The full three-phase CT scan Protocol is the preferred CT scan to be collected for the LTRC.  This scan is designed specifically to allow quantitative analysis of the lung as part of the LTRC project.  A subset of the CT scanners available at the Clinical Centers will be certified for use in obtaining this specific LTRC CT scan.  Each of these scanners will undergo thorough and continuous QA assessment and Protocol validation so they can remain certified for CT scan data collection. 

The precise parameters used for obtaining this LTRC CT dataset will be optimized for each certified CT scanner at a Clinical Center. Specifically, the full three-phase LTRC CT Scan Protocol will consist of three helically acquired datasets on a multidetector CT scanner (with no less than eight detectors) as well as scout/localization images as needed.  Thin-slice images (approximately 1.0 mm) will be obtained.  

These scans will be obtained in the supine position at full inspiration, suspended full expiration, and in the prone position at full inspiration.  Scans will be optimized to allow for single breath acquisition in less than 15 seconds. Radiation dose will be adjusted for the participant’s size.  The maximum effective dosage delivery for the LTRC full three-phase Protocol will be restricted to approximately  3 rem and 30 millisieverts (mSv). 

The images obtained from these scans will be sent to the Radiology Core Laboratory for analysis and storage. Several scan protocols, based on different CT scanner brands and models, with appropriate weight-based dose adjustments and specific breathing instructions for patients and technologist information sheets are included in the LTRC Manual of Operations.