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Direct measurement of CTDI on helical CT scans. | LitMetric

Direct measurement of CTDI on helical CT scans.

J Appl Clin Med Phys

Department of Radiology, University of Alabama at Birmingham, Birmingham, Alabama, USA.

Published: November 2022

AI Article Synopsis

Article Abstract

Purpose: Medical physics computed tomography (CT) practice involves measurements to determine CTDI on representative clinical CT protocols. In current practice the majority of CT exams employ helical scans. To determine CTDI for a helical scan, one measures CTDI with an axial scan, then divides by the pitch. Problems arise in CT units where one is unable to select an axial scan with the same detector configuration and pre-patient (bowtie) filtration that is employed on the helical scan. Presented is a method to measure CTDI on helical scans.

Methods: The body and head CTDI phantoms were supported on the gantry shroud with brackets attached to the phantom. The phantom is above the tabletop and remains stationary during helical scans as the table moves beneath the phantom. With the phantom stationary, the CTDI associated with head and body helical scans was measured. CTDI was also measured for head and body axial scans with the same pre-patient filtrations and detector configurations.

Results: For both the head and body CTDI phantom the agreement between the axial and helical CTDI measurements was <1.5%.

Conclusions: Body and head CTDI and CTDI can be directly measured by employing helical scans with the method in this paper.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9680572PMC
http://dx.doi.org/10.1002/acm2.13761DOI Listing

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