a voxel‐wise Spearmans correlation was calculated for the whole lungs between the two modalities.Results:The Bland‐Altman plot demonstrated strong agreement between PET‐V and CT‐V for assessment of lobar function (r=0.99, p<0.001; range mean difference: −5.5 to 3.0). The correlation between PET‐V and CT‐V at the voxel level was moderate(r=0.60, p<0.001).Conclusion:This preliminary study on the three patients data sets demonstrated strong agreement between PET and CT ventilation imaging for the assessment of pre‐treatment lung function at the lobar level. Agreement was only moderate at the level of voxel correlations. These results indicate that CT ventilation imaging has potential for assessing pre‐treatment lobar lung function in lung cancer patients.