Course Description
The first computed tomography (CT) clinical scan was performed in 1971. Since the introduction of these early systems, which were slow to acquire and reconstruct data, improvements in temporal and spatial resolution, including dual-source CT and other approaches to increase the number of slices acquired in parallel, now permit the capture of complete organs in a single rotation, thereby reducing noise and the generation of motion artifacts. The imaging itself is mathematically grounded in the Radon transform, the underlying algebraic principle of CT technology, which allows computation of the original function values from line-integral values and the reconstruction of the final image. Using the Fourier slice theorem, a related property, further grounds the process of filtered back-projection.

Three-dimensional CT image volumes are obtained by acquiring, reconstructing, and stacking multiple picture slices at slightly offset axial locations using a variety of analytic and algebraic algorithms. The development of third-generation CT scanners, combined with the introduction of multiple detector rows, facilitates the capture of large fields-of-view containing the entire target object in a single rotation. Moreover, the invention of helical CT technologies, in which projections from all angles in an axial plane can be interpolated, enables the use of standard reconstruction methods to visualize larger parts of the body with only a small number of detector rows.

Practical aspects of CT image reconstruction, including the spatial resolution of small objects, the prevention of noise and various artefacts (eg, scan, scatter, and motion), and polychromatic aberrations, are considered, as these imperfections can compromise the quality of the scan. Finally, the special calculations required for spectral CT detection, such as dual kVp and dual-kVp/dual-source techniques, are described, as these approaches generate measures directly related to the physical properties of the object or tissue under investigation.

Learning Objectives

After reading the content, the participant should be able to:

• EXPLAIN the underlying mathematical principles used in the process of computed tomography (CT) image formation.
• IDENTIFY the core analytic and algebraic methods, along with the essential acquisition geometries, required for CT image reconstruction.
• ASSESS the practical considerations required to achieve adequate spatial resolution, minimal noise, and the reduced influence of image artifacts.
• ANALYZE the factors that impact the X-ray attenuation of CT-measured objects, such as bone and soft tissue.
• DIFFERENTIATE the several detection techniques and technologies used in spectral CT measurements.

 

Category: Computed Tomography

In order to receive CE credit, you must first complete the activity content. When completed, go to the "Take CE Test!" link to access the post-test.

Submit the completed answers to determine if you have passed the post-test assessment. You must answer 21 out of 28 questions correctly to receive the CE credit. You will have no more than 3 attempts to successfully complete the post-test.

Participants successfully completing the activity content and passing the post-test will receive 2.5 ARRT Category A credits.

This program is approved by AHRA, a Recognized Continuing Education Evaluation Mechanism (RCEEM), approved by the ARRT to grant Category A CE credit.

Approved by the state of Florida for ARRT Category A credit.

Texas direct credit.

This activity may be available in multiple formats or from different sponsors. ARRT does not allow CE activities such as Internet courses, home study programs, or directed readings to be repeated for CE credit in the same biennium.

Category	Content Area	Credits
Computed Tomography	Image Production	2.5
Nuclear Medicine	Image Production	1
Radiation Therapy	Procedures	1

Category	Subcategory	Credits
Computed Tomography	Image Evaluation and Archiving	1.25
Computed Tomography	Image Formation	1.25
Nuclear Medicine	Instrumentation	1
Radiation Therapy	Treatment Volume Localization	1

Category	Credits
Digital	0
Fluoroscopy	0
Mammography	0