Translational Development of Photon-counting CT Imaging

Overview

Using an investigational CT scanner which uses a new type of detector to capture X-rays, (a photon counting CT detector), the goal of this experimental study is to compare conventional CT images to CT images using the photon counting detector in patients undergoing CT scans for clinically indicated reasons. The main question it aims to answer is whether the images produced using the new detectors are superior in quality. Participants will undergo the clinically indicated CT images and the photon counting detector CT images of a limited area during the same examination time.

NIH develops new imaging techniques as one of its priorities for accelerating science, including methods for non-invasive patient assessments. Computed tomographic (CT) imaging is a mainstay of diagnostic imaging. The latest major technological advance is photon counting CT (PCCT) which uses a new x-ray detector that measures x-ray penetration of the body and the energy of each x-ray photon. NIH Clinical Center will use a prototype Siemens PCCT CounT systems built for clinical investigational use. The scanner can perform standard CT and PCCT imaging. In this protocol, NIH patients already enrolled in a clinical research protocol and who are referred to Radiology for diagnostic CT as part of that research may be enrolled in this study of PCCT. The diagnostic CT scan requested by their medical care team will be performed on the CounT scanner, providing the clinically indicated imaging, along with a single abbreviated PCCT exam of an organ or body part to support PCCT feasibility of the PCCT to provide better images in several small groups of patients with selected medical conditions. The data will be used to characterize quality of the PCCT images and to develop testable hypotheses and new diagnostic applications using PCCT capabilities. Current CT systems, such as the Siemens SOMATOM Flash, have two x-ray tubes, each paired with an x-ray detector that measures total x-ray penetration of the patient and uses that information to create the images. The CounT scanner is a modified version of the Flash in which one of the two standard detectors has been replaced with a PCCT detector. The two imaging modes for the CounT scanner are (i) standard detector study as in a Flash scanner and (ii) PCCT scan. The patient scan will thus include clinically indicated radiation exposure with the standard detector and research radiation over a limited field with the PCCT detector. The CounT system is sited at the Clinical Center under a CRADA (Cooperative research and development agreement) with Siemens Medical Solutions. Compared to current scanners, PCCT is expected to offer four major advantages: * lower radiation dose * greater spatial resolution * reduced imaging noise * x-ray energy discrimination As a translational development protocol, all imaging studies are open-label and data may be analyzed as they are collected.