To develop a computer program that will improve CT image quality and decrease the amount of x-ray radiation that future patients may be exposed to when they have a CT examination.

We will be asking patients for their permission to save and use the sinogram from their CT scan. The sinogram will be de-identified and sent to an archive system for storage. It will be exported to a computer for processing using MBIR (model based iterative reconstruction). MBIR (model based iterative reconstruction) is a new method being developed to process CT sinograms. The newly reconstructed images will be reviewed by experts to determine if they are as readable and accurate as CT images created with the software that is currently being used. Sinogram data and the reconstructed images will be shared with collaborating researchers at General Electric Global Research.

Inclusion Criteria:

1. 18 years of age and older 2. No medical or psychiatric condition precluding informed consent

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Exclusion Criteria:

1. Inability to lie flat on the back with arms raised over the head for 30min.
2. Metallic implants or metallic devices in the chest or back.
3. Participation in other research trials involving ionizing radiation