The purpose of the study is to collect data to evaluate utility of the using photon-counting CT in a clinical setting.

Data collected in this study includes an assessment of image quality parameters including spatial resolution, image contrast, and noise that will evaluate the product and how this photon-counting CT technology can be used to reduce the overall radiation dose in CT imaging, and enhance clinical applications for CT technology. This data and analysis will help support regulatory submission.

Inclusion Criteria:

• Who are 18 years of age or older
• Able to sign and date the informed consent form
• Who have in the past 120 days or will in the future 30 days undergo a clinically-indicated CT exam of the head, neck, heart, chest, abdomen, pelvis, or extremities where images are available for this prior scheduled exam

Exclusion Criteria:

• Who are pregnant or lactating;
• Who were previously enrolled in this study;
• For contrast-enhanced CT exams, anyone with known or suspected allergy to iodinated contrast agents
• For contrast-enhanced CT exams, anyone with known or suspected renal insufficiency as determined by site medical personnel;
• Who need urgent or emergent care;
• Who have any conditions that, in the opinion of the PI or designee, would interfere with the evaluation of the results or constitute a health hazard for the subject; OR
• Who are unwilling to have GEHC personnel present for the CT exam.

The subject population will consist of adults that are 18-years of age or older, and who have undergone a prior clinically-indicated CT exam of at least one of the following anatomical area(s): head, neck, heart, chest, abdomen, pelvis, and/or extremities.

Scan data will be shared with other researchers but all will be completely deidentified.