1. MRI Based Lung Perfusion as a Tool to Evaluate Lung Function in Patients Undergoing Radiotherapy for Pulmonary Neoplasms Xiutao Shi, Warren D’Souza, and Nilesh Mistry Poster #: 1077 Department of Radiation Oncology, University of Maryland School of Medicine Baltimore, MD 20201

2. Aim and Methods Demonstrate the utility of MRI based lung perfusion imaging for evaluating lung function during radiation treatment Methods – 5 patients with NSCLC were studied – Perfusion imaging was carried out using dynamic contrast enhanced (DCE) MRI at 3 time points: before treatment, end of treatment, and 3-6 months after treatment – 3D pulmonary blood flow (PBF) and pulmonary blood volume (PBV) maps were evaluated – Preliminary analysis was carried out to establish a relationship between perfusion data and patient attribute

3. Age (yr) PBF before treatment (a.u.) PBF at end of treatment (a.u.) PBF in follow-up scan (a.u.) % decrease at end of treatment Pat. 1684.362.972.1832 Pat. 2661.430.880.8138 Pat. 3871.790.890.8750 Pat. 4541.350.822.5439 Pat. 5463.710.772.3579 Results Reduction in PBF was observed in all patients by end of treatment Younger patients were able to recover the lost PBF 3-6 months after treatment, but not the older patients No such trend was found in the PBV data

4. Discussion MRI based lung perfusion imaging, which imposed no additional dose to the patients, shows the potential as a tool to study the longitudinal lung function changes during radiation treatment Early results show that patient age may play a role in the recovery of lung function PBF is a better metric to study lung function than PBV Further studies and more patients are needed to establish a clear relationship