4-Dimensional CT Derived Ventilation Versus SPECT Aerosol Ventilation in Patients With Thoracic Malignancies

Overview

Objectives: Primary Objective: 1\. To determine the correlation between 4-dimensional computed tomography (4D CT) derived ventilation and single photon emission tomography (SPECT) aerosol Tc-99m determined ventilation. Secondary Objective: 1. To evaluate the reproducibility of the 4D CT derived ventilation and to obtain an estimate of the variance in a single setting. 2. To assess the correlation between hypoperfused and hypoventilated pulmonary regions in patients with thoracic malignancies. 3. To investigate the effect of continuous positive airway pressure (CPAP) on ventilation and tumor motion.

By using a 4-dimensional (4D) computed tomography (CT) scans researchers will create ventilation (circulation of air) calculations. This new calculation method is quicker and may produce better images than the standard ventilation calculations. If you agree to take part in this study and are found to be eligible, you will have lung function imaging. Lung function imaging gives researchers information on how well the lungs work, how air moves into the lungs with breathing, and blood circulation into the lungs. You will have three 4D CT scans performed while you are breathing quietly. A 2-inch plastic box will be placed on top of your chest to monitor the motion of your chest during the scanning. After you are out of the CT scanner (once the scanning is finished), ventilation images are calculated from the 4D CT images and will be compared with the standard ventilation imaging method. The 4D CT imaging will take about 30 minutes to complete. As part of standard care, once you have finished the 4D CT scan, you will have a single photon emission computed tomography (SPECT) pulmonary (lung) ventilation scan performed. The SPECT ventilation scan requires that you first breathe in a radioactive aerosol (or mist, called Tc-99m DPTA), which will help the study doctor tell where air goes when you breathe. Then you will be placed in the SPECT scanner, and images will be taken of your lungs. The SPECT imaging will take about 1 hour to complete. Within 10 days after the first imaging session, you will return for a second imaging session. During the second imaging session, you will have a standard of care SPECT pulmonary perfusion (blood supply to tissue and organs) test done. During this test, a radioactive substance is given by vein (called Tc-99m MAA). This substance will get trapped in the lungs, and the SPECT imaging will show the blood flow in the lungs. This test should take 45-60 minutes to complete. Once you complete the second imaging session, your participation will over in this study. This is an investigational study. All of the imaging scans used in this study are FDA approved and commercially available. The calculation of ventilation images from 4D CT scanning is investigational and authorized for use in research only. Up to 36 patients will take part in this study. All will be enrolled at M. D. Anderson.